Department of Occupational Health and Occupational Medicine, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou, China.
Deparment of Biomedical Engineering, Faculty of Engineering, the Hong Kong Polytechnic University.
Theranostics. 2019 Jul 9;9(17):5049-5064. doi: 10.7150/thno.32097. eCollection 2019.
: Abnormal Wnt/β-catenin signaling in the endometrium can lead to both embryo implantation failure and severe pathogenic changes of the endometrium such as endometrial cancer and endometriosis. However, how Wnt/β-catenin signaling is regulated in the endometrium remains elusive. We explored possible regulation of Wnt/β-catenin signaling by multi-drug resistance protein 4 (MRP4), a potential target in cancer chemotherapy, and investigated the mechanism. : Knockdown of MRP4 was performed in human endometrial cells or in a mouse embryo-implantation model . Immunoprecipitation, immunoblotting and immunofluorescence were used to assess protein interaction and stability. Wnt/β-catenin signaling was assessed by TOPflash reporter assay and quantitative PCR array. Normal and endometriotic human endometrial tissues were examined. Data from human microarray or RNAseq databases of more than 100 participants with endometriosis, endometrial cancer or IVF were analyzed. and tumorigenesis was performed. : MRP4-knockdown, but not its transporter-function-inhibition, accelerates β-catenin degradation in human endometrial cells. MRP4 and β-catenin are co-localized and co-immunoprecipitated in mouse and human endometrium. MRP4-knockdown in mouse uterus reduces β-catenin levels, downregulates a series of Wnt/β-catenin target genes and impairs embryo implantation, which are all reversed by blocking β-catenin degradation. Analysis of human endometrial biopsy samples and available databases reveals significant and positive correlations of MRP4 with β-catenin and Wnt/β-catenin target genes in the receptive endometrium in IVF, ectopic endometriotic lesions and endometrial cancers. Knockdown of MRP4 also inhibits and endometrial tumorigenesis. : A previously undefined role of MRP4 in stabilizing β-catenin to sustain Wnt/β-catenin signaling in endometrial cells is revealed for both embryo implantation and endometrial disorders, suggesting MRP4 as a theranostic target for endometrial diseases associated with Wnt/β-catenin signaling abnormality.
Wnt/β-catenin 信号通路异常可导致胚胎着床失败以及子宫内膜严重病变，如子宫内膜癌和子宫内膜异位症。然而，子宫内膜中 Wnt/β-catenin 信号通路如何被调控仍不清楚。我们探索了多药耐药蛋白 4（MRP4）对 Wnt/β-catenin 信号通路的可能调控作用，MRP4 是癌症化疗的一个潜在靶点，并研究了其机制。
在人子宫内膜细胞或小鼠胚胎着床模型中敲低 MRP4。用免疫沉淀、免疫印迹和免疫荧光评估蛋白相互作用和稳定性。通过 TOPflash 报告基因分析和定量 PCR 阵列评估 Wnt/β-catenin 信号通路。检测正常和子宫内膜异位症患者的人子宫内膜组织。分析了 100 多名患有子宫内膜异位症、子宫内膜癌或体外受精的患者的人微阵列或 RNAseq 数据库的数据。进行了肿瘤发生实验。
MRP4 敲低而非其转运功能抑制可加速人子宫内膜细胞中β-catenin 的降解。MRP4 和 β-catenin 在小鼠和人子宫内膜中发生共定位和共免疫沉淀。在小鼠子宫中敲低 MRP4 可降低β-catenin 水平，下调一系列 Wnt/β-catenin 靶基因，并损害胚胎着床，而通过阻断β-catenin 降解可逆转这些作用。对人子宫内膜活检样本和现有数据库的分析显示，在体外受精、异位子宫内膜病变和子宫内膜癌中，MRP4 与β-catenin 和 Wnt/β-catenin 靶基因呈显著正相关。MRP4 敲低也抑制了 和 子宫内膜肿瘤的发生。
揭示了 MRP4 在稳定β-catenin 以维持子宫内膜细胞中 Wnt/β-catenin 信号通路方面的一个以前未定义的作用，这对胚胎着床和子宫内膜疾病都有意义，表明 MRP4 可作为与 Wnt/β-catenin 信号通路异常相关的子宫内膜疾病的治疗靶点。
