Magnetic Nanoparticles: New Players in Antimicrobial Peptide

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Magnetic Nanoparticles: New Players in Antimicrobial Peptide Therapeutics C. López-Abarrategui1.*, V. Figueroa-Espí2, O. Reyes-Acosta3, E. Reguera4 and A.J. Otero-Gonzalez1 1

Center for Proteins Studies, Faculty of Biology, University of Havana, Havana, Cuba; 2Institute of Materials Science and Technology, University of Havana, Havana, Cuba; 3Center for Genetic Engineer and Biotechnology, Havana, Cuba; 4Center for Applied Science and Advanced Technology of IPN, Legaria Unit, Mexico, D. F., Mexico Abstract: Antimicrobial peptides are distributed in all forms of life presenting activity against bacteria, fungi, viruses, parasites and cancer. In spite of the tremendous potential of these molecules, very few of them have been successfully developed into therapeutics. The major problems associated with this new class of antimicrobials are molecule stability, toxicity in host cells and production cost. A novel strategy to overcome these obstacles is conjugation to nanomaterials. Magnetic nanoparticles have been widely studied in biomedicine due to their physicochemical properties. The conjugation of antimicrobial peptides to magnetic nanoparticles could combine the best properties of both, generating an improved antimicrobial nanoparticle. Here we provide an overview and discuss the potential application of magnetic nanoparticles conjugated to antimicrobial peptides in overcoming diseases.

Keywords: Antimicrobial peptides; host defense peptides; magnetic nanoparticles; immunomodulation; therapeutics. INTRODUCTION In the last three decades, several new infectious diseases have emerged, many of which are responsible for entirely novel and life-threatening disorders [1, 2]. A lack of new antibiotics for treatment of illnesses combined with the appearance of multi-drug-resistant strains has generated the urgent need for innovative strategies in the control of microorganisms [3]. In addition to infection disease, multiple cancers are also refractory to current chemotherapies and remain a major cause of death worldwide. This increasing resistance of heterogenic tumors requires the development of newer therapeutics with specifically targeted modes of action [4]. Antimicrobial peptides (AMPs), also known as host defense peptides (HDPs), are effector molecules of the innate immune system. They constitute a novel strategy for the development of antimicrobial or anticancer therapies [5, 6]. Although these molecules have been demonstrated in preclinical studies to be both broad spectrum (antimicrobial, anticancer, immunomodulatory, wound healing and angiogenesis) and highly potent, this success has not been translated to the clinic as yet [7]. The major drawbacks of AMPs have been instability, cytotoxicity, biodistribution, and manufacturing costs [5, 8]. Development of nanoparticles for entrapment and delivery of AMPs could represent an alternative to bypass the above mentioned clinic obstacles [9]. Magnetic nanoparticles (MNPs) could be an ideal carrier for AMPs due to the broad spectrum of activities of its (anticancer, antimicrobial, drug delivery, diagnosis) and the low toxicity demonstrated in vivo [10]. As antimicrobial and anticancer properties of both molecules have different mechanism of *Address correspondence to this author at the Center for Proteins Studies, Faculty of Biology, University of Havana, Havana, Cuba; Email: [email protected] 1875-5550/13 $58.00+.00

action, the conjugated (AMPs-MNP) may have an improved activity. Here we provide an overview, and discuss the potential application of magnetic nanoparticles conjugated to antimicrobial peptides in overcoming diseases. ANTIMICROBIAL PEPTIDES Natural AMPs have been identified as a defense strategy across many forms of life from prokaryotic organisms to vertebrates [11]. In general, AMPs are genetically encoded molecules grouped together in multigenic families such as defensins [12], cathelicidins [13], cecropins [14], clavanins [15], among others. AMPs are generally small molecules commonly around 12 to 50 amino acids residues, cationic (net charge of +2 to +7), and are frequently quite hydrophobic and amphipathic [16]. According to their secondary structure in solution, these molecules are generally be divided in four structural classes: -helix, -sheet stabilized by two or three di-sulfide bonds, extended structures with one or more predominant residues (like tryptophan and proline rich) and loop due to the presence of a single disulfide bridge [17]. Despite the wide sequence and structural variability found among these molecules, the cationic and amphipathic character of AMPs are determinant for their antimicrobial activity. Selectivity of AMPs for microorganisms is based on differences between host and microbial cells [18]. It is considered that the selectivity of antimicrobial peptides for microbial membranes is due to: (1) The existence of characteristic anionic compounds in pathogens that interact with AMPs and could serve as a molecular portal for cell entry [19]. (2) Differences in charge, phospholipid composition, and phospholipid distribution between host and microbial © 2013 Bentham Science Publishers

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membranes. The outer leaflet of microbial plasma membranes is composed by distinct anionic phospholipids (phosphatidylglycerol and cardiolipin), in contrast with the outer leaflet of host plasma membranes [6]. (3) Differences in sterols content. The absence of cholesterol permits a higher fluidity in microbial membranes which promote the insertion of AMPs and destabilization of the membrane [20]. (4) Differences in transmembrane potential. The transmembrane potential of microbial cells is more negative than in host cells so the initial interaction of AMPs with the bacterial membrane is enhanced [20]. These differences, especially in phospholipids organization and molecular packing, may explain the lower toxicity of antimicrobial peptides to host cells. Up to now, non-specific interactions of AMPs and membrane lipids has been widely accepted however recent data reveal a more complex scenario. The affinity of some defensins for specific microbial lipids has been clearly demonstrated [21]. In vitro experiments demonstrated that Plectasin, a fungal defensin produced by Pseudoplectania nigrella, inhibits the growth of Gram-positive bacteria through the binding to the cell wall precursor Lipid II [22]. Additionally, the binding of two plant defensins (DmAMP1 and RsAFP2) with sphingolipids has been determined [23, 24]. All this data confirmed the existence of specific interaction of AMPs with components of microbial membranes. This type of interaction derived in novel antimicrobial mechanism that could be conserved between different species. ANTIMICROBIAL ACTIVITY OF AMPs AMPs exhibit a broad spectrum of activity against a wide range of microorganisms [25, 26]. Different mechanisms of action have been proposed for these molecules [27, 28]. Some AMPs could have more than one microbial target at the cellular level, reducing the development of resistance by microorganisms. The antimicrobial activity of these peptides could be by direct action against microbial cells and/or by an indirect route involving the recruitment and activation of cells from the innate immune system at the site of infection. The principal target of antimicrobial peptides that inhibit the growth of microorganisms is the plasma membrane. As this structure is vital for all cells, destabilization of it causes cell death. Destabilization of the cytoplasmic membrane by AMPs could occur by formation of transmembrane pores or by non-pore mechanisms. These issues have been excellently discussed by Wimley et al. [29]. Interestingly, the formation of transmembrane pores has only been described for very few AMPs. Magainin, a 23-mer peptide isolated from the African clawed frog Xenopus laevis, is one of them. This antimicrobial peptide has a broad antimicrobial activity apparently due to the formation of toroidal pores in the cellular membrane of microorganisms [30, 31]. Unfortunately, many of the mechanisms proposed for describing AMPsmembrane interaction are derived from experimental data achieved with model membrane and therefore, the conclusions might be limited. In these assays, many important factors such as lipid domains, proteins and particular lipids are simplified. Furthermore, the experimental conditions are

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very different between bilayer permeabilization and microbial sterilization experiments [29]. Other microbial targets have also been described [32]. For example, inhibition of the biosynthesis of bacteria cell wall through lipid II interaction has been demonstrated for some AMPs [22, 33]. The fungal defensin, Plectasin, is one of the peptides that share this mechanism of action. Plectasin is highly active in vitro against Gram-positive bacteria, including strains resistant to conventional antibiotics. Furthermore, the cure of both experimental models of peritonitis and pneumonia in mice caused by Streptococcus pneumoniae has been demonstrated [34]. Recombinant Plectasin has been expressed in Pichia pastoris. By this approach, large quantities of Plectasin can be produced. Also, the purified recombinant peptide showed anti-Staphylococcus aureus activity over a wide range of pH (2.0 and 10.0), a high thermal stability at 100 oC for 1h and remarkable resistance to papain and pepsin [35]. These findings demonstrate the therapeutic potential of Plectasin. Others AMPs exert their antimicrobial effect in the microbial cytosol. One of them, Buforin II is a histone-derived antimicrobial peptide that causes cell death by translocating across membranes and interacting with nucleic acids [36]. Recently, analogs of Buforin II have been synthesized showing improved antimicrobial activity [37]. Furthermore, the proline-rich antibacterial peptides Pyrrhocoricin, Drosocin, and Apidaecin also have the capacity to translocate to cytosol and inhibit the chaperone-assisted protein folding activity of DnaK [38]. These molecules have not toxicity against host cells because they do not recognize the chaperone heat-shock protein 70, the human equivalent of DnaK. Recently, a synthetic proline-rich peptide (A3-APO) showed antibacterial activity by a dual mode of action. This peptide provoked destabilization of the cellular membrane besides the inhibition of DnaK [39]. Although the antibacterial activity in vitro of A3-APO is poor, in different mouse models of systemic and wound infections it shows superior efficacy compared with conventional antibiotics [40]. This discrepancy would be explained by an indirect antimicrobial action of this peptide. Indirect activities have been described for many antimicrobial peptides [41]. These peptides have immunomodulatory properties so they can recruit and activate a favorable innate immune response to resolve the infection. The innate defense regulator peptides (IDR) are synthetic peptides with this capacity [42]. In fact, IDR-1, a 5-mer derived peptide from the Indolicidin, induced protection in animal models against infection by antibiotic resistant bacteria in spite of the fact that IDR-1 does not have direct antimicrobial activity [43]. This peptide enhanced the levels of monocyte chemokines while reducing pro-inflammatory cytokine responses. Furthermore, protection depended on the activity of monocytes and macrophages since depletion of these cells abrogate it. Another immunomodulatory peptide (IDR-1002) was selected from a library of Bactenecin derivatives. The anti-infective activity of this peptide was higher than IDR-1, which correlated with a higher induction of chemokine by IDR-1002 [44]. The efficacy of IDR-1002 as adjuvant has also been demonstrated [45]. Another Bactenecin derivative, IDR-1018, showed as much immunomodulatory properties as direct antimicrobial activity [46]. The coadministration of

