Sharma Vikas, Joshi Jayadev, Yeh I-Ju, Doughman YongQiu, Blankenberg Daniel, Wald David, Montano Monica M
Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH, United States.
Genomic Medicine Institute, Cleveland Clinic Lerner Research Institute, Cleveland, OH, United States.
Front Oncol. 2022 Mar 24;12:824594. doi: 10.3389/fonc.2022.824594. eCollection 2022.
DNA methylation, catalyzed by DNA methyltransferase (DNMT), is a well-characterized epigenetic modification in cancer cells. In particular, promoter hypermethylation of and results in loss of expression on Androgen Receptor (AR) and Estrogen Receptor (ER), respectively, and is associated with a hormone refractory state. We now report that Glycogen Synthase Kinase 3 (GSK3) phosphorylates DNMT1 at S714, which is localized to a 62 amino acid region referred to as auto-inhibitory linker, which functions to occlude the DNA from the active site of DNMT1 to prevent the methylation of unmethylated DNA. Molecular Dynamics simulation indicates that phosphorylation at S714 resulted in conformational rearrangement of the autoinhibitory domain that inactivated its ability to block the methylation of unmethylated DNA and resulted in enhanced DNA binding. Treatment with a novel and more selective inhibitor of GSK3 resulted in decreased methylation of the promoter region of genes encoding the Androgen Receptor (AR) and Estrogen Receptor alpha (ERa) and re-expression of the AR and ERa in AR negative prostate cancer and ER negative breast cancer cells, respectively. As a result, concurrent treatment with the GSK3 inhibitor resulted in responsiveness of AR negative prostate cancer and ER negative breast cancer cells to inhibitors of the AR or ER, respectively, in and experimental models.
由DNA甲基转移酶（DNMT）催化的DNA甲基化是癌细胞中一种特征明确的表观遗传修饰。特别是，[基因名称1]和[基因名称2]的启动子高甲基化分别导致雄激素受体（AR）和雌激素受体（ER）表达缺失，并与激素难治状态相关。我们现在报告，糖原合酶激酶3（GSK3）在S714位点磷酸化DNMT1，该位点位于一个被称为自抑制连接子的62个氨基酸区域，其作用是将DNA与DNMT1的活性位点隔开，以防止未甲基化DNA的甲基化。分子动力学模拟表明，S714位点的磷酸化导致自抑制结构域的构象重排，使其失去阻断未甲基化DNA甲基化的能力，并导致DNA结合增强。用一种新型且更具选择性的GSK3抑制剂处理，导致雄激素受体（AR）和雌激素受体α（ERα）编码基因启动子区域的甲基化减少，以及AR阴性前列腺癌细胞和ER阴性乳腺癌细胞中AR和ERα的重新表达。结果，在[具体实验模型1]和[具体实验模型2]实验模型中，同时用GSK3抑制剂处理分别导致AR阴性前列腺癌细胞和ER阴性乳腺癌细胞对AR或ER抑制剂产生反应。
