Abstract: Objective To investigate the effect of isoflurane on malignant phenotype and chemotherapy sensitivity of bladder cancer cell line 5637. Methods The 5637 bladder cancer cells were divided into groups as follows: control group, isoflurane group, cisplatin group and isoflurane + cisplatin group. The number of BrdU positive cells was determined by BrdU staining. The cell apoptosis and cell cycle were measured by flow cytometry. The number of invasive cells were measured by transwell assay. The scratch healing rate was measured by wound healing experiment. The expression levels of Ki67, PCNA, Bax, Bcl-2, cleaved caspase-3 and caspase-3 proteins were detected by Western blotting. Results The number of BrdU positive cells, the expression levels of Ki67 and PCNA proteins, the G0 / G1 phase ratio, the number of S phase cells were decreased significantly in the isoflurane + cisplatin group compared to the cisplatin group, while the G2 / M phase ratio was increased significantly (P< 0. 05). The number of invasive cells and the scratch healing rate were decreased significantly in the isoflurane + cisplatin group when compared to the cisplatin group (P < 0. 05). The apoptosis rate, the Bax / Bcl-2 ratio, and the cleaved caspase-3 / caspase-3 ratio were increased significantly in the isoflurane + cisplatin group compared to the cisplatin group (P< 0. 05). Conclusion Isoflurane can induce apoptosis by inhibiting cell proliferation, invasion and migration, and enhance the sensitivity of 5637 cells to cisplatin. 

Key words: bladder cancer, isoflurane, cisplatin, chemotherapeutic sensitivity