miR-199a-5p调控自噬介导细胞逃逸失巢凋亡：卵巢癌转移新机制？

Disseminated planting and multiple metastases are important factor for difficult to treatment on advanced ovarian cancer. Several studies showed that normal cells separate from homologous organization could induce the special type of apoptosis--Anoikis, but ovarian cancer cells can resistance to anoikis after it separate from the primary tumor. Ovarian cancer cells can survive in hypoxic-ischemic environment until metastasis formation. However, the mechanisms of its resistance to anoikis are not yet fully elucidated. Autophagy was recently confirmed it is a biological phenomenon that cells under hypoxia, lack of nutrition harsh microenvironment swallow and digest the cytoplasmic ingredients to maintain cell life, whether ovarian cancer cells resistance to anoikis by autophagy was reported rare. miR-199a-5p is a non-coding RNA with the function to regulation of multiple target genes expression at the post-transcriptional level. Our previous study showed that, miR-199a-5p expression was down-regulated in highly metastatic ovarian cancer cell lines, increase its expression can inhibit cell autophagy. This study will explore the role of miR-199a-5p and target gene regulation of autophagy in cancer cells of different stages of metastasis at ovarian cancer clinical specimens, cell lines and experimental animals levels, and reliminary clarify molecular regulatory pathways of miR-199a-5p in resistance to anoikis and promotion to transfer by regulation autophagy, then provide a new theoretical basis for further understanding of the mechanisms of metastasis of ovarian cancer.

播散性种植、多发性转移是中晚期卵巢癌难冶的重要因素。研究表明，正常细胞脱离同源组织后即发生特殊类型的凋亡--失巢凋亡，而卵巢癌细胞在脱离原发灶后，具备抵抗失巢凋亡的能力，使细胞在缺血缺氧环境下仍能维持生命直至转移灶形成，然而其机制仍未完全阐明。自噬是新近证实在缺氧、缺营养等恶劣微环境下细胞自我吞噬并消化胞质成分以维持细胞生命的生物学现象，卵巢癌是否通过自噬抵抗失巢凋亡报道罕见。miR-199a-5p是在转录后水平调控多种基因表达的非编码RNA，我们前期研究表明，miR-199a-5p在高转移性卵巢癌细胞株中表达显著下调，提高其表达可抑制细胞自噬。本研究拟通过卵巢癌临床标本、细胞株、实验动物等层面，探索miR-199a-5p及靶基因对不同转移阶段癌细胞自噬的调控作用，初步明确miR-199a-5p通过自噬介导细胞逃逸失巢凋亡促进转移的分子调控通路，为进一步认识卵巢癌转移机制提供新的理论依据。

播散性种植、多发性转移是中晚期卵巢癌难冶的重要因素。探明卵巢癌转移的分子机制、抵制肿瘤转移，能明显提高卵巢癌患者的五年生存率。本研究以miR-199a-5p调控靶基因，影响细胞自噬功能进而促进细胞迁移为主线展开科学研究。首先，我们收集了52例上皮性卵巢癌患者的原发卵巢癌组织及3种不同的转移灶组织或细胞，对之进行了miR-199a-5p表达量及细胞自噬活性的检测，发现转移灶组织中的miR-199a-5p表达量明显下降，而细胞自噬水平明显增强。与此同时，我们通过体外培养高转移性卵巢癌细胞，并在细胞中上调或下调miR-199a-5p的表达，得到了与体内一致的结果，即下调miR-199a-5p的表达可明显增强细胞自噬水平而抑制凋亡，细胞迁移功能随之增强。通过生物信息学方法，我们预测到miR-199a-5p的2个重要调控靶基因，即DRAM1、ATG14，结构学方法验证了其确为miR-199a-5p调控的靶基因，而在细胞中上调或下调这两种蛋白的表达，细胞自噬水平发生明显变化，即DRAM1、ATG14上调后细胞自噬活性增强、细胞凋亡率下降并伴迁移功能增强，反之则自噬活性减弱、细胞凋亡增多且迁移功能下降，这一现象在卵巢癌裸鼠移植瘤上也得到了证实。因此，本研究探明了miR-199a-5p主要通过调控DRAM1、ATG14的表达而影响细胞自噬及凋亡水平，从而影响细胞迁移功能。本研究初步明确miR-199a-5p 通过自噬介导细胞逃逸失巢凋亡促进转移的分子调控通路，为进一步认识卵巢癌转移机制提供新的理论依据。