Magnetic Nanoparticles

IDR-1018 with antimalarial drugs increased survival of Plasmodium infected mice. In addition, downregulation of harmful inflammatory response was demonstrated [47]. Furthermore, Lactoferrin derived peptides, as well as cathelicidins and defensins also have immunomodulatory and antiinfective activities [48-53]. Finally, the use of these peptides in therapeutics, and others with the same principle of action, is unlikely to induce pathogen resistance due to the indirect interaction of these molecules with microbes [49]. ANTICANCER ACTIVITY OF AMPs Differences in the composition of the cellular membrane between cancerous and normal cells are the basis for the anti-tumor activity of AMPs. In fact, one of the major differences between these types of cells is the exposure on the outer leaflet of the cancer cell membrane of the negatively charged lipid phospatidylserine [6]. As mentioned, this contrast with the outer leaflet of the cellular membrane in normal cells that exhibit an overall neutral charge, fundamentally composed of phospatidylcholine and sphingomyelin [54]. Additionally, the overexpression of sialic acid residues and heparin sulfate in the surface of different tumoral cells has been demonstrated [55, 56]. These differences in the cellular membrane of cancerous cells increase the electronegativity of the outer leaflet. By this mechanism, the initial electrostatic interaction between AMPs and cancer cells is enhanced which permits the cellular specificity. The anticancer activity in vitro, for many antimicrobial peptides, has been demonstrated [6]. Although properties like the net charge, amphipaticity and hydrophobicity of the peptides are very important to their function; these parameters alone cannot be used as anticancer activity predictors [57]. The mechanism of action of AMPs against cancerous cells is the same as against microbial cells with the cellular and the mitochondrial membrane the principal targets [58]. For example, the antimicrobial peptide Lactoferricin B (LfcinB), derived from acid-pepsin cleavage of bovine Lactoferrin, showed a selective cytotoxicity against various human neuroblastoma cell lines. The induction of destabilization of the cellular membrane and depolarization of the mitochondria membrane in neuroblastomas by the action of LfcinB has been demonstrated [59]. Furthermore, LfcinB induced the cleavage of caspase-6, 7 and 9 followed by cellular death; although the treatment with caspase inhibitors did not affect the cytotoxicity of the peptide. Treatment of established neuroblastoma (SH-SY-5Y) xenografts with repeated injections of the peptide provoked significant tumor growth inhibition [59]. The antitumoral activity of LfcinB using an immune-deficient mice bearing B-lymphoma xenografts model was also demonstrated by other researchers [60]. Antimicrobial peptides had been successfully evaluated against human prostate cancer. In this case, a 15-mer synthetic peptide composed of D and L-amino acids (lysines and leucines [K6L9]) induced a complete inhibition of the human prostate tumor xenografts (CL1, 22RV1) after intratumoral injection [61]. This peptide also inhibited the development of lung and human breast metastases in mice [62, 63]. In all models, the cytotoxicity of the peptide was by cellular membrane depolarization. The importance of the use of diastereomers to increase the stability of the AMPs against

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proteases and serum components was also demonstrated. Despite the selectivity against cancer cells, this synthetic peptide has cytotoxicity against normal cells at concentration moderately higher than therapeutic doses [64]. A possible solution to increase the selectivity of anticancer peptides could be achieved by diminishing the cationic nature of the molecule. As solid tumor has an acidic environment, Makovitzki et al. substituted the lysines of the K6L9 peptide by histidines, making them cationic only at low pH. Using this approach, the cytotoxicity of the peptide diminished, and intratumor and systemic inoculation of the peptide induced a significant reduction of the tumor volume in a human prostate cancer xenograft mice model [64]. These data point out the importance of membrane disruption mechanisms in the development of therapeutics for inhibiting tumor growth and preventing metastases of various cancers. Anticancer peptides with non-membrane mechanisms of action have also been described. The antimicrobial peptide Gomesin isolated from hemocytes from the spider Acanthoscurria gomesiana induced antitumor activity in vitro and in vivo [65]. Gomesin provoked necrotic cell death and was cytotoxic to human neuroblastoma cells (SH-SY5Y) and rat pheochromocytoma cells (PC12). The mechanism of action implicates calcium entry through L-type calcium channels, activation of MAPK/ERK, PKC and PI3K signaling as well as the generation of reactive oxygen species. On the other hand, the antiangiogenesis and chemotactic effect of human alpha Defensin 1 (HNP-1) was correlated with the antitumor activity in a human lung adenocarcinoma xenograft in nude mice [66]. The authors employed a therapy based on a plasmid that expresses the antimicrobial peptide in the interior of cancerous cells. Decreased microvessel density and increased lymphocyte infiltration were observed in tumor tissue from HNP1-treated mice through histologic analysis. Also, the antitumoral activity of a 9-mer peptide (LTX-302) derived from LfcinB was demonstrated. In this experiment, the intratumoral injection of the peptide in lymphomas of Balb/c origin established by inoculation in syngeneic mice induced complete regression of the tumors in the majority of the animals. The same therapy was inefficient in nude mice, demonstrating the effect of the adaptive immune system in the recovery. In fact, successfully treated mice were protected against re-challenge with the same tumor cells, but not against other. Furthermore, the antitumoral effect could be adoptively transferred with spleen cells of LTX-302 treated mice and resistance was abrogated by depletion of CD4+ or CD8+ T cells [67]. This experiment demonstrated the importance of the adaptive immune system in the antitumor therapy. Actually, as tumor creates a tolerogenic microenvironment to evade the immune system [68, 69] a therapy that overcome the immunosuppression could be very promising [70]. In this way, antimicrobial peptides could be very useful due to their immunomodulatory properties [71]. Besides the direct killing, principally by disturbing the cellular membrane of tumoral cells, they could activate the immune system [50, 72, 73] and restore an effective antitumoral immune response. As some antimicrobial peptides have different mechanism of action, which can act simultaneously, the generation of tumor resistance to them is more difficult [27]. Further-


more, the communication of many antimicrobial peptides with the immune system also limits the selective pressure on cancer cells. However, due to the complex interactions between the tumor and the host [74] newer therapies that combine various targets is required. CLINICAL EFFICACY OF AMPs Despite the multifunctional activity of AMPs and success in preclinical models, the clinical results of these molecules have not been good enough to approve them for medical use. Excellent reviews have covered this subject [5, 7]. Principally, two groups of antimicrobial peptides have been tested in clinics [41]. The first one has a direct action against microorganisms with a broad spectrum of activity. These peptides could be used as antibiotics, although the efficacy in clinical trials only has been demonstrated as topical agents. The other group is composed by peptides that do not have a direct action against microbial cells to exert anti-infective properties. These peptides have immunomodulatory activity. Some of the most active peptides in the first group are Pexiganan, Iseganan and Omiganan. Although Phase III trials were conducted with each peptide, none of them successfully passed [5]. Pexiganan (MSI-78), a 22-mer analog of magainin, is a bactericidal peptide with a MIC90 (minimal concentration at which 90% of isolates are inhibited) of 32 g/ml. Attempts to induce resistance in several bacterial species or cross-resistance with different classes of antibiotics were unsuccessful [75]. Biophysical studies have shown that this peptide is unstructured in solution. Upon binding to the membrane forms an antiparallel dimer of amphipathic helices and disrupts the membrane by toroidal pore formation [76]. Recently, this peptide could be re-entered in Phase III trials in order to be approved as a new drug application [5]. Iseganan is an analog of protegrin-1 that has a broad spectrum bactericidal activity. The induction of resistance or cross-resistance to this peptide has not been described [77]. However, toxicity was demonstrated in a Phase III trial for the treatment of ventilator-associated pneumonia [7]. On the other hand, the 12-mer analog of Indolicidin, Omiganan (ILRWPWWPWRRK-NH2.5Cl) has a broad bactericidal and fungicidal activity [78]. The mechanism of action has not been elucidated yet, although the interaction with membranes plays a key role in the direct antimicrobial activity [79]. Interestingly, this peptide also displays antiinflammatory activity which is essential for the treatment of acne and Rosacea. In fact, Omiganan was significantly effective in Phase II clinical trials against severe acne and Rosacea, and should go into Phase III trials for Rosacea soon [5]. Unfortunately, almost all peptides that composed this clinical group only can be applied as topical formulations. One of the exceptions, PMX-30063 (Polymedix), a defensin mimetic made up of -amino acids has shown potent broadspectrum antibacterial activity. Furthermore, the analog was well tolerated systemically in Phase I trials and was also demonstrated ex vivo antibacterial activity [5]. Peptides from the second group (immunomodulatory activity) are in the initial phases of clinical trials. The most prominent peptides so far are derivatives from the human Lactoferrin and the immune defense regulators (IDRs) [5]. Lactoferrin is an iron-binding glycoprotein first identified in breast milk as a protein product of mammary epithelial cells.


Studies in animal models have shown a potent anticancer activity induced by their immunomodulatory properties [80, 81]. A Phase I trial of oral Talactoferrin , a recombinant form of human Lactoferrin, in refractory solid tumors was accomplished. Talactoferrin was well tolerated and the 88% of the patients had a decrease in their tumor growth rate [82]. Favorable results were achieved in a Phase 2 trial of Talactoferrin in previously treated patients with metastatic renal cell carcinoma [83]. The wound healing in diabetic patients with foot ulceration has also been evaluated in a Phase 1/Phase 2 clinical trial. Topical Talactoferrin appears to be safe and well tolerated and improves healing of diabetic neuropathic ulcers [84]. On the other hand, the in vivo antimicrobial activity of the peptide hLF1-11 (first N-terminal amino acids from human Lactoferrin), modulation of the inflammatory response and monocyte-macrophage differentiation toward cells with enhanced antimicrobial properties have been demonstrated [50]. hLF1-11 has completed Phase I trials with no serious adverse events, however the development of this molecule has been closed [85]. AMPs have failed to translate to the clinics. There is no doubt; alternatives to reduce the toxicity of antimicrobial peptides are urgently needed. This could be done increasing the selectivity of AMPs for microbial cells, or enhancing the delivery of AMPs to microbial cells. In the last few years, an outstanding advance in the design and optimization of AMPs had occurred [86, 87]; so newer peptides with higher selectivity and enhanced activity would be available for clinics. On the other hand, the advances in nanotechnology have also been enormous [88]. Different nanostructures have been emerged to develop biomedical applications [89-91]. In fact, nanosystems have been used in order to increase the stability, efficacy, and biodistribution of AMPs [88, 92, 93]. Additionally, chemically modified nanoparticles with specific cell surface ligands could enhance the site specific delivery of AMPs [88]. Interestingly, magnetic nanoparticles are between the most promissory nanoparticles for biomedical applications [10], but have not been sufficiently used with antimicrobial peptides yet. Magnetic nanoparticles could improve the efficacy of AMPs in the clinics. MAGNETIC NANOPARTICLES Term “iron oxides” includes numerous families of substances generally defined by the formula FexOyHz (in most of the cases Z=0). Chemical formula of ferrites is usually expressed as MO.Fe2O3. Transition metals like Mn, Co, Zn, Cu, and Ni are typical divalent M atoms in the ferrite structure. When atom M is Fe, it is called magnetite (Fe3O4), a ferrimagnetic oxide that contain both Fe (II) and Fe (III) ions [94]. Maghemite (-Fe2O3) is isostructural with magnetite, but with a cation deficient site. Magnetite and maghemite have the highest saturation magnetization (80–100 Am2kg–1), well above the magnetization observed for other iron oxides, as bulk materials [10]. The particle size reduction, below the single domain region leads to a progressive decrease for the saturation magnetization to finally enter in the paramagnetic state, where the nanoparticle magnetic moment is found fluctuating among directions of easy magnetization by the effect of thermal energy (kT). The paramagnetic region for a given iron oxide depends on the involved M metal, structural features, surface anchored ligands, etc. Related to the magnetic



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moment fluctuation, the superparamagnetic state is characterized by absence of hysteresis loop in the recorded magnetization curve versus applied magnetic field [95]. Generally, iron oxide-based ferrofluids contain a mixture of maghemite and magnetite in their paramagnetic state in order to minimize aggregation effects.

an antibacterial quaternary ammonium were bactericidal against Escherichia coli [110]. Furthermore, silica-coated magnetite-decorated poly(styrene-co-acrylate acid) nanoparticles conjugated with N-halamine showed enhanced antibacterial activity against both Gram-positive and Gram-negative bacteria compared with their bulk counterparts [111].

