缺氧肿瘤细胞抑制ITGA3分泌的机制研究

项目名称： 缺氧肿瘤细胞抑制ITGA3分泌的机制研究

项目编号： No.31500670

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 生物科学

项目作者： 任艳

作者单位： 深圳华大生命科学研究院

项目金额： 20万元

中文摘要： 由于肿瘤细胞快速生长引起的缺氧，随着肿瘤细胞的适应性调控， 成为促进肿瘤恶化和迁移的重要原因。我们对缺氧肿瘤细胞的全、糖蛋白质组变化及随后的功能研究表明：肿瘤缺氧通过调控多条信号传导通路促进其迁移。其中，我们注意到缺氧调控的ITGA3的变化比较特殊：其蛋白表达总量没有明显的变化，仅在糖基化修饰上有明显的减少，因此导致其分泌到细胞膜上的量显著下降，从而提高细胞侵袭。我们进一步的研究发现其第6和7位点的糖基化修饰同时阻断会导致其分泌的完全缺失。可能正是由于糖链的缺失引发的结构变化，导致其无法与协作蛋白结合而无法分泌。我们拟主要采用IP结合蛋白质组学方法，以无分泌突变型为对照，鉴定ITGA3分泌过程中的动态蛋白质相互作用网络及作用顺序，并揭示这些蛋白对缺氧肿瘤细胞中ITGA3分泌及对细胞功能的影响。对于这种新型机制的揭秘可以填补目前研究的空白，并有利于发现肿瘤缺氧对细胞迁移调控的新方向。

中文关键词： 膜受体蛋白质复合物；整合素；alpha；3；糖基化修饰；转运蛋白；肿瘤细胞缺氧

英文摘要： As solid tumors grow, those areas distant from the existing blood vessels can become chronically or intermittently hypoxia. These hypoxic conditions place tremendous pressure on tumor cells and drive development of increasingly malignant and metastatic phenotypes. In our previous studies of whole proteomics and glycol-proteomics for A431 cancer hypoxia, many pathways were found modulated by hypoxia, some of which were found with positive effects on cell migration. The changes of integrin alpha 3 (ITGA3) induced by hypoxia were interesting: independent of its protein level change, N-glycosylation modifications of ITGA3 were inhibited by hypoxia, which prevented its efficient translocation to the plasma membrane and promoted cell invasion under hypoxia. Mutagenesis studies demonstrated that simultaneous mutation of glycosites 6 and 7 of ITGA3 prevented its accumulation at K562 cell surface, which blocked integrin alpha 3 and beta 1 heterodimer formation and thus abolished its interaction with extracellular ligands. The conformation changes due to lack of glycans on sites 6 and 7 should be the keys to open the mysterious doors to reveal the interaction of integrin α3β1 complex. Immunoprecipitation and proteomics will be used to find ITGA3 partners which help its traffic to plasma membrane and binding orders. It could give clues for underlying mechanism behind ITGA3 secretion and metastatic cascades and provide new insights in the studies on cancer cell hypoxia and novel information for understanding glycoprotein secretion.

英文关键词： membrane receptor protein complex;integrin alpha 3;glycosylation;transport protein;cacer cell hypoxia