Embelin靶向N-Shc/ZAP-70/PI3K/Akt轴调控CD8+T细胞在炎症相关性结直肠癌中的机制研究

N-Shc, a member of the Shc（Src homolog and collagen homolog）family of protein adaptors, as a promoter of malignant cell proliferation and survival, which can impair lymphocytes activation and survival via ZAP-70/PI3K/Akt signaling. However, no relevant study on colorectal cancer has been reported. We previously reported that Embelin effectively suppresses colon carcinogenesis in a mouse model of AOM/DSS-induced colitis-associated cancer, and this effect may be mediated by regulating the tumor microenvironment. Embelin restored the proliferative activity of T lymphocytes and increased the infiltration of CD8+T cells in tumor milieu. In addition, Embelin decreased N-Shc expression in the spleen and tumor tissue of CAC-bearing mice. We therefore speculate that Embelin limits the tumor initiation and progression by activating T cells and enhancing their anti-tumor activity via N-Shc/ZAP-70/PI3K/Akt mediated signals. In this study, we will investigate the effects of Embelin on the activation, differentiation and anti-tumor activity of CD8+T cells, with a particular focus on the activation of ZAP-70/PI3K/Akt signal by N-Shc inhibition. We look forward to identifying N-Shc as a novel biomarker and potential therapeutic target in colorectal cancer, and also providing theoretical foundations and application basis for Embelin’s clinical immunotherapy.

N-Shc通过ZAP-70/PI3K/Akt轴抑制T细胞活化、增殖，与肿瘤密切相关，但其与结直肠癌的相关性研究未见报道。我们既往研究发现信筒子素（Embelin）可抑制小鼠炎症相关性结直肠癌（CAC），机制与调控肿瘤免疫微环境相关。本研究前期工作发现：Embelin可恢复CAC小鼠体内T细胞活性，增加CD8+T细胞数量，同时可显著降低小鼠脾脏和结肠肿瘤间质中N-Shc表达。由此推测：Embelin可通过下调N-Shc促进CD8+T细胞增殖、恢复其抗肿瘤活性、并可能影响其分化，进而发挥抗炎、抗肿瘤的作用。本研究拟体内外探讨Embelin通过N-Shc/ZAP-70/PI3K/Akt轴对CD8+T细胞增殖、分化及肿瘤杀伤活性的影响及机制；研究其对CAC小鼠体内N-Shc表达的影响及与肿瘤的关系；结合临床标本检测，明确N-Shc是结直肠癌预后不良的标志，并评价其作为干预靶点的可能性。

N-Shc通过ZAP-70/PI3K/Akt轴抑制T细胞活化、增殖，与肿瘤密切相关，但其与结直肠癌的相关性研究未见报道。我们既往研究发现信筒子素（Embelin）可抑制小鼠炎症相关性结直肠癌（CAC），机制与调控肿瘤免疫微环境相关，且Embelin可恢复CAC小鼠体内T细胞活性，增加CD8+T细胞数量，同时可显著降低小鼠脾脏和结肠肿瘤间质中N-Shc的表达，由此推测Embelin可通过下调N-Shc，恢复ZAP-70/PI3K/Akt通路活性，促进CD8+T细胞增殖、恢复其抗肿瘤活性、并可能影响其分化，进而发挥抗炎、抗肿瘤的作用。通过检测51例本院结直肠癌患者手术标本，我们发现肿瘤组织中N-Shc表达水平显著高于癌旁组织，肿瘤组织中N-Shc高表达时，CD8+T细胞数目显著减少，且N-Shc表达水平与性别、原发肿瘤、远处转移、肿瘤分期无关，与年龄（P=0.0409）、淋巴结转移（P=0.0159）相关。进一步通过小鼠模型证实，Embelin干预下炎症相关性结直肠癌小鼠结肠组织中N-Shc表达量显著下降，体外研究证实Embelin可部分恢复ZAP-70/PI3K/Akt通路活性。以上研究结果表明N-Shc是结直肠癌预后不良的标志，但需进一步完善后续实验，明确Embelin通过N-Shc/ZAP-70/PI3K/Akt轴对CD8+T细胞增殖、分化及肿瘤杀伤活性的影响。