HOTAIR通过调控NPM1表达参与雌激素介导的子宫内膜癌发展的机制研究

Estrogen stimulation has been considered as one key contributor to the development of estrogen-dependent EC (type I), which accounts for most cases of EC. However, estrogen-mediated mechanism in the development of type I EC is still unclear. NPM1 (nucleophosmin 1) is an important protein that has been reported to be involved in the development of various cancer types. Recent studies also indicate the potential role of NPM1 in EC development, involving endometrial hyperplasia induced by estrogen, whereas the proliferation of tumor cells can be prevented significantly by inhibition on NPM1 protein levels. Our previous studies also revealed that NPM1 expression was gradually increased with the increase of clinical stages of EC; meanwhile other studies have shown that HOTAIR expression also increases with the development of EC. And, the expression of HOTAIR was reviewed in EC tissues from different clinical stages through pre-experimental analysis, while significantly positive correlation was observed between the increase of NPM1 expression and HOTAIR upregulation. Thus, it was suggested that HOTAIR might function in estrogen-mediated mechanism in the development of type I EC by regulating NPM1 expression. Therefore, this study tried to study the potential regulatory mechanism of HOTAIR on NPM1 expression by various molecular biological techniques through in vitro studies, and also their functions in estrogen-mediated EC development by using mouse models with subcutaneous tumor xenografts. This study aimed to expand estrogen-mediated mechanism during EC development, and to offer new treatment ideas in EC and theoretical basis for clinical detection and prognosis.

雌激素刺激是I型子宫内膜癌发生发展的关键因素，但具体机制尚不清楚。核磷蛋白1（NPM1）是参与多种肿瘤发生发展的重要蛋白。近期研究指出，NPM1参与雌激素诱导的子宫内膜增生，且抑制NPM1表达就会抑制肿瘤细胞的增殖。我们的前期研究也发现，NPM1表达增加与子宫内膜癌临床分期呈正相关。还有研究指出，HOTAIR表达增加与子宫内膜癌进展有关。且我们通过回顾性实验分析，发现HOTAIR高表达与NPM1表达增多呈正相关。由此，我们推测，HOTAIR可能通过调控NPM1的表达参与雌激素介导的子宫内膜癌发生发展。本课题拟从体外水平，运用多种分子生物学技术，探究HOTAIR对NPM1表达的调控机制，并通过建立裸鼠移植瘤模型，验证HOTAIR/NPM1在雌激素介导的子宫内膜癌发展中的作用。此项目的完成将有助于拓展雌激素介导的子宫内膜癌发展机制，并为临床发现和治疗子宫内膜癌提供新的治疗思路和理论依据。

项目背景:子宫内膜癌（EC）是女性生殖道常见的三大恶性肿瘤之 一，占女性生殖道恶性肿瘤的20%～30%。长期雌激素刺激是I型EC的发生发展的关键因素。但雌激素引起EC的机制还尚不清楚。长链非编码RNA（lncRNA）在EC进展中发挥重要作用。本课题组前期研究发现，患者EC组织中lncRNA HOTAIR 表达水平与参与雌激素诱导的子宫内膜增生的NPM1表达增加呈正相关。此外，我们通过生物信息学预测并验证HOTAIR可以直接结合miR-646，抑制miR-646表达，而且miR-646也可以靶向调控NPM1的表达。这提示在雌激素介导的EC发生发展过程中，可能存在HOTAIR/miR-646/NPM1的调控机制。研究内容: 明确HOTAIR、miR-646与NPM1在不同临床分期EC组织中的分布与表达的规律;明确存在HOTAIR/miR-646/NPM1的调控模式; 探讨HOTAIR/miR-646/NPM1参与雌激素介导的EC发生发展的作用机制;明确NIFK-AS1、miR-146a与Notch1在PBMC和来自EC患者的TAM中的表达;探讨NIFK-AS1/miR-146a/Notch1参与雌激素介导的EC发生发展的作用机制。重要结果: 在人EC组织和细胞系中HOTAIR和NPM1高表达，miR-646低表达; HOTAIR靶向抑制miR-646，NPM1是miR-646的靶标;HOTAIR/miR-646/NPM1可以调控EC细胞的活力、迁移和侵袭。关键数据及科学意义:HOTAIR在人EC组织和细胞系中高表达，而HOTAIR促进EC细胞的活力、迁移和侵袭；NIFK-AS1在EC患者中分离出的TAMs中低表达，而NIFK-AS1抑制了雌激素诱导的EC细胞的增殖、迁移和侵袭。说明HOTAIR和NIFK-AS1可作为治疗子宫内膜癌的潜在靶标。