In the normal mammalian cells, epigenetic changes such as dna methylation and histone acetylation play an important role in the gene expression. hypermethylation of cpg islands of the promoter region of tumor suppressor genes plays a major role in carcinogenesis through transcriptional silencing. estrogen receptor alpha (erα or esr 1) gene is a tumor suppressor gene that expresses in a variety of tissues. hypermethylation of this gene is one of the causes of cancers. dna demethlating agents such as genistein (ge) can restore silenced genes by dna methyltransfrase (dnmt) inhibition. soy isoflavone ge can reactivate erα by which induce cell cycle arrest and modulate key regulator cell cycle proteins. recently, we indicated that ge reactivated erα, inhibited cell growth and induced apoptosis in hepatocellular carcinoma (hcc) plc/prf/5. our previous result stimulated us to design the current study to evaluate the effect of ge on erα reactivation and also proliferative and apoptotic effects of ge on the human hepatocellular carcinoma hepg2 cell line.
Materials and methods: hepg 2 cells were treated with ge and quantitative real time rt-pcr, mtt assay and flow cytometry assay were used to determine the effect of ge on erα gene expression, viability and apoptosis respectively.
Results: ge had a biphasic effect on viability. it inhibited the growth of liver cancer cells and induced apoptosis with a time- and dose-dependent manner and also reactivated erα gene expression with high concentration significantly. it demonstrated proliferative effect at a low concentration.
Conclusion: ge can significantly inhibit the growth of hcc cells and play a significant role in apoptosis and reactivation of erα gene.