背景:癌症相关成纤维细胞(CAFs)在最近的研究中得到了深入的研究,目的是找到更多关于其参与肿瘤进展机制的具体证据。这是目前未知的。CAFs可以分泌载有蛋白质的外泌体,脂质和RNA,所有这些都会影响肿瘤微环境。本研究将microRNA-93-5p(miR-93-5p)鉴定为负责CAF对结直肠癌(CRC)的促瘤作用的新型外泌体货物。
方法:从癌组织中分离CAFs和正常成纤维细胞(NFs),并与手术切除CRC患者的癌旁组织相匹配。miR-93-5p之间的相互作用,通过ChIP和双荧光素酶报告基因测定鉴定叉头盒A1(FOXA1)和TGFB3。用CCK-8、集落形成、和流式细胞术。在照射下评估裸鼠中SW480细胞的肿瘤发生。
结果:发现FOXA1与CRC细胞的放射抗性降低相关,并被证实为miR-93-5p的靶标。CAFs来源的外泌体含有比NFs更高的miR-93-5p,这增强了SW480细胞的增殖并从辐射诱导的细胞凋亡中拯救了它们。miR-93-5p被鉴定为CAFs对SW480细胞的外泌体效应的介质,可能是通过下调FOXA1和上调TGFB3。FOXA1可以与TGFB3的启动子结合,从而抑制TGFB3的核积累。此外,含有miR-93-5p的CAFs来源的外泌体增加了受照射的裸鼠中SW480细胞的肿瘤生长。
结论:本研究确定miR-93-5p是一种特异性的外泌体货物,可以挽救CRC细胞免受辐射诱导的细胞凋亡。
BACKGROUND: Cancer-associated fibroblasts (CAFs) have been intensively studied in recent studies with aims of finding more concrete evidence on their mechanism of involvement in tumor progression, which is currently unknown. CAFs can secrete exosomes which are loaded with proteins, lipids and RNAs, all of which affect tumor microenvironment. The present study identified microRNA-93-5p (miR-93-5p) as a novel exosomal cargo responsible for the pro-tumorigenic effects of CAFs on colorectal cancer (CRC).
METHODS: CAFs and normal fibroblasts (NFs) were isolated from cancerous tissues and matched with paracancerous tissues that had been surgically resected from CRC patients. The interaction among miR-93-5p, forkhead box A1 (FOXA1) and
TGFB3 was identified through ChIP and dual luciferase reporter assays. The proliferation and apoptosis of SW480 cells co-cultured with CAFs-derived exosomes under irradiation were evaluated by CCK-8, colony formation, and flow cytometric assays. Tumorigenesis of SW480 cells in nude mice was assessed under the irradiation.
RESULTS: FOXA1 was found to be associated with reduced radioresistance in CRC cells and was verified as a target of miR-93-5p. CAFs-derived exosomes contained higher miR-93-5p than those from NFs, which augmented SW480 cell proliferation and rescued them from radiation-induced apoptosis. miR-93-5p was identified as a mediator of the exosomal effects of CAFs on SW480 cells, possibly through downregulating FOXA1 and upregulating
TGFB3. FOXA1 could bind to the promoter of
TGFB3, thereby inhibiting nuclear accumulation of
TGFB3. Also, CAFs-derived exosomes containing miR-93-5p increased the tumor growth of SW480 cells in irradiated nude mice.
CONCLUSIONS: The present study identifies miR-93-5p as a specific exosomal cargo that rescues CRC cells against radiation-induced apoptosis.