基于胰岛素受体/mTOR信号通路探讨二甲双胍联合达英-35逆转PCOS来源早期子宫内膜癌的分子机制

Clinically, the cure rate of patients with PCOS derived endometrial cancer and precancerous lesions, which were under the combined treatment with metformin and Diane-35, is up to 95%. While treatment success rate of efficient progesterone (megestrol) drug reverse method that recommended by the 2014 NCCN guidelines, is only 66%. Estrogen stimulation，insulin resistance and PI3K / AKT / mTOR signaling pathway which regulated by insulin / IGF-1 signaling pathway induce abnormal endometrial hyperplasia is believed to be involved in endometrial cancer. Hyperandrogenism is associated with insulin resistance.Our previous study showed that GLUT4 expression is downregulate ang ARs is upregulate in endometrial carcinoma Therefore, further study on the pathological mechanism of the PCOS derived endometrial cancer and precancerous lesions and the molecular mechanism of the combined treatment with metformin and Diane-35 reverse PCOS derived endometrial cancer is important. This study intends to verify, in molecular, cellular, animal experiments and clinical levels, the reversal mechanism of combined treatment of PCOS derived endometrial cancer with metformin and Diane-35 by regulating the expression of GLUT4 androgen receptor-mediated insulin receptor ARs/mTOR signaling pathway, which provide a theoretical basis for clinical treatment of the disease.

近年本课题组发现二甲双胍联合达英-35（降雄作用）治疗PCOS来源的子宫内膜癌，治愈率达到95%以上；而NCCN指南推荐的高效孕酮治愈率仅66%左右。持续雌激素刺激、胰岛素抵抗和受胰岛素/IGF-1信号通路调控的PI3K /AKT/mTOR信号通路活化引起子宫内膜异常增生被认为参与了子宫内膜癌的发生。高雄激素血症和胰岛素抵抗密切相关，预实验显示子宫内膜癌组织中糖转运体GLUT4低表达、雄激素受体ARs高表达；而二甲双胍刺激离体子宫内膜可升高GLUT4表达、降低ARs表达。推测该联合治疗通过GLUT4和ARs影响PI3K /AKT/mTOR信号通路活性在治疗中发挥着重要作用。本研究拟通过分子、细胞、动物实验以及临床标本，研究该联合治疗逆转PCOS来源的子宫内膜癌中GLUT4、ARs表达和PI3K /AKT/mTOR信号通路间分子调控机制，为有效地保留这类年轻患者的生育能力提供理论和实验依据。

多囊卵巢综合征（PCOS）存在的高雄激素、胰岛素抵抗伴随代偿性高胰岛素以及长期雌激素刺激下的孕激素缺乏状态诱发的子宫内膜异常增生、癌变具有特殊性，能在二甲双胍改善糖代谢和短效口服避孕药降雄、补充孕激素后得到逆转。本课题组前期临床研究中发现二甲双胍联合达英-35逆转PCOS患者伴随子宫内膜癌变状态治愈率高于NCCN推荐的醋酸甲地孕酮；在联合治疗后雄激素受体（ARs）表达减少、葡萄糖转运蛋白4（GLUT4）表达增多、胰岛素受体/mTOR信号通路下游关键分子表达受抑制。在基础研究部分，我们首先通过建立双氢睾酮诱导的PCOS样大鼠模型，通过观察PCOS模型动物体重、动情周期、糖代谢的整体改变以及局部子宫内膜的外观、腺体、ARs和GLUT4等关键分子的分布与表达，发现PCOS状态下子宫内膜相对增厚，ARs表达增加、GLUT4表达减少；在使用二甲双胍、达英35治疗后，上述情况得到改善；其次通过细胞功能实验验证二甲双胍联合达英35处理对子宫内膜癌细胞的作用，发现二甲双胍联合达英35处理后抑制了子宫内膜癌细胞的增殖，促进细胞自噬和凋亡水平，通过过表达ARs或者敲低GLUT4的表达水平之后，二甲双胍联合达英35的作用被抑制，细胞恢复增殖能力，凋亡水平极大地降低。最后通过裸鼠移植瘤体内实验证明，AR/GLUT4介导了二甲双胍联合达英35对 子宫内膜癌瘤的抑制作用。综上，达英35、二甲双胍联合治疗对多囊卵巢综合征伴随的子宫内膜异常增生、癌变具有确切的治疗作用，其作用机制与胰岛素受体/mTOR信号通路表达降低以及关键蛋白ARs表达降低、GLUT4表达增加有关，上述通路与关键分子有望作为子宫内膜增生、癌变患者治疗关键靶点，为希望保留生育功能的PCOS合并子宫内膜病变患者提供新的治疗方案。