Zhang Yvyin, Wang Peihong, Wang Yang, Shen Yang
Shanghai Institute of Hematology, State Key Laboratory of Medical Genomics, National Research Center for Translational Medicine (Shanghai), Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
Department of Hematology, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou, 510000, China.
Biomark Res. 2023 Jan 24;11(1):8. doi: 10.1186/s40364-022-00447-4.
Gilteritinib is the only drug approved as monotherapy for acute myeloid leukemia (AML) patients harboring FMS-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) mutation throughout the world. However, drug resistance inevitably develops in clinical. Sitravatinib is a multi-kinase inhibitor under evaluation in clinical trials of various solid tumors. In this study, we explored the antitumor activity of sitravatinib against FLT3-ITD and clinically-relevant drug resistance in FLT3 mutant AML.
Growth inhibitory assays were performed in AML cell lines and BaF3 cells expressing various FLT3 mutants to evaluate the antitumor activity of sitravatinib in vitro. Immunoblotting was used to examine the activity of FLT3 and its downstream pathways. Molecular docking was performed to predict the binding sites of FLT3 to sitravatinib. The survival benefit of sitravatinib in vivo was assessed in MOLM13 xenograft mouse models and mouse models of transformed BaF3 cells harboring different FLT3 mutants. Primary patient samples and a patient-derived xenograft (PDX) model were also used to determine the efficacy of sitravatinib.
Sitravatinib inhibited cell proliferation, induced cell cycle arrest and apoptosis in FLT3-ITD AML cell lines. In vivo studies showed that sitravatinib exhibited a better therapeutic effect than gilteritinib in MOLM13 xenograft model and BaF3-FLT3-ITD model. Unlike gilteritinib, the predicted binding sites of sitravatinib to FLT3 did not include F691 residue. Sitravatinib displayed a potent inhibitory effect on FLT3-ITD-F691L mutation which conferred resistance to gilteritinib and all other FLT3 inhibitors available, both in vitro and in vivo. Compared with gilteritinib, sitravatinib retained effective activity against FLT3 mutation in the presence of cytokines through the more potent and steady inhibition of p-ERK and p-AKT. Furthermore, patient blasts harboring FLT3-ITD were more sensitive to sitravatinib than to gilteritinib in vitro and in the PDX model.
Our study reveals the potential therapeutic role of sitravatinib in FLT3 mutant AML and provides an alternative inhibitor for the treatment of AML patients who are resistant to current FLT3 inhibitors.
吉瑞替尼是全球唯一被批准用于治疗携带FMS样酪氨酸激酶3内部串联重复（FLT3-ITD）突变的急性髓系白血病（AML）患者的单药治疗药物。然而，临床上不可避免地会出现耐药性。西曲替尼是一种多激酶抑制剂，正在多种实体瘤的临床试验中进行评估。在本研究中，我们探讨了西曲替尼对FLT3-ITD的抗肿瘤活性以及对FLT3突变型AML临床相关耐药性的影响。
在AML细胞系和表达各种FLT3突变体的BaF3细胞中进行生长抑制试验，以评估西曲替尼的体外抗肿瘤活性。采用免疫印迹法检测FLT3及其下游信号通路的活性。进行分子对接以预测FLT3与西曲替尼的结合位点。在MOLM13异种移植小鼠模型和携带不同FLT3突变体的转化BaF3细胞小鼠模型中评估西曲替尼在体内的生存获益。还使用原发性患者样本和患者来源的异种移植（PDX）模型来确定西曲替尼的疗效。
西曲替尼抑制FLT3-ITD AML细胞系的细胞增殖，诱导细胞周期阻滞和凋亡。体内研究表明，在MOLM13异种移植模型和BaF3-FLT3-ITD模型中，西曲替尼比吉瑞替尼表现出更好的治疗效果。与吉瑞替尼不同，西曲替尼与FLT3的预测结合位点不包括F691残基。西曲替尼在体外和体内对赋予吉瑞替尼和所有其他可用FLT3抑制剂耐药性的FLT3-ITD-F691L突变均显示出强效抑制作用。与吉瑞替尼相比，西曲替尼通过更有效和稳定地抑制p-ERK和p-AKT，在细胞因子存在的情况下对FLT3突变仍保留有效活性。此外，在体外和PDX模型中，携带FLT3-ITD的患者原始细胞对西曲替尼比对吉瑞替尼更敏感。
我们的研究揭示了西曲替尼在FLT3突变型AML中的潜在治疗作用，并为治疗对当前FLT3抑制剂耐药的AML患者提供了一种替代抑制剂。
