Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, FL 32610, USA.
Exp Hematol. 2012 Jan;40(1):22-34. doi: 10.1016/j.exphem.2011.10.003. Epub 2011 Oct 20.
Hyperkinetic Jak2 tyrosine kinase signaling has been implicated in several hematological disorders, including myeloproliferative neoplasms. Effective Jak2 inhibitors can have significant therapeutic potential. Here, using structure-based virtual screening, we identified a benzothiophene-derived Jak2 inhibitor named A46. We hypothesized that this compound would inhibit Jak2-V617F-mediated pathologic cell growth. To test this, A46 was analyzed for its ability to inhibit recombinant Jak2 protein catalysis; suppress Jak2-mediated pathogenic cell growth in vitro; inhibit the aberrant ex vivo growth of Jak2-V617F-expressing primary human bone marrow cells; and inhibit Jak2-mediated pathogenesis in vivo. To this end, we found that A46 selectively inhibited Jak2-V617F protein when compared to wild-type Jak2 protein. The drug also selectively inhibited the proliferation of Jak2-V617F-expressing cells in both a time- and dose-dependent manner, and this correlated with decreased Jak2 and signal transducers and activators of transcription 5 phosphorylation within treated cells. The Jak2-V617F cell growth inhibition correlated with an induction of cell cycle arrest and promotion of apoptosis. A46 also inhibited the pathologic growth of primary Jak2-V617F-expressing bone marrow cells ex vivo. Lastly, using a mouse model of Jak2-V617F-mediated myeloproliferative neoplasia. A46 significantly reduced the splenomegaly and megakaryocytic hyperplasia in the spleens of treated mice and the levels of interleukin-6 in the plasma. Collectively, our data demonstrate that the benzothiophene-based compound, A46, suppresses Jak2-mediated pathogenesis, thereby making it a potential candidate drug against Jak2-mediated disorders.
过表达的 Jak2 酪氨酸激酶信号已被认为与几种血液疾病有关，包括骨髓增生性肿瘤。有效的 Jak2 抑制剂具有显著的治疗潜力。在这里，我们通过基于结构的虚拟筛选，发现了一种名为 A46 的苯并噻吩衍生 Jak2 抑制剂。我们假设该化合物将抑制 Jak2-V617F 介导的病理性细胞生长。为了验证这一点，我们分析了 A46 抑制重组 Jak2 蛋白催化的能力；抑制 Jak2 介导的体外致病性细胞生长；抑制 Jak2-V617F 表达的原代人骨髓细胞的异常体外生长；以及抑制 Jak2 介导的体内发病机制。为此，我们发现 A46 选择性地抑制 Jak2-V617F 蛋白，而不是野生型 Jak2 蛋白。该药物还选择性地抑制 Jak2-V617F 表达细胞的增殖，呈时间和剂量依赖性，这与处理细胞中 Jak2 和信号转导子和转录激活子 5 的磷酸化减少相关。Jak2-V617F 细胞生长抑制与细胞周期停滞的诱导和凋亡的促进相关。A46 还抑制了 Jak2-V617F 表达的原代骨髓细胞的病理性生长。最后，在 Jak2-V617F 介导的骨髓增生性肿瘤的小鼠模型中，A46 显著降低了治疗小鼠脾脏肿大和巨核细胞增生以及血浆中白细胞介素-6 的水平。总的来说，我们的数据表明，基于苯并噻吩的化合物 A46 抑制 Jak2 介导的发病机制，因此它是一种针对 Jak2 介导的疾病的潜在候选药物。
