Zhao Jinghua, Tian Huan, Zhao Xiaona, Lan Lan, Liu Huanhuan, Sun Yi, Yu Fengyan
Dept of Breast Surgery, Yat-Sen Breast Tumor Hospital, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, China.
Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, China.
Int J Biol Sci. 2024 Jul 15;20(10):3956-3971. doi: 10.7150/ijbs.89822. eCollection 2024.
Platelet extracellular vesicles (PEVs) play an important role in tumor development. However, the mechanisms underlying their biogenesis have not been fully elucidated. Protein kinase Cα (PKCα) is an important regulator of platelet activation, but the effect of PKCα on EV generation is unclear. We used small-particle flow cytometry and found that the number of PEVs was increased in patients with breast cancer compared to those with benign breast disease. This was accompanied by increased levels of activated PKCα in breast cancer platelets. Treating platelets with the PKCα agonist phorbol 12-myristate 13-acetate (PMA) increased the phosphorylation PKCα and induced PEV production, while the PKCα inhibitor GÖ6976 showed the opposite effects. Notably, incubating platelets from patients with benign tumors with the culture supernatant of MDA-MB-231 cells induced PKCα phosphorylation in the platelets. Mass spectrometry and coimmunoprecipitation assays showed that Dynamin 2 (DNM2), a member of the guanosine-triphosphate-binding protein family, might cooperate with activated PKCα to regulate PEV production by breast cancer platelets. Similar results were observed in a mouse model of lung metastasis. In addition, PEVs were engulfed by breast cancer cells and promoted cancer cell migration and invasion via delivery. These findings suggested that PKCα cooperates with DNM2 to induce PEV generation, and PEV release might triggered by factors in the breast cancer environment.
血小板细胞外囊泡（PEVs）在肿瘤发展中起重要作用。然而，其生物发生的潜在机制尚未完全阐明。蛋白激酶Cα（PKCα）是血小板活化的重要调节因子，但PKCα对细胞外囊泡生成的影响尚不清楚。我们使用小颗粒流式细胞术发现，与患有良性乳腺疾病的患者相比，乳腺癌患者的PEVs数量增加。这伴随着乳腺癌血小板中活化PKCα水平的升高。用PKCα激动剂佛波醇12 - 肉豆蔻酸酯13 - 乙酸酯（PMA）处理血小板会增加PKCα的磷酸化并诱导PEV产生，而PKCα抑制剂GÖ6976则表现出相反的效果。值得注意的是，用MDA - MB - 231细胞的培养上清液孵育良性肿瘤患者的血小板会诱导血小板中PKCα磷酸化。质谱和免疫共沉淀分析表明，鸟苷三磷酸结合蛋白家族成员发动蛋白2（DNM2）可能与活化的PKCα协同作用，以调节乳腺癌血小板的PEV产生。在肺转移小鼠模型中也观察到了类似结果。此外，PEVs被乳腺癌细胞吞噬，并通过传递促进癌细胞迁移和侵袭。这些发现表明，PKCα与DNM2协同诱导PEV生成，并且PEV释放可能由乳腺癌环境中的因素触发。
