Cancer-secreted exosomal miRNAs are emerging mediators of cancer-stromal cross-talk in the tumor environment. Our previous miRNAs array of cervical squamous cell carcinoma (CSCC) clinical specimens identified upregulation of miR-221-3p. Here, we show that miR-221-3p is closely correlated with peritumoral lymphangiogenesis and lymph node (LN) metastasis in CSCC. More importantly, miR-221-3p is characteristically enriched in and transferred by CSCC-secreted exosomes into human lymphatic endothelial cells (HLECs) to promote HLECs migration and tube formation in vitro, and facilitate lymphangiogenesis and LN metastasis in vivo according to both gain-of-function and loss-of-function experiments. Furthermore, we identify vasohibin-1 (VASH1) as a novel direct target of miR-221-3p through bioinformatic target prediction and luciferase reporter assay. Re-expression and knockdown of VASH1 could respectively rescue and simulate the effects induced by exosomal miR-221-3p. Importantly, the miR-221-3p-VASH1 axis activates the ERK/AKT pathway in HLECs independent of VEGF-C. Finally, circulating exosomal miR-221-3p levels also have biological function in promoting HLECs sprouting in vitro and are closely associated with tumor miR-221-3p expression, lymphatic VASH1 expression, lymphangiogenesis, and LN metastasis in CSCC patients. In conclusion, CSCC-secreted exosomal miR-221-3p transfers into HLECs to promote lymphangiogenesis and lymphatic metastasis via downregulation of VASH1 and may represent a novel diagnostic biomarker and therapeutic target for metastatic CSCC patients in early stages.

中文翻译：

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宫颈鳞状细胞癌分泌的外泌体 miR-221-3p 通过靶向 VASH1 促进淋巴管生成和淋巴转移。

癌症分泌的外泌体 miRNA 是肿瘤环境中癌症-基质串扰的新兴介质。我们之前的宫颈鳞状细胞癌 (CSCC) 临床标本的 miRNA 阵列确定了 miR-221-3p 的上调。在这里，我们表明 miR-221-3p 与 CSCC 中的肿瘤周围淋巴管生成和淋巴结 (LN) 转移密切相关。更重要的是，miR-221-3p 在 CSCC 分泌的外泌体中富集并通过其转移到人淋巴管内皮细胞 (HLEC) 中以促进 HLEC 在体外迁移和管形成，并根据两者的增益促进体内淋巴管生成和 LN 转移。功能和功能丧失实验。此外，我们通过生物信息学靶点预测和荧光素酶报告基因分析将 vasohibin-1 (VASH1) 鉴定为 miR-221-3p 的新直接靶点。VASH1 的重新表达和敲低可以分别挽救和模拟外泌体 miR-221-3p 诱导的作用。重要的是，miR-221-3p-VASH1 轴激活 HLEC 中的 ERK/AKT 通路，不依赖于 VEGF-C。最后，循环外泌体 miR-221-3p 水平还具有促进 HLEC 在体外萌芽的生物学功能，并且与 CSCC 患者的肿瘤 miR-221-3p 表达、淋巴 VASH1 表达、淋巴管生成和 LN 转移密切相关。总之，CSCC 分泌的外泌体 miR-221-3p 转移到 HLECs 中，通过下调 VASH1 促进淋巴管生成和淋巴转移，可能代表早期转移性 CSCC 患者的新型诊断生物标志物和治疗靶点。