瘦素诱导乳腺癌细胞的凋亡抵抗及其分子机制

目的 观察瘦素对乳腺癌细胞凋亡的影响,并探讨其分子机制.方法 采用TransAM酶联免疫吸附法(ELISA)检测瘦素对乳腺癌细胞T47D凋亡的影响,采用四甲基偶氮唑蓝(MTT)法检测细胞毒性,并测定T47D细胞caspase-9的活性.采用实时荧光定量逆转录聚合酶链反应(RT-PCR)和Western blot法测定瘦素对T47D细胞survivin mBNA和蛋白表达水平的影响.采用BNA干扰技术沉默信号转导和转录激活因子3(STAT3)基因,并采用实时荧光定量逆转录聚合酶链反应(RT-PCR)和Westem blot法测定瘦素对沉默STAT3基因后T47D细胞survivin mRNA和蛋白表达水平的影响.结果 瘦素可以促进人乳腺癌细胞T47D的增殖,增殖抑制率为63.6%;减少多西他赛诱导的细胞凋亡,达31.9%.不同浓度瘦素均可促进T47D细胞survivin mRNA的表达,其中以10 nmol/L时作用最明显.10 nmol/L瘦素作用60 min后,T47D细胞中survivin mRNA的表达量是瘦素作用前的4.6倍;作用2 h后,T47D细胞中survivin蛋白的表达增强.将STAT3小干扰RNA(siRNA)转入T47D细胞30 min后,survivin mRNA表达的变化倍率为0.55±0.15.经瘦素处理后,STAT3 siRNA质粒转染组和空质粒对照组survivin mRNA表达的变化倍率分别为0.56±0.18和1.61±0.22.将STAT3 siRNA转入T47D细胞后,survivin蛋白表达下降.经瘦素处理后,转染空质粒的细胞survivin蛋白的表达增加,而转入STAT3 siRNA的细胞survivin蛋白无明显变化.结论 在乳腺癌T47D细胞中,瘦素/STAT3信号通路是上调survivin表达的有效途径.

Apoptosis resistance induced by leptin and its mechanism in breast cancer cells

Objective To explore the apoptosis resistance induced by Leptin and its mechanism in breast cancer cells in vitro.Methods The leptin-mediated reduction of docetaxel-induced apoptosis in human breast cancer T47D cells was evaluated by TransAM ELISA,MTT and caspase-9 assay.The leptinpromoted survivin expression was analyzed by Western-blot and RT-PCR.The reversing effect of STAT3 knockdown on leptin-induced survivin upregulation was measured by Western-blot and RT-PCR.Results Leptin promoted T47D cells proliferation and the inhibitory rate was-63.6%.It reduced docetaxel-induced apoptosis in T47D cells by 31.9%.Leptin at different concentrations promoted survivin protein and mRNA expression in T47D cells.The expression of survivin mRNA was 4.6 fold compared with the T47D cells not treated with leptin(10 nmol/L).The expression of survivin mRNA in T47D cells was 0.55±0.15 fold after transfected with small interfering RNA(siRNA)of STAT3.The expression of survivin mRNA in STAT3 siRNA group and mock transfected group were 0.56±0.18 fold and 1.61±0.22 fold after treated by leptin,respectively.The survivin protein level of T47D mock transfected cells was increased after treated by leptin,but the protein level of T47D transfected with STAT3 siRNA cells were not changed significantly.Conclusion Leptin/STAT3 signaling is a novel pathway for up-regulation of survivin expression in breast cancer cells.