摘要:
目的:探讨信号转导与转录活化因子3(STAT3)对恶性转化的肝卵圆细胞WB-F344的作用及其机制.方法:用N-甲基-N'-亚硝基胍(MNNG)和过氧化氢(H2O2)制备WB-F344肝卵圆细胞恶性转化模型,通过流式细胞术检测非整倍体细胞数量、Western blot检测甲胎蛋白(AFP)表达水平和软琼脂集落形成实验测定克隆形成率评价细胞的恶性转化,用葡萄糖氧化酶法检测细胞葡萄糖水平,用比色法检测细胞乳酸水平,用Western blot实验检测STAT3、p-STAT3和葡萄糖转运蛋白2(GLUT2)的蛋白水平,并通过WST-1法、活细胞计数法、流式细胞术测定细胞周期的S期细胞比例和增殖指数,以及Western blot检测增殖细胞核抗原(PCNA)表达水平来评价细胞增殖能力.结果:与对照组比较,转化的肝卵圆细胞克隆形成率增加(P<0.05),非整倍体细胞增多(P<0.01),AFP表达增强(P<0.05);葡萄糖消耗增多(P<0.05),乳酸产生增多(P<0.01); GLUT2表达上调(P<0.01),STAT3的活化增强(P<0.01);细胞活力增强(P<0.01),S期细胞比例增多(P<0.01),细胞增殖指数增加(P<0.01), PCNA表达上调(P<0.01).与模型组比较,STAT3的抑制剂stattic明显抑制恶性转化的肝卵圆细胞的克隆形成(P<0.01),促使非整倍体细胞显著减少(P<0.01)和AFP表达降低(P<0.05);减少葡萄糖消耗(P<0.05)和乳酸的产生(P<0.01);降低GLUT2(P<0.01)的表达水平;抑制恶性转化的肝卵圆细胞活力(P<0.05),降低S期细胞比例(P<0.01)、细胞增殖指数(P<0.01)和PCNA表达水平(P<0.05).结论:STAT3可能通过上调GLUT2表达而加快葡萄糖摄取、增强Warburg效应并促进细胞增殖,从而促进肝卵圆细胞的恶性转化.%AIM:To investigate the influence of signal transducer and activator of transcription 3(STAT3)on Warburg effect in the malignant transformation of WB-F344 rat hepatic oval cells.METHODS:The WB-F344 cells were treated with N-methyl-N'-nitro-N-nitrosoguanidine(MNNG)and hydrogen peroxide(H2O2)to induce the malignant trans-formation.Evaluation of the transformed cells were measured by the soft agar colony formation assay and DNA aneuploidy with flow cytometry.The levels of glucose and lactate in the culture medium of the cells were detected by chromatography. The protein levels of alpha-fetoprotein(AFP),STAT3,p-STAT3 and glucose transporter 2(GLUT2)in the cells were ex-amined by Western blot analysis.The cell proliferation were evaluated by WST-1 assay,viable cell counting,measuring the S-phase fraction(SPF)and proliferation index(PI)using the data from flow cytometry analysis,and detecting proliferating cell nuclear antigen(PCNA)protein expression by Western blot.RESULTS:Compared with the control cells,the forma-tion of colonies in soft agar(P<0.05)and DNA aneuploidy(P<0.01)were elevated in transformed cells,and the ex-pression level of AFP was also augmented(P<0.05).The increases in the level of both glucose consumption(P<0.05) and lactate production(P<0.01)show that Warburg effect was enhanced in transformed cells.Meanwhile, the protein levels of GLUT2(P<0.01)and p-STAT3(P<0.01)in transformed cells were higher than those in the control cells.The cell proliferation parameters including SPF(P<0.01),PI(P<0.01), viable cell number and PCNA expression(P<0.01)in transformed cells were also elevated as compared with the control cells.Interestingly, stattic, an inhibitor of STAT3 activation,resulted in declines in glucose consumption(P<0.05)and lactate production(P<0.01)in the trans-formed cells.In addition,compared with transformed cells,formation of colonies in soft agar(P<0.01),DNA aneuploidy (P<0.01),AFP(P<0.05), GLUT2(P<0.05), and cell proliferation parameters including SPF(P<0.01), PI (P<0.01),viable cell number(P<0.05)and PCNA expression(P<0.05)were also decreased following stattic treat-ment in transformed cells.CONCLUSION:STAT3 promotes Warburg effect and cell proliferation probably by upregula-ting GLUT2 expression in the malignant transformation of hepatic oval cells.