Background

Activating mutations in the Fms-like tyrosine kinase 3 (FLT3) are among the most prevalent oncogenic mutations in acute myeloid leukaemia. Inhibitors selectively targeting FLT3 kinase have shown promising clinical activity; their success in the clinic, however, has been limited due to the emergence of acquired resistance.

Methods

CCT245718 was identified and characterised as a dual Aurora A/FLT3 inhibitor through cell-based and biochemical assays. The ability of CCT245718 to overcome TKD-mediated resistance was evaluated in a cell line-based model of drug resistance to FLT3 inhibitors.

Results

CCT245718 exhibits potent antiproliferative activity towards FLT3-ITD + AML cell lines and strongly binds to FLT3-ITD and TKD (D835Y) mutants in vitro. Activities of both FLT3-ITD and Aurora A are also inhibited in cells. Inhibition of FLT3 results in reduced phosphorylation of STAT5, downregulation of survivin and induction of apoptotic cell death. Moreover, CCT245718 overcomes TKD-mediated resistance in a MOLM-13-derived cell line containing FLT3 with both ITD and D835Y mutations. It also inhibits FLT3 signalling in both parental and resistant cell lines compared to FLT3-specific inhibitor MLN518, which is only active in the parental cell line.

Conclusions

Our results demonstrate that CCT245718 is a potent dual FLT3/Aurora A inhibitor that can overcome TKD-mediated acquired resistance.

中文翻译：

---

CCT245718，一种双重 FLT3/Aurora A 抑制剂克服了 D835Y 介导的急性髓细胞白血病细胞对 FLT3 抑制剂的抗性

背景

Fms 样酪氨酸激酶 3 (FLT3) 的激活突变是急性髓性白血病中最普遍的致癌突变之一。选择性靶向 FLT3 激酶的抑制剂已显示出有希望的临床活性；然而，由于获得性抗药性的出现，它们在临床上的成功受到了限制。

方法

CCT245718 通过基于细胞的和生化分析被鉴定并表征为双重 Aurora A/FLT3 抑制剂。在基于细胞系的 FLT3 抑制剂耐药模型中评估了 CCT245718 克服 TKD 介导的耐药性的能力。

结果

CCT245718 对 FLT3-ITD + AML 细胞系表现出有效的抗增殖活性，并在体外与 FLT3-ITD 和 TKD (D835Y) 突变体强烈结合。FLT3-ITD 和 Aurora A 的活性也在细胞中受到抑制。FLT3 的抑制导致 STAT5 的磷酸化降低、survivin 的下调和凋亡细胞死亡的诱导。此外，CCT245718 在含有具有 ITD 和 D835Y 突变的 FLT3 的 MOLM-13 衍生细胞系中克服了 TKD 介导的耐药性。与 FLT3 特异性抑制剂 MLN518 相比，它还抑制亲代和耐药细胞系中的 FLT3 信号传导，后者仅在亲代细胞系中具有活性。

结论

我们的结果表明，CCT245718 是一种有效的双重 FLT3/Aurora A 抑制剂，可以克服 TKD 介导的获得性耐药。