There are two different types of magnetic iron-oxide nanoparticles (IONP) used for biological applications: ironoxide nanoparticles (IONPs), with a hydrodynamic diameter of 50-100 nm, and ultra-small iron-oxide nanoparticles (USIONPs) with a diameter lower than 50 nm [96]. MNPs have been widely studied for biomedical applications, particularly as magnetic resonance imaging (MRI) contrast agents [97]; magnetic fluid hyperthermia therapy [98], for drug and gene delivery [99, 100] and also for magnetic separation of cells and proteins [101]. Furthermore, magnetic nanoparticles can be guided by means of application of an external magnetic field allowing its applications in magnetictargeting biomedical [10].

Bacitracin-conjugated iron oxide (Fe3O4) nanoparticles have shown higher antimicrobial activity against both Grampositive and Gram-negative organisms, in comparison with the bacitracin peptide [112]. Due to this enhanced activity, functionalized magnetic nanoparticles allow lower dosages and collateral effects of the antibiotic. Moreover, cell cytotoxicity tests indicate that bacitracin-MNPs show very low cytotoxicity to human fibroblast cells, even at relatively high concentrations. Due to the antibacterial effect and magnetism, the bacitracin-functionalized magnetic nanoparticles have potential application in magnetic-targeting biomedical applications. In this sense, Subbiahdoss et al., report that carboxyl-grafted SPIONs, magnetically concentrated in a biofilm, cause an approximately 8-fold higher percentage of dead Staphylococci than does gentamicin for a gentamicinresistant strain in a developing biofilm [113].

For several biomedical applications, magnetic nanodevices should have very small size and narrow size distribution together with high magnetization values. In order to obtain high magnetization values, newer strategies with coreshell metal-based nanoparticles have been used. For example, iron-based NPs (comprised of an Fe core surrounded by an iron oxide layer) have greater magnetic properties than IONPs [102]. Also, core-shell nanoparticles based on the coupling of magnetically hard (CoFe2O4) and soft (MnFe2O4) components have been synthesized. This coreshell nanoparticles (CoFe2O4@MnFe2O4) also have an improved magnetic behavior [103]. Furthermore, MNPs must combine high magnetic susceptibility for an optimum magnetic response and loss of magnetization after magnetic field elimination. Finally, it is necessary and optimal surface coating in order to ensure tolerance and biocompatibility, as well as specific localization at the biological target site [10]. The toxicity of MNPs depends on numerous factors including the dose, chemical composition, size, structure, solubility, surface chemistry, route of administration, biodegradability, pharmacokinetics, and biodistribution [104]. Many cytotoxicity assays of MNPs with different size, surface coating, surface charge and doses have been conducted [105108]. Cytotoxicity of nanoparticles may be more marked in vitro than in vivo because in cell culture conditions the NPs and/or their degradation products remain in close contact with the cells and may act as a depot showing constant effect, affecting cell viability. In vivo, however, NPs and its degradation products are continuously eliminated from the body [109]. In this case, toxicity changes mainly with the composition, physicochemical properties, and route of administration, whereas the determination of the dose range and the dose schedule can reduce side effects and toxicity. NPMs IN THE TREATMENT OF INFECTIOUS DISEASES In the last years, superparamagnetic iron oxide nanoparticles (SPIONs) have been studied for magnetic-targeting biomedical application. The antimicrobial activity of magnetic nanoparticles has been investigated using different approaches. For example, magnetite nanoparticles coated with

The synthesis of multimodal nanoparticles with magnetic core and silver shell allow overcome silver nanoparticles limitations [114] and its use is suitable for bacterial inactivation in biological fluids [115]. Magnetic binary nanocomposites of iron oxide and silver nanoparticles revealed very significant antibacterial and antifungal activities against ten tested bacterial strains (MIC from 15.6 mg/L to 125 mg/L) and four candida species (MIC from 1.9 mg/L to 31.3 mg/L) [116]. It has been reported a better antibacterial activity for magnetite nanoparticles modified with sodium and calcium salts of poly (gamma-glutamic acid) NaPGA and CaPGA than commercial antibiotics linezolid and cefaclor [117]. An in vitro cytotoxicity study in human skin fibroblast cells as measured by MTT assay showed non-toxic effect of these nanoparticles. Also a broad-range of bactericidal activity for another magnetite nanoparticle, this time, surface-modified by poly (hexamethylene biguanide) moieties has been demonstrated [118]. These MNPs were capable to bound lipopolysaccharide and glycopeptide components of the bacterial membranes as well as nucleic acids and whole bacteria. It has demonstrated that aziridine- and biguanide-modified NPs are broadly virucidal and capable of nonspecific binding both enveloped and non-enveloped viruses, thus providing a method for the magnet-based virus removal [119]. Our group has synthesized citric acid-functionalized manganese ferrites for biomedical applications. These nanoparticles were conjugated with the antifungal peptide Cmp5. The antifungal activity of both, MNPs and MNPsCmp5, were demonstrated. The antimicrobial activity of the conjugated was higher than their bulk counterparts (unpublished results). NPMs IN THE TREATMENT OF CANCER Magnetic nanoparticles have been widely used in the treatment of cancer diseases [120]. Their theranostic potential is the reason for the preferential application of these nanoparticles in cancer [121]. From the late 1980s, many


clinical studies were performed in order to demonstrate the capacity of paramagnetic particles in the diagnostic of cancer [122]. Nowadays, the revolution in cancer diagnostics continues. For example, initially the specificity of the interaction of SPIONs with tissues was guided by size. Nanoparticles with more than 50 nm of hydrodynamic diameter are preferentially sequestered by hepatic and splenic macrophages. The lack of macrophages in cancerous tissues is a key identifier that differentiates between healthy and malignant regions. Therefore, nanoparticles of this size have been clinically used in humans to imaging liver tumors [123]. On the other hand, very small nanoparticles (diameter < 50 nm) are not taken by the liver and spleen macrophages and can access other tissues [124]. In fact, this type of nanoparticles has been used for detecting abnormalities at lymph nodes in different types of cancer [125, 126]. Recently, have been demonstrated the specificity of folate-poly (ethylene) glycolSPIONs for experimental treatment of lung cancer in mice [127]. In this experiment the nanoparticles were labeling with the fluorescent probe Cy5.5 and the entrance of folatePEG-SPIONs to the cells was by receptor mediated endocytosis as was corroborated by competence experiments with free folic acid. The specificity to other cancer tissues had been carry out by the conjugation of monoclonal antibodies against tumor specific antigens. In this case, Ma et al. developed a multilayered core/shell based on magnetic nanoparticle and quantum dots (Fe3O4/SiO2) [128]. These nanoparticles were conjugated to the monoclonal antibody against human epidermal growth factor receptor-2 (HER2) that is overexpressed in some tumor cells. Using this approach was possible to take multimodal images of breast tumors in mice by near-infrared fluorescence and T2-weighted magnetic resonance. In fact, the last two nanoparticle systems have the advantage of been used not only as a contrast agent of magnetic resonance imaging, as they also could be used as fluorescent probes. Another approach for the delivery of magnetic nanoparticles to cancer cells was introduced by Ghosh et al.. They used the M13 filamentous bacteriophage as a scaffold to display a peptide with affinity for SPARC glycoprotein (protein that is overexpressed in various cancers) and multiple magnetic nanoparticles for magnetic resonance imaging of tumors in mice. This approach is better than functionalizing the peptide directly to nanoparticles because each SPARC-targeting molecule delivers many nanoparticles inside the cell, with an improvement in the image contrast [129]. Although the applications of magnetic nanoparticles to cancer diagnostic have been widely studied, it has also been advances in other areas. For example, imaging of atherosclerotic plaques [130, 131], inflammatory responses [132, 133], and macrophage infiltration in transplanted organs [134]. Another of the most used application of magnetic nanoparticles to the treatment of cancer is the magnetic fluid hyperthermia (MFH) [135]. The MFH consists in the locally administration of magnetic nanoparticles in fluid suspension into the tumor site with its subsequent exposure to an alternate magnetic field (AMF). Under these conditions, magnetic nanoparticles dissipate energy in the form of heat, causing a localized increase in temperature at the tumor site [10]. By other hand, the susceptibility of the cancerous cells to temperature permits the necrosis of these cells but does not damage surrounding normal tissue [136]. The heat release by


nanoparticles depends on their magnetic properties (magnetization, magnetic anisotropy, size), on the frequency and amplitude of the AMF [98, 102, 137, 138]. Some of the main magnetic heating mechanisms include: Néel (rotation of the magnetic moment) and Brownian (rotation of the nanoparticle) relaxations [139]. However, the accumulation of magnetic nanoparticles in endosomal vacuoles following intratumoral administration has been recently demonstrated [140, 141]. Due to the highly packed assemblies of nanoparticles within these intracellular vesicles, the Brownian contribution to heating is abrogated. Therefore, Néel relaxation mainly induces the intracellular hyperthermia [142, 143]. Several examples in preclinical and clinical studies have proved the efficacy of MFH in the treatment of cancer. In a mouse xenograft model of human head and neck cancer, epithelial tumor cell destruction was demonstrated. In this experiment, the temperature of the tumor center was elevated to 40 oC during the first 5-10 minutes of treatment [144]. Furthermore, the therapeutic effect of Fe2O3 nanoparticles in a mouse xenograft model of human liver cancer was also proved [145]. In this experiment, they observed weight and volume reduction of the tumor that was dose-dependent. Additionally, the inhibition of proliferation and apoptosis of the hepatocarcinoma cells was demonstrated by in vitro experiments. On the other hand, the effect of bimagnetic (Fe/Fe3O4) core/shell nanoparticles covered by dopamineoligoethylene glycol ligands attached to 4tetracarboxyphenyl porphyrin units in the treatment of subcutaneous mouse melanomas (B16-F10) have been evaluated [146]. Tumor cells require more porphyrins as prosthetic groups than normal cells due to their exacerbated metabolism of carbohydrates [147]. For this reason, porphyrin units enhance nanoparticles uptake by tumor. The intratumoral injection of these nanoparticles provoked a significant antitumor effect on murine melanoma after three-short 10 minutes exposures to AMF. Interestingly, the antitumor effect after the intravenous administration of the nanoparticles was also demonstrated. The same group has been worked in the cell-delivered of magnetic nanoparticles to the tumor site. For this purpose, tumor-tropic neural progenitor cells (NPCs) have been employed for the treatment of murine melanoma [148]. The NPs were efficiently loaded in NPCs forming aggregates in the cytosol with minimal cytotoxicity. The NPCs loaded could travel to subcutaneous melanoma, and after three AMF exposures the tumor regression was significant. Recently, they used RAW264.7 cells (mouse monocyte-macrophage like cells) as tumor homing cells [149] that have the advantage of been key player of the innate immune system. After tumor development in a murine model of disseminated peritoneal pancreatic cancer, cells loaded with NPs were injected intraperitoneally and three days after injection mice were exposed for 20 minutes to an AMF. A significantly increase survival was demonstrated, with an average post-tumor insertion life expectancy increase of 31%. On the other hand, several clinical trials have been conducted to prove the safety of magnetic nanoparticles in the thermotherapy of prostate cancer [150-152]. One of the advantages of the MFH is the development of an antitumoral immunity. Ito et al. demonstrated the antitumoral immunity in the T-9 rat glioma induced by the expression of heat-shock protein 70 (HSP70) after the MFH [153].


