Changxuan You1, Yu Yang2, Beili Gao3. 1. Oncology Department/ Overseas Patient Center, Nanfang Hospital, Southern Medical University, Guangzhou, China. 2. Department of Oncology, the Second Affiliated Hospital of Harbin Medical University, Harbin Medical University, Harbin, China. 3. Department of Respiration, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
Abstract
BACKGROUND/AIMS: CD133+ cancer cells display low sensitivity to anti-cancer treatment; thus, combination treatment with adjuvant drugs is required to improve the efficiency of cancer therapy. The aim of this study was to explore the effect of imperatorin, a linear furanocoumarin compound, on γδ T cell-mediated cytotoxicity against CD133+ lung cancer cells. METHODS: CD133+ and CD133- subgroups from A549 and PC9 lung cancer cells were sorted by using flow cytometry. The cytotoxicity of γδ T cells against cancer cells was evaluated by measuring lactate dehydrogenase release. The concentration of tumor necrosis factor-related apoptosis-inducing ligand in the co-culture system was determined by using an enzyme-linked immunosorbent assay. Mitochondrial membrane potential, expression of death receptor 4 (DR4) and DR5 on the cell surface, and rate of apoptosis were measured by flow cytometry. Cytochrome c release and cellular protein expression were detected by western blot analysis. RESULTS: Compared with CD133- cells, CD133+ cells were resistant to γδ T cell-mediated cytotoxicity. However, imperatorin significantly increased the sensitivity of CD133+ lung cancer cells to γδ T cell treatment in vitro and in vivo. Mechanically, we found that myeloid cell leukemia 1 (MCL-1), an important anti-apoptotic protein belonging to the Bcl-2 family, was overexpressed in CD133+ A549 and PC9 cells compared to their corresponding CD133- cells. Co-treatment with imperatorin and γδ T cells suppressed the expression of MCL-1, and thus promoted the mitochondrial apoptosis mediated by γδ T cells in CD133+ A549 and PC9 lung cancer cells. CONCLUSION: Up-regulated MCL-1 in CD133+ lung cancer cells is responsible for their resistance to γδ T cells. Furthermore, the combination of γδ T cells with imperatorin sensitized CD133+ lung cancer cells to γδ T cell-mediated cytotoxicity by targeting MCL-1.
BACKGROUND/AIMS: CD133+ cancer cells display low sensitivity to anti-cancer treatment; thus, combination treatment with adjuvant drugs is required to improve the efficiency of cancer therapy. The aim of this study was to explore the effect of imperatorin, a linear furanocoumarin compound, on γδ T cell-mediated cytotoxicity against CD133+ lung cancer cells. METHODS:CD133+ and CD133- subgroups from A549 and PC9 lung cancer cells were sorted by using flow cytometry. The cytotoxicity of γδ T cells against cancer cells was evaluated by measuring lactate dehydrogenase release. The concentration of tumor necrosis factor-related apoptosis-inducing ligand in the co-culture system was determined by using an enzyme-linked immunosorbent assay. Mitochondrial membrane potential, expression of death receptor 4 (DR4) and DR5 on the cell surface, and rate of apoptosis were measured by flow cytometry. Cytochrome c release and cellular protein expression were detected by western blot analysis. RESULTS: Compared with CD133- cells, CD133+ cells were resistant to γδ T cell-mediated cytotoxicity. However, imperatorin significantly increased the sensitivity of CD133+ lung cancer cells to γδ T cell treatment in vitro and in vivo. Mechanically, we found that myeloid cell leukemia 1 (MCL-1), an important anti-apoptotic protein belonging to the Bcl-2 family, was overexpressed in CD133+ A549 and PC9 cells compared to their corresponding CD133- cells. Co-treatment with imperatorin and γδ T cells suppressed the expression of MCL-1, and thus promoted the mitochondrial apoptosis mediated by γδ T cells in CD133+ A549 and PC9 lung cancer cells. CONCLUSION: Up-regulated MCL-1 in CD133+ lung cancer cells is responsible for their resistance to γδ T cells. Furthermore, the combination of γδ T cells with imperatorin sensitized CD133+ lung cancer cells to γδ T cell-mediated cytotoxicity by targeting MCL-1.