NID1通过EMT促进卵巢癌侵袭转移的分子机制研究

We have previously conducted a secretory/releasing proteomic study in ovarian cancer, and found that nidogen 1, NID1, is a novel candidate dignostic biomarker of ovarian cancer (published in Proteomics 2012). As a critical component in basement membrane, however, its detailed function in cancer remains unknown, and needs further exploration. Our further functional analysis also demonstrated that ectopic overexpression of NID1 significantly enhanced the migratory and invasive activity, and simultaneously induced epithelial-mesenchymal transition (EMT) phenotype in ovarian cancer cells. Notably, as an extracellular ligand, NID1 has been demontrated to be capable of binding to the important cell adhesion receptor,integrin alpha3 beta1. Based on those results, we thus propose a novel hypothesis, i.e., "NID1 induces EMT and further promotes metastasis of ovarian cancer cells via the classic Integrin-FAK pathway". In the present study, we will utilize various molecular and cellular techniques to prove the hypothesis, i.e., to invetigate the role of NID1 in EMT and metastasis in human ovarian cancer, and clarify the underlying molecular mechanism and relavent clinical significance. This study has both scientific significance and potential application value, i.e., not only contributing greatly to the theory of molecular oncology, but also promoting the potential application of NID1-based diagnosis and therapy in ovarian cancer management.

NID1是我们在前期卵巢癌蛋白质组研究中筛选到的新的候选卵巢癌标志物之一，结果已发表于Proteomics杂志。作为细胞外基质特化结构- - 基膜的重要成分，NID1在肿瘤发生发展中的作用不甚清楚，是一个值得深入研究的新领域。初步功能试验表明，NID1外源过表达后导致卵巢癌细胞迁移侵袭能力显著增强并伴随EMT发生；文献已证实NID1可与Integrin结合；我们由此提出学术猜想："NID1通过Integrin-FAK通路诱发EMT而促进卵巢癌侵袭转移"。本课题拟在此基础上，综合采用多种分子肿瘤学研究技术，对NID1在EMT和卵巢癌侵袭转移中的作用、分子机制及临床意义进行深入解析，以证实我们的学术猜想。本研究不仅对于丰富分子肿瘤学基础理论具有重要科学意义，而且对于推动以NID1为靶点的卵巢癌分子诊断与靶向治疗也极具潜在应用价值。

研究背景：NID1（Nidogen-1）是我们在前期卵巢癌蛋白质组研究中新发现的候选卵巢癌诊断标志物。NID1作为细胞外基质特化结构——基膜的重要成分，它在卵巢癌发生发展中的作用并不清楚。结合文献调研（“肿瘤侵袭、EMT和基膜三者存在密切关联”）和前期临床数据（“卵巢癌样本中NID1的高表达与淋巴结转移相关”），我们推测NID1极可能在卵巢癌的侵袭转移过程中发挥重要作用。以此为据，本课题从以下五方面深入开展NID1对卵巢癌细胞侵袭转移和顺铂耐药性的影响及其分子机制的研究，以期为NID1作为候选的卵巢癌预后标志物和治疗靶标的研究价值提供科学依据。研究内容及结果：（1）NID1是与间质表型相关的卵巢癌预后因子：NID1高表达于纺锤型卵巢癌细胞系和间质表型的卵巢癌组织，其高表达显示卵巢癌患者预后差；（2）NID1促进卵巢癌细胞发生不完全EMT：稳定过表达外源NID1的OVCAR-3细胞发生不完全EMT，瞬时敲降NID1的HEY细胞发生不完全MET；（3）NID1促进卵巢癌细胞侵袭/转移：稳定过表达外源NID1的OVCAR-3细胞的划痕愈合、转移和侵袭能力均增强。瞬时敲降NID1的HEY细胞的转移和侵袭能力均减弱；（4）NID1增强卵巢癌细胞的顺铂耐药性：稳定过表达外源NID1的OVCAR-3细胞具有更强的顺铂哪个，并伴随着药物转运蛋白MDR1和ABCG2水平升高。瞬时敲降NID1的HEY细胞的顺铂耐药性 ，同时其MDR1和ABCG2水平降低；（5）NID1通过激活ERK/MAPK通路来调控卵巢癌细胞EMT：过表达外源NID1活化OVCAR-3细胞的ERK/MAPK通路，U0126（MEK1抑制剂）将其抑制后，细胞EMT进程、划痕愈合能力、转移能力和顺铂耐药性均减弱。科学意义：本课题阐明了NID1对卵巢癌细胞侵袭转移和顺铂耐药性的影响极其分子机制，并提示NID1可作为候选的卵巢癌预后标志物和治疗靶标。