AB153. Down-regulated expression of excision of repair cross-complementing gene 1 reduces resistance to hydroxycamptothecine in bladder cancer

OBJECTIVE: The purpose of the study was to explore the potential mechanisms that interference of excision of repair cross-complementing gene 1 (ERCC1) mediated by lentiviral vector in bladder cancer T24 Cells. METHODS: the expression of ERCC1 was observed by immunohistochemical method in 25 cases of primary bladder cancer and recurrent bladder cancer tissues respectively from 25 patients. T24 cells were silenced targeting ERCC1 by lentiviruses .The transfection efficiency for ERCC1 was observed by fluorescence microscope and the interference efficiency was detected by real-time polymerase clain reaction and western blot assay. CCK-8 assay was used to assess the cell proliferation. Effects of cell apoptosis were detected by flow cytometry. Finally, the pathway of apoptosis was studied by using western blot method. RESULTS: As a result, we discovered that the expression level of ERCC1 in recurrent bladder cancer tissues (52%) was significantly higher than that in primary bladder cancer tissues (20%) (P<0.05). Compared with the T24 cells that did not silence the ERCC1 gene (control group) at different time periods (29.45%, 36.48%, 38.45%, 40.35%), the proliferation of T24 cells that silenced ERCC1 gene (experimental group) (27.25%, 37.45%, 32.5%, 42.05%) was not significantly changed (P>0.05). Hydroxycamptothecine (HCPT) inhibited the proliferation of T24 cells in dosage and time dependent manner. The inhibitory effect of HCPT on the experimental group was significantly higher than that of the control group (P<0.05).With the HCPT concentration increased, the apoptosis rate of the experimental group was significantly higher than that of the control group (P<0.05). After silencing of ERCC1, the sensitivity of T24 cells was increased to HCPT which could inhibit cell proliferation and induce cell apoptosis. CONCLUSIONS: Therefore, ERCC1 may be a potential target protein used to guide the postoperative chemotherapy of bladder cancer.