原钙粘蛋白10对子宫内膜腺样癌发病抑制作用研究

Endometrial cancer is the most common gynecological malignancy with unclear mechanism. Current medical treatments for the advanced patients and recurrence are far from ideal. It has been demonstrated that tumor suppressor genes inactivation mediated by DNA hypermethylation always causes malignant transformation and carcinogenesis, which plays an essential role in the development of cancer. Recently, Protocadherin10 (PCDH10) was noted as a tumor suppresser gene and silenced due to DNA hypermethylation in gastric, liver, and prostate cancers etc. However, the underlying mechanism of its tumor-suppressive functions is poorly understood. Similarly, our preliminary data suggests that PCDH10 is silenced by DNA methylation in human endometrioid endometrial adenocarcinoma (EEC). Moreover, expression of PCDH10 can inhibit the proliferation of endometrial cancer cells. In this study, we are going to determine the relationship between PCDH10 expression level, DNA methylation status and clinical characteristics in EEC. And then, the effect of PCDH10 on EEC carcinogenesis activities will be investigated by using cell culture and nude mice xenograft model. Furthermore, the next generation sequence (mRNA) will be used to characterize PCDH10 mediated genome-wide transcriptome changes, in order to explore PCDHD10 regulated target genes and signaling pathways in EEC. Our study will broaden the understanding of pathogenesis of EEC and may also provide a new potential target for the chemotherapy.

子宫内膜癌是最常见的妇科恶性肿瘤，其发病机制未完全清楚，对晚期病人和复发病人疗效欠佳。研究表明抑癌基因在肿瘤的发病中发挥重要作用，抑癌基因特异性甲基化失活常导致细胞恶变和肿瘤发生。原钙粘蛋白10（PCDH10）是最近发现的抑癌基因，该基因在胃癌、肝癌和前列腺癌等多种癌症中因DNA甲基化而表达沉默。但PCDH10抑癌作用的分子机制尚未有报道。我们前期实验结果提示子宫内膜腺样癌中也存在PCDH10甲基化而表达沉默，恢复其表达可抑制子宫内膜腺样癌细胞增殖。本课题首先研究PCDH10表达水平及甲基化水平与子宫内膜腺样癌临床特征关系；再通过体外细胞模型和裸鼠荷瘤模型研究PCDH10对子宫内膜腺样癌细胞肿瘤生物学活性的影响；最后采用第二代高通量测序方法进行全基因组mRNA测序，探索 PCDH10调节的靶基因及信号通路。本研究结果将拓宽对子宫内膜腺样癌发病分子机制的认识并为其化疗药物研发提供新靶点。

PCDH10作为一种钙黏附穿膜蛋白在多种癌症中因DNA甲基化而表达失活。前期研究已证实PCDH10是子宫内膜腺样癌的抑癌基因，恢复其表达后能广泛抑制肿瘤细胞的增殖，但PCDH10发挥抑癌作用的分子机制尚未见报道。本课题研究主要包含以下内容：1、收集子宫内膜腺样癌临床标本并检测 PCDH10 表达水平及甲基化水平；2、通过子宫内膜腺样癌细胞系体外试验和裸鼠荷瘤模型在体实验研究其对癌细胞侵蚀和迁移能力的影响；3、通过第二代测序方法进行RNA-seq找出受PCDH10调控的信号通路。研究结果发现：①在子宫内膜腺样癌临床标本和癌细胞系中，PCDH10表达均低于正常子宫内膜组织。PCDH10 表达水平与其启动子区甲基化水平负相关，与临床转移正相关；②子宫内膜腺样癌细胞系和裸鼠荷瘤模型实验均证实PCDH10是子宫内膜腺样癌的抑癌基因，其表达可以抑制肿瘤细胞增殖和侵蚀，促进细胞凋亡；③PCDH10通过抑制Wnt/beta-catenin信号通路，进而调节长链非编码RNA：MALAT1，以及细胞因子DEPDC-1诱导肿瘤细胞凋亡，最终抑制子宫内膜腺样癌的发生发展。这些结果提示，PCDH10作为抑癌基因其表达水平与临床预后密切相关，其通过Wnt/beta-catenin信号通路调节子宫内膜腺样癌的发生，抑制Wnt/beta-catenin信号通路的药物有望成为子宫内膜腺样癌化疗新药物。