基于lncRNA-MAGI2-AS3调控的肿瘤细胞分泌物对乳腺癌细胞生物学特性的影响及分子机制的研究

Breast cancer is the most common malignant tumor in females. According to the latest statistics from the 2015 Chinese Cancer Registration Report, the annual number of new cases of breast cancer ranks first among all female malignant tumors and it has seriously threatened women's physical and mental health and their life safety. Currently, surgery, radiotherapy and chemotherapy remain the primary treatment of breast cancer. In spite of the significant effects of these traditional treatment methods for early stage tumor patients, the efficacy is poor in patients with mid-term and advanced tumors. Therefore, raising the level of treatment for breast cancer has important clinical application values. The long non-coding RNA (lncRNA) is a class of functional RNA molecules longer than 200nt with no abilities of encoding proteins. lncRNA regulates the expression and translation of genes mainly via epigenetics, transcriptional and post-transcriptional levels and thus is involved in the biological functions of tumors. This study intends to adopt lncRNA-MAGI2-AS3-expressing vectors to transfect breast cancer cell strains and use the supernatant of transfected cell culture medium as the core. The therapeutic effects on breast cancer are explored through in vitro experiments and animal experiments, which may provide new ideas for the treatment of breast cancer and a good reference for the treatment of other tumors, thereby taking a step forward in curing human tumors.

乳腺癌是女性最常见的恶性肿瘤，据《2015中国肿瘤登记年报》的最新统计显示，在中国，乳腺癌每年新发病例数位居女性恶性肿瘤的第一位，已严重威胁到妇女的身心健康与生命安全。目前，手术、放疗、化疗仍是乳腺癌的主要治疗手段，虽然这些传统的治疗方法对早期肿瘤患者作用显著,但对于中晚期患者效果欠佳，因此，提高乳腺癌治疗水平具有重要的临床应用价值。长链非编码RNA(lncRNA)是一类长度大于200nt的不具备编码蛋白质能力的功能性RNA分子。lncRNA主要通过表观遗传学、转录及转录后水平调控基因的表达和翻译，从而参与肿瘤生物学功能。本研究拟将lncRNA-MAGI2-AS3表达载体转染乳腺癌细胞株，以转染后的细胞培养上清液为核心，通过体外细胞实验及动物实验探讨其对乳腺癌的治疗作用，这有可能为乳腺癌的治疗提供新的思路，或许这也能为治疗其它肿瘤提供良好的借鉴，为人类攻克肿瘤向前迈进一步。

MAGI2-AS3作为已发现的lncRNA，有报道称在肺癌组织中表达下调，但在乳腺癌的研究中鲜有报道，我们的实验结果显示，lncRNA MAGI2-AS3在乳腺癌组织及乳腺癌患者外周血单核细胞中表达水平减低，这表明其作为乳腺癌的诊断标志物具有重要的临床应用价值；通过构建MAGI2-AS3表达载体并转染乳腺癌细胞株后，细胞的恶性行为受到抑制，我们还发现转染后的细胞培养上清同样具有抑制乳腺癌细胞恶性行为的作用，通过蛋白组学定量分析技术检测了转染后乳腺癌细胞及其培养上清中表达差异的蛋白，进一步实验结果显示，lncRNA MAGI2-AS3可以上调Fas/FasL的表达，从而诱导乳腺癌细胞的凋亡，miR-374a可以被lncRNA MAGI2-AS3竞争性结合，从而导致miR-374a下游的靶基因PTEN 在蛋白水平表达上调进而导致了乳腺癌细胞迁移和侵袭的抑制，我们还发现，上调lncRNA MAGI2-AS3可以抑制乳腺癌细胞中EGF的分泌。以上结果表明，lncRNA MAGI2-AS3有望成为乳腺癌新的诊断标志物，同时，通过对部分lncRNA MAGI2-AS3调控的作用靶点的研究，为改善乳腺癌的治疗提供了理论依据。