Traxler P, Bold G, Frei J, Lang M, Lydon N, Mett H, Buchdunger E, Meyer T, Mueller M, Furet P
Novartis Pharmaceuticals, Novartis Limited, Basel, Switzerland.
J Med Chem. 1997 Oct 24;40(22):3601-16. doi: 10.1021/jm970124v.
In the course of the random screening of a pool of CIBA chemicals, the two pyrazolopyrimidines 1 and 2 have been identified as fairly potent inhibitors of the EGF-R tyrosine kinase. Using a pharmacophore model for ATP-competitive inhibitors interacting with the active site of the EGF-R protein tyrosine kinase (PTK), the class of the pyrazolo[3,4-d]pyrimidines was then optimized in an interactive process leading to a series of 4-(phenylamino)-1H-pyrazolo[3,4-d]-pyrimidines as highly potent inhibitors of the EGF-R tyrosine kinase. The most potent compounds 13, 14, 15, 17, 19, 22, 26, 28, and 30 of this series inhibited the EGF-R PTK with IC50 values below 10 nM. High selectivity toward a panel of nonreceptor tyrosine kinases (c-Src, v-Abl and serine/threonine kinases (PKC alpha, CDK1) was observed. In cells, EGF-stimulated cellular tyrosine phosphorylation was inhibited by compounds 13, 15, 19, 22, and 23 at IC50 values below 50 nM, whereas PDGF-induced tyrosine phosphorylation was not affected by concentrations up to 10 microM, thus indicating high selectivity for the inhibition of the ligand-activated EGF-R signal transduction pathway. Compounds 15 and 19 inhibited proliferation of the EGF-dependent MK cell line with IC50 values below 0.5 microM. In addition, two compounds, 9 and 11, showing satisfactory oral bioavailability in mice after oral administration, exhibited good in vivo efficacy at doses of 12.5 and 50 mg/kg in a nude mouse tumor model using xenografts of the EGF-R overexpressing A431 cell line. From SAR studies, a binding mode for 4-(phenylamino)-1H-pyrazolo[3,4-d]pyrimidines, especially for compound 15, at the ATP-binding site of the EGF-R tyrosine kinase is proposed. 4-(Phenylamino)-1H-pyrazolo[3,4-d]pyrimidines represent a new class of highly potent tyrosine kinase inhibitors which preferentially inhibit the EGF-mediated signal transduction pathway and have the potential for further evaluation as anticancer agents.
在对一批汽巴化学品进行随机筛选的过程中，两种吡唑并嘧啶1和2被鉴定为表皮生长因子受体（EGF-R）酪氨酸激酶的相当有效的抑制剂。利用与EGF-R蛋白酪氨酸激酶（PTK）活性位点相互作用的ATP竞争性抑制剂的药效团模型，然后在一个交互式过程中对吡唑并[3,4-d]嘧啶类进行优化，得到了一系列4-（苯胺基）-1H-吡唑并[3,4-d]嘧啶作为EGF-R酪氨酸激酶的高效抑制剂。该系列中最有效的化合物13、14、15、17、19、22、26、28和30抑制EGF-R PTK的IC50值低于10 nM。观察到对一组非受体酪氨酸激酶（c-Src、v-Abl）和丝氨酸/苏氨酸激酶（蛋白激酶Cα、细胞周期蛋白依赖性激酶1）具有高选择性。在细胞中，化合物13、15、19、22和23在IC50值低于50 nM时抑制EGF刺激的细胞酪氨酸磷酸化，而血小板衍生生长因子（PDGF）诱导的酪氨酸磷酸化在浓度高达10 μM时不受影响，这表明对抑制配体激活的EGF-R信号转导途径具有高选择性。化合物15和19以IC50值低于0.5 μM抑制依赖EGF的MK细胞系的增殖。此外，两种化合物9和11在小鼠口服给药后显示出令人满意的口服生物利用度，在使用过表达EGF-R的A431细胞系异种移植瘤的裸鼠肿瘤模型中，以12.5和50 mg/kg的剂量表现出良好的体内疗效。从构效关系（SAR）研究中，提出了4-（苯胺基）-1H-吡唑并[3,4-d]嘧啶，特别是化合物15在EGF-R酪氨酸激酶ATP结合位点的结合模式。4-（苯胺基）-1H-吡唑并[3,4-d]嘧啶代表了一类新型的高效酪氨酸激酶抑制剂，它们优先抑制EGF介导的信号转导途径，并有作为抗癌药物进一步评估的潜力。
