癌相关成纤维细胞通过外泌体lncRNA激活自噬通路促进舌鳞癌化疗抵抗的机制研究

Chemotherapy resistance is the essential cause of tumor treatment failure. Our previous study demonstrated that cancer associated fibroblasts (CAFs) promoted metastasis and chemoresistance of tongue squamous cell carcinoma (TSCC). Compared with parental TSCC cells, cisplatin activated autophagy process and reduced chemotherapy sensitivity in cisplatin-resistant TSCC cells. Moreover, cisplatin induced autophagy activation of parental TSCC cells co-cultured with CAFs. However, whether CAFs promote chemoresistance of TSCC via autophagy activation remains obscure. If so, what is the mechanism? Our preliminary data showed that CAFs derived exosomes promoted chemoresistance in TSCC cells. We selected long non-coding RNA (lncRNA) that were differentially expressed in exosomes derived from CAFs and matched tumor counterpart normal fibroblasts, and found that functional lncRNA mediated autophagy activation and chemoresistance in cisplatin-resistant TSCC cells. Accordingly, we propose a scientific hypothesis: CAFs induce chemotherapy resistance of TSCC via autophagy activation mediated by functional lncRNA from CAFs derived exosomes. In this project, we intend to knock down lncRNA expression in CAFs derived exosomes, investigate their functions in regulating autophagy activation and chemoresistance, and explore the molecular mechanisms of lncRNA interaction with autophagy signaling proteins in vitro and in vivo. Then we will correlate expression of functional lncRNA with chemotherary sensitivity and prognosis of TSCC patients. This project will provide experimental foundations development of targeted therapy aimed for reversing TSCC chemoresistance.

化疗抵抗是肿瘤治疗失败的重要原因。我们前期已证实：癌相关成纤维细胞（CAFs）促进舌鳞癌侵袭转移与化疗抵抗。相较舌鳞癌亲本细胞，耐药细胞在顺铂作用下自噬激活、化疗敏感性降低；然而，与CAFs共培养后，化疗药物可直接激活亲本细胞自噬。那么，CAFs是否介导自噬激活从而导致舌鳞癌化疗抵抗？机制是什么？在预实验中，CAFs外泌体促进舌鳞癌化疗抵抗，筛选外泌体异常表达长非编码RNA（lncRNA），其中RP13-463N16.6介导耐药细胞自噬激活与化疗耐受。据此我们提出假设：CAFs通过外泌体携带功能lncRNA，介导自噬激活，导致舌鳞癌化疗抵抗。本项目拟通过干预外泌体lncRNA表达，在体外和体内模型中探索lncRNA对舌鳞癌自噬激活、化疗抵抗的调控功能，阐明lncRNA与自噬信号蛋白相互作用的分子机理，检测外泌体lncRNA与化疗敏感性、患者预后的关系，为靶向治疗舌鳞癌化疗抵抗提供实验依据。

化疗耐药是口腔鳞癌患者预后不良的重要因素，癌相关成纤维细胞（CAFs）在化疗耐药中扮演重要角色。本项目实验发现顺铂处理后的CAFs上清显著增强口腔鳞癌细胞的顺铂耐药性，取CAFs培养上清行细胞因子抗体芯片分析发现GDF15分泌显著升高。进一步研究发现：①GDF15高表达的口腔鳞癌患者预后较差；②GDF15能增强口腔鳞癌细胞的顺铂耐受性；③通过高通量测序发现GDF15处理后口腔鳞癌细胞LASP1表达上升, PI3K/AKT信号通路激活④敲低LASP1可抑制口腔鳞癌PI3K/AKT信号通路激活，降低舌鳞癌细胞顺铂耐受性。我们提出科学假说：化疗药物损伤导致CAFs高分泌GDF15，GDF15通过LASP1/PI3K/AKT信号通路提高口腔鳞癌细胞的顺铂耐受性。本项目通过功能机制实验、动物模型及临床资料分析，探索GDF15/LASP1/PI3K/AKT信号轴在口腔鳞癌顺铂化疗耐药的机制，为治疗口腔鳞癌顺铂化疗耐药提供新的理论依据与思路。