Experimental Medicine Unit, Oncology R&D, GSK, Collegeville, USA.
Protein Mass Spectrometry, In Vitro/In Vivo Translation, Research, GSK, Collegeville, USA.
Sci Rep. 2020 Dec 17;10(1):22155. doi: 10.1038/s41598-020-78800-6.
Arginine methylation has been recognized as a post-translational modification with pleiotropic effects that span from regulation of transcription to metabolic processes that contribute to aberrant cell proliferation and tumorigenesis. This has brought significant attention to the development of therapeutic strategies aimed at blocking the activity of protein arginine methyltransferases (PRMTs), which catalyze the formation of various methylated arginine products on a wide variety of cellular substrates. GSK3368715 is a small molecule inhibitor of type I PRMTs currently in clinical development. Here, we evaluate the effect of type I PRMT inhibition on arginine methylation in normal human peripheral blood mononuclear cells and utilize a broad proteomic approach to identify type I PRMT substrates. This work identified heterogenous nuclear ribonucleoprotein A1 (hnRNP-A1) as a pharmacodynamic biomarker of type I PRMT inhibition. Utilizing targeted mass spectrometry (MS), methods were developed to detect and quantitate changes in methylation of specific arginine residues on hnRNP-A1. This resulted in the development and validation of novel MS and immune assays useful for the assessment of GSK3368715 induced pharmacodynamic effects in blood and tumors that can be applied to GSK3368715 clinical trials.
精氨酸甲基化已被认为是一种具有多种效应的翻译后修饰，从转录调控到代谢过程，这些过程有助于异常细胞增殖和肿瘤发生。这引起了人们对开发旨在阻断蛋白精氨酸甲基转移酶（PRMTs）活性的治疗策略的极大关注，这些酶催化在广泛的细胞底物上形成各种甲基化的精氨酸产物。GSK3368715 是一种目前正在临床开发中的 I 型 PRMT 小分子抑制剂。在这里，我们评估了 I 型 PRMT 抑制对正常人外周血单核细胞中精氨酸甲基化的影响，并利用广泛的蛋白质组学方法来鉴定 I 型 PRMT 底物。这项工作确定异质核核糖核蛋白 A1（hnRNP-A1）为 I 型 PRMT 抑制的药效生物标志物。利用靶向质谱（MS）方法，开发了用于检测和定量 hnRNP-A1 上特定精氨酸残基甲基化变化的方法。这导致了新型 MS 和免疫测定法的开发和验证，这些方法可用于评估 GSK3368715 在血液和肿瘤中的药效动力学效应，可应用于 GSK3368715 的临床试验。
