ABSTRACT
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.
ABSTRACT
<p><b>OBJECTIVE</b>To explore the dynamic changes of transforming growth factor-α (TGF-α) and transforming growth factor-β1 (TGF-β1) of liver cirrhosis induced by multiple pathogenic factors in rats.</p><p><b>METHODS</b>Animals in the cirrhosis group were fed a mixture of maize flour, lard, cholesterol and alcohol plus subcutaneously injection with carbon tetrachloride (CCl₄), the CCl₄(0.5 ml/100 g · w) was injected at the first day of experiment and the 40% CCl₄oil solution (0.3 ml /100 g · w) was injected at an interval of three days. The thirty-six male SD rats were randomly divided into liver cirrhosis group of the 4th, 6th and 8 th week, and normal control group of the 4th, 6th and 8th week. The contents of alanine transferase (ALT), endotoxin, tumor necrosis factor-α (TNF-α) and homocysteine (Hcy) in plasma were evaluated. Histopathological changes of the liver were observed under microscope with the staining of HE. The expressions of TGF-α and TGF-β1 were analyzed by the method of immunohistochemistry.</p><p><b>RESULTS</b>Compared with the corresponding normal control group, the levels of ALT, endotoxin, TNF-α and Hcy in plasma were gradually significantly increased in liver cirrhosis group of the 4th, 6th and 8th week (P < 0.05); the expression of TGF-α in the liver tissues was significantly increased at the 4th week (P < 0.05); the expression of TGF-β1 in the liver tissues was gradually significantly increased in every model group (P < 0.05).</p><p><b>CONCLUSION</b>In the formation process of cirrhosis, the expression of TGF-α was increased in liver of cirrhosis group at the 4th week, and later it was suppressed; the expression of TGF-β1 was continuously increased. The characteristic dynamic changes of TGF-α and TGF-β1 might be related to sustained endotoxemia, the high level of TNF-α and hyperhomocysteinemia.</p>