Department of Neurosurgery, Shanghai Tongji Hospital, Tongji University School of Medicine, 389 Xincun Road, Shanghai, China.
Mol Neurobiol. 2022 Nov;59(11):6724-6739. doi: 10.1007/s12035-022-02999-w. Epub 2022 Aug 23.
Hypoxia is intimately associated with enhanced glycolysis in gliomas, and hypoxia-inducible factor 1α (HIF-1α) plays a critical role in this process. RLIP76 (Ral-interacting protein 76) functions as a multifunctional mediator and is aberrantly expressed in various malignant tumors, including glioma. However, the underlying mechanism of RLIP76 and HIF-1α in glioma glycolysis remains largely unclear. In the present study, we demonstrated that RLIP76 is a hypoxia-inducible molecule that contributes to facilitating glycolysis in glioma cells under hypoxic conditions. In addition, hypoxia-induced RLIP76 is a novel target of HIF-1α and enhances the two important HIF-1α-target glycolytic proteins glucose transporter type 1 (GLUT1) and lactate dehydrogenase A (LDHA) in hypoxia. Mechanistically, RLIP76 can directly bind to HIF-1α in the nucleus and regulate the stability of HIF-1α by alleviating HIF-1α ubiquitination and therefore activates GLUT1 and LDHA to accelerate glycolysis in hypoxia. Furthermore, the enhanced glycolysis is necessary for the role of RLIP76 to promote glioma development in vivo, confirming the ability of RLIP76 to regulate tumor cell glycolysis. Collectively, our results demonstrate a previously unappreciated function of RLIP76 in hypoxia-mediated glycolytic metabolism and implicate that RLIP76 might be a valuable therapeutic target for gliomas.
缺氧与胶质瘤中增强的糖酵解密切相关,缺氧诱导因子 1α(HIF-1α)在这一过程中起着关键作用。RLIP76(Ral 相互作用蛋白 76)作为多功能介质发挥作用,在包括胶质瘤在内的各种恶性肿瘤中异常表达。然而,RLIP76 和 HIF-1α 在胶质瘤糖酵解中的潜在机制在很大程度上仍不清楚。在本研究中,我们证明 RLIP76 是一种缺氧诱导分子,有助于促进缺氧条件下胶质瘤细胞的糖酵解。此外,缺氧诱导的 RLIP76 是 HIF-1α 的一个新靶点,并增强了两种重要的 HIF-1α 靶向糖酵解蛋白葡萄糖转运蛋白 1(GLUT1)和乳酸脱氢酶 A(LDHA)在缺氧下的表达。在机制上,RLIP76 可以直接与核内的 HIF-1α 结合,并通过减轻 HIF-1α 的泛素化来调节 HIF-1α 的稳定性,从而激活 GLUT1 和 LDHA,以加速缺氧下的糖酵解。此外,增强的糖酵解是 RLIP76 在体内促进胶质瘤发展的作用所必需的,证实了 RLIP76 调节肿瘤细胞糖酵解的能力。总之,我们的结果表明 RLIP76 在缺氧介导的糖酵解代谢中具有以前未被认识的功能,并暗示 RLIP76 可能是治疗胶质瘤的有价值的靶点。