Cao Wenpeng, Zeng Zhirui, Pan Runsang, Wu Hao, Zhang Xiangyan, Chen Hui, Nie Yingjie, Yu Zijiang, Lei Shan
Department of Anatomy, School of Basic Medicine, Guizhou Medical University, Guiyang, China.
Department of Physiology, School of Basic Medicine, Guizhou Medical University, Guiyang, China.
Front Oncol. 2021 Jun 17;11:675991. doi: 10.3389/fonc.2021.675991. eCollection 2021.
Hypoxia is associated with the development of pancreatic cancer (PC). However, genes associated with hypoxia response and their regulatory mechanism in PC cells were unclear. The current study aims to investigate the role of the hypoxia associated gene fucosyltransferase 11 (FUT11) in the progression of PC.
In the preliminary study, bioinformatics analysis predicted FUT11 as a key hypoxia associated gene in PC. The expression of FUT11 in PC was evaluated using quantitative real-time PCR (qRT-PCR), Western blot and immunohistochemistry. The effects of FUT11 on PC cells proliferation and migration under normoxia and hypoxia were evaluated using Cell Counting Kit 8, 5-ethynyl-2'-deoxyuridine (EDU) assay, colony formation assay and transwell assay. The effects of FUT11 was examined in mouse tumor models of liver metastasis and subcutaneous xenograft. Furthermore, Western blot, luciferase assay and immunoprecipitation were performed to explore the regulatory relationship among FUT11, hypoxia-inducible factor 1α (HIF1α) and pyruvate dehydrogenase kinase 1 (PDK1) in PC.
FUT11 was markedly increased of PC cells with hypoxia, upregulated in the PC clinical tissues, and predicted a poor outcome of PC patients. Inhibition of FUT11 reduced PC cell growth and migratory ability of PC cells under normoxia and hypoxia conditions , and growth and tumor cell metastasis . FUT11 bound to PDK1 and regulated the expression PDK1 under normoxia and hypoxia. FUT11 interacted with PDK1 and decreased the ubiquitination of PDK1, lead to the activation of AKT/mTOR signaling pathway. FUT11 knockdown significantly increased the degradation of PDK1 under hypoxia, while treatment with MG132 can relieve the degradation of PDK1 induced by FUT11 knockdown. Overexpression of PDK1 in PC cells under hypoxia conditions reversed the suppressive impacts of FUT11 knockdown on PC cell growth and migration. In addition, HIF1α bound to the promoter of FUT11 and increased its expression, as well as co-expressed with FUT11 in PC tissues. Furthermore, overexpression of FUT11 partially rescued the suppressive effects of HIF1α knockdown on PC cell growth and migration in hypoxia condition.
Our data implicate that hypoxia-induced FUT11 contributes to proliferation and metastasis of PC by maintaining the stability of PDK1, thus mediating activation of AKT/mTOR signaling pathway, and suggest that FUT11 could be a novel and effective target for the treatment of pancreatic cancer.
缺氧与胰腺癌（PC）的发生发展相关。然而，与缺氧反应相关的基因及其在PC细胞中的调控机制尚不清楚。本研究旨在探讨缺氧相关基因岩藻糖基转移酶11（FUT11）在PC进展中的作用。
在初步研究中，生物信息学分析预测FUT11是PC中一个关键的缺氧相关基因。采用定量实时PCR（qRT-PCR）、蛋白质免疫印迹法和免疫组织化学法评估PC中FUT11的表达。使用细胞计数试剂盒8、5-乙炔基-2'-脱氧尿苷（EDU）检测、集落形成检测和Transwell检测评估FUT11在常氧和缺氧条件下对PC细胞增殖和迁移的影响。在肝转移和皮下异种移植的小鼠肿瘤模型中检测FUT11的作用。此外，进行蛋白质免疫印迹法、荧光素酶检测和免疫沉淀以探讨PC中FUT11、缺氧诱导因子1α（HIF1α）和丙酮酸脱氢酶激酶1（PDK1）之间的调控关系。
缺氧时PC细胞中FUT11明显增加，在PC临床组织中上调，并预测PC患者预后不良。抑制FUT11可降低常氧和缺氧条件下PC细胞的生长及PC细胞的迁移能力，以及生长和肿瘤细胞转移。FUT11在常氧和缺氧条件下与PDK1结合并调节PDK1的表达。FUT11与PDK1相互作用并降低PDK1的泛素化，导致AKT/mTOR信号通路激活。敲低FUT11可显著增加缺氧时PDK1的降解，而用MG132处理可缓解FUT11敲低诱导的PDK1降解。缺氧条件下在PC细胞中过表达PDK1可逆转FUT11敲低对PC细胞生长和迁移的抑制作用。此外，HIF1α与FUT11的启动子结合并增加其表达，且在PC组织中与FUT11共表达。此外，过表达FUT11可部分挽救缺氧条件下HIF1α敲低对PC细胞生长和迁移的抑制作用。
我们的数据表明，缺氧诱导的FUT11通过维持PDK1的稳定性促进PC的增殖和转移，从而介导AKT/mTOR信号通路的激活，并提示FUT11可能是治疗胰腺癌的一个新的有效靶点。
