Department of Genetics, Medical College of Soochow University, Suzhou, 215123, China.
Department of Radiotherapy & Oncology, The Second Affiliated Hospital of Soochow University, San Xiang Road No. 1055, Suzhou, 215004, China.
Mol Cancer. 2019 Feb 8;18(1):22. doi: 10.1186/s12943-019-0949-7.
Though esophageal cancer is three to four times more common among males than females worldwide, this type of cancer still ranks in the top incidence among women, even more than the female specific cancer types. The occurrence is currently attributed to extrinsic factors, including tobacco use and alcohol consumption. However, limited attention has been given to gender-specific intrinsic genetic factors, especially in female.
We re-annotated a large cohort of microarrays on 179 ESCC patients and identified female-specific differently expressed lncRNAs. The associations between FMR1-AS1 and the risk and prognosis of ESCC were examined in 206 diagnosed patients from eastern China and validated in 188 additional patients from southern China. The effects of FMR1-AS1 on the malignant phenotypes on female ESCC cells were detected in vitro and in vivo. ChIRP-MS, reporter gene assays and EMSA were conducted to identify the interaction and regulation among FMR1-AS1, TLR7 and NFκB.
We found FMR1-AS1 expression is exclusively altered and closely associated with the level of sXCI in female ESCC patients, and its overexpression may correlate to poor clinical outcome. ChIRP-MS data indicate that FMR1-AS1 could be packaged into exosomes and released into tumor microenvironment. Functional studies demonstrated that FMR1-AS1 could bind to endosomal toll-like receptor 7 (TLR7) and activate downstream TLR7-NFκB signaling, promoting the c-Myc expression, thus inducing ESCC cell proliferation, anti-apoptosis and invasion ability. Exosome incubation and co-xenograft assay indicate that FMR1-AS1 exosomes may secreted from ESCC CSCs, transferring stemness phenotypes to recipient non-CSCs in tumor microenvironment. Furthermore, we also found a correlation between the serum levels of FMR1-AS1 and the overall survival (OS) of the female ESCC patients.
Our results highlighted exosomal FMR1-AS1 in maintaining CSC dynamic interconversion state through the mechanism of activating TLR7-NFκB signaling, upregulating c-Myc level in recipient cells, which may be taken as an attractive target approach for advancing current precision cancer therapeutics in female patients.
尽管全球范围内食管癌在男性中的发病率是女性的三到四倍，但这种癌症在女性中的发病率仍然位居前列，甚至超过了女性特有的癌症类型。目前，这种疾病的发生归因于外在因素，包括吸烟和饮酒。然而，人们对性别特异性内在遗传因素的关注有限，尤其是在女性中。
我们重新注释了 179 名 ESCC 患者的大量微阵列，并鉴定了女性特异性差异表达的 lncRNA。在中国东部的 206 名确诊患者中检查了 FMR1-AS1 与 ESCC 风险和预后的关联，并在中国南部的 188 名额外患者中进行了验证。在体外和体内检测了 FMR1-AS1 对女性 ESCC 细胞恶性表型的影响。ChIRP-MS、报告基因检测和 EMSA 用于鉴定 FMR1-AS1、TLR7 和 NFκB 之间的相互作用和调节。
我们发现 FMR1-AS1 的表达仅在女性 ESCC 患者中发生改变，并与 sXCI 的水平密切相关，其过表达可能与不良的临床结局相关。ChIRP-MS 数据表明，FMR1-AS1 可以被包裹在细胞外体中并释放到肿瘤微环境中。功能研究表明，FMR1-AS1 可以与内体 Toll 样受体 7（TLR7）结合并激活下游 TLR7-NFκB 信号通路，促进 c-Myc 表达，从而诱导 ESCC 细胞增殖、抗凋亡和侵袭能力。外泌体孵育和共异种移植实验表明，FMR1-AS1 外泌体可能由 ESCC CSCs 分泌，将干性表型转移到肿瘤微环境中的受体非 CSCs。此外，我们还发现 FMR1-AS1 的血清水平与女性 ESCC 患者的总生存期（OS）之间存在相关性。
我们的研究结果强调了细胞外体 FMR1-AS1 通过激活 TLR7-NFκB 信号通路、上调受体细胞中 c-Myc 水平的机制，维持 CSC 动态转化状态，这可能成为提高女性患者当前精准癌症治疗的一个有吸引力的靶标方法。