The necrosis caused by the MFH in tumoral cells correlated with the HSP70 expression. In fact, HSP70-peptides complexes purified from tumor cells after the hyperthermia treatment were immunized in F334 rats with implanted tumor T-9 cells, and the tumor growth was significantly reduced. In another approach, the induction of cytotoxic T lymphocytes (CTL) after the MFH treatment of melanocytes was demonstrated [154]. In this case, after the intracellular hyperthermia the level of HSP72 was raised, and the induction of anti-tumor specific CTL was dependent of the release of HSP-peptide complex from tumor cells. The importance of HSPs in the cross-priming of antigens has been demonstrated [155, 156]. Also these molecules significantly contribute to the maturation of dendritic cells and the communication between the innate immune system and the adaptive system [157, 158]. However, the overexpression of HSPs in tumor cells not always correlated with the induction of CTL by cross-presentation [159]. In fact, there are different pathways for the cross-presentation of antigens by dendritic cells [160]. Actually, when MFH is combined with dendritic cell immunotherapy on mouse EL4 T-lymphoma almost a complete regression of the tumor (75%) was observed, while only a 12,5 % was observed in the treatment with MFH alone [161]. This experiment indicates the central role of dendritic cells in the induction of CTL. Moreover, not only the necrosis, but also the apoptosis of tumor cells induce an antitumoral immune response [162, 163]. A therapy that could generate a tumor-specific immune response permits to eliminate not only local tumors exposed to treatment, but also tumors at other sites [153], including the possibility to eradicate metastatic cancer cells [164]. One of the approaches in order to induce a tumor-specific immune response is the application of the MFH in combination with adjuvants [164, 165]. A group of molecules that could be used as adjuvants to combine with the MFH treatment is the antimicrobial peptide family. As above mentioned, antimicrobial peptides are constituents of the innate immune system and many of them have immunomodulatory activities [166]. These peptides have chemotactic activity for different cells of the innate and the adaptive immune system [167, 168]. Also can induce the secretion of cytokines and chemokines with the concomitant activation of cells from the innate immune system [50, 169]. Moreover, these molecules could directly destroy cancer cells by destabilization of the plasmatic membrane [6]. All these properties from antimicrobial peptides in combination with the MFH by AMPs conjugation to magnetic nanoparticles could generate a novel and more efficacious treatment against cancer. In fact, the increase in stability and biodistribution without loss of functional activity of AMPs followed conjugation to nanoparticles has been demonstrated [92, 93]. CONCLUDING REMARKS Despite the multifunctional activity of AMPs and success in preclinical models, the clinical results of these molecules have not been good enough to approve them for medical use. Alternatives to reduce the toxicity, and increase the stability, efficacy and biodistribution of antimicrobial peptides are urgently needed. Nanotechnology could provide a solution for these problems. Specifically, magnetic nanoparticles could be a perfect carrier for AMPs due to the broad spec-


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trum of activities (anticancer, antimicrobial, drug delivery, diagnosis) and the low toxicity of them. As antimicrobial and anticancer properties of both molecules have different mechanism of action, the conjugated (AMPs-MNP) could have an improved activity. CONFLICT OF INTEREST The author(s) confirm that this article content has no conflicts of interest. ACKNOWLEDGEMENTS We would like to thanks the financial support of CNPq (project 490180-2011-6), Brazil and the kind language reviewing of Dr. Christine McBeth from Harvard Medical Schools, Boston Mass, USA. REFERENCES [1]

[2] [3] [4] [5] [6] [7] [8] [9] [10]

[11] [12] [13] [14]

[15] [16] [17]

Kruijshaar, M. E.; Watson, J. M.; Drobniewski, F.; Anderson, C.; Brown, T. J.; Magee, J. G.; Smith, E. G.; Story, A.; Abubakar, I. Increasing antituberculosis drug resistance in the United Kingdom: analysis of National Surveillance Data. BMJ., 2008, 336(7655), 1231-1234. Snell, N. J. Examining unmet needs in infectious disease. Drug Discov. Today, 2003, 8(1), 22-30. Arias, C. A.; Murray, B. E. Antibiotic-resistant bugs in the 21st century - a clinical super-challenge. N. Engl. J. Med., 2009, 360(5), 439-443. Kang, S. J.; Ji, H. Y.; Lee, B. J. Anticancer activity of undecapeptide analogues derived from antimicrobial peptide, Brevinin-1EMa. Arch. Pharm. Res., 2012, 35, 791-799. Afacan, N. J.; Yeung, A. T.; Pena, O. M.; Hancock, R. E. Therapeutic potential of host defense peptides in antibiotic-resistant infections. Curr. Pharm. Des., 2012, 18, 807-819. Riedl, S.; Zweytick, D.; Lohner, K. Membrane-active host defense peptides--challenges and perspectives for the development of novel anticancer drugs. Chem. Phys. Lipids, 2011, 164(8), 766-781. Eckert, R. Road to clinical efficacy: challenges and novel strategies for antimicrobial peptide development. Future Microbiol., 2011, 6(6), 635-651. Brogden, N. K.; Brogden, K. A. Will new generations of modified antimicrobial peptides improve their potential as pharmaceuticals? Int. J. Antimicrob. Agents, 2011, 38(3), 217-225. Brandelli, A. Nanostructures as promising tools for delivery of antimicrobial peptides. Mini Rev. Med. Chem., 2012, 12(8), 731741. Reddy, L. H.; Arias, J. L.; Nicolas, J.; Couvreur, P. Magnetic nanoparticles: design and characterization, toxicity and biocompatibility, pharmaceutical and biomedical applications. Chem. Rev., 2012, 112(11), 5818-5878. Zasloff, M. Antimicrobial peptides of multicellular organisms. Nature, 2002, 415(6870), 389-395. Lehrer, R. I.; Lichtenstein, A. K.; Ganz, T. Defensins: antimicrobial and cytotoxic peptides of mammalian cells. Annu. Rev. Immunol., 1993, 11, 105-128. Zanetti, M.; Gennaro, R.; Romeo, D. Cathelicidins: a novel protein family with a common proregion and a variable C-terminal antimicrobial domain. FEBS Lett., 1995, 374(1), 1-5. Andra, J.; Berninghausen, O.; Leippe, M. Cecropins, antibacterial peptides from insects and mammals, are potently fungicidal against Candida albicans. Med. Microbiol. Immunol., 2001, 189(3), 169173. Lee, I. H.; Zhao, C.; Cho, Y.; Harwig, S. S.; Cooper, E. L.; Lehrer, R. I. Clavanins, alpha-helical antimicrobial peptides from tunicate hemocytes. FEBS Lett., 1997, 400(2), 158-162. Jenssen, H.; Hamill, P.; Hancock, R. E. Peptide antimicrobial agents. Clin. Microbiol. Rev., 2006, 19(3), 491-511. Alba, A.; Lopez-Abarrategui, C.; Otero-Gonzalez, A. J. Host defense peptides: an alternative as antiinfective and immunomodulatory therapeutics. Biopolymers, 2012, 98(4), 251-267.

602 Current Protein and Peptide Science, 2013, Vol. 14, No. 7 [18] [19]

[20] [21] [22]

[23]

[24]

[25]

[26] [27] [28] [29] [30]

[31] [32] [33]

[34]

[35]

[36]

[37]

