Extracellular vesicles (EVs) are emerging as mediators of a range of pathological processes, including cancer. However, their role in bone metastases has been poorly explored. We investigated EV-mediated effects of osteotropic breast cancer cells (MDA-MB-231) on bone resident cells and endothelial cells. Pretreatment of osteoblasts with conditioned medium (CM) of MDA-MB-231 (MDA) cells promoted pro-osteoclastogenic and pro-angiogenic effects by osteoblast EVs (OB-EVs), as well as an increase of RANKL-positive OB-EVs. Moreover, when treating osteoblasts with MDA-EVs, we observed a reduction of their number, metabolic activity, and alkaline phosphatase (Alp) activity. MDA-EVs also reduced transcription of Cyclin D1 and of the osteoblast-differentiating genes, while enhancing the expression of the pro-osteoclastogenic factors Rankl, Lcn2, Il1b, and Il6. Interestingly, a cytokine array on CM from osteoblasts treated with MDA-EVs showed an increase of the cytokines CCL3, CXCL2, Reg3G, and VEGF, while OPG and WISP1 were downregulated. MDA-EVs contained mRNAs of genes involved in bone metabolism, as well as cytokines, including PDGF-BB, CCL3, CCL27, VEGF, and Angiopoietin 2. In line with this profile, MDA-EVs increased osteoclastogenesis and in vivo angiogenesis. Finally, intraperitoneal injection of MDA-EVs in mice revealed their ability to reach the bone microenvironment and be integrated by osteoblasts and osteoclasts. In conclusion, we showed a role for osteoblast-derived EVs and tumor cell-derived EVs in the deregulation of bone and endothelial cell physiology, thus fueling the vicious cycle induced by bone tumors. © 2019 American Society for Bone and Mineral Research.

中文翻译：

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嗜骨性乳腺癌细胞的细胞外囊泡会影响骨驻留细胞。

细胞外囊泡（EVs）逐渐成为包括癌症在内的一系列病理过程的介体。但是，它们在骨转移中的作用尚未得到很好的研究。我们调查了骨基质细胞和内皮细胞的EV介导的骨质疏松性乳腺癌细胞（MDA-MB-231）的影响。用MDA-MB-231（MDA）细胞的条件培养基（CM）预处理成骨细胞，可通过成骨细胞电动车（OB-EV）促进促破骨细胞作用和促血管生成作用，并增加RANKL阳性OB-EV。此外，当用MDA-EVs处理成骨细胞时，我们观察到它们的数量，代谢活性和碱性磷酸酶（Alp）活性均降低。MDA-EV还可减少Cyclin D1和成骨细胞分化基因的转录，同时增强促破骨细胞生成因子Rank1，Lcn2，Il1b，和Il6。有趣的是，用MDA-EVs处理的成骨细胞在CM上的细胞因子阵列显示出细胞因子CCL3，CXCL2，Reg3G和VEGF的增加，而OPG和WISP1被下调。MDA-EVs包含与骨代谢有关的基因的mRNA，以及包括PDGF-BB，CCL3，CCL27，VEGF和Angiopoietin 2在内的细胞因子。根据这种情况，MDA-EVs增加了破骨细胞生成和体内血管生成。最后，小鼠腹膜内注射MDA-EVs揭示了它们达到骨微环境并被成骨细胞和破骨细胞整合的能力。总之，我们显示了成骨细胞源电动汽车和肿瘤细胞源电动汽车在骨骼和内皮细胞生理失调中的作用，从而加剧了骨肿瘤诱发的恶性循环。©2019美国骨骼和矿物质研究学会。MDA-EVs处理成骨细胞后，CM上的细胞因子阵列显示细胞因子CCL3，CXCL2，Reg3G和VEGF增加，而OPG和WISP1被下调。MDA-EVs包含与骨代谢有关的基因的mRNA，以及包括PDGF-BB，CCL3，CCL27，VEGF和Angiopoietin 2在内的细胞因子。根据这种情况，MDA-EVs增加了破骨细胞生成和体内血管生成。最后，小鼠腹膜内注射MDA-EVs揭示了它们达到骨微环境并被成骨细胞和破骨细胞整合的能力。总之，我们显示了成骨细胞源电动汽车和肿瘤细胞源电动汽车在骨骼和内皮细胞生理失调中的作用，从而加剧了骨肿瘤诱发的恶性循环。©2019美国骨骼和矿物质研究学会。MDA-EVs处理成骨细胞后，CM上的细胞因子阵列显示细胞因子CCL3，CXCL2，Reg3G和VEGF增加，而OPG和WISP1被下调。MDA-EVs包含与骨代谢有关的基因的mRNA，以及包括PDGF-BB，CCL3，CCL27，VEGF和Angiopoietin 2在内的细胞因子。根据这种情况，MDA-EVs增加了破骨细胞生成和体内血管生成。最后，在小鼠腹膜内注射MDA-EVs揭示了它们达到骨微环境并被成骨细胞和破骨细胞整合的能力。总之，我们显示了成骨细胞源电动汽车和肿瘤细胞源电动汽车在骨骼和内皮细胞生理失调中的作用，从而加剧了骨肿瘤诱发的恶性循环。©2019美国骨骼和矿物质研究学会。