PIEZO1响应结直肠癌基质硬度调控前体耗竭T细胞“状态转换”的机制研究

肿瘤内耗竭T细胞是免疫检查点抑制剂（ICIs）起效的关键靶细胞。但是，耗竭T细胞存在不同分化状态，前体耗竭T细胞（TPEX）而非终末耗竭T细胞（TTEX）是ICIs治疗响应的主要力量。TPEX向TTEX分化，即TPEX细胞“状态转换”，是ICIs治疗抵抗的重要原因。我们发现：基质硬度这一力学信号，是影响结直肠癌TPEX细胞状态转换及ICIs疗效的重要因素。进一步预实验表明，力感应钙离子通道PIEZO1激活可诱导转录因子ATOH8和NFAT2的核转位，协同促进TPEX细胞状态转换。由此我们推测：PIEZO1主导的力-生物信号转导是TPEX细胞状态转换的关键环节。本项目拟采用原子力显微镜、钙成像及荧光显微等技术手段，探究PIEZO1-ATOH8/NFAT2联动感应基质硬度促进结直肠癌中TPEX细胞“状态转换”的机制，为预测和逆转结直肠癌ICIs治疗抵抗提供理论支撑。

Exhausted T cells are the major cell population in response to immune checkpoint inhibitors (ICIs) treatment. They presented different differentiation stages, in which precursor exhausted T cells (TPEX), but not terminal exhausted T cells (TTEX), are the main effectors that support ICIs treatment response. The irreversible differentiation from TPEX to TTEX, namely the "state transition" of TPEX cells, is an essential reason for ICIs treatment resistance. In our preliminary findings, matrix stiffness, a kind of mechanical signal, is an important factor affecting the state transition of TPEX cells and the efficacy of ICIs in colorectal cancer. Furthermore, the activation of the mechanosensitive calcium channel PIEZO1 could induce nuclear translocation of transcription factors ATOH8 and NFAT2, which synergistically promote the state transition of TPEX cells. Therefore, we speculated that PIEZO1-dependent mechanical signal transduction may be the key mechanism for matrix stiffness to mediate the state transition of TPEX cells. This study intends to use experimental techniques including atomic force microscopy, calcium imaging and fluorescence microscopy, to explore the mechanism of PIEZO1-ATOH8/NFAT2 signalling axis responding to matrix stiffness to drive the state transition of TPEX cells in colorectal cancer. These findings would serve as theoretical support for predicting and reversing ICIs treatment resistance in colorectal cancer.