Résumé
Objective To study the effects of the HBV x gene (HBx) on the biological characteristics and the expression of DNA repair enzyme hMTH1 mRNA of the L02/HBx transgene cell model. Methods Light microscopy was used to observe the morphologic characteristics of gene-transfected cell strain Lff2/HBx that stably expressed the HBx protein and the control groups of L02 and L02/PcDNA3.1. The changes of L02/HBx on the proliferation, cell cycle and apoptosis were observed by MTT assays and flow cytometry analysis respectively. Moreover, the malignant transformation of L02/HBxwas assayed by colony formation in soft agar and the expression of DNA repair enzyme hMTH1 mRNA was assayed in each group by real-time qPCR. Results Inversion phase contrast microscope showed that the morphologic characteristics of L02/HBx had changed obviously compared with control groups. The MTT showed that L02/HBx proliferated more quickly and flow cytometry analysis indicated that HBx could accelerate the progression of cell cycle and inhibit apoptosis. Colony formation in soft agar demonstrated that the rate of colony formation of L02/HBx was remarkably higher than the L02 and the L02/peDNA3. 1 cells (P<0. 05). The real-time qPCR detection showed that the expression of hMTH1 mRNA in L02/HBx was significantly higher than that in the control groups ( P < 0. 05 ). Conclusion HBx could play an important role in the malignant transformation of L02/HBx and the over expression of hMTH1 mRNA.
Résumé
To study the expression of DNA repair enzyme hMTH1 mRNA and protein in hepatocellular carcinoma (HCC) tissues, tissues adjacent to the cancers, normal liver cells and hepatoma cell lines, and to investigate their function in the progress of HCC, semi-quantitative reverse-transcription polymerase chain reaction (RT-PCR) was employed to examine the expression of hMTH1 mRNA in matched HCC tissues (HT)/surrounding tissues (HST) of HCC, normal liver cell L02 and hepatoma cell lines SMMC7721, HepG2. hMTH1 protein was detected in corresponding HT as well as their HST by immunohistochemistry. Our results showed that the expression level of hMTH1 mRNA in HT was higher than that in HST (t=2.424, P <0.05). The expression level of hMTH1 mRNA in two hepatoma cell lines was higher than that in normal liver cell line (F=6.810, P <0.01). The expression of hMTH1 mRNA in SMMC7721 was similar to that in HepG2. hMTH1 protein was 88.2 % (15 of 17) positive in HT and 82.4 % (14 of 17) in HST. The protein level of hMTH1 in HT was correspondingly higher than in their HST (t=2.618,P<0.05). It is concluded that hMTH1 mRNA and protein were over-expressed in HCC and hepatoma cell lines. It may be one of the key events during the carcinogenesis,progression of HCC and may promote the malignant growth. These results suggest that hMTH1 plays a role in HCC and may be a candidate marker for the diagnosis of HCC.