Targeting splicing in myelodysplasia through GSK-3

（请保持文字，不要PDF） 剪接因子SRSF 2和SF 3B 1的复发性突变在脊髓发育不良中很常见 （MDS）。这些获得功能的突变是相互排斥的，并且总是杂合的， 这表明具有剪接因子突变的细胞需要一些野生型剪接活性， 生存进一步干扰剪接装置是致命的，造成治疗上的弱点 用于剪接因子突变肿瘤。因此，小分子剪接抑制剂目前正在被研究。 探索治疗剪接因子突变型MDS，但他们有无法忍受的副作用， 迄今为止，有限的功效表明需要抑制剪接的新方法。我们发现 信号蛋白糖原合成酶激酶-3（GSK-3）磷酸化多个剪接， 影响并调节多种mRNA的选择性剪接。抑制GSK-3 在具有杂合子的造血细胞系中选择性破坏剪接并促进细胞死亡 SRSF 2或SF 3B 1突变。我们的长期目标是将GSK-3的作用定义为 一种新的，全球性的剪接调节剂，并测试GSK-3抑制剂是否选择性地 对于具有剪接因子突变的MDS细胞是体内致死的。我们的初步数据支持这一点 假设在造血细胞系，但重要的是建立这些发现，在原发性 来自MDS和CMML患者的人细胞。我们将表达SRSF 2 wt或致病的 在MDS患者的原代细胞中SRSF 2 P95 H突变，以询问是否表达SRSF 2 P95 H。 致病性突变在其他同基因背景下赋予对GSK-3抑制的敏感性。 这些实验将提供关键的初步数据，并为未来的研究奠定基础。 研究GSK-3作为剪接的全局调节因子和潜在的 剪接因子突变型MDS的治疗靶点。

(PLEASE KEEP IN WORD, DO NOT PDF) Recurrent mutations in the splicing factors SRSF2 and SF3B1 are common in myelodysplasia (MDS). These gain of function mutations are mutually exclusive and invariably heterozygous, indicating that cells with splicing factor mutations require some wild-type splicing activity to survive. Further perturbation of the splicing apparatus is lethal, creating a therapeutic vulnerability for splicing factor mutant neoplasms. Thus, small molecule splicing inhibitors are currently being explored to treat splicing factor mutant MDS, but they have had intolerable side effects and limited efficacy so far, indicating that new approaches to inhibit splicing are needed. We found that the signaling protein glycogen synthase kinase-3 (GSK-3) phosphorylates multiple splicing factors and regulates the alternative splicing of a broad range of mRNAs. Inhibition of GSK-3 disrupts splicing and promotes cell death selectively in hematopoietic cell lines with heterozygous mutations in SRSF2 or SF3B1. Our long-term goals are to define the role of GSK-3 as a novel, global regulator of splicing and to test whether GSK-3 inhibitors are selectively lethal in vivo for MDS cells with splicing factor mutations. Our preliminary data support this hypothesis in hematopoietic cell lines, but it is important to establish these findings in primary human cells from patients with MDS and CMML. We will express SRSF2wt or the pathogenic SRSF2P95H mutation in primary cells from patients with MDS to ask whether expression of the pathogenic mutation confers sensitivity to GSK-3 inhibition in an otherwise isogenic context. These experiments will provide critical preliminary data and lay the groundwork for future experiments to investigate the role of GSK-3 as a global regulator of splicing and as a potential therapeutic target in splicing factor mutant MDS.