肿瘤相关成纤维细胞(CAFs)是肿瘤微环境中丰富且异质的基质细胞,通过将外泌体转移到癌细胞中,在调节肿瘤进展和治疗抗性方面发挥重要作用。然而,CAFs如何调节食管鳞状细胞癌(ESCC)的进展和放射抗性仍未完全了解.采用免疫组织化学方法对174例接受手术治疗的ESCC患者和78例接受确定性放化疗的ESCC患者的预处理活检标本进行了成纤维细胞活化蛋白(FAP)在CAFs中的表达。我们根据FAP表达对CAFs进行排序,收集条件培养基(CM)以培养ESCC细胞。在源自FAP+CAF和FAP-CAF的外泌体中测量被认为调节ESCC进展和/或放射抗性的几种lncRNA的表达水平。随后,细胞计数试剂盒-8,5-乙炔基-2'-脱氧尿苷,transwell,菌落形成,进行和异种移植物测定以研究FAP+CAF和FAP-CAF之间的功能差异。最后,我们采用一系列体外和体内试验来评价AFAP1-AS1对ESCC细胞放射敏感性的影响.基质CAFs中FAP的表达与神经浸润呈正相关,血管浸润,入侵深度,淋巴结转移,缺乏临床完全缓解和生存率差。用CM/FAP+CAFs培养ESCC细胞显著增加肿瘤增殖,迁移,入侵和抗辐射,与CM/FAP-CAF培养物相比。重要的是,FAP+CAF通过将功能性lncRNAAFAP1-AS1经由外泌体直接转移至ESCC细胞而发挥作用。功能研究表明,AFAP1-AS1通过增强ESCC细胞的DNA损伤修复来促进放射抗性。临床上,ESCC患者血浆AFAP1-AS1水平升高与dCRT反应不良相关.我们的发现表明,FAP+CAFs通过转移外泌体lncRNAAFAP1-AS1促进ESCC细胞的放射抗性;并且可能是ESCC治疗的潜在治疗靶标。
Cancer-associated fibroblasts (CAFs) are abundant and heterogeneous stromal cells in the tumor microenvironment, which play important roles in regulating tumor progression and therapy resistance by transferring exosomes to cancer cells. However, how CAFs modulate esophageal squamous cell carcinoma (ESCC) progression and radioresistance remains incompletely understood. The expression of fibroblast activation protein (FAP) in CAFs was evaluated by immunohistochemistry in 174 ESCC patients who underwent surgery and 78 pretreatment biopsy specimens of ESCC patients who underwent definitive chemoradiotherapy. We sorted CAFs according to FAP expression, and the conditioned medium (CM) was collected to culture ESCC cells. The expression levels of several lncRNAs that were considered to regulate ESCC progression and/or radioresistance were measured in exosomes derived from FAP+ CAFs and FAP- CAFs. Subsequently, cell counting kit-8, 5-ethynyl-2\'-deoxyuridine, transwell, colony formation, and xenograft assays were performed to investigate the functional differences between FAP+ CAFs and FAP- CAFs. Finally, a series of in vitro and in vivo assays were used to evaluate the effect of AFAP1-AS1 on radiosensitivity of ESCC cells. FAP expression in stromal CAFs was positively correlated with nerve invasion, vascular invasion, depth of invasion, lymph node metastasis, lack of clinical complete response and poor survival. Culture of ESCC cells with CM/FAP+ CAFs significantly increased cancer proliferation, migration, invasion and radioresistance, compared with culture with CM/FAP- CAFs. Importantly, FAP+ CAFs exert their roles by directly transferring the functional lncRNA AFAP1-AS1 to ESCC cells via exosomes. Functional studies showed that AFAP1-AS1 promoted radioresistance by enhancing DNA damage repair in ESCC cells. Clinically, high levels of plasma AFAP1-AS1 correlated with poor responses to dCRT in ESCC patients. Our findings demonstrated that FAP+ CAFs promoted radioresistance in ESCC cells through transferring exosomal lncRNA AFAP1-AS1; and may be a potential therapeutic target for ESCC treatment.