CLASP2调控膀胱癌PD-L1细胞膜定位表达的机制研究

晚期膀胱癌出现浸润转移的一个重要原因是免疫逃逸。肿瘤细胞膜的程序性死亡分子配体1（PD-L1）可与炎症细胞的程序性死亡分子1（PD-1）结合，促炎症细胞凋亡，从而实现免疫逃逸，所以研究PD-L1的调控机制对逆转免疫逃逸、治疗晚期膀胱癌有重要意义。但国内外尚无膀胱癌PD-L1异常表达的机制报道。我们前期研究发现胞质连接蛋白2（CLASP2）与膀胱癌的恶性程度密切相关；预实验发现CLASP2可调控微管功能及空间分布，招募转运PD-L1的马达蛋白KIF1C，从而影响PD-L1的细胞膜定位表达，这可能是一个膀胱癌异常表达PD-L1的新机制。我们将重点应用“动态”免疫荧光等技术，从临床标本、细胞实验、小鼠模型三个层面，进一步验证及深入研究该机制，以明确CLASP2调控微管功能的具体方式；确证马达蛋白KIF1C的转运作用及其与PD-L1的交互作用结构域。本课题的成果将为膀胱癌的治疗提供新靶点。

One of the main reasons of infiltration and metastasis of advanced-stage bladder cancer is immune escape. Programmed cell death ligand 1 (PD-L1) on the plasma membrane of bladder cancer cells could bind with programmed cell death protein 1 (PD-1) on inflammatory cells, which would consequently induce the apoptosis of inflammatory cells and immune escape. Therefore, the investigation of regulations of PD-L1 in bladder cancer would be very meaningful for reversing immune escape and treating bladder cancer. However, the mechanisms of regulation of PD-L1 in bladder cancer have not been reported yet. Our previous study demonstrated that cytoplasmic linker-associated protein 2 (CLASP2) was closely related to the malignance of bladder cancer. And the pilot investigations showed that CLASP2 could regulate the function and distribution of microtubules, recruit motor protein KIF1C, and modulate plasma membrane localized expression of PD-L1, which would be a new mechanism of abnormal expression of PD-L1 in bladder cancer. We would further confirm and investigate this mechanism by utilizing various techniques, such as dynamic immunofluorescent observation. The study would be performed on three levels of protocols including clinical samples, cellular experiments in vitro, and mice experiments. The exact mechanism of CLASP2 modulating microtubule functions, the role of KIF1C trafficking PD-L1 and their interactive domains will be revealed. New targets of bladder cancer treatment would be provided via implement of present study.