PD-L1对结肠癌干细胞“干性”的调控作用及机制研究

It is necessary to explore molecule and mechanism of the modulation of colon cancer stem cells for the prevention and treatment of colon cancer. The preliminary experimental results showed that tumor spheres and CD133+CSCs possess higher level of PD-L1, and PD-L1 expression is positively correlated with the expression of CSCs stemness related molecules in colon cancer tissue, suggesting that there is a correlation between PD-L1 and CSCs. Based on the previous work, the present project plans to carry out the following studies: 1) PD-L1 stably over-expression or knockdown colon cancer cell lines will be used to analyze the impact of PD-L1 expression on CSCs stemness in colon cancer through in vitro and in vivo; 2) To search for PD-L1 downstream molecule that associated with CSCs functions using high-throughput sequencing and other approaches, and explore whether the role of PD-L1 in regulating CSCs stemness can be mediated by PD-L1 downstream molecule; 3) Colon cancer cell lines, primary cells and human clinical tissue specimens will be employed to reveal the expression profile of PD-L1, its downstream molecule and CSCs related molecules in CSCs, the correlation between the expression of PD-L1 and its downstream molecule, CSCs related molecules and clinical pathological significance in cancer tissues. The project results will provide a new target for targeting colon cancer CSCs.

探索调控结肠癌肿瘤干细胞（Cancer stem cells，CSCs）的分子及机制，对结肠癌的防治具有重要意义。申请人前期实验发现，PD-L1基因在肿瘤球和CD133+CSCs中表达明显上调；在结肠癌组织中，PD-L1表达与CSCs干性分子表达成正相关，这提示PD-L1与结肠癌CSCs之间具有相关性。本项目拟在前期研究基础上开展如下研究：1）利用稳定过表达和干扰PD-L1结肠癌细胞，从细胞和动物水平研究PD-L1对结肠癌CSCs干性调控作用；2）利用高通量测序等多种方法寻找PD-L1下游与CSCs功能相关分子，揭示PD-L1下游调控分子在PD-L1调控结肠癌CSCs干性中发挥的作用；3）利用结肠癌细胞株、原代细胞及临床组织标本，分析PD-L1、下游调控分子及CSCs干性分子在CSCs上的表达谱，及其在癌组织中表达的相关性及临床病理意义。项目研究结果将为靶向结肠癌CSCs提供新的治疗靶点。

探索调控结肠癌肿瘤干细胞（Cancer stem cells，CSCs）的分子及机制，对结肠癌的防治具有重要意义。申请人前期实验发现，PD-L1在肿瘤球和CD133+CSCs中表达明显上调；在结肠癌组织中，PD-L1表达与CSCs干性分子表达成正相关，这提示PD-L1与结肠癌CSCs之间具有相关性。本项目拟在前期研究基础上开展如下研究：1）利用稳定过表达和干扰PD-L1结肠癌细胞，从细胞和动物水平研究PD-L1对结肠癌CSCs干性调控作用；2）利用高通量测序等多种方法寻找PD-L1下游与CSCs功能相关分子，揭示PD-L1下游调控分子在PD-L1调控结肠癌CSCs干性中发挥的作用；3）利用结肠癌细胞株、原代细胞及临床组织标本，分析PD-L1、下游调控分子及CSCs干性分子在CSCs上的表达谱，及其在癌组织中表达的相关性及临床病理意义。.本项目研究结果表明，PD-L1在肿瘤球和CD133+CD44+的细胞中表达升高；PD-L1表达上调通过促进肿瘤球形成，增加CD133+CD44+细胞比例，上调干性相关基因表达来维持肿瘤干细胞的自我更新能力；体内外实验还验证了PD-L1在耐药的CRC细胞中表达上调；有限稀释法梯度成瘤实验结果表明，过表达PD-L1的CRC细胞在1X104密度接种裸鼠皮下时，就可以明显成瘤，干扰PD-L1表达的CRC细胞成瘤能力明显降低。机制层面进一步阐述PD-L1与HMGA1直接结合，上调HMGA1的表达，激活PI3K/AKT和MEK/ERK信号通路，促进CRC中CSCs扩增。最后在临床标本中，验证了PD-L1与CSC相关分子及HMGA1表达成明显正相关。本项目研究结果将为靶向结肠癌CSCs提供新的治疗靶点。