factor receptor (EGFR) mutated cells (PC9 and HCC827) were co-cultured with macrophage and then treated with TKI (Erlotinib and Gefitinib). PC9 and ...
P05-47
Subodh Sharma1, Soo Jin Kim1, Taehee Kim1, Yong Hwan Kim2, 1 1 2 1* Ji Yeong Mun , Han Na Choi , Min Woong Kang , Sang Do Lee Department of Physiology1, Department of thoracic surgery2, Chungnam National University School of Medicine, Daejeon, 301-747, Korea
ABSTRACT It is well known that tumor-associated macrophages (TAMs), which are abundant in the microenvironment of several tumors, including non-small-cell lung cancer (NSCLC), secrete pro-tumorigenic factors that contribute to cancer progression. However, there is no evidence indicating the involvement of macrophage in inducing drug resistance in case of lung cancer. To see the effect of macrophage in induction of resistance to tyrosine kinase inhibitors (TKI), epidermal growth factor receptor (EGFR) mutated cells (PC9 and HCC827) were co-cultured with macrophage and then treated with TKI (Erlotinib and Gefitinib). PC9 and HCC827 cells co-cultured with macrophage were much more resistant to erlotinib and gefitinib than those cultured alone. Macrophage can induce cancer cells to enhance migration and invasion via secretion of soluble factors. Therefore we prepared THP-1 cells derived macrophage conditioned medium (CM), and then treated to the PC9 cells. Enhanced migration and invasion of PC9 cells were confirmed upon induction with macrophage CM. Gefitinib induced apoptosis, DNA fragmentation, and cleaved of apoptotic protein PARP and caspase-3 were markedly reduced in macrophage CM treated PC9 cells. U937 cells derived macrophage CM also showed inducibility of gefitinib resistance. Whereas, THP-1 and U937 derived monocyte CM had no effect on gefitinib resistance indicating these induction of gefitinib resistance is specific to soluble factors secreted from macrophage. From these results, we can conclude that soluble factors secreted from macrophage induce EGFR TKIs resistance as well as migration and invasion in EGFR mutated NSCLC cells.
INTRODUCTION The epidermal growth factor receptor (EGFR) mutation is one of the important and prevalent kinds of mutation in non-small-cell lung cancer (NSCLC) cells. In case of NSCLC, most of the EGFR-mutant lung cancers are extremely sensitive to tyrosine kinase inhibitors (TKI) such as gefitinib and erlotinib. Although the majority of sensitive EGFRmutant lung cancer patients initially show a good clinical response, drug resistance invariably occurs and the disease progresses, which leads to acquired resistance. There are several comprehensive reviews about the role of tumor associated macrophages (TAMs) in cancer progression such as migration, invasion, survival, and angiogenesis. Despite lots of improvements in understanding of macrophage induced pathophysiological mechanisms leading to tumor progression, little reports have been made in macrophage mediated anti-cancer drug resistance. Therefore we investigated that macrophage induces resistance against anti-cancer drug, EGFR TKI as well as migration and invasion of cancer cells through the secretion of soluble factors.
RESULTS • Co-culture of EGFR mutated cells with macrophage reduced growth inhibitory action of tyrosine kinase inhibitors Figure 1. Induction of TKI resistance
A
B
on EGFR mutated cells co-cultured with macrophage EGFR mutated PC9 (A) and HCC827 (B) cells were co-cultured with macrophage. Co-cultured EGFR mutated cells were then treated with TKIs (100 nM) for 72 hours. Viable cells were measured using MTT assay and compared with corresponding control. Data represent mean ± SEM of three independent experiments, *** P
