P21激活激酶-4与雌激素受体α交互调控促进子宫内膜癌细胞增殖的机制研究

Contradiction between “long-term non- antagonistic estrogen stimulation is an important pathogenic factor of type I endometrial cancer ( endometrial cancer ) ” theory and “relatively slow progression of anti-estrogen treatment” clinical phenomenon indicates subsequent regulatory mechanisms in addition to estrogen stimulation . If estrogen is mainly to promote the progression of endometrial cancer by activating its receptor,then the protein kinase which has a regulatory function of multiple signaling pathways of proliferation has a relationship with ERα should be a high probability event. Our preliminary experiments show that estrogen can upregulate the expression and activity of protein kinase Pak4 ; dual luciferase reporter system detects Pak4 promote ERα transcriptional activity ; co-immunoprecipitation and yeast two-hybrid experiments confirmed Pak4 can form complexes with ERα . Subject on the basis of preliminary results, we aim to test the interaction effect and mechanism of regulation Pak4 with ERα. Impact of regulation between ERα and Pak4 on biological behavior of endometrial cancer will also be detected. We also try to find out the relationship between Pak4 and ERα with type I endometrial cancer incidence and prognosis of patients. We will explore the possibility of using small molecule inhibitors targeting Pak4 in the treatment of type I endometrial cancer. The study will deepen the complex understanding of sex hormone -dependent mechanism , and provide a valuable experimental basis for individualized molecular targeted therapy.

“长期无拮抗雌激素刺激是I型子宫内膜癌（内膜癌）重要致病因素”的理论与“抗雌激素治疗效果的徘徊”的临床现象之间的矛盾提示存在除雌激素刺激之外的其他调控机制。如果雌激素主要是通过活化其受体从而促进内膜癌细胞增殖，那么具有调控多重增殖相关信号通路功能的蛋白激酶Pak4与ERα存在关联应该是大概率事件。课题组预实验表明，雌激素可上调Pak4的活性及表达；双荧光素酶报告系统检测提示Pak4介导了ERα转录活性；免疫共沉淀和酵母双杂交实验证实了Pak4与ERα可形成复合物。本研究在预实验基础上，验证Pak4与ERα的交互调控作用及其机制；检测Pak4与ERα的交互调控对内膜癌生物学行为的影响；明确Pak4、ERα与I型内膜癌患者发病及预后的关系；探索使用小分子活性抑制剂靶向Pak4治疗I型内膜癌的可行性。研究将在理论上加深对内膜癌复杂的性激素依赖机制的理解，为个体化分子靶向治疗提供有价值的实验依据。

子宫内膜癌是女性生殖系统最常见的恶性肿瘤。“长期无拮抗雌激素刺激是I型子宫内膜癌（内膜癌）重要致病因素”的理论与“抗雌激素治疗效果的徘徊”的临床现象之间的矛盾提示存在除雌激素刺激之外的其他调控机制。假设长期雌激素刺激是内膜癌发生的早期事件，且主要通过改变其受体ERα的磷酸化状态以启动下游靶基因的转录，那么，包括Pak4在内的蛋白激酶对内膜癌细胞的促增殖作用与ERα存在关联是大概率事件。课题组预实验显示，雌激素作用下内膜癌细胞Pak4与ERα存在正性反馈调控。课题在预实验的基础上，证实了Pak4及p-Pak4在内膜癌组织中高表达，且与肿瘤分期分级等临床病理参数正相关；雌激素可通过PI3K/AKT信号通路促进Pak4的表达及活性；雌激素可促进Pak4及磷酸化Pak4在细胞核内聚集，并上调ERα的转录活性；降调Pak4表达可通过改变细胞G0/G1期进程，从而抑制细胞增殖；在裸鼠中，降调Pak4的表达可抑制由雌激素诱导的细胞成瘤。本研究的结果在理论上加深我们对对内膜癌复杂的性激素调控机制的理解，同时为临床前通过调控Pak4进而诱导体内ERα表达下调的分子靶向治疗提供坚实的实验依据。