他莫昔芬耐药乳腺癌通过外泌体-STAT3轴诱导中性粒细胞N2型极化及正反馈调控机制研究

乳腺癌是女性首位好发肿瘤，约70%需接受内分泌治疗。他莫昔芬（TAM）作为最重要的基石药物，其耐药性一直是未解决的临床及科学难题。有研究提示，乳腺癌内分泌耐药受免疫微环境调控，但机制鲜有报道。我们通过生物信息学及临床样本分析验证，首次发现中性粒细胞浸润是乳腺癌TAM耐药的重要特征，且相比于非耐药细胞，TAM耐药乳腺癌细胞（TRBC）通过外泌体诱导中性粒细胞STAT3磷酸化水平增加，并向免疫抑制型（N2型）极化；此外，N2型中性粒细胞也具有促进乳腺癌细胞的TAM耐药性的功能。基于此，本项目拟通过蛋白组学及RNA-Seq分析，鉴定TRBC外泌体中发挥上述功能的关键分子及作用机制；建立人乳腺癌类器官及小鼠TAM耐药模型，动态观察TRBC与中性粒细胞的相互影响及靶向中性粒细胞的治疗价值。本项目将从中性粒细胞的角度系统阐述乳腺癌TAM耐药与免疫微环境的相互关系，为开发相应治疗策略提供理论及实验依据。

Breast cancer remains as the first malignant disease in women, and about 70% of cases require endocrine therapy. Tamoxifen (TAM) is one of the most important endocrine therapeutic drugs in breast cancer, its resistance was still an unsolved problem in clinical practice and worth further research. Recent studies suggested that endocrine resistance of breast cancer could be regulated by immune microenvironment, but the mechanism is rarely reported. Through bioinformatic analysis and breast cancer sample validation, we found for the first time that neutrophil infiltration was an important feature of TAM resistance of breast cancer, and compared with non-resistant cells, tamoxifen resistant breast cancer cells (TRBC) induced phosphorylation of neutrophilic STAT3 via exosomes, which resulted in polarization of neutrophils to immunosuppressive subtype (N2 type). In addition, the N2 neutrophils promoted TAM resistance of breast cancer cells as a positive feedback. On this basis, this project intends to use proteomics, RNA-seq and other techniques to identify the key molecules in TRBC exosomes that induce the neutrophilic STAT3 phosphorylation and its N2 polarization; meanwhile, we try to establish human breast cancer organoids and TAM-resistance breast cancer model in mice, so as to dynamically observe the interaction between TRBC and neutrophils in the process of TAM resistance, and also the significance of neutrophil targeted therapy. From the perspective of neutrophils, this project will systematically elaborate the interaction between endocrine resistance and immune microenvironment of breast cancer, and providing theoretical and experimental basis of the development of related therapeutic strategy.