YAP介导的铁死亡/4HNE代谢重排调控结肠癌免疫微环境的机制及其功能研究

肿瘤浸润CD8+T细胞的丰度与PD-1/PD-L1免疫治疗的疗效密切相关。多数结肠癌缺乏CD8+T细胞浸润，对免疫治疗不敏感，具体机制有待阐明。4HNE是铁死亡/脂质过氧化代谢的标志毒副产物，可直接或以谷胱甘肽耦合物GS-HNE形式被醛酮还原酶AKR1s清除。我们前期在结肠癌细胞中通过转录组学发现癌基因YAP可上调铁死亡关键因子ACSL4（脂质过氧化代谢的限速酶）表达，但明显抑制AKR1s表达；质谱检测提示YAP通过调控ACSL4/AKR1s表达，促进GS-HNE的蓄积和胞外分泌；而GS-HNE在体外研究中可明显抑制CD8+T细胞存活。因此我们推测，YAP通过重塑结肠癌铁死亡/4HNE代谢，促进GS-HNE分泌，进而抑制肿瘤浸润CD8+T细胞的存活。本研究将通过体内外实验阐明YAP介导的铁死亡/4HNE代谢重排对结肠癌免疫微环境的作用及其机制，并探索逆转结肠癌免疫治疗抵抗的新策略。

The abundance of tumor infiltrating CD8+T cells is closely related to the efficacy of PD-1/PD-L1 immunotherapy. Most colon cancers lack CD8+T cell infiltration and are insensitive to immunotherapy. The specific mechanism remains to be clarified. 4HNE is a symbolic toxic byproduct of ferroptosis/lipid peroxidation, and can be cleared directly or in the form of glutathione-conjugate (GS-HNE) by aldo-keto reductases (AKR1s). Our previous RNA-seq data showed that oncogene YAP can up-regulate the expression of ACSL4 (the rate-limiting enzyme of lipid peroxidation and the key regulating factor of ferroptosis), but significantly inhibit the expression of AKR1s in colon cancer cells. LC-MS/MS assay indicated that YAP promoted the accumulation and secretion of GS-HNE by regulating the expression of ACSL4/AKR1s. GS-HNE can inhibit the survival of T cells in vitro. Therefore, we hypothesized that YAP could inhibit the survival of tumor-infiltrating CD8+T cells by reprogramming ferroptosis/4HNE metabolism and promoting GS-HNE secretion in colon cancer. In this study, we will elucidate the effect of YAP-mediated ferroptosis/4HNE metabolic reprogramming on the tumor immune microenvironment of colon cancer and the underlying mechanisms, and explore new strategies to reverse the immunotherapy resistance in colon cancer.