Role of hepatocyte nuclear factor 4 alpha in cell proliferation and gemcitabine resistance in pancreatic adenocarcinoma

BackgroundHepatocyte nuclear factor 4 (HNF4) is a tissue-specific transcription factor that regulates the expression of numerous genes in hepatocytes and pancreatic cells. HNF4 has been reported to affect cell proliferation and chemoresistance in several cancers. However, the role of HNF4 in pancreatic adenocarcinoma (PDAC) has not been studied extensively and remains unclear.MethodsBy utilizing immunohistochemical (IHC) staining, we measured the expression of HNF4 in PDAC tissues. By silencing HNF4 in PDAC cell lines, we assessed the impact of HNF4 on pancreatic cancer cell proliferation and gemcitabine sensitivity. We used CCK8 and colony formation assays to examine the effect of HNF4 on cell proliferation. A flow cytometry assay was used to assess cell apoptosis. The expression of gemcitabine-related genes was detected by quantitative real-time PCR (qRT-PCR) and Western blotting. IHC was utilized to assess the correlation between HNF4 and human equilibrative nucleoside transporter 1 (hENT1) expression in PDAC patients. Chromatin immunoprecipitation (ChIP) and dual-luciferase reporter assays were used to confirm that hENT1 is a target gene of HNF4.ResultsIncreased HNF4 expression was detected in PDAC tissues; patients with higher HNF4 expression displayed worse prognosis. To elucidate the function of HNF4, we examined its role in pancreatic cancer cell proliferation, apoptosis and gemcitabine resistance. In HNF4-silenced Capan-1 and MiaPaCa-2 cells, we observed decreased cell proliferation and increased sensitivity to gemcitabine compared to those of controls. The mechanism of HNF4 in gemcitabine-related chemosensitivity was then explored. In response to HNF4 silencing, the expression levels of gemcitabine-related proteins, hENT1 and deoxycytidine kinase (dCK) were significantly increased. Additionally, hENT1 was negatively correlated with HNF4 in PDAC tissue samples. Moreover, we identified hENT1 as a downstream target of HNF4.ConclusionHNF4 is a prognostic marker for overall survival, is required for pancreatic cancer cell proliferation and promotes resistance to gemcitabine by downregulating hENT1. Therefore, targeting HNF4 might reverse gemcitabine resistance and provide novel treatment strategies for PDAC.