Meng Yuru, Kang Shijun, Fishman David A
Department of Immunology, University of Illinois at Chicago, Chicago 60612, USA.
Cancer Immunol Immunother. 2005 Aug;54(8):807-14. doi: 10.1007/s00262-004-0642-5. Epub 2005 Jan 21.
Previous reports support that lysophosphatidic acid (LPA) upregulates Fas ligand (FasL) cell surface presentation on the ovarian cancer cells. In this study, we aim to investigate soluble FasL (sFasL) secretion associated with the small membrane microvesicles upon LPA stimulation, and to analyze the roles of cytoskeletal reorganization in FasL transport induced by LPA. Ovarian cancer cells were stimulated with LPA and spent media were harvested, concentrated, and ultracentrifugated to collect the supernatant and pellet. Western blot suggested that sFasL released from ovarian cancer cells were the mature form, and these sFasL are released with the small membrane microvesicles. Flow cytometry showed that the majority of microvesicles secreted contained FasL on their membrane, and these small membrane microvesicles are bioactive against activated human T lymphocytes. The microtubule-disrupting reagent nocodazole, not the actin-filament-disrupting reagent cytochalasin D pretreatment blocked FasL-expressing small membrane microvesicle release stimulated by LPA, suggesting that microtubules play an essential role in FasL microvesicle transport and exocytosis. LPA may promote ovarian cancer metastasis by counterattacking peritoneal cavity anti-tumor immunity.
先前的报道支持溶血磷脂酸(LPA)上调卵巢癌细胞表面Fas配体(FasL)的表达。在本研究中,我们旨在研究LPA刺激后与小膜微泡相关的可溶性FasL(sFasL)分泌情况,并分析细胞骨架重组在LPA诱导的FasL转运中的作用。用LPA刺激卵巢癌细胞,收集、浓缩并超速离心培养液以收集上清液和沉淀。蛋白质印迹法表明,卵巢癌细胞释放的sFasL是成熟形式,且这些sFasL与小膜微泡一起释放。流式细胞术显示,分泌的大多数微泡膜上含有FasL,且这些小膜微泡对活化的人T淋巴细胞具有生物活性。破坏微管的试剂诺考达唑而非破坏肌动蛋白丝的试剂细胞松弛素D预处理可阻断LPA刺激的表达FasL的小膜微泡释放,这表明微管在FasL微泡转运和胞吐作用中起重要作用。LPA可能通过反击腹腔抗肿瘤免疫来促进卵巢癌转移。