脂联素通过AMPK通路对PCOS患者并发子宫内膜癌的调控作用及其机制研究

Estrogen-dependent endometrial cancer is one of the most fatal long-term complications of polycystic ovary syndrome (PCOS). Our previous research confirmed that compared with age-matching health women, PCOS and endometrial cancer patients had lower adiponectin (APN) level, which showed a negative correlation with increasing expression levels of CYP19 and ERα in tumors. Our result indicated that APN stimulated AMPK phosphorylation, reducing the expression of CYP19 and ERα in cancer cells, and sequentially inhibiting cancer cell proliferation and invasion. Furthermore, inhibiting AMPK pathway could block the above effect of APN. Therefore, we hypothesize that adiponectin regulates target genes expression (CYP19 and ERα) through AMPK pathway, and thereby plays an important role in the tumorigenesis and tumor-development in PCOS patients. Our study aims to: 1) Screen for potential transcription factors involved in APN-stimulated AMPK pathway; 2) Obtain the evidence that the transcription factors can bind and regulate the target genes directly; 3) Ascertain that the transcriptional regulation of target genes via above transcription factors can impact cancer cells proliferation and invasion; 4) Confirm that APN can regulate target genes through AMPK pathway and play an important role in tumor development in bearing tumor mice in vivo. The findings of our study will elucidate the mechanism of APN-mediated estrogen-dependent tumorigenesis and development of endometrial cancer in PCOS patients, and will reveal new intervention targets for its prevention and treatment.

雌激素依赖性子宫内膜癌是多囊卵巢综合征（PCOS）最致命的远期并发症之一。我们前期研究发现血脂联素水平降低是PCOS 和子宫内膜癌患者的共同特征，且与癌组织中芳香化酶CYP19和雌激素受体ERα的高表达密切相关；经过实验、分析和论证，我们率先证实脂联素是通过激活LKB1/AMPK通路，下调癌细胞CYP19和ERα表达，抑制子宫内膜癌细胞增殖和侵袭。但是，脂联素激活AMPK后通过哪些转录因子调控CYP19和ERα基因的表达，影响激素依赖性子宫内膜癌的发生发展尚不清楚。本项目旨在筛选并验证AMPK 激活后下游活性改变的转录因子；获得其调控上述基因表达进而影响子宫内膜癌细胞增殖、迁移和侵袭的直接证据，阐明脂联素在PCOS 并发激素依赖性肿瘤发生发展中的作用及分子机制，为确立新的预防和治疗干预靶点提供更充分的科学依据。

低脂联素水平是多囊卵巢综合征（PCOS）的重要病理生理特点，且与其远期并发症密切相关。研究提示脂联素能够抑制激素依赖性肿瘤如乳腺癌、子宫内膜癌细胞的增殖，但其具体机制尚不明确。PCOS并发激素依赖性肿瘤患者癌组织中雌激素代谢关键酶芳香化酶CYP19、雌激素受体ERα的表达异常成为潜在切入点。我们的研究证实了脂联素与子宫内膜癌细胞中CYP19的表达呈负相关，并且其能够抑制肿瘤细胞的增殖。通过生物信息学预测、脂联素外源性刺激、siRNA干扰等方法筛选出转录因子C/EBPα，进一步采用免疫共沉淀技术获得了其参与转录调控CYP19基因表达的直接证据。通过对信号通路上关键节点的检测，我们证实了脂联素是通过AMPK信号通路发挥前诉作用。本项目通过筛选脂联素激活AMPK后下游活性改变的转录因子C/EBPα；获得其调控CYP19基因表达的直接证据，明确其调控靶基因对细胞增殖的影响；阐明PCOS低脂联素水平在其远期并发激素依赖性肿瘤中的作用及分子机制，为其预防和治疗提供新的干预靶点。