Pevarello Paolo, Brasca Maria Gabriella, Orsini Paolo, Traquandi Gabriella, Longo Antonio, Nesi Marcella, Orzi Fabrizio, Piutti Claudia, Sansonna Pietro, Varasi Mario, Cameron Alexander, Vulpetti Anna, Roletto Fulvia, Alzani Rachele, Ciomei Marina, Albanese Clara, Pastori Wilma, Marsiglio Aurelio, Pesenti Enrico, Fiorentini Francesco, Bischoff Jim R, Mercurio Ciro
Department Chemistry, Nerviano Medical Sciences, BU-Oncology and BU-Preclinical Science, Viale Pasteur 10, 20014 Nerviano (MI), Italy.
J Med Chem. 2005 Apr 21;48(8):2944-56. doi: 10.1021/jm0408870.
Inhibitors of cyclin-dependent kinases (CDK) such as CDK2/cyclin A-E are currently undergoing clinical trials to verify their potential as new anticancer agents. In a previous article we described the lead discovery process of a 3-aminopyrazole class of CDK2/cyclin A-E inhibitors. The endpoint of this process was PNU-292137, a compound endowed with in vivo antitumor activity in a mouse tumor xenograft model. We optimized this lead compound to improve some physicochemical properties, notably solubility and plasma protein binding. This lead optimization process brought us to the discovery of (2S)-N-(5-cyclopropyl-1H-pyrazol-3-yl)-2-[4-(2-oxo-1-pyrrolidinyl)phenyl]propanamide (PHA-533533, 13), a compound with a balanced activity vs druglike profile. Compound 13 inhibited CDK2/cyclin A with a K(i) of 31 nM, counteracting tumor cell proliferation of different cell lines with an IC(50) in the submicromolar range. Solubility was improved more than 10 times over the starting lead, while plasma protein binding was decreased from 99% to 74%. With exploitation of this globally enhanced in vitro profile, 13 was more active than PNU-292137 in vivo in the A2780 xenograft model showing a tumor growth inhibition of 70%. Proof of mechanism of action was obtained in vivo by immunohistochemical analysis of tumor slices of 13-treated vs untreated animals.
细胞周期蛋白依赖性激酶（CDK）抑制剂，如CDK2/细胞周期蛋白A-E，目前正在进行临床试验，以验证其作为新型抗癌药物的潜力。在之前的一篇文章中，我们描述了3-氨基吡唑类CDK2/细胞周期蛋白A-E抑制剂的先导化合物发现过程。该过程的终点是PNU-292137，一种在小鼠肿瘤异种移植模型中具有体内抗肿瘤活性的化合物。我们对该先导化合物进行了优化，以改善其一些物理化学性质，特别是溶解度和血浆蛋白结合率。这种先导化合物优化过程使我们发现了（2S）-N-（5-环丙基-1H-吡唑-3-基）-2-[4-（2-氧代-1-吡咯烷基）苯基]丙酰胺（PHA-533533，13），一种活性与类药特性平衡的化合物。化合物13抑制CDK2/细胞周期蛋白A的K(i)为31 nM，以亚微摩尔范围内的IC(50)对抗不同细胞系的肿瘤细胞增殖。溶解度比起始先导化合物提高了10倍以上，而血浆蛋白结合率从99%降至74%。利用这种整体增强的体外特性，13在A2780异种移植模型中的体内活性比PNU-292137更高，显示出70%的肿瘤生长抑制率。通过对用13处理和未处理动物的肿瘤切片进行免疫组织化学分析，在体内获得了作用机制的证据。
