Ribosome inactivating plant protein mediated regulation of transcriptomic profile in liver cancer cells

Background: Hepatocellular carcinoma (HCC) is the primary malignancy of the liver that accounts for about 90% of liver cancers. Utilization of natural compounds could be instrumental for HCC patients with better therapeutic efficacy and lesser side effects. A plant based ribosomal inactivating protein (riproximin) has shown substantial antineoplastic properties against the variety of cancer cell lines. The purpose of this study was to investigate the cytotoxic effects of riproximin on cell proliferation of liver cancer cells and to determine the expressional changes induced in cell cycle and cell stress relevant genes. Methods: The HepG2 cell line (liver cancer cells) was cultured in under suitable conditions and exposed to different concentrations of riproximin (0.38–50ng/ml) for 24-72 hours followed by cytotoxicity analysis. Afterwards, the cells were exposed to riproximin (1-20ng/ml) for 48 hours and RNA was extracted using a commercial extraction kit. RT PCRs were carried for analysis of cell cycle (CCND1, CDKN1A) and cell stress (GADD45A) relevant genes. Fold changes were calculated by Livak 2-ΔΔCT method by comparing Cq values of experimental (riproximin treated) and untreated control samples. Results: Findings revealed concentration and time dependent inhibitory effects of riproximin on liver cancer cells. The growth inhibition was maximum at 72 hours with 50ng/ml concentration. RT PCRs results showed that riproximin inhibited the expression of cell cycle promoter gene (CCND1), while cell cycle inhibitor (CDKN1A) and cell cycle inducers (GADD45A) were up regulated. Conclusion: Riproximin harbors significant cytotoxic effects against liver cancer cells. Expressional variations in multiple related genes are imposed by riproximin in the liver cancer cells.