Department of Medical Imaging and Radiological Technology, Yuanpei University of Medical Technology, Hsinchu 300, Taiwan.
Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei 100, Taiwan.
Int J Mol Sci. 2019 Mar 11;20(5):1230. doi: 10.3390/ijms20051230.
Internal tandem duplication of FLT3 juxtamembrane domain (FLT3-ITD)-positive acute myeloid leukemia (AML) leads to poor clinical outcomes after chemotherapy. We aimed to establish a cytarabine-resistant line from -ITD-positive MV4-11 (MV4-11-P) cells and examine the development of resistance. The -ITD mutation was retained in MV4-11-R; however, the protein was underglycosylated and less phosphorylated in these cells. Moreover, the phosphorylation of ERK1/2, Akt, MEK1/2 and p53 increased in MV4-11-R. The levels of Mcl-1 and p53 proteins were also elevated in MV4-11-R. A p53 D281G mutant emerged in MV4-11-R, in addition to the pre-existing R248W mutation. MV4-11-P and MV4-11-R showed similar sensitivity to cabozantinib, sorafenib, and MK2206, whereas MV4-11-R showed resistance to CI-1040 and idarubicin. MV4-11-R resistance may be associated with inhibition of Akt phosphorylation, but not ERK phosphorylation, after exposure to these drugs. The multi-kinase inhibitor cabozantinib inhibited FLT3-ITD signaling in MV4-11-R cells and MV4-11-R-derived tumors in mice. Cabozantinib effectively inhibited tumor growth and prolonged survival time in mice bearing MV4-11-R-derived tumors. Together, our findings suggest that Mcl-1 and Akt phosphorylation are potential therapeutic targets for p53 mutants and that cabozantinib is an effective treatment in cytarabine-resistant FLT3-ITD-positive AML.
FLT3 跨膜区内部串联重复（FLT3-ITD）阳性急性髓系白血病（AML）患者经化疗后临床结局较差。本研究旨在建立 FLT3-ITD 阳性 MV4-11（MV4-11-P）细胞的阿糖胞苷耐药株，并研究耐药的发生机制。MV4-11-R 中保留了 ITD 突变，但该蛋白在这些细胞中发生了低聚糖基化和少磷酸化。此外，MV4-11-R 中 ERK1/2、Akt、MEK1/2 和 p53 的磷酸化增加。MV4-11-R 中 Mcl-1 和 p53 蛋白的水平也升高。除了先前存在的 R248W 突变外，MV4-11-R 中还出现了 p53 D281G 突变。MV4-11-P 和 MV4-11-R 对卡博替尼、索拉非尼和 MK2206 的敏感性相似，但 MV4-11-R 对 CI-1040 和伊达比星耐药。MV4-11-R 耐药可能与这些药物作用后 Akt 磷酸化而不是 ERK 磷酸化的抑制有关。多激酶抑制剂卡博替尼抑制 MV4-11-R 细胞和小鼠中 MV4-11-R 衍生肿瘤中的 FLT3-ITD 信号。卡博替尼可有效抑制携带 MV4-11-R 衍生肿瘤的小鼠的肿瘤生长并延长其生存时间。总之，我们的研究结果表明，Mcl-1 和 Akt 磷酸化可能是 p53 突变体的潜在治疗靶点，卡博替尼是治疗阿糖胞苷耐药性 FLT3-ITD 阳性 AML 的有效药物。
