Effect of cisplatin and paclitaxel on the cytotoxicity of cytokine-in-duced killer cells on esophagus carcinoma and its molecular mecha-nisms / 中国肿瘤临床

ABSTRACT

Objective:To explore the effect of paclitaxel (PTX) and cisplatin (DDP) on the expression of NKG2D ligands of hu-man esophagus carcinoma cell EC9706 and on the cytotoxicity of cytokine-induced killer (CIK) cells, as well as to discuss its molecu-lar mechanisms. Methods: The half maximal inhibitory concentration (IC50) values of PTX and DDP against EC9706 cells for 24 h were measured by MTT assay. The expression levels of NKG2D ligands (MICA, MICB, ULBP1, ULBP2, and ULBP3) on the EC9706 cell surface before and after 24 h culture with 1/2 IC50 of PTX or DDP were assayed by flow cytometry. Cytotoxicity of CIK cells against EC9706 cells before and after 24 h culture with 1/2 IC50 PTX or DDP was analyzed by lactate dehydrogenase release assay at an effector to target cell ratio (ET) of 201 and 301, respectively. The expression levels of DNA damage repair genes (ATM, ATR, CHK1, CHK2, and p53) of EC9706 cells before and after 24 h incubation with 1/2 IC50 PTX or DDP were detected by quantitative fluorescent PCR. Results:The IC50 values of PTX and DDP were 10 and 5μg/mL, respectively. MICB, ULBP2, and ULBP3 on EC9706 cells were upregulated after 24 h culture with 1/2 IC50 PTX (P0.05), whereas ATM, ATR, CHK1, and CHK2 were over-expressed after 24 h treatment with 1/2 IC50 DDP (P<0.05). Conclusion:PTX or DDP can enhance the susceptibility of EC9706 cells to CIK cell-mediated lysis by upregulating the expression of NKG2D ligands through activating DNA damage repair genes.