Matsuzaki, K. Control of cell selectivity of antimicrobial peptides. Biochim. Biophys. Acta, 2009, 1788(8), 1687-1692. Matsuzaki, K.; Sugishita, K.; Miyajima, K. Interactions of an antimicrobial peptide, magainin 2, with lipopolysaccharidecontaining liposomes as a model for outer membranes of gramnegative bacteria. FEBS Lett., 1999, 449(2-3), 221-224. Matsuzaki, K.; Sugishita, K.; Fujii, N.; Miyajima, K. Molecular basis for membrane selectivity of an antimicrobial peptide, magainin 2. Biochemistry, 1995, 34(10), 3423-3429. Wilmes, M.; Cammue, B. P.; Sahl, H. G.; Thevissen, K. Antibiotic activities of host defense peptides: more to it than lipid bilayer perturbation. Nat. Prod. Rep., 2011, 28(8), 1350-1358. Schneider, T.; Kruse, T.; Wimmer, R.; Wiedemann, I.; Sass, V.; Pag, U.; Jansen, A.; Nielsen, A. K.; Mygind, P. H.; Raventos, D. S.; Neve, S.; Ravn, B.; Bonvin, A. M.; De, M. L.; Andersen, A. S.; Gammelgaard, L. K.; Sahl, H. G.; Kristensen, H. H. Plectasin, a fungal defensin, targets the bacterial cell wall precursor Lipid II. Science, 2010, 328(5982), 1168-1172. Thevissen, K.; Francois, I. E.; Takemoto, J. Y.; Ferket, K. K.; Meert, E. M.; Cammue, B. P. DmAMP1, an antifungal plant defensin from dahlia (Dahlia merckii), interacts with sphingolipids from Saccharomyces cerevisiae. FEMS Microbiol. Lett., 2003, 226(1), 169-173. Aerts, A. M.; Francois, I. E.; Meert, E. M.; Li, Q. T.; Cammue, B. P.; Thevissen, K. The antifungal activity of RsAFP2, a plant defensin from raphanus sativus, involves the induction of reactive oxygen species in Candida albicans. J. Mol. Microbiol. Biotechnol., 2007, 13(4), 243-247. Otero-Gonzalez, A. J.; Magalhaes, B. S.; Garcia-Villarino, M.; Lopez-Abarrategui, C.; Sousa, D. A.; Dias, S. C.; Franco, O. L. Antimicrobial peptides from marine invertebrates as a new frontier for microbial infection control. FASEB J., 2010, 24(5), 1320-1334. Mor, A. Multifunctional host defense peptides: antiparasitic activities. FEBS J., 2009, 276(22), 6474-6482. Hale, J. D.; Hancock, R. E. Alternative mechanisms of action of cationic antimicrobial peptides on bacteria. Expert. Rev. Anti. Infect. Ther., 2007, 5(6), 951-959. Barbosa, P. P.; Del Sarto, R. P.; Silva, O. N.; Franco, O. L.; Grosside-Sa, M. F. Antibacterial peptides from plants: what they are and how they probably work. Biochem. Res. Int., 2011, 2011, 250349. Wimley, W. C.; Hristova, K. Antimicrobial peptides: successes, challenges and unanswered questions. J. Membr. Biol., 2011, 239(1-2), 27-34. Zasloff, M. Magainins, a class of antimicrobial peptides from Xenopus skin: isolation, characterization of two active forms, and partial cDNA sequence of a precursor. Proc. Natl. Acad. Sci. U.S.A., 1987, 84(15), 5449-5453. Ludtke, S. J.; He, K.; Heller, W. T.; Harroun, T. A.; Yang, L.; Huang, H. W. Membrane pores induced by magainin. Biochemistry, 1996, 35(43), 13723-13728. Brogden, K. A. Antimicrobial peptides: pore formers or metabolic inhibitors in bacteria? Nat. Rev. Microbiol., 2005, 3(3), 238-250. Schmitt, P.; Wilmes, M.; Pugniere, M.; Aumelas, A.; Bachere, E.; Sahl, H. G.; Schneider, T.; stoumieux-Garzon, D. Insight into invertebrate defensin mechanism of action: oyster defensins inhibit peptidoglycan biosynthesis by binding to lipid II. J. Biol. Chem., 2010, 285(38), 29208-29216. Mygind, P. H.; Fischer, R. L.; Schnorr, K. M.; Hansen, M. T.; Sonksen, C. P.; Ludvigsen, S.; Raventos, D.; Buskov, S.; Christensen, B.; De, M. L.; Taboureau, O.; Yaver, D.; Elvig-Jorgensen, S. G.; Sorensen, M. V.; Christensen, B. E.; Kjaerulff, S.; FrimodtMoller, N.; Lehrer, R. I.; Zasloff, M.; Kristensen, H. H. Plectasin is a peptide antibiotic with therapeutic potential from a saprophytic fungus. Nature, 2005, 437(7061), 975-980. Zhang, J.; Yang, Y.; Teng, D.; Tian, Z.; Wang, S.; Wang, J. Expression of plectasin in Pichia pastoris and its characterization as a new antimicrobial peptide against Staphyloccocus and Streptococcus. Prot. Expr. Purif., 2011, 78(2), 189-196. Park, C. B.; Kim, H. S.; Kim, S. C. Mechanism of action of the antimicrobial peptide buforin II: buforin II kills microorganisms by penetrating the cell membrane and inhibiting cellular functions. Biochem. Biophys. Res. Commun., 1998, 244(1), 253-257. Jang, S. A.; Kim, H.; Lee, J. Y.; Shin, J. R.; Kim da, J.; Cho, J. H.; Kim, S. C. Mechanism of action and specificity of antimicrobial


[38]

[39]

[40]

[41] [42] [43]

[44]

[45]

[46]

[47]

[48] [49] [50]

[51]

[52]

[53] [54]

peptides designed based on buforin IIb. Peptides, 2012, 34, 283289. Otvos, L., Jr.; O, I.; Rogers, M. E.; Consolvo, P. J.; Condie, B. A.; Lovas, S.; Bulet, P.; Blaszczyk-Thurin, M. Interaction between heat shock proteins and antimicrobial peptides. Biochemistry, 2000, 39(46), 14150-14159. Rozgonyi, F.; Szabo, D.; Kocsis, B.; Ostorhazi, E.; Abbadessa, G.; Cassone, M.; Wade, J. D.; Otvos, L., Jr. The antibacterial effect of a proline-rich antibacterial peptide A3-APO. Curr. Med. Chem., 2009, 16(30), 3996-4002. Ostorhazi, E.; Holub, M. C.; Rozgonyi, F.; Harmos, F.; Cassone, M.; Wade, J. D.; Otvos, L., Jr. Broad-spectrum antimicrobial efficacy of peptide A3-APO in mouse models of multidrug-resistant wound and lung infections cannot be explained by in vitro activity against the pathogens involved. Int. J. Antimicrob. Agents, 2011, 37, 480-484. Hancock, R. E.; Sahl, H. G. Antimicrobial and host-defense peptides as new anti-infective therapeutic strategies. Nat. Biotechnol., 2006, 24(12), 1551-1557. Jenssen, H.; Hancock, R. E. Therapeutic potential of HDPs as immunomodulatory agents. Methods Mol. Biol., 2010, 618, 329347. Scott, M. G.; Dullaghan, E.; Mookherjee, N.; Glavas, N.; Waldbrook, M.; Thompson, A.; Wang, A.; Lee, K.; Doria, S.; Hamill, P.; Yu, J. J.; Li, Y.; Donini, O.; Guarna, M. M.; Finlay, B. B.; North, J. R.; Hancock, R. E. An anti-infective peptide that selectively modulates the innate immune response. Nat. Biotech., 2007, 25(4), 465472. Nijnik, A.; Madera, L.; Ma, S.; Waldbrook, M.; Elliott, M. R.; Easton, D. M.; Mayer, M. L.; Mullaly, S. C.; Kindrachuk, J.; Jenssen, H.; Hancock, R. E. Synthetic cationic peptide IDR-1002 provides protection against bacterial infections through chemokine induction and enhanced leukocyte recruitment. J. Immunol., 2010, 184(5), 2539-2550. Cullen, T. W.; Giles, D. K.; Wolf, L. N.; Ecobichon, C.; Boneca, I. G.; Trent, M. S. Helicobacter pylori versus the host: remodeling of the bacterial outer membrane is required for survival in the gastric mucosa. PLoS Pathog., 2011, 7(12), e1002454. Wieczorek, M.; Jenssen, H.; Kindrachuk, J.; Scott, W. R.; Elliott, M.; Hilpert, K.; Cheng, J. T.; Hancock, R. E.; Straus, S. K. Structural studies of a peptide with immune modulating and direct antimicrobial activity. Chem. Biol., 2010, 17, 970-980. Modak, R.; Das Mitra, S.; Krishnamoorthy, P.; Bhat, A.; Banerjee, A.; Gowsica, B. R.; Bhuvana, M.; Dhanikachalam, V.; Natesan, K.; Shome, R.; Shome, B. R.; Kundu, T. K. Histone H3K14 and H4K8 hyperacetylation is associated with Escherichia coli-induced mastitis in mice. Epigenetics, 2012, 7(5), 492-501. Wuerth, K.; Hancock, R. E. New insights into cathelicidin modulation of adaptive immunity. Eur. J. Immunol., 2011, 41(10), 28172819. Yeung, A. T.; Gellatly, S. L.; Hancock, R. E. Multifunctional cationic host defence peptides and their clinical applications. Cell Mol. Life Sci., 2011, 68(13), 2161-2176. van der Does, A. M.; Joosten, S. A.; Vroomans, E.; Bogaards, S. J.; van Meijgaarden, K. E.; Ottenhoff, T. H.; van Dissel, J. T.; Nibbering, P. H. The antimicrobial peptide hLF1-11 drives monocytedendritic cell differentiation toward dendritic cells that promote antifungal responses and enhance Th17 polarization. J. Innate Immun., 2012, 4(3), 284-292. de la Rosa, G.; Yang, D.; Tewary, P.; Varadhachary, A.; Oppenheim, J. J. Lactoferrin acts as an alarmin to promote the recruitment and activation of APCs and antigen-specific immune responses. J. Immunol., 2008, 180(10), 6868-6876. Mei, H. F.; Jin, X. B.; Zhu, J. Y.; Zeng, A. H.; Wu, Q.; Lu, X. M.; Li, X. B.; Shen, J. beta-defensin 2 as an adjuvant promotes antimelanoma immune responses and inhibits the growth of implanted murine melanoma in vivo. PLoS One, 2012, 7(2), e31328. Hazlett, L.; Wu, M. Defensins in innate immunity. Cell Tissue Res., 2011, 343(1), 175-188. Verkleij, A. J.; Zwaal, R. F.; Roelofsen, B.; Comfurius, P.; Kastelijn, D.; van Deenen, L. L. The asymmetric distribution of phospholipids in the human red cell membrane. A combined study using phospholipases and freeze-etch electron microscopy. Biochim. Biophys. Acta, 1973, 323(2), 178-193.

Magnetic Nanoparticles [55] [56]

[57] [58] [59]

[60]

[61]

[62]

[63] [64]

[65]

[66]

[67]

[68]

[69] [70] [71] [72]

[73]

