激活STING/IFN-I通路活化与募集CD8+T细胞：益气扶正法协同PD-1/PD-L1抑制剂治疗食管癌的分子机制？

Immunotherapy including PD-1/PD-L1 inhibitors is a milestone in the field of cancer therapy. However, the efficiency of PD-1/PD-L1 inhibitors in cancer needs to be improved. Activating and recruiting of CD8+ T cells are essential to improve the response rate of PD-1/PD-L1 inhibitors. Previously, we found that ShenQi FuZheng Injection can increase the proportion of activated CD8+ T cells in microenvironment of tumor. In further study we found that ShenQi FuZheng Injection combined with PD-1 antibody decreased the proliferation rate of cancer cells, as well as increased the apoptosis rate and activated CD8+ T cells numbers, but the mechanism was unclear. STING/IFN-I pathway plays a key role in activating and recruiting CD8+ T cells and Ginseng Radix et Rhizoma extract can induce IFN-I secretion. We hypothesized that the therapy of Replenishing Qi and Reinforcing the healthy Qi may promote the activation and recruitment of CD8+ T cells by activating STING/IFN-I pathway and play a synergistic role with PD-1/PD-L1 inhibitors in esophageal squamous cell carcinoma (ESCC). This project intends to observe the synergistic effect of the therapy of ShenQi FuZheng Injection and PD-1/PD-L1 inhibitors in ESCC from the animal-cell-molecular level, and to analyze its mechanism. By this way new ideas for expanding the population of immunotherapy and experimental support for the theory of "Replenishing Qi and Reinforcing the healthy Qi" would be provided in the treatment of malignant tumor.

以PD-1/PD-L1抑制剂为代表的免疫治疗是肿瘤治疗领域的里程碑，如何活化募集CD8+T细胞从而提高其应答率是目前研究热点。益气扶正法通过增强免疫功能防治肿瘤，但具体机制不明。在前期发现参芪扶正注射液增加肿瘤微环境中活化的CD8+T细胞并增强PD-1抗体抗食管癌作用的基础上，结合STING/IFN-I通路在CD8+T细胞活化募集中发挥关键作用及人参诱导IFN-I分泌的最新进展，提出“益气扶正法通过激活STING/IFN-I通路活化与募集CD8+T细胞从而提高PD-1/PD-L1抑制剂治疗食管鳞癌应答率”的假说。本研究拟从动物-细胞-分子层次验证假说，解析参芪扶正注射液联合PD-1/PD-L1抗体治疗食管鳞癌的协同效应与CD8+T细胞活化募集的相关性，并从STING/IFN-I通路阐明其调节免疫的分子机制，为临床应用益气扶正法提高PD-1/PD-L1抑制剂应答率提供实验依据。

以PD-1/PD-L1抑制剂为代表的免疫治疗是肿瘤治疗领域的里程碑，如何活化募集CD8+T细胞从而提高其应答率是目前研究热点。益气扶正法通过增强免疫功能防治肿瘤，但具体机制不明。在前期发现参芪扶正注射液增加肿瘤微环境中活化的CD8+T细胞并增强PD-1抗体抗食管癌作用的基础上，结合STING/IFN-I通路在CD8+T细胞活化募集中发挥关键作用以及人参诱导IFN-I分泌的最新进展，本研究进一步从动物-细胞-分子层次验证解析益气扶正法代表药物参芪扶正注射液联合PD-1/PD-L1抗体治疗食管鳞癌的协同效应及其与CD8+T细胞活化募集的相关性，并从STING/IFN-I通路阐明其调节免疫的分子机制。本研究发现与单用PD-1/PD-L1抗体治疗相比，PD-1/PD-L1抗体联合益气扶正中药组小鼠的肿瘤重量及体积显著减少，肿瘤组织中CD8+T细胞、CD8+PD-1+ T细胞、CD8+CD44+ T细胞数量以及CXCL9、pSTING、IFN-α蛋白含量显著增多。在细胞水平，STING基因扩增或正常的PBMCs细胞与食管鳞癌细胞共培养后，与单用PD-1/PD-L1抗体相比，PD-1/PD-L1抗体联合益气扶正中药组处理的食管鳞癌细胞增殖、转移能力显著减弱，PBMCs细胞中的CD8+T细胞、CD8+PD-1+ T细胞、CD8+CD44+ T细胞数量以及CXCL9、pSTING、IFN-α蛋白含量显著增高。敲减STING基因的PBMCs细胞与食管鳞癌细胞共培养后，与单用PD-1/PD-L1抗体相比，PD-1/PD-L1抗体联合益气扶正中药组处理的食管鳞癌细胞增殖、转移能力无显著差异，PBMCs细胞中的CD8+T细胞、CD8+PD-1+ T细胞、CD8+CD44+ T细胞数量以及CXCL9、pSTING、IFN-α蛋白含量均无显著差异。本研究验证了“益气扶正法通过激活STING/IFN-I通路活化与募集CD8+T细胞从而提高PD-1/PD-L1抑制剂治疗食管鳞癌应答率”的假说，为临床应用益气扶正法提高PD-1/PD-L1抑制剂应答率提供实验依据。