Carfilzomib inhibits the progression of hepatocellular cancer via upregulating GADD45a expression

Hepatocellular carcinoma (HCC) ranks among one of the most prevalent and lethal cancers affecting humans. Currently, there are limited effective treatments available for HCC. In the search for potential anti-HCC agents, we found that carfilzomib, a proteasome inhibitor, exerts anti-HCC activities. However, the underlying mechanisms of action are main unclear. In this study, we evaluated the effectiveness of carfilzomib against HCC capability and explored its underlying mechanisms. Cell Counting Kit 8 (CCK8), EdU (5-ethynyl-2-deoxyuridine) staining, and colony formation assays were employed to analyze the antiproliferative ability of carfilzomib on MHCC-97H and Huh7 cells. Additionally, flow cytometry was used to assess the effect on the cell cycle. Western blotting was utilized to examine the protein expression levels associated with cell cycle arrest. Furthermore, short hairpin RNA (shRNA) transfection was used to investigate the role of GADD45a (growth arrest and DNA damage 45a) on carfilzomib-induced cell cycle arrest. A xenograft tumor model using nude mouse was employed to evaluate the anti-HCC activity of carfilzomib in vivo. The finding demonstrated that carfilzomib inhibited the proliferation, invasion, and migration in both MHCC-97H and Huh7 cells. In addition, carfilzomib caused cell cycle arrest by suppressing the expression of cyclin A1, cyclin E1, cyclin-dependent kinases 2 (CDK2), and cyclin-dependent kinases 4 (CDK4). It also upregulated the expression of GADD45a, and inhibition of GADD45a through shRNA abolished carfilzomib-induced cell cycle arrest in HCC cells. Importantly, carfilzomib demonstrated its ability to inhibit the Huh7 cell growth in vivo. Our research has revealed, for the first time, that carfilzomib inhibited the progression of HCC cells by upregulating GADD45a expression. These findings suggest that carfilzomib could be a potential chemotherapeutic agent against HCC.