Bafna, S.; Kaur, S.; Batra, S. K. Membrane-bound mucins: the mechanistic basis for alterations in the growth and survival of cancer cells. Oncogene, 2010, 29(20), 2893-2904. Aviel-Ronen, S.; Lau, S. K.; Pintilie, M.; Lau, D.; Liu, N.; Tsao, M. S.; Jothy, S. Glypican-3 is overexpressed in lung squamous cell carcinoma, but not in adenocarcinoma. Mod. Pathol., 2008, 21(7), 817-825. Dennison, S. R.; Harris, F.; Bhatt, T.; Singh, J.; Phoenix, D. A. A theoretical analysis of secondary structural characteristics of anticancer peptides. Mol. Cell Biochem., 2010, 333(1-2), 129-135. Papo, N.; Shai, Y. Host defense peptides as new weapons in cancer treatment. Cell Mol. Life Sci., 2005, 62(7-8), 784-790. Eliassen, L. T.; Berge, G.; Leknessund, A.; Wikman, M.; Lindin, I.; Lokke, C.; Ponthan, F.; Johnsen, J. I.; Sveinbjornsson, B.; Kogner, P.; Flaegstad, T.; Rekdal, O. The antimicrobial peptide, lactoferricin B, is cytotoxic to neuroblastoma cells in vitro and inhibits xenograft growth in vivo. Int. J. Cancer, 2006, 119(3), 493-500. Furlong, S. J.; Mader, J. S.; Hoskin, D. W. Bovine lactoferricin induces caspase-independent apoptosis in human B-lymphoma cells and extends the survival of immune-deficient mice bearing Blymphoma xenografts. Exp. Mol. Pathol., 2010, 88(3), 371-375. Papo, N.; Braunstein, A.; Eshhar, Z.; Shai, Y. Suppression of human prostate tumor growth in mice by a cytolytic D-, L-amino acid peptide: membrane lysis, increased necrosis, and inhibition of prostate-specific antigen secretion. Cancer Res., 2004, 64(16), 57795786. Papo, N.; Seger, D.; Makovitzki, A.; Kalchenko, V.; Eshhar, Z.; Degani, H.; Shai, Y. Inhibition of tumor growth and elimination of multiple metastases in human prostate and breast xenografts by systemic inoculation of a host defense-like lytic peptide. Cancer Res., 2006, 66(10), 5371-5378. Papo, N.; Shahar, M.; Eisenbach, L.; Shai, Y. A novel lytic peptide composed of DL-amino acids selectively kills cancer cells in culture and in mice. J. Biol. Chem., 2003, 278(23), 21018-21023. Makovitzki, A.; Fink, A.; Shai, Y. Suppression of human solid tumor growth in mice by intratumor and systemic inoculation of histidine-rich and pH-dependent host defense-like lytic peptides. Cancer Res., 2009, 69(8), 3458-3463. Soletti, R. C.; del, B. L.; Daffre, S.; Miranda, A.; Borges, H. L.; Moura-Neto, V.; Lopez, M. G.; Gabilan, N. H. Peptide gomesin triggers cell death through L-type channel calcium influx, MAPK/ERK, PKC and PI3K signaling and generation of reactive oxygen species. Chem. Biol. Interact., 2010, 186(2), 135-143. Xu, N.; Wang, Y. S.; Pan, W. B.; Xiao, B.; Wen, Y. J.; Chen, X. C.; Chen, L. J.; Deng, H. X.; You, J.; Kan, B.; Fu, A. F.; Li, D.; Zhao, X.; Wei, Y. Q. Human alpha-defensin-1 inhibits growth of human lung adenocarcinoma xenograft in nude mice. Mol. Cancer Ther., 2008, 7(6), 1588-1597. Berge, G.; Eliassen, L. T.; Camilio, K. A.; Bartnes, K.; Sveinbjornsson, B.; Rekdal, O. Therapeutic vaccination against a murine lymphoma by intratumoral injection of a cationic anticancer peptide. Cancer Immunol. Immunother., 2010, 59(8), 1285-1294. Demoulin, S.; Herfs, M.; Delvenne, P.; Hubert, P. Tumor microenvironment converts plasmacytoid dendritic cells into immunosuppressive/tolerogenic cells: insight into the molecular mechanisms. J. Leukoc. Biol., 2013. Lindau, D.; Gielen, P.; Kroesen, M.; Wesseling, P.; Adema, G. J. The immunosuppressive tumor network: MDSCs, Tregs and NKT cells. Immunology, 2012, 138(2), 105-115. Umansky, V. New strategies for melanoma immunotherapy: how to overcome immunosuppression in the tumor microenvironment. Oncoimmunology, 2012, 1(5), 765-767. Choi, K. Y.; Mookherjee, N. Multiple immune-modulatory functions of cathelicidin host defense peptides. Front. Immunol., 2012, 3, 149. Ganguly, D.; Chamilos, G.; Lande, R.; Gregorio, J.; Meller, S.; Facchinetti, V.; Homey, B.; Barrat, F. J.; Zal, T.; Gilliet, M. SelfRNA-antimicrobial peptide complexes activate human dendritic cells through TLR7 and TLR8. J. Exp. Med., 2009, 206(9), 19831994. Niyonsaba, F.; Ushio, H.; Nakano, N.; Ng, W.; Sayama, K.; Hashimoto, K.; Nagaoka, I.; Okumura, K.; Ogawa, H. Antimicrobial peptides human beta-defensins stimulate epidermal keratinocyte


[74] [75]

[76]

[77] [78]

[79] [80] [81]

[82]

[83]

[84]

[85] [86] [87] [88] [89] [90] [91]

[92] [93] [94]

603

migration, proliferation and production of proinflammatory cytokines and chemokines. J. Invest. Dermatol., 2007, 127(3), 594-604. Dunn, G. P.; Old, L. J.; Schreiber, R. D. The immunobiology of cancer immunosurveillance and immunoediting. Immunity, 2004, 21(2), 137-148. Ge, Y.; MacDonald, D. L.; Holroyd, K. J.; Thornsberry, C.; Wexler, H.; Zasloff, M. In vitro antibacterial properties of pexiganan, an analog of magainin. Antimicrob. Agents Chemother., 1999, 43(4), 782-788. Gottler, L. M.; Ramamoorthy, A. Structure, membrane orientation, mechanism, and function of pexiganan--a highly potent antimicrobial peptide designed from magainin. Biochim. Biophys. Acta, 2009, 1788(8), 1680-1686. Giles, F. J.; Redman, R.; Yazji, S.; Bellm, L. Iseganan HCl: a novel antimicrobial agent. Expert. Opin. Investig. Drugs, 2002, 11(8), 1161-1170. Sader, H. S.; Fedler, K. A.; Rennie, R. P.; Stevens, S.; Jones, R. N. Omiganan pentahydrochloride (MBI 226), a topical 12-amino-acid cationic peptide: spectrum of antimicrobial activity and measurements of bactericidal activity. Antimicrob. Agents Chemother., 2004, 48, 3112-3118. Melo, M. N.; Castanho, M. A. Omiganan interaction with bacterial membranes and cell wall models. Assigning a biological role to saturation. Biochim. Biophys. Acta, 2007, 1768, 1277-1290. Gao, N.; Kumar, A.; Guo, H.; Wu, X.; Wheater, M.; Yu, F. S. Topical flagellin-mediated innate defense against Candida albicans keratitis. Invest. Ophthalmol. Vis. Sci., 2011, 52(6), 3074-3082. Tomalka, J.; Ganesan, S.; Azodi, E.; Patel, K.; Majmudar, P.; Hall, B. A.; Fitzgerald, K. A.; Hise, A. G. A novel role for the NLRC4 inflammasome in mucosal defenses against the fungal pathogen Candida albicans. PLoS Pathog., 2011, 7(12), e1002379. Lebeer, S.; Claes, I. J.; Verhoeven, T. L.; Vanderleyden, J.; De Keersmaecker, S. C. Exopolysaccharides of Lactobacillus rhamnosus GG form a protective shield against innate immune factors in the intestine. Microb. Biotechnol., 2011, 4(3), 368-374. Alegado, R. A.; Chin, C. Y.; Monack, D. M.; Tan, M. W. The twocomponent sensor kinase KdpD is required for Salmonella typhimurium colonization of Caenorhabditis elegans and survival in macrophages. Cell Microbiol., 2011, 13(10), 1618-1637. Glittenberg, M. T.; Kounatidis, I.; Christensen, D.; Kostov, M.; Kimber, S.; Roberts, I.; Ligoxygakis, P. Pathogen and host factors are needed to provoke a systemic host response to gastrointestinal infection of Drosophila larvae by Candida albicans. Dis. Model. Mech., 2011, 4(4), 515-525. Velden, W. J.; van Iersel, T. M.; Blijlevens, N. M.; Donnelly, J. P. Safety and tolerability of the antimicrobial peptide human lactoferrin 1-11 (hLF1-11). BMC. Med., 2009, 7, 44. Hilpert, K.; Fjell, C. D.; Cherkasov, A. Short linear cationic antimicrobial peptides: screening, optimizing, and prediction. Methods Mol. Biol., 2008, 494, 127-159. Fjell, C. D.; Hiss, J. A.; Hancock, R. E.; Schneider, G. Designing antimicrobial peptides: form follows function. Nat. Rev. Drug. Discov., 2011, 11, 37-51. Brandelli, A. Nanostructures as promising tools for delivery of antimicrobial peptides. Mini Rev. Med. Chem., 2012, 12, 731-741. Seil, J. T.; Webster, T. J. Antimicrobial applications of nanotechnology: methods and literature. Int. J. Nanomedicine, 2012, 7, 2767-2781. Wang, M. D.; Shin, D. M.; Simons, J. W.; Nie, S. Nanotechnology for targeted cancer therapy. Expert. Rev. Anticancer Ther., 2007, 7(6), 833-837. Kingsley, J. D.; Dou, H.; Morehead, J.; Rabinow, B.; Gendelman, H. E.; Destache, C. J. Nanotechnology: a focus on nanoparticles as a drug delivery system. J. Neuroimmune Pharmacol., 2006, 1(3), 340-350. Urban, P.; Valle-Delgado, J. J.; Moles, E.; Marques, J.; Diez, C.; Fernandez-Busquets, X. Nanotools for the delivery of antimicrobial peptides. Curr. Drug Targets, 2012, 13, 1158-1172. Costa, F.; Carvalho, I. F.; Montelaro, R. C.; Gomes, P.; Martins, M. C. Covalent immobilization of antimicrobial peptides (AMPs) onto biomaterial surfaces. Acta Biomater., 2011, 7(4), 1431-1440. Horak, D.; Babic, M.; Mackova, H.; Benes, M. J. Preparation and properties of magnetic nano- and microsized particles for biological


[95]

[96]

[97] [98] [99] [100] [101] [102]

[103]

[104] [105]

[106]

[107] [108]

[109]

[110]

[111]

[112]

