ABSTRACT
Objective To study the expression of RUNX3 mRNA in primary liver cancer (PHC) tissue and its surrounding normal tissue,and its clinical significance.MethodsReverse transcription polymerase chain reaction (RT-PCR) was performed to detect the expression of RUNX3 mRNA in tumor and peritumor tissues in 51 patients with PHC.The relationship between RUNX3 mRNA expression and some clinical pathological parameters was analyzed.ResultsThe relative expression values of RUNX3 mRNA in the tumor tissue and the surrounding normal tissue were 0.4509±0.0963 and 0.9147± 0.0222,respectively.The difference was significant (t=33.6087,P＜0.001).The RUNX3 mRNA expression in tumor tissue correlated with some clinical pathological parameters including low tumor differentiation,positive cancer embolus and intrahepatic invasion and metastasis.The RUNX3 mRNA expression was not correlated with other clinicopathological parameters including gender,cancer diameter,cancer location,hemorrhage and necrosis of cancer,and histotype.ConclusionRUNX3 may be a new tumor suppressor gene for PHC.
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Objective To investigate the relationship between the methylation of CpG island of RUNX3 gene promoter and its expression in a human cutaneous malignant melanoma cell line A375, and to assess the role of RUNX3 gene methylation in the pathogenesis of human cutaneous malignant melanoma. Methods Cultured A375 cells were treated with various concentrations (0, 1, 5, 10, 20 μmol/l) of 5-azacyti-dine for 24 or 72 hours followed by another 5 days of culture. Then, methylation-specific PCR (MSP) was performed to evaluate the methylation status of RUNX3 promoter region, and Western-blot analysis to detect the protein expression of RUNX3 in A375 cells. Results The RUNX3 gene promoter region was hypermethylated in untreated A375 cells, along with the absence of protein expression of RUNX3. However, after the treatment with 5-azacytidine, the promoter region of RUNX3 gene was demethylated partly, and the expression of RUNX3 protein was restored in A375 cells. Further, the expression intensity was directly correlated with the concentration of 5-azacytidine. Conclusions The promoter hypermethylation of RUNX3 gene may be related to the silencing of RUNX3 gene expression in A375 cells, whereas 5-azacytidine can cause the demethylation of RUNX3 gene, reactivate the gene which has been inactivated by the promoter hypermethylation, and finally induce the re-expression of RUNX3 protein.
ABSTRACT
Objective To investingate the effect of 5-Aza2'-deoxycytidine(5-Aza-CdR)on cell growth and to explore the possibility of re-expression of the hypermethylated and silenced RUNX3 gene in hepatocarcinoma cell line HepG2.Methods The change in expression of the tumor suppressor gene RUNX3 mRNA in cultured HepG2 cells was observed by RT-PCR before and after 5-Aza-CdR treatment.Activity of cell growth was observed by MTT assay and colony-forming test.The cell cycle was analyzed by flow cytometry.Apoptotic morphology was observed by transmitting electron microscopy.Results The gene was reactivated by two different doses of 5-Aza-CdR treatment in HepG2 cell without expressing RUNX3.The hepatocarcinoma cell line treated with 5-Aza-CdR displayed a slowed growth rate in contrast to the control group.The colony formation rate of HepG2 cell treated with 5-Aza-CdR decreased dramatically(P