缺氧下神经生长因子受体p75在膀胱癌细胞中表达的变化及生物学特点
Effects of hypoxia on expression of nerve growth factor receptor p75 in human bladder carcinoma cells and its biological characteristics

目的:探讨缺氧条件下神经生长因子受体(p75 NGFR)在不同组织来源膀胱癌细胞株中表达的变化及生物学特性的变化。方法:选取不同膀胱癌组织来源的鳞癌细胞株SCaBER和中分化的移行细胞癌细胞株5637。采用免疫荧光细胞化学染色及RT-PCR检测常氧和缺氧24、48、72 h 2个膀胱癌细胞系中p75 NGFR蛋白和mRNA的表达情况,流式细胞术检测缺氧1、3、5、7 d膀胱癌细胞凋亡情况,MTT法检测丝裂霉素(MMC)处理24、48、72 h对缺氧条件下膀胱癌细胞的抑制率的影响。结果:p75 NGFR蛋白及mRNA表达在2个细胞系缺氧24、48 h有所下降,但与常氧组相比差异无统计学意义(P>0.05); 在72 h有显著降低,与其余各组相比差异有统计学意义(P<0.05)。膀胱癌SCaBER、5637细胞在缺氧第3天开始凋亡率低于常氧组(P<0.05); 缺氧48、72 h后MMC对膀胱癌细胞的抑制率低于常氧组(P<0.05)。结论:缺氧条件下,p75 NGFR在膀胱癌细胞的表达随时间逐渐降低,膀胱癌细胞的凋亡率降低,MMC对膀胱癌细胞的抑制率下降。
Aim: To explore the effects of hypoxia on the expression of nerve growth factor receptor p75(p75 NGFR)in human bladder carcinoma cells and its biological characteristics.Methods: The protein and mRNA expressions of p75 NGFR in 2 bladder carcinoma cell lines(SCaBER and 5637)which originated from different tissue were assessed by immunofluorescence staining and RT-PCR in the normoxic condition and in hypoxic condition(10% O2,5% CO2,85% N2). Flow cytometry was used to detect the apoptosis of bladder cancer cells under hypoxia. Inhibition of mitomycin(MMC)on bladder cancer cell growth under hypoxic conditions was assessed by MTT.Results: It was showed that under hypoxic con ditions for 24 h and 48 h, the positive rate of p75 NGFR expression in 2 cell lines(SCaBER and 5637)decreased, but had no significant difference compared with normoxia group. Hypoxia for 72 h markedly down-regulated the expression of p75 NGFR of 2 cell lines, when compared with normoxia group and hypoxia for 24 h and 48 h groups(P<0.05). The apoptosis rate of SCaBER and 5637 cells was significantly lower than that of normoxia group on the 3rd day after hypoxia(P<0.05).It was found that the inhibition rates of MMC on bladder cancer cells under hypoxia for 48 h and 72 h were lower than those in normoxia group(P<0.05).Conclusion: Hypoxia might inhibit expression of p75 NGFR in SCaBER and 5637 cells in a time-dependent manner. The apoptosis of bladder cancer cells is decreased, and the inhibitory rate of MMC on bladder cancer cells is decreased