Comparison of the Kinase Profile of Midostaurin (Rydapt) with That of Its Predominant Metabolites and the Potential Relevance of Some Newly Identified Targets to Leukemia Therapy
作者:Paul W. Manley、Giorgio Caravatti、Pascal Furet、Johannes Roesel、Phi Tran、Trixie Wagner、Markus Wartmann
DOI:10.1021/acs.biochem.8b00727
日期:2018.9.25
The multitargeted protein kinase inhibitor midostaurin is approved for the treatment of both newly diagnosed FLT3-mutated acute myeloid leukemia (AML) and KIT-driven advanced systemic mastocytosis. AML is a heterogeneous malignancy, and investigational drugs targeting FLT3 have shown disparate effects in patients with FLT3-mutated AML, probably as a result of their inhibiting different targets and pathways at the administered doses. However, the efficacy and side effects of drugs do not just reflect the biochemical and pharmacodynamic properties of the parent compound but are often comprised of complex cooperative effects between the properties of the parent and active metabolites. Following chronic dosing, two midostaurin metabolites attain steady-state plasma trough levels greater than that of the parent drug. In this study, we characterized these metabolites and determined their profiles as kinase inhibitors using radiometric transphosphorylation assays. Like midostaurin, the metabolites potently inhibit mutant forms of FLT3 and KIT and several additional kinases that either are directly involved in the deregulated signaling pathways or have been implicated as playing a role in AML via stromal support, such as IGF1R, LYN, PDPK1, RET, SYK, TRKA, and VEGFR2. Consequently, a complex interplay between the kinase activities of midostaurin and its metabolites is likely to contribute to the efficacy of midostaurin in AML and helps to engender the distinctive effects of the drug compared to those of other FLT3 inhibitors in this malignancy.
多靶点蛋白激酶抑制剂米哚妥林被批准用于治疗新诊断的FLT3突变急性髓性白血病(AML)和KIT驱动的晚期系统性肥大细胞增多症。急性髓细胞白血病是一种异质性恶性肿瘤,针对FLT3的研究药物在FLT3突变急性髓细胞白血病患者中显示出不同的疗效,这可能是由于这些药物在给药剂量下抑制了不同的靶点和途径。然而,药物的疗效和副作用并不仅仅反映了母体化合物的生化和药效学特性,往往还包括母体和活性代谢物之间复杂的协同作用。长期用药后,两种米哚妥林代谢物的稳态血浆谷值水平高于母药。在这项研究中,我们对这些代谢物进行了特征描述,并使用放射性转磷酸化测定法确定了它们作为激酶抑制剂的特性。与米哚妥林一样,这些代谢物也能有效抑制突变形式的 FLT3 和 KIT 以及其他几种激酶,这些激酶要么直接参与了失调的信号通路,要么被认为通过基质支持在急性髓细胞性白血病中发挥作用,如 IGF1R、LYN、PDPK1、RET、SYK、TRKA 和 VEGFR2。因此,midostaurin 及其代谢物的激酶活性之间的复杂相互作用很可能有助于midostaurin在急性髓细胞性白血病中的疗效,并有助于使该药物在这种恶性肿瘤中产生与其他FLT3抑制剂不同的效果。