ITGB2 介导的 CAFs 代谢转换通过氧化磷酸化系统中线粒体 NADH 的氧化促进 OSCC 增殖。
ITGB2-mediated metabolic switch in CAFs promotes OSCC proliferation by oxidation of NADH in mitochondrial oxidative phosphorylation system.
机构信息
Central Laboratory, Nanjing Stomatological Hospital, Medical School of Nanjing University, 30 Zhongyang Road, Nanjing 210008, China.
Department of Anesthesiology, Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing 210008, China.
出版信息
Theranostics. 2020 Oct 26;10(26):12044-12059. doi: 10.7150/thno.47901. eCollection 2020.
Integrins, the coordinator of extracellular and intracellular signaling, are often found to be aberrant in tumors and can reshape the tumor microenvironment. Although previous studies showed that integrin beta 2 (ITGB2) is important for host defense, its expression profile and role in tumors, especially in cancer associated fibroblasts (CAFs) are still unknown. Immunofluorescence stain and fluorescence activated cell sorting were used to analyze the ITGB2 expression profile in oral squamous cell carcinoma (OSCC). RT-PCR and western blot were used to compare ITGB2 expression in normal fibroblasts (NFs) and cancer associated fibroblasts (CAFs). Clinical data and function-based experiments were used to investigate the promoting tumor growth ability of ITGB2 expressing CAFs. Enhanced glycolysis activity was identified by using bioinformatics analyses and GC/MS assays. MCT1 knockdown OSCC cell lines were constructed to explore the pro-proliferative mechanisms of ITGB2 expressing CAFs in multiple and assays. We found that CAFs exhibited significantly higher ITGB2 expression than the matched NFs. In addition, higher ITGB2 expression in CAFs was correlated with higher TNM stages and more Ki67+ tumor cells, indicating its ability to promote OSCC proliferation. Further, co-culture assay demonstrated that ITGB2-mediated lactate release in CAFs promoted OSCC cell proliferation. Mechanically, ITGB2 regulated PI3K/AKT/mTOR pathways to enhance glycolysis activity in CAFs. Accordingly, lactate derived from ITGB2-expressing CAFs was absorbed and metabolized in OSCC to generate NADH, which was then oxidized in the mitochondrial oxidative phosphorylation system (OXPHOS) to produce ATP. Notably, inhibiting the OXPHOS system with metformin delayed the proliferative capacity of OSCC cells cultured in the ITGB2-expressing CAFs medium. Our study uncovered the ITGB2 pro-tumoral CAFs that activated the PI3K/AKT/mTOR axis to promote tumor proliferation in OSCC by NADH oxidation in the mitochondrial oxidative phosphorylation system.
整合素是细胞外和细胞内信号的协调者,常发现其在肿瘤中异常,可重塑肿瘤微环境。尽管先前的研究表明整合素β 2(ITGB2)对于宿主防御很重要,但它在肿瘤中的表达谱和作用,特别是在癌相关成纤维细胞(CAFs)中的表达谱和作用仍不清楚。免疫荧光染色和荧光激活细胞分选用于分析口腔鳞状细胞癌(OSCC)中 ITGB2 的表达谱。RT-PCR 和 Western blot 用于比较正常成纤维细胞(NFs)和癌相关成纤维细胞(CAFs)中 ITGB2 的表达。临床数据和基于功能的实验用于研究表达 ITGB2 的 CAFs 促进肿瘤生长的能力。通过生物信息学分析和 GC/MS 测定鉴定增强的糖酵解活性。构建 MCT1 敲低的 OSCC 细胞系,以在多种和实验中探索表达 ITGB2 的 CAFs 的促增殖机制。我们发现 CAFs 中 ITGB2 的表达明显高于匹配的 NFs。此外,CAFs 中 ITGB2 的表达越高,与更高的 TNM 分期和更多的 Ki67+肿瘤细胞相关,表明其促进 OSCC 增殖的能力。进一步的共培养实验表明,ITGB2 介导的 CAFs 中乳酸的释放促进了 OSCC 细胞的增殖。机制上,ITGB2 调节 PI3K/AKT/mTOR 通路以增强 CAFs 中的糖酵解活性。因此,来自表达 ITGB2 的 CAFs 的乳酸在 OSCC 中被吸收和代谢,产生 NADH,然后在线粒体氧化磷酸化系统(OXPHOS)中氧化产生 ATP。值得注意的是,用二甲双胍抑制 OXPHOS 系统会延迟在表达 ITGB2 的 CAFs 培养基中培养的 OSCC 细胞的增殖能力。我们的研究揭示了 ITGB2 促进肿瘤的 CAFs,通过线粒体氧化磷酸化系统中的 NADH 氧化激活 PI3K/AKT/mTOR 轴促进 OSCC 中的肿瘤增殖。