Platelets promote tumor metastasis by inducing promalignant phenotypes in cancer cells and directly contributing to cancer-related thrombotic complications. Platelet-derived extracellular vesicles (EVs) can promote epithelial-mesenchymal transition (EMT) in cancer cells, which confers high-grade malignancy. 12S-hydroxyeicosatetraenoic acid (12-HETE) generated by platelet type 12-lipoxygenase (12-LOX) is considered a key modulator of cancer metastasis through unknown mechanisms. In platelets, 12-HETE can be esterified into plasma membrane phospholipids (PLs), which drive thrombosis. Using cocultures of human platelets and human colon adenocarcinoma cells (line HT29) and LC-MS/MS, we investigated the impact of platelets on cancer cell biosynthesis of 12S-HETE and its esterification into PLs and whether platelet ability to transfer its molecular cargo might play a role. To this aim, we performed coculture experiments with CFSE[5-(and-6)-carboxyfluorescein diacetate, succinimidyl ester]-loaded platelets. HT29 cells did not generate 12S-HETE or express 12-LOX. However, they acquired the capacity to produce 12S-HETE mainly esterified in plasmalogen phospholipid forms following the uptake of platelet-derived medium-sized EVs (mEVs) expressing 12-LOX. 12-LOX was detected in plasma mEV of patients with adenomas/adenocarcinomas, implying their potential to deliver the protein to cancer cells in vivo. In cancer cells exposed to platelets, endogenous but not exogenous 12S-HETE contributed to changes in EMT gene expression, mitigated by three structurally unrelated 12-LOX inhibitors. In conclusion, we showed that platelets induce the generation of primarily esterified 12-HETE in colon cancer cells following mEV-mediated delivery of 12-LOX. The modification of cancer cell phospholipids by 12-HETE may functionally impact cancer cell biology and represent a novel target for anticancer agent development.

中文翻译：

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血小板通过递送 12-脂氧合酶在结肠癌细胞中诱导游离和磷脂酯化的 12-羟基二十碳四烯酸生成。

血小板通过诱导癌细胞中的恶性表型并直接导致癌症相关的血栓并发症来促进肿瘤转移。血小板衍生的细胞外囊泡 (EVs) 可以促进癌细胞的上皮间质转化 (EMT)，从而导致高度恶性。由血小板型 12-脂氧合酶 (12-LOX) 产生的 12S-羟基二十碳四烯酸 (12-HETE) 被认为是通过未知机制导致癌症转移的关键调节剂。在血小板中，12-HETE 可以酯化成质膜磷脂 (PLs)，从而导致血栓形成。使用人血小板和人结肠腺癌细胞（HT29 系）和 LC-MS/MS 共培养，我们研究了血小板对 12S-HETE 的癌细胞生物合成及其酯化为 PL 的影响，以及血小板转移其分子货物的能力是否可能发挥作用。为此，我们使用载有 CFSE [5-(and-6)-carboxyfluorescein diacetate, succinimidyl ester] 的血小板进行了共培养实验。HT29 细胞不产生 12S-HETE 或表达 12-LOX。然而，在摄取表达 12-LOX 的血小板衍生的中型 EV (mEV) 后，他们获得了生产主要以缩醛磷脂形式酯化的 12S-HETE 的能力。在腺瘤/腺癌患者的血浆 mEV 中检测到 12-LOX，这意味着它们有可能在体内将蛋白质传递给癌细胞。在暴露于血小板的癌细胞中，内源性而非外源性 12S-HETE 促成了 EMT 基因表达的变化，由三种结构不相关的 12-LOX 抑制剂缓解。总之，我们发现血小板在 mEV 介导的 12-LOX 递送后诱导结肠癌细胞中主要酯化的 12-HETE 的产生。12-HETE 对癌细胞磷脂的修饰可能在功能上影响癌细胞生物学，并代表抗癌剂开发的新靶点。