Vascular endothelial dysfunction and platelet activation play a key role in tumor metastasis, and therefore, both of these processes are considered important therapeutic targets in cancer. The aim of our studies was to analyze antimetastatic activity of combination therapy using nitric oxide donor DETA/NO and antiplatelet drug clopidogrel. Nitric oxide acts as a vasoprotective mediator, while clopidogrel inhibits ADP-mediated platelet aggregation. 4T1-luc2-tdTomato cell line transplanted intravenously (i.v.) and 4T1 cell line transplanted orthotopically were used as metastatic mammary gland cancer models. Moreover, antiaggregation action of compounds was tested ex vivo on the blood samples taken from breast cancer patients. We have shown that in selected dosage regimes, DETA/NO combined with clopidogrel significantly reduced lung metastatic foci formation in an i.v. model, and such inhibition was transiently observed also in an orthotopic model. The antimetastatic effect was correlated with a significant increase of prostacyclin (PGI2) metabolite and reduction of endothelin-1, sE-selectin, sI-CAM, and TGF-β plasma levels as well as decreased V-CAM expression on the endothelium. Combination therapy decreased fibrinogen binding to the resting platelets at the early stage of tumor progression (day 14). However, at the later stages (days 21 and 28), the markers of platelet activation were detected (increased JON/A antibody bound, P-selectin level, binding of fibrinogen, and vWf). Decreased aggregation as well as a lower release of TGF-β were detected in platelets incubated ex vivo with compounds tested from metastatic breast cancer patients. Although combination therapy increases E-cadherin, the increase of N-cadherin and α-SMA in tumor tissue was also observed. The results showed that at the early stages of tumor progression, combined therapy with DETA/NO and clopidogrel improves vasoprotective and antiplatelet activity. However, in advanced tumors, some adverse effects toward platelet activation can be observed.

中文翻译：

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DETA / NO和氯吡格雷联合治疗通过改善的血管保护作用抑制小鼠乳腺癌模型的转移

血管内皮功能障碍和血小板活化在肿瘤转移中起关键作用，因此，这两个过程均被认为是癌症的重要治疗靶标。我们研究的目的是分析使用一氧化氮供体DETA / NO和抗血小板药物氯吡格雷的联合疗法的抗转移活性。一氧化氮起血管保护介质的作用，而氯吡格雷则抑制ADP介导的血小板凝集。静脉内（iv）移植的4T1-luc2-tdTomato细胞系和原位移植的4T1细胞系用作转移性乳腺癌模型。此外，离体测试了化合物对从乳腺癌患者身上采集的血液样品的抗聚集作用。我们已经证明，在选定的剂量方案中，在静脉注射模型中，DETA / NO与氯吡格雷联用显着降低了肺转移灶的形成，在原位移植模型中也短暂观察到了这种抑制作用。防转移作用与前列环素（PGI2）代谢产物的显着增加和内皮素-1，sE-选择素，sI-CAM和TGF-β血浆水平的降低以及内皮细胞上V-CAM表达的降低有关。在肿瘤进展的早期阶段（第14天），联合治疗可降低纤维蛋白原与静止血小板的结合。但是，在随后的阶段（第21和28天），检测到了血小板活化的标志物（结合的JON / A抗体增加，P-选择蛋白水平，血纤蛋白原的结合和vWf）。在与转移性乳腺癌患者测试的化合物离体孵育的血小板中，检测到聚集减少以及TGF-β释放降低。尽管联合疗法增加了E-钙黏着蛋白，但在肿瘤组织中也观察到了N-钙黏着蛋白和α-SMA的增加。结果表明，在肿瘤进展的早期，DETA / NO和氯吡格雷联合治疗可改善血管保护和抗血小板活性。但是，在晚期肿瘤中，可以观察到一些对血小板活化的不利影响。