Sun Qiqing, Xu Wenyan, Ji Shunrong, Qin Yi, Liu Wensheng, Hu Qiangsheng, Zhang Zheng, Liu Mengqi, Yu Xianjun, Xu Xiaowu
1Department of Pancreatic Surgery, Fudan University Shanghai Cancer Center, Shanghai, 200032 China.
2Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032 China.
Cancer Cell Int. 2019 Mar 4;19:49. doi: 10.1186/s12935-019-0767-4. eCollection 2019.
Hepatocyte nuclear factor 4α (HNF4α) is a tissue-specific transcription factor that regulates the expression of numerous genes in hepatocytes and pancreatic β cells. HNF4α has been reported to affect cell proliferation and chemoresistance in several cancers. However, the role of HNF4α in pancreatic adenocarcinoma (PDAC) has not been studied extensively and remains unclear.
By utilizing immunohistochemical (IHC) staining, we measured the expression of HNF4α in PDAC tissues. By silencing HNF4α in PDAC cell lines, we assessed the impact of HNF4α on pancreatic cancer cell proliferation and gemcitabine sensitivity. We used CCK8 and colony formation assays to examine the effect of HNF4α 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 HNF4α 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 HNF4α.
Increased HNF4α expression was detected in PDAC tissues; patients with higher HNF4α expression displayed worse prognosis. To elucidate the function of HNF4α, we examined its role in pancreatic cancer cell proliferation, apoptosis and gemcitabine resistance. In HNF4α-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 HNF4α in gemcitabine-related chemosensitivity was then explored. In response to HNF4α silencing, the expression levels of gemcitabine-related proteins, hENT1 and deoxycytidine kinase (dCK) were significantly increased. Additionally, hENT1 was negatively correlated with HNF4α in PDAC tissue samples. Moreover, we identified hENT1 as a downstream target of HNF4α.
HNF4α is a prognostic marker for overall survival, is required for pancreatic cancer cell proliferation and promotes resistance to gemcitabine by downregulating hENT1. Therefore, targeting HNF4α might reverse gemcitabine resistance and provide novel treatment strategies for PDAC.
肝细胞核因子4α（HNF4α）是一种组织特异性转录因子，可调节肝细胞和胰腺β细胞中众多基因的表达。据报道，HNF4α在几种癌症中影响细胞增殖和化疗耐药性。然而，HNF4α在胰腺腺癌（PDAC）中的作用尚未得到广泛研究，仍不清楚。
通过免疫组织化学（IHC）染色，我们检测了PDAC组织中HNF4α的表达。通过在PDAC细胞系中沉默HNF4α，我们评估了HNF4α对胰腺癌细胞增殖和吉西他滨敏感性的影响。我们使用CCK8和集落形成试验来检测HNF4α对细胞增殖的影响。采用流式细胞术检测细胞凋亡。通过定量实时PCR（qRT-PCR）和蛋白质印迹法检测吉西他滨相关基因的表达。利用IHC评估PDAC患者中HNF4α与人类平衡核苷转运体1（hENT1）表达之间的相关性。采用染色质免疫沉淀（ChIP）和双荧光素酶报告基因试验来证实hENT1是HNF4α的靶基因。
在PDAC组织中检测到HNF4α表达增加；HNF4α表达较高的患者预后较差。为了阐明HNF4α的功能，我们研究了其在胰腺癌细胞增殖、凋亡和吉西他滨耐药性中的作用。在HNF4α沉默的Capan-1和MiaPaCa-2细胞中，与对照组相比，我们观察到细胞增殖减少，对吉西他滨的敏感性增加。然后探讨了HNF4α在吉西他滨相关化疗敏感性中的机制。响应于HNF4α沉默，吉西他滨相关蛋白、hENT1和脱氧胞苷激酶（dCK）的表达水平显著增加。此外，在PDAC组织样本中，hENT1与HNF4α呈负相关。此外，我们确定hENT1是HNF4α的下游靶标。
HNF4α是总体生存的预后标志物，是胰腺癌细胞增殖所必需的，并通过下调hENT1促进对吉西他滨的耐药性。因此，靶向HNF4α可能会逆转吉西他滨耐药性，并为PDAC提供新的治疗策略。
