Tumor suppressor genes are differentially regulated with dietary folate modulations in a rat model of hepatocellular carcinoma

The current study evaluated the outcome of dietary folate modulations on the expression of tumor suppressor genes (TSGs) during developmental stages of hepatocellular carcinoma (HCC) in a Wistar rat model. In addition to dietary folate modulations, male rats were administered diethylnitrosamine (DEN) intraperitoneally once a week upto 18 weeks to induce HCC. Serum folate levels were found to be decreased and increased in folate deficiency (FD) and folate-oversupplemented (FO) groups respectively when compared to folate normal (FN) rats. Apoptosis was observed in FD in fibrosis and HCC stages. mRNA expression analysis by RT-PCR of TSGs (DPT, p16, RUNX3, RASSF1AandSOCS1) and protein expression by western blot (RASSF1A, RUNX3 and p16) depicted differential expression in FD and FO in various stages of HCC development. Bisulfite sequencing forp16andRASSF1Apromoter was performed. The promoter region ofp16gene was hypermethylated at 7th and that ofRASSF1Awas hypomethylated at 10th CpG in cirrhotic category in FD rats. Hyper and hypomethylation at 10th and 24th CpG respectively in RASSF1A promoter was observed in HCC category in both FD and FO groups. All TSGs showed differential expression at transcript and protein level. Increased expression ofDPT, RASSF1A,SOCS1and decreased expression ofRUNX3could be playing role in HCC development in FD rats. Reduced expression ofRUNX3, RASSF1AandSOCS1in HCC category was demonstrated in FO rats. Thus, the studied TSGs are differentially expressed with dietary folate modulations during the development of HCC in DEN-treated rat model and the promoter methylation might be a contributing mechanism under these conditions.

Automated summary

The study evaluated the impact of dietary folate modulations on the expression of tumor suppressor genes during hepatocellular carcinoma development, finding differential expression patterns and promoter methylation in folate deficiency and oversupplemented groups. The results suggest that TSGs play a role in HCC development, with potential contributions from promoter methylation.