Mitochondrial carnitine palmitoyl transferase-Ⅱ inactivity aggravates lipid accumulation in rat hepatocarcinogenesis

AIM To investigate the dynamic alteration of mitochondrial carnitine palmitoyl transferase Ⅱ(CPT-Ⅱ) expression during malignant transformation of rat hepatocytes.METHODS Sprague-Dawley male rats were fed with normal, high fat(HF), and HF containing 2-fluorenylacetamide(2-FAA) diet, respectively. According to the Hematoxylin and Eosin staining of livers, rats were divided into control, fatty liver, degeneration, pre-cancerous, and cancerous groups. Liver lipids were dyed with Oil Red O, CPT-Ⅱ alterations were analyzed by immunohistochemistry, and compared with CPT-Ⅱ specific concentration(μg/mg protein). Levels of total cholesterol(Tch), triglyceride(TG), and aminotransferases [alanine aminotransferase(ALT), aspartate aminotransferase(AST)] were determined by the routine methods.RESULTS After intake of HF and/or HF+2-FAA diets, the rat livers showed mass lipid accumulation. The lipid level in the control group was significantly lower than that in other groups. The changes of serum TG and Tch levels were abnormally increasing, 2-3 times more than those in the controls(P < 0.05). During the rat liver morphological changes from normal to cancer development process with hepatocyte injury, serum AST and ALT levels were significantly higher(4-8 times, P < 0.05) than those in the control group. The specific concentration of CPT-Ⅱ in liver tissues progressively decreased during hepatocyte malignant transformation, with the lowest CPT-Ⅱ levels in the cancer group than in any of the other groups(P < 0.05).CONCLUSION Low CPT-Ⅱ expression might lead to abnormal hepatic lipid accumulation, which should promote the malignant transformation of hepatocytes.

Oncogenic Wnt3a expression as an estimable prognostic marker for hepatocellular carcinoma

AIM: To investigate member 3a of Wingless-type MMTV integration site family (Wnt3a) expression in cancerous and surrounding tissues and the relationship between clinicopathologic features of hepatocellular carcinoma (HCC) and Wnt3a expression.METHODS: Wnt3a expression and cellular distribution and clinicopathologic characteristics in cancerous tissue and matched surrounding tissues were analyzed in 80 HCC patients from January 2006 to August 2008 by tissue microarrays and immunohistochemistry. The overall and disease-free survival rates were estimated using the Kaplan-Meier method and compared with the log-rank test. The prognostic analysis was carried out with univariate and multivariate Cox regressions models.RESULTS: The incidence of oncogenic Wnt3a expression in the cancerous group was up to 96.25% (77 of 80), which was significantly higher (χ2 = 48.818, P < 0.001) than that in the surrounding group (46.25%, 37 of 80). Brown Wnt3a staining gradually increased with clinical staging that showed very strong staining in advanced HCC. The clinicopathologic features of high Wnt3a expression in HCC were related to poorly-differentiated grade (χ2 = 20.211, P < 0.001), liver cirrhosis (χ2 = 8.467, P < 0.004), hepatitis B virus (HBV) infection (χ2 = 12.957, P < 0.001), higher tumor-node-metastasis stage (χ2 = 22.960, P < 0.001), and 5-year survival rate (χ2 = 15.469, P < 0.001).CONCLUSION: Oncogenic Wnt3a expression associated with HBV infection and cirrhotic liver might be an independent prognostic factor for HCC.

Reversal of multidrug resistance of hepatocellular carcinoma cells by metformin through inhibiting NF-κB gene transcription

AIM: To interfere with the activation of nuclear factor-κB(NF-κB) with metformin and explore its effect in reversing multidrug resistance(MDR) of hepatocellular carcinoma(HCC) cells.METHODS: Expression of P-glycoprotein(P-gp) and NF-κB in human HepG 2 or HepG 2/adriamycin(ADM) cells treated with pC MV-NF-κB-small interference RNA(siR NA) with or without metformin, was analyzed by Western blot or fluorescence quantitative PCR. Cell viability was tested by CCK-8 assay. Cell cycle and apoptosis were measured by flow cytometry and Annexin-V-PE/7-AnnexinV apoptosis detection double staining assay, respectively. RESULTS: P-gp overexpression in HepG 2 and HepG 2/ADM cells was closely related to mdr1 mR NA(3.310 ± 0.154) and NF-κB mR NA(2.580 ± 0.040) expression. NF-κB gene transcription was inhibited by specific siR NA with significant down-regulation of P-gp and enhanced HCC cell chemosensitivity to doxorubicin. After pretreatment with metformin, Hep G2/ADM cells were sensitized to doxorubicin and P-gp was decreased through the NF-κB signaling pathway. The synergistic effect of metformin and NF-κB siR NA were found in HepG 2/ADM cells with regard to proliferation inhibition, cell cycle arrest and inducing cell apoptosis. CONCLUSION: Metformin via silencing NF-κB signaling could effectively reverse MDR of HCC cells by downregulating MDR1/P-gp expression.