异柠檬酸脱氢酶1 K224位点乙酰化通过Ago2/miR-9-5p通路调节NHE1介导的酸性微环境在结直肠癌侵袭转移中的机制研究

Nonhistone acetylation plays an important part in metastasis process of carcinoma. However, the key acetylated protein and critical acetylated site in CRC metastasis are still obscure. Our preliminary work using acetylated proteomics and site-directed mutation for amino acid showed that K224 of IDH1 was the key acetylated site for liver metastasis of CRC. Abnormal acidic microenvironment was deemed to be a key factor in formation and metastasis of colorectal cancer. IDH1 K224 acetylation might affect the acidic microenvironment around colorectal cancer. IDH1 K224 acetylation might regulate Ago2/miR-9-5p/NHE1 signaling pathway to influence pH-mediated CRC metastasis. However, the underlying mechanisms are still obscure. In this study, we aims to investigate the relationship between IDH1 K224 acetylation and Ago2, or miR-9-5p, or NHE1 expression, as well as the prognosis in CRC tissue samples, to demonsrate IDH1 K224 acetylation indeed influence the acidic microenvironment around tumors, and to explore the mechanism by which IDH1 K224 acetylation regulates Ago2/ miR-9-5p/NHE1 signaling pathway. The research of IDH1 K224 acetylation associated pathways might throw a new light for treatment of liver metastasis in CRC.

非组蛋白乙酰化修饰在肿瘤转移中起重要作用，但结直肠癌肝转移关键的乙酰化非组蛋白和位点尚属未知。本课题组前期通过蛋白质乙酰化修饰组学等筛选和验证出IDH1 K224位点乙酰化发挥关键作用；异常的细胞外酸性微环境被认为是结直肠癌转移的关键环节，IDH1 K224位点乙酰化影响细胞外酸性微环境。该位点乙酰化可能通过Ago2/miR-9-5p/NHE1通路影响肿瘤酸性微环境调控结直肠癌转移，但分子机制尚不清楚。本课题拟在人结直肠癌组织中探讨IDH1 K224位点乙酰化与Ago2、miR-9-5p、NHE1表达相关性及与预后关系；明确IDH1 K224位点乙酰化调控肿瘤酸性微环境影响结直肠癌转移；探索IDH1 K224位点乙酰化通过Ago2/miR-9-5p通路调控NHE1介导的肿瘤酸性微环境的分子机制。IDH1 K224位点乙酰化影响肿瘤酸性微环境通路研究可能为结直肠肝转移治疗提供新靶点和新策略。

肝转移是影响结直肠癌预后的重要因素，非组蛋白乙酰化在肿瘤转移中发挥重要作用，但结直肠癌肝转移关键的乙酰化非组蛋白和位点尚属未知。我们课题组前期通过蛋白质乙酰化修饰组学等筛选出IDH1蛋白K224位点乙酰化可能在结肠癌肝转移中发挥关键作用；异常的细胞外酸性微环境被认为是结直肠癌转移的关键环节，进一步研究发现IDH1 K224位点乙酰化通过影响NHE1的表达来改变细胞外酸性微环境。IDH1蛋白K224位点乙酰化可能通过Ago2/miR-9-5p/NHE1通路影响肿瘤酸性微环境调控结直肠癌转移，但分子机制尚不清楚。本课题首先在人结直肠癌组织中探讨IDH1 K224位点乙酰化与Ago2、NHE1表达相关性及与预后关系；发现IDH1 蛋白 K224 位点乙酰化水平与Ago2表达呈负相关，而与NHE1的表达则呈正相关。我们在突变 IDH K224 乙酰化位点后，用microRNA芯片检测，发现IDH1 K224R位点乙酰化水平下调后，miR-9-5p 表达变化最显著，进一步研究证明细胞膜表面的NHE1蛋白是miR-9-5p靶基因。IDH1 K224位点乙酰化通过提高Ago2的羟基化水平而促进了miR-9-5p的生成，进而降低了NHE1的表达，最终影响了肿瘤酸性微环境。IDH1 K224位点乙酰化影响肿瘤酸性微环境通路研究可能为结直肠肝转移治疗提供新靶点和新策略。