ABSTRACT
Objective: To investigate the effects of octamer-binding transcription factor 4 pseudogene 5 (OCT4-pg5) and octamer-binding transcription factor 4B (OCT4B) expression on cisplatin sensitivity of bladder cancer T24 cells. Methods: The expression of OCT4-pg5 and OCT4B in bladder cancer cells and tissues were quantified by real-time quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR). To examine the effect of OCT4-pg5 and OCT4B on cisplatin sensitivity, cells were transfected with OCT4-pg5 si-RNA, OCT4B si-RNA and their control si-RNA by lipofectamine 2000 followed by a 48 h cisplatin treatment. CCK8 was used to assess the half-maximal inhibitory concentration (IC50) of cisplatin in T24 cells. OCT4-pg5 and OCT4B expression were detected by RT-qPCR or Western blot. Next, flow cytometry was used to examine the effects of OCT4-pg5 and OCT4B on T24 cells apoptosis and cell-cycle distribution. Results: RT-qPCR results showed that OCT4-pg5 and OCT4B were highly expressed in bladder cancer cells and tissues. Moreover, OCT4-pg5 expression was positively correlated with OCT4B expression in 23 bladder cancer tissues. Cells transfected with OCT4-pg5 si-RNA or OCT4B si-RNA showed a much lower IC50 of cisplatin, compared with cells in the control group. RT-qPCR or Western blot results showed OCT4-pg5 or OCT4B expression was significantly down-regulated after being transfected with OCT4-pg5 si-RNA or OCT4B si-RNA in cisplatin treated T24 cells. The flow cytometry results showed that OCT4-pg5 suppression or OCT4B suppression of cisplatin treated T24 cells resulted in a significant increase of cell apoptosis and marked the transition from the S phase to G0/G1 phase. Conclusions Downregulating OCT4-pg5 and OCT4B could enhance the sensitivity of bladder cancer T24 cells to cisplatin.