[113]

and environmental separations. J. Sep. Sci., 2007, 30(11), 17511772. Mahmoudi, M.; Stroeve, P.; Milani, A. S.; Arbab, S. A. Superparamagnetic iron oxide nanoparticles: synthesis, surface engineering, cytotoxicity and biomedical applications; Nova Science Publisher: New York, 2011. Salaklang, J.; Steitz, B.; Finka, A.; O'Neil, C. P.; Moniatte, M.; van, d. V.; Giorgio, T. D.; Hofmann, H.; Hubbell, J. A.; Petri-Fink, A. Superparamagnetic nanoparticles as a powerful systems biology characterization tool in the physiological context. Angew. Chem. Int. Ed. Engl., 2008, 47(41), 7857-7860. Xu, W.; Kattel, K.; Park, J. Y.; Chang, Y.; Kim, T. J.; Lee, G. H. Paramagnetic nanoparticle T1 and T2 MRI contrast agents. Phys. Chem. Chem. Phys., 2012, 14(37), 12687-12700. Laurent, S.; Dutz, S.; Hafeli, U. O.; Mahmoudi, M. Magnetic fluid hyperthermia: focus on superparamagnetic iron oxide nanoparticles. Adv. Colloid Interface Sci., 2011, 166(1-2), 8-23. Taira, S.; Moritake, S.; Hatanaka, T.; Ichiyanagi, Y.; Setou, M. Functionalized magnetic nanoparticles as an in vivo delivery system. Methods Mol. Biol., 2009, 544, 571-587. Laurentt, N.; Sapet, C.; Le Gourrierec, L.; Bertosio, E.; Zelphati, O. Nucleic acid delivery using magnetic nanoparticles: the magnetofection technology. Ther. Deliv., 2011, 2(4), 471-482. Gu, H.; Xu, K.; Xu, C.; Xu, B. Biofunctional magnetic nanoparticles for protein separation and pathogen detection. Chem. Commun. (Camb.), 2006, (9), 941-949. Hadjipanayis, C. G.; Bonder, M. J.; Balakrishnan, S.; Wang, X.; Mao, H.; Hadjipanayis, G. C. Metallic iron nanoparticles for MRI contrast enhancement and local hyperthermia. Small, 2008, 4(11), 1925-1929. Lee, J. H.; Jang, J. T.; Choi, J. S.; Moon, S. H.; Noh, S. H.; Kim, J. W.; Kim, J. G.; Kim, I. S.; Park, K. I.; Cheon, J. Exchange-coupled magnetic nanoparticles for efficient heat induction. Nat. Nanotechnol., 2011, 6(7), 418-422. Arruebo, M.; Fernández-Pacheco, R.; Ibarra, M. R.; Santamaría, J. Magnetic nanoparticles for drug delivery. Nano. Today, 2007, 2(3), 22-32. Gupta, A. K.; Curtis, A. S. Surface modified superparamagnetic nanoparticles for drug delivery: interaction studies with human fibroblasts in culture. J. Mater. Sci. Mater. Med., 2004, 15(4), 493496. Wilhelm, C.; Billotey, C.; Roger, J.; Pons, J. N.; Bacri, J. C.; Gazeau, F. Intracellular uptake of anionic superparamagnetic nanoparticles as a function of their surface coating. Biomaterials, 2003, 24(6), 1001-1011. Berry, C. C.; Wells, S.; Charles, S.; Curtis, A. S. Dextran and albumin derivatised iron oxide nanoparticles: influence on fibroblasts in vitro. Biomaterials, 2003, 24(25), 4551-4557. de Freitas, E. R.; Soares, P. R.; Santos, R. P.; dos Santos, R. L.; da, S., Jr.; Porfirio, E. P.; Bao, S. N.; Lima, E. C.; Morais, P. C.; Guillo, L. A. In vitro biological activities of anionic gamma-Fe2O3 nanoparticles on human melanoma cells. J. Nanosci. Nanotechnol., 2008, 8(5), 2385-2391. Kim, J. S.; Yoon, T. J.; Yu, K. N.; Kim, B. G.; Park, S. J.; Kim, H. W.; Lee, K. H.; Park, S. B.; Lee, J. K.; Cho, M. H. Toxicity and tissue distribution of magnetic nanoparticles in mice. Toxicol. Sci., 2006, 89(1), 338-347. Dong, H.; Huang, J.; Koepsel, R. R.; Ye, P.; Russell, A. J.; Matyjaszewski, K. Recyclable antibacterial magnetic nanoparticles grafted with quaternized poly(2-(dimethylamino)ethyl methacrylate) brushes. Biomacromolecules, 2011, 12(4), 1305-1311. Dong, A.; Lan, S.; Huang, J.; Wang, T.; Zhao, T.; Xiao, L.; Wang, W.; Zheng, X.; Liu, F.; Gao, G.; Chen, Y. Modifying Fe3O4functionalized nanoparticles with N-halamine and their magnetic/antibacterial properties. ACS Appl. Mater. Interfaces, 2011, 3(11), 4228-4235. Zhang, W.; Shi, X.; Huang, J.; Zhang, Y.; Wu, Z.; Xian, Y. Bacitracin-conjugated superparamagnetic iron oxide nanoparticles: synthesis, characterization and antibacterial activity. Chem. Phys. Chem., 2012, 13(14), 3388-3396. Subbiahdoss, G.; Sharifi, S.; Grijpma, D. W.; Laurent, S.; van der Mei, H. C.; Mahmoudi, M.; Busscher, H. J. Magnetic targeting of surface-modified superparamagnetic iron oxide nanoparticles


[114] [115]

[116]

[117]

[118]

[119]

[120]

[121] [122] [123] [124]

[125]

[126]

[127]

[128]

[129]

[130]

yields antibacterial efficacy against biofilms of gentamicin-resistant staphylococci. Acta Biomater., 2012, 8(6), 2047-2055. Mahmoudi, M.; Serpooshan, V. Silver-coated engineered magnetic nanoparticles are promising for the success in the fight against antibacterial resistance threat. ACS Nano., 2012, 6(3), 2656-2664. Wang, L.; Luo, J.; Shan, S.; Crew, E.; Yin, J.; Zhong, C. J.; Wallek, B.; Wong, S. S. Bacterial inactivation using silver-coated magnetic nanoparticles as functional antimicrobial agents. Anal. Chem., 2011, 83(22), 8688-8695. Prucek, R.; Tucek, J.; Kilianova, M.; Panacek, A.; Kvitek, L.; Filip, J.; Kolar, M.; Tomankova, K.; Zboril, R. The targeted antibacterial and antifungal properties of magnetic nanocomposite of iron oxide and silver nanoparticles. Biomaterials, 2011, 32(21), 4704-4713. Inbaraj, B. S.; Kao, T. H.; Tsai, T. Y.; Chiu, C. P.; Kumar, R.; Chen, B. H. The synthesis and characterization of poly(gammaglutamic acid)-coated magnetite nanoparticles and their effects on antibacterial activity and cytotoxicity. Nanotechnology, 2011, 22(7), 075101. Bromberg, L.; Chang, E. P.; Hatton, T. A.; Concheiro, A.; Magarinos, B.; Varez-Lorenzo, C. Bactericidal core-shell paramagnetic nanoparticles functionalized with poly(hexamethylene biguanide). Langmuir, 2011, 27(1), 420-429. Bromberg, L.; Bromberg, D. J.; Hatton, T. A.; Bandin, I.; Concheiro, A.; varez-Lorenzo, C. Antiviral properties of polymeric aziridine- and biguanide-modified core-shell magnetic nanoparticles. Langmuir, 2012, 28(9), 4548-4558. Wang, S. Y.; Liu, M. C.; Kang, K. A. Magnetic nanoparticles and thermally responsive polymer for targeted hyperthermia and sustained anti-cancer drug delivery. Adv. Exp. Med. Biol., 2013, 765, 315-321. Xie, J.; Jon, S. Magnetic nanoparticle-based theranostics. Theranostics, 2012, 2, 122-124. Bonnemain, B. Superparamagnetic agents in magnetic resonance imaging: physicochemical characteristics and clinical applications. A review. J. Drug Target., 1998, 6(3), 167-174. Vithanarachchi, S. M.; Allen, M. J. Strategies for target-specific contrast agents for magnetic resonance imaging. Curr. Mol. Imaging, 2012, 1(1), 12-25. Papisov, M. I.; Bogdanov Jr, A.; Schaffer, B.; Nossiff, N.; Shen, T.; Weissleder, R.; Brady, T. J. Colloidal magnetic resonance contrast agents: effect of particle surface on biodistribution. J. Magn. Magn. Mater., 1993, 122(1-3), 383-386. Kimura, K.; Tanigawa, N.; Matsuki, M.; Nohara, T.; Iwamoto, M.; Sumiyoshi, K.; Tanaka, S.; Takahashi, Y.; Narumi, Y. Highresolution MR lymphography using ultrasmall superparamagnetic iron oxide (USPIO) in the evaluation of axillary lymph nodes in patients with early stage breast cancer: preliminary results. Breast Cancer, 2010, 17(4), 241-246. Koh, D. M.; George, C.; Temple, L.; Collins, D. J.; Toomey, P.; Raja, A.; Bett, N.; Farhat, S.; Husband, J. E.; Brown, G. Diagnostic accuracy of nodal enhancement pattern of rectal cancer at MRI enhanced with ultrasmall superparamagnetic iron oxide: findings in pathologically matched mesorectal lymph nodes. AJR Am. J. Roentgenol., 2010, 194(6), W505-W513. Yoo, M. K.; Park, I. K.; Lim, H. T.; Lee, S. J.; Jiang, H. L.; Kim, Y. K.; Choi, Y. J.; Cho, M. H.; Cho, C. S. Folate-PEGsuperparamagnetic iron oxide nanoparticles for lung cancer imaging. Acta Biomater., 2012, 8(8), 3005-3013. Ma, Q.; Nakane, Y.; Mori, Y.; Hasegawa, M.; Yoshioka, Y.; Watanabe, T. M.; Gonda, K.; Ohuchi, N.; Jin, T. Multilayered, core/shell nanoprobes based on magnetic ferric oxide particles and quantum dots for multimodality imaging of breast cancer tumors. Biomaterials, 2012, 33(33), 8486-8494. Ghosh, D.; Lee, Y.; Thomas, S.; Kohli, A. G.; Yun, D. S.; Belcher, A. M.; Kelly, K. A. M13-templated magnetic nanoparticles for targeted in vivo imaging of prostate cancer. Nat. Nanotechnol., 2012, 7(10), 677-682. Trivedi, R. A.; Mallawarachi, C.; King-Im, J. M.; Graves, M. J.; Horsley, J.; Goddard, M. J.; Brown, A.; Wang, L.; Kirkpatrick, P. J.; Brown, J.; Gillard, J. H. Identifying inflamed carotid plaques using in vivo USPIO-enhanced MR imaging to label plaque macrophages. Arterioscler. Thromb. Vasc. Biol., 2006, 26(7), 1601-1606.

