新型选择性Axl/Flt3小分子双重抑制剂的设计、合成及生物活性研究

Axl is a new potential therapeutic target for anti-AML drug development. Overexpression and activation of Axl is also closely correlated to the acquired resistance against Flt3 inhibitor therapies in AML patients. Selective Axl/Flt3 dual inhibitor may be considered as a new therapeutic strategy to overcome the clinical resistance of AML patients against Flt3 inhibitor therapies. ASP2215 is the only reported Axl/Flt3 dual inhibitor, but this compound exhibits low target selectivity. It also demonstrated strong inhibition against a panel of kinases. The potential “off-target” toxicity may limit its future clinical application. We have successfully designed and synthesized a series of 4-oxo-1, 4-dihydroquinoline-3-carboxamide derivatives as novel potent Axl/Flt3 inhibitor. One of the representative compounds, D30123, strongly inhibited Axl and Flt3 kinase functions with IC50 values of 1.5 and 15.5 nM, respectively. But it is significantly less potent against a panel of 380 kinases. The compound also demonstrates promising antitumor efficacy both in vitro and in vivo. In this proposal, we will conduct a systematically structural optimization to further improve the potency, target specificity and druglike properties of the molecules by using D30123 as a lead compound. We will also perform the mechanism study by investigating effect of the inhibitors on AML cancer cells and the tumor microenvironment. Our study will lay some foundation for future development of selective Axl/Flt3 inhibitors as new therapeutic agents for resistant and/or non-resistant AML patients.

Axl是抗AML药物研究的潜在新靶标，其异常表达或活化还与Flt3抑制剂类抗AML药物临床耐药密切相关。Axl/Flt3双重抑制剂有望成为治疗和克服AML耐药的新策略。目前仅有ASP2215被报道作为Axl/Flt3双重抑制剂，但其靶标选择性较差。脱靶毒性可能会限制其临床开发。我们已成功设计合成了具有喹喏酮结构的新型Axl/Flt3双重抑制剂，化合物D30123对Axl和Flt3的IC50分别为1.5和15.5 nM，而对其它380余种激酶活性明显较弱。化合物还展示出优异的体内外抗肿瘤效果。本项目拟以此为基础，利用基于结构的理性药物设计方法对化合物进行系统的结构优化，进一步提高化合物的生物活性和靶标特异性，改善其药代性质等成药性指标；并通过研究分子对AML细胞和肿瘤微环境的影响等阐明其抗肿瘤机制。研究将为新型AML靶向药物开发奠定基础。

Axl是抗急性髓系白血病（AML）药物研究的潜在新靶标，其异常表达或活化还与另一有潜力的抗AML靶标Flt3抑制剂的临床耐药密切相关，因此，Axl/Flt3双重抑制剂有望成为治疗和克服AML耐药的新策略。.国内外报道的Axl/Flt3双重抑制剂仅见ASP2215，但其靶标选择性较差, 脱靶毒性可能会限制其临床开发。我们在前期发现并合成了喹喏酮结构的新型Axl/Flt3双重抑制剂D30123（对Axl和Flt3的IC50分别为1.5和15.5 nM）。本项目以D30123为基础，在基于结构的理性药物设计方法上对化合物进行进一步的系统结构优化，以提高化合物的活性、选择性及成药性，寻找潜在的新型抗AML药物。.基于以上策略，本项目合成了一系列分子近100个。通过对喹唑啉7位取代基团进行亲水性侧链优化，提高了化合物的生物活性、药代性质等成药性指标，由此获得了有良好活性和成药性的候选物D30134。D30134对Axl与Flt3的激酶活性IC50分别为2.2nM和1.9nM，并显示出良好的体内外抗AML活性。它对人AML细胞MV4-11体外增殖的IC50值为7nM，在小鼠的人AML移植瘤模型上显著抑制肿瘤的生长，口服10mg/kg剂量组的肿瘤生长抑制（TGI）为104.9%，其中部分小鼠肿瘤消退，且小鼠体重无明显变化，耐受性好。.以D30134为代表的相关研究成果已申请发明专利，D30134因其良好的抗AML潜力和成药性已转让海和药业（里程碑转让金额8.05亿元) 。D30134在2021年4月获国家药监局临床审批，目前正在中国和澳大利亚同步进行国际多中心I期临床试验。