Design, Synthesis, and Bioactivity Evaluation of Dual-Target Inhibitors of Tubulin and Src Kinase Guided by Crystal Structure

Klisyri (KX01) is a dual tubulin/Src
protein inhibitor that has
shown potential therapeutic effects in several tumor models. However,
a phase II clinical trial in patients with bone-metastatic castration-resistant
prostate cancer was halted because of lack of efficacy. We previously
reported that KX01 binds to the colchicine site of β-tubulin
and its morpholine group lies close to α-tubulin’s surface.
Thus, we hypothesized that enhancing the interaction of KX01 with
α-tubulin could increase tubulin inhibition and synthesized
a series of KX01 derivatives directed by docking studies. Among these
derivatives, 8a exhibited more than 10-fold antiproliferation
activity in several tumor cells than KX01 and significantly improved in vivo antitumor effects. The X-ray crystal structure suggested
that 8a both bound to the colchicine site and extended
into the interior of α-tubulin to form potent interactions,
presenting a novel binding mode. A potential clinical candidate for
cancer therapy was identified in this study.

Klisyri（KX01）是一种双重抑制物，作用于微管蛋白/Src蛋白，其在多种肿瘤模型中展现出潜在的疗效。然而，在针对骨转移去势抵抗性前列腺癌患者进行的II期临床试验因疗效不足而被终止。我们先前的研究表明，KX01与β-微管蛋白的秋水仙碱位点结合，其哌啶基团靠近α-微管蛋白的表面。因此，我们假设增强KX01与α-微管蛋白的相互作用可以提高微管蛋白的抑制效果，并基于对接研究合成了一系列KX01衍生物。在这些衍生物中，8a在多种肿瘤细胞中的抗增殖活性比KX01高出10倍以上，并在体内抗肿瘤效果上显著改善。X射线晶体结构表明，8a不仅与秋水仙碱位点结合，还延伸至α-微管蛋白内部，形成有效的相互作用，呈现出一种新型的结合模式。本研究中识别出了一种具有潜在临床治疗癌症应用价值的候选药物。