三阴乳腺癌恶性度大预后差，尽管其免疫原性相对强，但免疫检查点抑制剂临床试验疗效未达到预期。肿瘤细胞自噬如何影响T细胞对其攻击的能力及分子机制尚不清楚。我们发现TNBC中自噬基因低表达且与预后差相关；动物实验显示自噬缺陷的4T1细胞抑制肿瘤浸润性T细胞的数量及活性，且对PD1抗体治疗敏感性降低；细胞实验显示自噬缺陷的TNBC细胞可能更容易逃避T细胞攻击，其分子机制与细胞外基质TNC蛋白相关。本课题拟进一步在自噬缺陷的模型上研究T细胞对TNBC细胞的杀伤作用，对其增殖成瘤的抑制作用，明确自噬能力低是TNBC患者对T细胞免疫治疗耐受的重要原因；通过从选择性自噬降解异常的角度阐明TNC蛋白在自噬缺陷细胞中高表达的分子机制，明确其通过与T细胞表面整合素受体结合来抑制T细胞信号通路，探讨其能否成为TNBC患者免疫治疗的疗效预测指标；明确TNC单抗与免疫检查点抑制剂的联合用药作用，为患者提供新的治疗策略

Compared with other forms of breast cancer, triple negative breast cancer (TNBC) is associated with advanced stage at diagnosis, increased risk of poorer outcome and lack of specific targets. Accumulating evidence suggests that TNBC may be the most regulated by intratumoral T cells, and thus the most responsive to immunotherapies. Immune-checkpoint inhibitors have achieved certain effect in the clinical trials, there is still much to do to improve the effect. Although autophagy is a catabolic process that widely involves in the whole process of human cancer, the role of autophagy in cells stimulating or limiting the T cell immune system’s attack on tumor cells has not been well understood.In our preliminary study, we found that protein levels of autophagy-related genes decreased in TNBC breast cancer tissues. Animal experiments showed that autophagy-deficient 4T1 tumors inhibited the number and activity of tumor infiltrating T cells, and decreased the sensitivity to anti-PD1 antibody treatment. Inhibition of autophagic activity in MEF and MDA-MB-231 cells resulted in impaired susceptibility to cytotoxic T-cell-mediated lysis. Through SILAC proteomics analysis, we identified the extracellular matrix protein Tenascin-C (TNC), upregulated in autophagy-deficient cells as a potential immunosuppressive molecule. In this proposal, we will establish the autophagy-deficient TNBC cell models and animal models. Within these models, we will explore the inhibitory effect（including T cell mediated cytotoxicity and proliferation）of activated T cells on tumor cells with different autophagic activity , to further confirm that cancer cells with low autophagic activity is prone to escape T cell immune attack. We will investigate the mechanism that extracellular matrix protein TNC is highly expressed in autophagy-deficient TNBC cells because of abnormality of selective autophagy degradation. We will also explore the mechanisms that how TNC interacts with integrin on the cell surface of T cells and inhibits T-cell activation. More importantly, we will evaluate the synergistic effect of anti-TNC antibody and T cell immune-checkpoint inhibitors for providing new strategies for TNBC treatment.