Magnetic Nanoparticles [131] [132]

[133]

[134]

[135] [136] [137] [138]

[139] [140] [141]

[142] [143]

[144]

[145]

[146]

[147] [148]

[149]

Sosnovik, D. E.; Nahrendorf, M.; Weissleder, R. Magnetic nanoparticles for MR imaging: agents, techniques and cardiovascular applications. Basic Res.Cardiol., 2008, 103(2), 122-130. Rausch, M.; Sauter, A.; Frohlich, J.; Neubacher, U.; Radu, E. W.; Rudin, M. Dynamic patterns of USPIO enhancement can be observed in macrophages after ischemic brain damage. Magn. Reson. Med., 2001, 46(5), 1018-1022. Gorelik, M.; Orukari, I.; Wang, J.; Galpoththawela, S.; Kim, H.; Levy, M.; Gilad, A. A.; Bar-Shir, A.; Kerr, D. A.; Levchenko, A.; Bulte, J. W.; Walczak, P. Use of MR cell tracking to evaluate targeting of glial precursor cells to inflammatory tissue by exploiting the very late antigen-4 docking receptor. Radiology, 2012, 265(1), 175-185. Kanno, S.; Lee, P. C.; Dodd, S. J.; Williams, M.; Griffith, B. P.; Ho, C. A novel approach with magnetic resonance imaging used for the detection of lung allograft rejection. J. Thorac. Cardiovasc. Surg., 2000, 120(5), 923-934. Latorre, M.; Rinaldi, C. Applications of magnetic nanoparticles in medicine: magnetic fluid hyperthermia. P. R. Health Sci. J., 2009, 28(3), 227-238. Kobayashi, T. Cancer hyperthermia using magnetic nanoparticles. Biotechnol. J., 2011, 6(11), 1342-1347. Ito, A.; Shinkai, M.; Honda, H.; Kobayashi, T. Medical application of functionalized magnetic nanoparticles. J. Biosci. Bioeng., 2005, 100(1), 1-11. Mehdaoui, B.; Meffre, A.; Carrey, J.; Lachaize, S.; Lacroix, L.-M.; Gougeon, M.; Chaudret, B.; Respaud, M. Optimal size of nanoparticles for magnetic hyperthermia: a combined theoretical and experimental study. Adv. Funct. Mater., 2011, 21(23), 4573-4581. Hergt, R.; Dutz, S.; Zeisberger, M. Validity limits of the Neel relaxation model of magnetic nanoparticles for hyperthermia. Nanotechnology, 2010, 21(1), 015706. Giustini, A. J.; Ivkov, R.; Hoopes, P. J. Magnetic nanoparticle biodistribution following intratumoral administration. Nanotechnology, 2011, 22(34), 345101. Levy, M.; Wilhelm, C.; Devaud, M.; Levitz, P.; Gazeau, F. How cellular processing of superparamagnetic nanoparticles affects their magnetic behavior and NMR relaxivity. Contrast Media Mol. Imaging., 2012, 7(4), 373-383. Fortin, J. P.; Gazeau, F.; Wilhelm, C. Intracellular heating of living cells through Neel relaxation of magnetic nanoparticles. Eur. Biophys. J., 2008, 37(2), 223-228. Dutz, S.; Kettering, M.; Hilger, I.; Muller, R.; Zeisberger, M. Magnetic multicore nanoparticles for hyperthermia--influence of particle immobilization in tumour tissue on magnetic properties. Nanotechnology, 2011, 22(26), 265102. Zhao, Q.; Wang, L.; Cheng, R.; Mao, L.; Arnold, R. D.; Howerth, E. W.; Chen, Z. G.; Platt, S. Magnetic nanoparticle-based hyperthermia for head & neck cancer in mouse models. Theranostics, 2012, 2, 113-121. Yan, S.; Zhang, D.; Gu, N.; Zheng, J.; Ding, A.; Wang, Z.; Xing, B.; Ma, M.; Zhang, Y. Therapeutic effect of Fe2O3 nanoparticles combined with magnetic fluid hyperthermia on cultured liver cancer cells and xenograft liver cancers. J. Nanosci. Nanotechnol., 2005, 5(8), 1185-1192. Balivada, S.; Rachakatla, R. S.; Wang, H.; Samarakoon, T. N.; Dani, R. K.; Pyle, M.; Kroh, F. O.; Walker, B.; Leaym, X.; Koper, O. B.; Tamura, M.; Chikan, V.; Bossmann, S. H.; Troyer, D. L. A/C magnetic hyperthermia of melanoma mediated by iron(0)/iron oxide core/shell magnetic nanoparticles: a mouse study. BMC. Cancer, 2010, 10, 119. Kannagi, R. Molecular mechanism for cancer-associated induction of sialyl Lewis X and sialyl Lewis A expression—The Warburg effect revisited. Glycoconj. J., 2003, 20(5), 353-364. Rachakatla, R. S.; Balivada, S.; Seo, G. M.; Myers, C. B.; Wang, H.; Samarakoon, T. N.; Dani, R.; Pyle, M.; Kroh, F. O.; Walker, B.; Leaym, X.; Koper, O. B.; Chikan, V.; Bossmann, S. H.; Tamura, M.; Troyer, D. L. Attenuation of mouse melanoma by A/C magnetic field after delivery of bi-magnetic nanoparticles by neural progenitor cells. ACS Nano., 2010, 4(12), 7093-7104. Basel, M. T.; Balivada, S.; Wang, H.; Shrestha, T. B.; Seo, G. M.; Pyle, M.; Abayaweera, G.; Dani, R.; Koper, O. B.; Tamura, M.; Chikan, V.; Bossmann, S. H.; Troyer, D. L. Cell-delivered magnetic nanoparticles caused hyperthermia-mediated increased sur-


[150]

[151]

[152] [153]

[154]

[155]

[156]

[157]

[158]

[159]

[160] [161]

[162]

[163]

[164]

[165]

605

vival in a murine pancreatic cancer model. Int. J. Nanomed., 2012, 7, 297-306. Johannsen, M.; Gneveckow, U.; Thiesen, B.; Taymoorian, K.; Cho, C. H.; Waldofner, N.; Scholz, R.; Jordan, A.; Loening, S. A.; Wust, P. Thermotherapy of prostate cancer using magnetic nanoparticles: feasibility, imaging, and three-dimensional temperature distribution. Eur. Urol., 2007, 52(6), 1653-1661. Johannsen, M.; Gneveckow, U.; Taymoorian, K.; Thiesen, B.; Waldofner, N.; Scholz, R.; Jung, K.; Jordan, A.; Wust, P.; Loening, S. A. Morbidity and quality of life during thermotherapy using magnetic nanoparticles in locally recurrent prostate cancer: results of a prospective phase I trial. Int. J. Hyperthermia, 2007, 23(3), 315-323. Johannsen, M.; Thiesen, B.; Wust, P.; Jordan, A. Magnetic nanoparticle hyperthermia for prostate cancer. Int. J. Hyperthermia, 2010, 26(8), 790-795. Ito, A.; Shinkai, M.; Honda, H.; Yoshikawa, K.; Saga, S.; Wakabayashi, T.; Yoshida, J.; Kobayashi, T. Heat shock protein 70 expression induces antitumor immunity during intracellular hyperthermia using magnetite nanoparticles. Cancer Immunol. Immunother., 2003, 52(2), 80-88. Sato, A.; Tamura, Y.; Sato, N.; Yamashita, T.; Takada, T.; Sato, M.; Osai, Y.; Okura, M.; Ono, I.; Ito, A.; Honda, H.; Wakamatsu, K.; Ito, S.; Jimbow, K. Melanoma-targeted chemo-thermo-immuno (CTI)-therapy using N-propionyl-4-S-cysteaminylphenol-magnetite nanoparticles elicits CTL response via heat shock protein-peptide complex release. Cancer Sci., 2010, 101(9), 1939-1946. More, S. H.; Breloer, M.; von Bonin, A. Eukaryotic heat shock proteins as molecular links in innate and adaptive immune responses: Hsp60-mediated activation of cytotoxic T cells. Int. Immunol., 2001, 13(9), 1121-1127. Basta, S.; Stoessel, R.; Basler, M.; van den, B. M.; Groettrup, M. Cross-presentation of the long-lived lymphocytic choriomeningitis virus nucleoprotein does not require neosynthesis and is enhanced via heat shock proteins. J. Immunol., 2005, 175(2), 796-805. Breloer, M.; Dorner, B.; More, S. H.; Roderian, T.; Fleischer, B.; von Bonin, A. Heat shock proteins as "danger signals": eukaryotic Hsp60 enhances and accelerates antigen-specific IFN-g production in T cells. Eur. J. Immunol., 2001, 31, 2051-2059. Asea, A.; Kraeft, S. K.; Kurt-Jones, E. A.; Stevenson, M. A.; Chen, L. B.; Finberg, R. W.; Koo, G. C.; Calderwood, S. K. HSP70 stimulates cytokine production through a CD14-dependant pathway, demonstrating its dual role as a chaperone and cytokine. Nat. Med., 2000, 6(4), 435-442. Matera, L.; Forno, S.; Galetto, A.; Moro, F.; Garetto, S.; Mussa, A. Increased expression of HSP70 by colon cancer cells is not always associated with access to the dendritic cell cross-presentation pathway. Cell Mol. Biol. Lett., 2007, 12(2), 268-279. Rock, K. L.; Shen, L. Cross-presentation: underlying mechanisms and role in immune surveillance. Immunol. Rev., 2005, 207, 166183. Tanaka, K.; Ito, A.; Kobayashi, T.; Kawamura, T.; Shimada, S.; Matsumoto, K.; Saida, T.; Honda, H. Heat immunotherapy using magnetic nanoparticles and dendritic cells for T-lymphoma. J. Biosci. Bioeng., 2005, 100(1), 112-115. Nowak, A. K.; Lake, R. A.; Marzo, A. L.; Scott, B.; Heath, W. R.; Collins, E. J.; Frelinger, J. A.; Robinson, B. W. Induction of tumor cell apoptosis in vivo increases tumor antigen cross-presentation, cross-priming rather than cross-tolerizing host tumor-specific CD8 T cells. J. Immunol., 2003, 170(10), 4905-4913. Selenko, N.; Majdic, O.; Jager, U.; Sillaber, C.; Stockl, J.; Knapp, W. Cross-priming of cytotoxic T cells promoted by apoptosisinducing tumor cell reactive antibodies? J. Clin. Immunol., 2002, 22(3), 124-130. Xi, S. B.; Lu, W. J.; Wu, H. Y.; Tong, P.; Sun, Y. P. Surface spinglass, large surface anisotropy, and depression of magnetocaloric effect in La(0.8)Ca(0.2)MnO(3) nanoparticles. J. Appl. Phys., 2012, 112(12), 123903. Ito, A.; Tanaka, K.; Kondo, K.; Shinkai, M.; Honda, H.; Matsumoto, K.; Saida, T.; Kobayashi, T. Tumor regression by combined immunotherapy and hyperthermia using magnetic nanoparticles in an experimental subcutaneous murine melanoma. Cancer Sci., 2003, 94(3), 308-313.

606 Current Protein and Peptide Science, 2013, Vol. 14, No. 7 [166] [167]

Lai, Y.; Gallo, R. L. AMPed up immunity: how antimicrobial peptides have multiple roles in immune defense. Trends. Immunol., 2009, 30(3), 131-141. Yang, D.; Chen, Q.; Chertov, O.; Oppenheim, J. J. Human neutrophil defensins selectively chemoattract naive T and immature dendritic cells. J. Leukoc. Biol., 2000, 68(1), 9-14.

Received: December 24, 2012

Revised: February 28, 2013

Accepted: March 01, 2013

López-Abarrategui et al. [168] [169]

Yang, D.; Oppenheim, J. J. Antimicrobial proteins act as "Alarmins" in joint immune defense. Arthritisrheum, 2004, 50(11), 3401-3403. Davidson, D. J.; Currie, A. J.; Reid, G. S.; Bowdish, D. M.; MacDonald, K. L.; Ma, R. C.; Hancock, R. E.; Speert, D. P. The cationic antimicrobial peptide LL-37 modulates dendritic cell differentiation and dendritic cell-induced T cell polarization. J. Immunol., 2004, 172(2), 1146-1156.