Oncogenic epithelial cell-derived exosomes containing Rac1 and PAK2 induce angiogenesis in recipient endothelial cells.
Oncogenic epithelial cell-derived exosomes containing Rac1 and PAK2 induce angiogenesis in recipient endothelial cells.
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DOI：
10.18632/oncotarget.7573
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发表时间：
2016-04-12
期刊：
影响因子：
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通讯作者：
Mathias RA
中科院分区：
文献类型：
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作者：
Gopal SK;Greening DW;Hanssen EG;Zhu HJ;Simpson RJ;Mathias RA
转移级联描述了原发肿瘤细胞向远处继发部位的转移。肿瘤前缘的细胞被认为经历上皮-间质转化（EMT），以增强其运动性和侵袭扩散。EMT细胞是否直接促进肿瘤血管生成，以及外泌体（30- 150nm细胞外囊泡）的作用在很大程度上仍然未知。我们检测了来自MDCK细胞、稳定表达YBX1 （MDCKYBX1，中间EMT）的MDCK细胞和ras转化的MDCK细胞（21D1细胞，完全EMT）的外泌体的功能影响。补充MDCKYBX1或21D1外泌体后，2F-2B细胞的运动性和管的形成（长度和分支）显著增加，而MDCK外泌体则没有。接下来，将含有外泌体补充的2F-2B细胞的Matrigel™塞皮下注射到小鼠体内。仅在添加MDCKYBX1或21D1外泌体的桥塞中观察到全身灌注。比较蛋白质组学显示，21D1外泌体含有vegf相关蛋白，而MDCKYBX1外泌体富含活化的Rac1和PAK2。为了验证，在补充外泌体之前，用PAK抑制剂对2F-2B细胞和HUVECs进行预处理。PAK抑制通过减少管长度和分支到基线水平来消除MDCKYBX1外泌体的作用。相比之下，21D1外泌体的作用没有显著降低。我们的研究结果首次证明，经历EMT的致癌细胞可以通过外泌体与内皮细胞进行交流，并建立了外泌体Rac1/PAK2作为血管生成启动子，可能在转移级联的早期阶段起作用。
The metastatic cascade describes the escape of primary tumour cells to distant secondary sites. Cells at the leading tumour edge are thought to undergo epithelial-mesenchymal transition (EMT), to enhance their motility and invasion for spreading. Whether EMT cells directly promote tumour angiogenesis, and the role of exosomes (30-150 nm extracellular vesicles) remains largely unknown. We examined the functional effects of exosomes from MDCK cells, MDCK cells stably expressing YBX1 (MDCKYBX1, intermediate EMT), and Ras-transformed MDCK cells (21D1 cells, complete EMT). 2F-2B cell motility and tube formation (length and branching) was significantly increased following supplementation with MDCKYBX1 or 21D1 exosomes, but not MDCK exosomes. Next, Matrigel™ plugs containing exosome-supplemented 2F-2B cells were subcutaneously injected into mice. Systemic perfusion was only observed for plugs supplemented with MDCKYBX1 or 21D1 exosomes. Comparative proteomics revealed that 21D1 exosomes contained VEGF-associated proteins, while MDCKYBX1 exosomes were enriched with activated Rac1 and PAK2. To validate, 2F-2B cells and HUVECs were pre-treated with PAK inhibitors prior to exosome supplementation. PAK inhibition nullified the effects of MDCKYBX1 exosomes by reducing the tube length and branching to baseline levels. By contrast, the effects of 21D1 exosomes were not significantly decreased. Our results demonstrate for the first time that oncogenic cells undergoing EMT can communicate with endothelial cells via exosomes, and establish exosomal Rac1/PAK2 as angiogenic promoters that may function from early stages of the metastatic cascade.