低氧诱导因子HIF-1α调控CX3CR1在胰腺癌细胞中的表达

Regulation of CX3CR1 expression in pancreatic cancer cells by hypoxia inducible factor 1α

目的:以胰腺癌细胞株Patu8988为研究对象,通过过表达和干扰低氧诱导因子(HIF-1α),观察CX3CR1表达水平的变化,并探讨CX3CR1在胰腺癌中的调控机制。方法:分别构建pcDNA3.1-HIF-1α过表达质粒和HIF-1α-siRNA,转染胰腺癌细胞株Patu8988,经Western blot、半定量PCR检测CX3CR1的表达情况。采用染色质免疫沉淀(chromatin immunoprecipitation,ChIP)、荧光素酶技术探查HIF-1α与CX3CR1启动子区的结合情况。结果:Patu8988转染pcDNA3.1-HIF-1α后CX3CR1的表达增加,敲除HIF-1α后CX3CR1的表达减少。HIF-1α与CX3CR1启动子区的低氧反应元件直接结合,并上调CX3CR1启动子的活性(P<0.01)。结论:HIF-1α调控CX3CR1在胰腺癌细胞中的表达。

Objective： This study aimed to investigate the effect ofhypoxia inducible factor la （HIF-la） expression on CX3CR1 and its regulatory mechanism in pancreatic cancer cell line Patu8988. Methods： The highly expressed plasmid pcDNA3.1 HIF-1 a and siRNA HIF-lct were initially constructed. After the plasmid was separately transfected to the pancreatic cancer cells, CX3CR1 and HIF-lct expressions were assayed by westem blot analysis and real-time quantitative reverse transcriptase-polymerase chain reaction. The relationship between HIF-1 a and CX3CR 1 promoter was determined by chromatin immunoprecipitation and luciferase technology. Results： The overexpressed HIF-1 a could upregulate the CX3CR1 expression in pancreatic cancer cells. The CX3CR1 expression was significantly reduced when HIF-1 a was knocked down. Chromatin immunoprecipitation assay demonstrated that HIF-1 a could be directly bound to the hypoxia-response element （5＇-A/GCGTG-3＇） of the CX3CR1 promoter. This binding activity was significantly enhanced under hypoxic condition. CX3CR1 promoter-induced HIF-1 a overexpression could significantly upregulate the expression of luciferase reporter genes in pancreatic cancer cells （P〈0.01）. Conclusion： HIF-la could regulate CX3CR1 expression in pancreatic cancer cells.