Platelets have been extensively implicated in the progression of cancer and platelet-derived extracellular vesicles (PEVs) are gaining growing attention as potential mediators of the platelet-cancer interplay. PEVs are shed from platelet membrane in response to extracellular stimuli and carry important biological signals for intercellular communication. In this study we demonstrate that PEVs specifically bind to different breast cancer cells and elicit cell-specific functional responses. PEVs were massively internalized by the metastatic cell lines MDA-MB-231 and SKBR3 and the ductal carcinoma cell line BT474, but not by the MCF-7 cell line. In SKBR3 cells, PEVs decreased mitochondrial dehydrogenase activities and altered cell cycle progression without affecting cell viability. Conversely, PEVs potently stimulated migration and invasion of MDA-MB-231, without affecting the distribution in the different phases of the cell cycle. In all the analyzed breast cancer cells, PEVs triggered a sustained increase of intracellular Ca²⁺, but only in MDA-MB-231 cells, this was associated to the stimulation of selected signaling proteins implicated in migration, including p38MAPK and myosin light chain. Importantly, inhibition of myosin light chain phosphorylation by a Rho kinase inhibitor prevented PEVs-stimulated migration of MDA-MB-231 cells. Our results demonstrate that PEVs are versatile regulators of cancer cell behavior and elicit a variety of different responses depending on the specific breast cancer cell subtype.

血小板已被广泛地牵涉到癌症的发展中，并且作为血小板-癌症相互作用的潜在介质，源自血小板的细胞外囊泡（PEV）越来越受到关注。PEV响应细胞外刺激而从血小板膜脱落，并携带重要的生物学信号进行细胞间通讯。在这项研究中，我们证明了PEV特异性结合不同的乳腺癌细胞并引起细胞特异性功能反应。PEVs被转移细胞系MDA-MB-231和SKBR3以及导管癌细胞系BT474大量内在化，但未被MCF-7细胞系内化。在SKBR3细胞中，PEV降低了线粒体脱氢酶活性并改变了细胞周期进程，却不影响细胞活力。反过来，PEVs有效刺激MDA-MB-231的迁移和侵袭，而不会影响细胞周期不同阶段的分布。在所有分析过的乳腺癌细胞中，PEV触发了细胞内钙的持续增加²⁺，但仅在MDA-MB-231细胞中，这与刺激涉及迁移的选定信号蛋白有关，包括p38MAPK和肌球蛋白轻链。重要的是，Rho激酶抑制剂对肌球蛋白轻链磷酸化的抑制阻止了PEV刺激的MDA-MB-231细胞迁移。我们的结果表明，PEV是癌细胞行为的多功能调节剂，并根据特定的乳腺癌细胞亚型引起多种不同的反应。