Methylation status and mRNA expression of caspase-8 in human hepatocellular carcinoma cells resistant to tumor necrosis factor-related apoptosis-inducing ligand / 第三军医大学学报

ABSTRACT

Objective To study the association of methylation status of C5 of the cytosine in the CpG di-nucleotide of caspase-8 promoter and expression of caspase-8 mRNA with the resistance to tumor necrosis factor-related apoptosis-inducing ligand(TRAIL) in human hepatocellular carcinoma cell lines,and to evaluate the effect of demethylation agent 5-Aza-2′-deoxycytidine(5-Aza-CdR) on the resistance to TRAIL of human hepatocellular carcinoma cell lines.Methods Methylation status of caspase-8 promoter was measured with methylation-specific PCR method(MSP).Expression of caspase-8 mRNA was detected with RT-PCR.Apoptosis induced by TRAIL was observed by Acridine Orange/Ethidium Bromide(AO/EB) staining.Results Unmethylated status of caspase-8 promoter was found in both HepG2 and SMMC 7721 hepatocellular carcinoma cells.5-Aza-CdR neither up-regulated caspase-8 mRNA expression nor increased the sensitivity of hepatocellular carcinoma cells to TRAIL.Conclusion caspase-8 promoter methylation status and caspase-8 mRNA expression are not related to the resistance to TRAIL.5-Aza-CdR can not increase the sensitivity of hepatocellular carcinoma cells to TRAIL.