Abrogating K458 acetylation enhances hepatocyte nuclear factor 4α (HNF4α)‐induced differentiation therapy for hepatocellular carcinoma

OBJECTIVES: In this study we aimed to assess the impact of acetylation of hepatocyte nuclear factor 4α (HNF4α) on lysine 458 on the differentiation therapy of hepatocellular carcinoma (HCC). METHODS: Periodic acid-Schiff (PAS) staining, Dil-acetylated low-density lipoprotein (Dil-Ac-LDL) uptake, and senescence-associated β-galactosidase (SA-β-gal) activity analysis were performed to assess the differentiation of HCC cells. HNF4α protein was detected by western blot and immunohistochemistry (IHC). The effects of HNF4α-K458 acetylation on HCC malignancy were evaluated in HCC cell lines, a Huh-7 xenograft mouse model, and an orthotopic model. The differential expression genes in Huh-7 xenograft tumors were screened by RNA-sequencing analysis. RESULTS: K458R significantly enhanced the inhibitory effect of HNF4α on the malignancy of HCC cells, whereas K458Q reduced the inhibitory effects of HNF4α. Moreover, K458R promoted, while K458Q decreased, HNF4α-induced HCC cell differentiation. K458R stabilized HNF4α, while K458Q accelerated the degradation of HNF4α via the ubiquitin proteasome system. K458R also enhanced the ability of HNF4α to inhibit cell growth of HCC in the Huh-7 xenograft mouse model and the orthotopic model. RNA-sequencing analysis revealed that inhibiting K458 acetylation enhanced the transcriptional activity of HNF4α without altering the transcriptome induced by HNF4α in HCC. CONCLUSION: Our data revealed that inhibiting K458 acetylation of HNF4α might provide a more promising candidate for differential therapy of HCC.