Department of Obstetrics and Gynecology, The First Affiliated Hospital of Guangzhou Medical University, 510120, Guangzhou, China.
Department of Immunology, School of Basic Medical Sciences, Guangdong Provincial Key Laboratory of Proteomics, Southern Medical University, 510515, Guangzhou, China.
Angiogenesis. 2019 Aug;22(3):397-410. doi: 10.1007/s10456-019-09665-1. Epub 2019 Apr 15.
Recently, cancer-derived exosomes were shown to have pro-metastasis function in cancer, but the mechanism remains unclear. Angiogenesis is essential for tumor progression and is a great promising therapeutic target for advanced cervical cancer. Here, we investigated the role of cervical cancer cell-secreted exosomal miR-221-3p in tumor angiogenesis.
miR-221-3p was found to be closely correlated with microvascular density in cervical squamous cell carcinoma (CSCC) by evaluating the microvascular density with immunohistochemistry and miR-221-3p expression with in situ hybridization in clinical specimens. Using the groups of CSCC cell lines (SiHa and C33A) with miR-221-3p overexpression and silencing, the CSCC exosomes were characterized by electron microscopy, western blotting, and fluorescence microscopy. The enrichment of miR-221-3p in CSCC exosomes and its transfer into human umbilical vein endothelial cells (HUVECs) were confirmed by qRT-PCR. CSCC exosomal miR-221-3p promoted angiogenesis in vitro in Matrigel tube formation assay, spheroid sprouting assay, migration assay, and wound healing assay. Then, exosome intratumoral injection indicated that CSCC exosomal miR-221-3p promoted tumor growth in vivo. Thrombospondin-2 (THBS2) was bioinformatically predicted to be a direct target of miR-221-3p, and this was verified by using the in vitro and in vivo experiments described above. Additionally, overexpression of THBS2 in HUVECs rescued the angiogenic function of miR-221-3p.
Our results suggest that CSCC exosomes transport miR-221-3p from cancer cells to vessel endothelial cells and promote angiogenesis by downregulating THBS2. Therefore, CSCC-derived exosomal miR-221-3p could be a possible novel diagnostic biomarker and therapeutic target for CSCC progression.
最近的研究表明，癌症来源的外泌体在癌症中具有促进转移的功能，但具体机制尚不清楚。血管生成对于肿瘤的进展至关重要，是治疗晚期宫颈癌的一个很有前途的治疗靶点。在这里，我们研究了宫颈癌细胞分泌的外泌体 miR-221-3p 在肿瘤血管生成中的作用。
通过免疫组织化学评估临床标本中的微血管密度和原位杂交评估 miR-221-3p 的表达，发现 miR-221-3p 与宫颈鳞状细胞癌（CSCC）中的微血管密度密切相关。使用 miR-221-3p 过表达和沉默的 CSCC 细胞系（SiHa 和 C33A）的组，通过电子显微镜、western blot 和荧光显微镜对 CSCC 外泌体进行了表征。通过 qRT-PCR 证实了 CSCC 外泌体中 miR-221-3p 的富集及其向人脐静脉内皮细胞（HUVEC）的转移。CSCC 外泌体 miR-221-3p 在 Matrigel 管形成试验、球体发芽试验、迁移试验和划痕愈合试验中促进了体外血管生成。然后，外泌体瘤内注射表明 CSCC 外泌体 miR-221-3p 促进了体内肿瘤的生长。通过上述体外和体内实验验证，生物信息学预测血栓反应蛋白 2（THBS2）是 miR-221-3p 的直接靶点。此外，在 HUVEC 中过表达 THBS2 可挽救 miR-221-3p 的血管生成功能。
我们的研究结果表明，CSCC 外泌体将 miR-221-3p 从癌细胞转运到血管内皮细胞，并通过下调 THBS2 促进血管生成。因此，CSCC 来源的外泌体 miR-221-3p 可能是 CSCC 进展的一个潜在的新型诊断生物标志物和治疗靶点。
