Ⅰ型1,4,5-三磷酸肌醇受体在低氧诱导胰腺癌转移中的分子机制研究

Molecular mechanism of ITPR1 in hypoxia-induced metastasis of pancreatic cancer

目的探讨Ⅰ型1,4,5-三磷酸肌醇受体(ITPR1)在低氧诱导胰腺癌转移中的分子机制。方法免疫组化检测低氧诱导因子-1α(HIF-1α)、ITPR1、表皮生长因子受体(EGFR)、磷酸化JAK激酶2(p-JAK2)和信号转导及转录激活因子3(STAT3)在胰腺导管腺癌(PDAC)及正常胰腺组织中的表达及其临床意义;实时荧光定量PCR(qRT-PCR)、免疫印迹(WB)及双荧光素酶报告基因系统分析在低氧微环境下ITPR1调控EGFR相关分子机制;MTS增殖、Transwell迁移侵袭实验探讨低氧状态下ITPR1对Panc-1细胞增殖、迁移和侵袭的影响。结果HIF-1α、ITPR1、EGFR信号通路在PDAC组织中表达均增高,且HIF-1α、ITPR1、EGFR、STAT3与PDAC转移有关,HIF-1α及EGFR是影响PDAC患者术后生存时间的独立风险因素;低氧可提高Panc-1中HIF-1α、ITPR1、EGFR通路的表达量,且敲低ITPR1后EGFR轴相关因子表达下降;沉默HIF-1α后ITPR1表达下降,ITPR1启动子区存在HIF-1α的结合位点。敲低ITPR1后细胞增殖能力下降,在常氧和低氧状态下细胞增殖能力相似;敲低ITPR1后细胞迁移和侵袭能力下降,而在低氧状态下体外迁移和侵袭能力提高。结论低氧增强胰腺癌的转移可能是通过HIF-1α调控ITPR1的表达而实现,而ITPR1可调控EGFR/JAK2/STAT3信号通路的表达。

Objective To investigate the molecular mechanism of inositol 1,4,5-triphosphate receptor type I(ITPR1 in hypoxia-induced metastasis of pancreatic cancer. Methods Immunohistochemistry(IHC)was used to detect the expressions of hypoxia-induced factor(HIF)-1α,ITPR1,epidermal growth factor receptor(EGFR),p-JAK2 and STAT3 in pancreatic ductal adenocarcinoma(PDAC)and normal pancrea tissues and to explore their clinical significance.The molecular mechanisms by which ITPR1 regulated EGFR signaling pathway in hypoxia were analyzed by real-time fluores-cence quantitative PCR(qRT-PCR),Western blotting(WB)and dual-luciferase report gene system.The effects of ITPR1 on proliferation,migration and invasion of pancreatic cancer cells under hypoxia were studied via experiments on MTS proliferation,Transwell migration and invasion.Results The expressions of HIF-1α,ITPR1 and EGFR pathways in PDAC tissues increased along with the increase in PDAC.EGFR pathway in PDAC tissues.The expressions of HIF-1α,ITPR1,EGFR and STAT3 were related to the metastasis of PDAC. HIF-1α and EGFR were independent risk factors that influenced the survival time of patients with PDAC after operation. Hypoxia could increase the expressions of HIF-1α,ITPR1 and EGFR pathway in Panc-1. The expression of EGFR axis-related factors decreased. There was a binding site of HIF-1α in ITPR1 promoter region. After the knock-down of ITPR1,the proliferation of Panc-1 cells decreased,as in normoxia and hypoxia. However,migration and invasion in vitro of Panc-1 were enhanced under hypoxic conditions,while cell migration and invasion decreased after knocking down ITPR1. Conclusion Hypoxia may enhance the metastasis of pancreatic cancer by regulating the expressions of ITPR1 with HIF-1α,while ITPR1 may regulate the expression of EGFR/JAK2/STAT3 signaling pathway.