Department of Radiation Oncology, The Affiliated Huaian No.1 People's Hospital of Nanjing Medical University, Huai'an, China.
Department of Radiation Oncology, Lianshui County People's Hospital, Kangda College of Nanjing Medical University, Huai'an, China.
Mol Carcinog. 2024 Oct;63(10):1922-1937. doi: 10.1002/mc.23782. Epub 2024 Jun 27.
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.
癌症相关成纤维细胞 (CAFs) 是肿瘤微环境中丰富且异质性的基质细胞，通过向癌细胞转移外泌体，在调节肿瘤进展和治疗耐药性方面发挥重要作用。然而，CAFs 如何调节食管鳞状细胞癌 (ESCC) 的进展和放射抵抗仍不完全清楚。通过对 174 例接受手术的 ESCC 患者和 78 例接受根治性放化疗的 ESCC 患者的术前活检标本进行免疫组织化学评估，评估 CAFs 中成纤维细胞激活蛋白 (FAP) 的表达。我们根据 FAP 表达对 CAFs 进行排序，并收集条件培养基 (CM) 培养 ESCC 细胞。在源自 FAP CAFs 和 FAP CAFs 的外泌体中测量了几个被认为调节 ESCC 进展和/或放射抵抗的 lncRNA 的表达水平。随后，通过细胞计数试剂盒-8、5-乙炔基-2'-脱氧尿苷、transwell、集落形成和异种移植实验来研究 FAP CAFs 和 FAP CAFs 之间的功能差异。最后，进行了一系列体外和体内实验来评估 AFAP1-AS1 对 ESCC 细胞放射敏感性的影响。基质 CAFs 中的 FAP 表达与神经浸润、血管浸润、浸润深度、淋巴结转移、缺乏临床完全缓解和不良生存呈正相关。与用 CM/FAP CAFs 培养相比，用 CM/FAP CAFs 培养 ESCC 细胞显著增加了癌细胞的增殖、迁移、侵袭和放射抵抗。重要的是，FAP CAFs 通过外泌体将功能性 lncRNA AFAP1-AS1 直接转移到 ESCC 细胞中发挥作用。功能研究表明，AFAP1-AS1 通过增强 ESCC 细胞的 DNA 损伤修复促进放射抵抗。临床研究表明，高水平的血浆 AFAP1-AS1 与 ESCC 患者对 dCRT 的反应不良相关。我们的研究结果表明，FAP CAFs 通过转移外泌体 lncRNA AFAP1-AS1 促进 ESCC 细胞的放射抵抗；并且可能是 ESCC 治疗的潜在治疗靶点。
