Cinobufagin inhibits proliferation and induces apoptosis of hepatocarcinoma cells by activating apoptosis, AKT, and ERK pathways

Abstract

Cinobufagin is one of the pharmaceutically active ingredients in the parotoid glands of the Chinese toad Bufo bufo gargarizans Cantor. This study was conducted to investigate the effect of cinobufagin on viability, migration, and apoptosis of hepatocellular carcinoma (HCC) cells and its mechanisms. Human HCC cells (HepG2) were treated with cinobufagin and assessed for viability, apoptosis, and migration using CCK-8 assay, flow cytometry, and wound healing assay. The expression of genes related to the p53, AKT, and ERK pathways was detected using RT-PCR and Western blot analysis. Cell viability assays showed that cinobufagin reduced the viability of HepG2 cells in a concentration- and time-dependent manner. Significantly increased apoptosis was detected in cinobufagin-treated cells as compared with non-treated cells. The migration ability of HepG2 cells was significantly reduced after they were exposed to cinobufagin as compared with control. RT-PCR and Western blot analyses showed that the expression levels of p53, caspase-3, and Bax were significantly upregulated, and the expression levels of AKT and ERK were significantly downregulated after cinobufagin treatment. Our data demonstrated that cinobufagin reduces the viability and induces apoptosis of HepG2 cells. The cytotoxicity is likely achieved by upregulating the p53 pathway and downregulating the Akt and ERK pathways.

Pharmacological Effects of Cinobufagin

“…Several studies have shown that CBF can inhibit proliferation of hepatocellular carcinoma cells. Wendong Feng et al used CCK-8 assay to examine the growth of cells treated with CBF [ 16 ]. The results showed that when CBF concentration increased from 0 to 320 ng/l, the inhibition of HepG2 cells increased from 0% to 65% at 12 h, to 87% at 24 h, and to 99% at 48 h, and the LD50 of CBF was estimated to be 170, 78, and 40 ng/L, respectively.…”

“…Mechanistic studies indicated that CBF could inhibit proliferation and induce apoptosis of HepG2 cells by upregulating the p53 pathway and downregulating the Akt and ERK pathways [ 16 ]. In addition, CBF triggers defects in spindle formation and cap-dependent translation in liver cancer cells by inhibiting the AURKA-mTOR-eIF4E axis [ 17 ].…”