人参皂苷Rg3通过CXCL16/CXCR6轴促进CD8+T细胞浸润增加抗肺癌免疫治疗疗效

PD-1/PD-L1 inhibitors as immunotherapy have become an important treatment for non-small cell lung cancer, however lack of CD8+T cells impairs their efficacy. Chemokine CXCL16 and its receptor CXCR6 could increase tumor infiltrating immune cells. Our previous study found that in Lewis tumor bearing mice model, traditional Chinese medicine Rg3 could increase the efficacy of PD-1 antibody, promote invasion of CD8+T cells in tumor, upregulate CXCL16 level significantly. Moreover, it is reported that CXCL16 was expressed in lung cancer tissue and lung cancer cell lines. Thus, we speculated that Rg3 might regulate the chemotaxis and activation of CD8+T cells by CXCL16/CXCR6 axis between lung cancer cells and immune cells, and play synergistic effects with PD-1 antibodies. This study will confirm the hypothesis by using flow cytometry analysis, immunohistochemistry, ELISA, Western blot, PCR in vitro and in vivo. This study will provide a theoretical basis for the combined application of Chinese medicine and immunotherapy, explain the unique advantages of combination of traditional Chinese and Western medicine for cancer, and drive the future "bench to bedside" transformation.

以PD-1/PD-L1抑制剂为代表的免疫治疗已成为非小细胞肺癌的重要治疗手段，缺乏CD8+T细胞浸润是其疗效欠佳的机制之一。已有研究证实趋化因子CXCL16及其受体CXCR6可以增加肿瘤浸润免疫细胞。我们的前期研究发现在Lewis荷瘤小鼠模型中，中药Rg3可以增加PD-1抗体的疗效，促进CD8+T细胞在肿瘤中的浸润，同时发现CXCL16显著上调。结合文献报道CXCL16在肺癌组织和肺癌细胞系中表达，因此我们推测Rg3可能通过肺癌细胞与免疫细胞之间的CXCL16/CXCR6轴调节CD8+T细胞的趋化和激活，进而协同PD-1抗体发挥抗癌作用。本研究拟进一步通过体外和体内实验，利用流式细胞术、免疫组化、ELISA、Transwell共培养、Western blot、PCR等方法来证实上述假说，为中药与免疫治疗联合提供理论依据，阐释中西医结合抗癌的独特优势，为将来的“基础-临床”转化奠定基础。

PD-1抑制剂为已经成为非小细胞肺癌治疗的重要组成部分，缺乏CD8+T细胞浸润是其疗效欠佳的机制之一，化疗和抗血管生成药物是西医增加增加疗效的主要方法，而中药的相关研究较少。本研究选取扶正中药代表人参皂苷Rg3，探索与PD-1协同起效的内在机制。本实验首先在Lewis荷瘤小鼠模型中发现中药Rg3可以增加PD-1抗体的疗效，促进CD8+T细胞在肿瘤中的浸润，同时发现趋化因子CXCL16显著上调。接下来通过体外和体内实验，采用人源和鼠源两种肺癌细胞株A549和LLC，利用流式细胞术、ELISA、T细胞与肿瘤细胞共培养、Western blot、中和抗体等方法证实CXCL16/CXCR6是Rg3能够趋化CD8+T细胞浸润肿瘤组织的关键机制，为中药与免疫治疗联合提供了新的理论依据。