RESUMO
Matrix metalloproteinase (MMP)-activated prodrugs were formed by coupling MMP-cleavable peptides to doxorubicin. The resulting conjugates were excellent in vitro substrates for MMP-2, -9, and -14. HT1080, a fibrosarcoma cell line, was used as a model system to test these prodrugs because these cells, like tumor stromal fibroblasts, expressed several MMPs. In cultured HT1080 cells, simple MMP-cleavable peptides were primarily metabolized by neprilysin, a membrane-bound metalloproteinase. MMP-selective metabolism in cultured HT1080 cells was obtained by designing conjugates that were good MMP substrates but poor neprilysin substrates. To determine how conjugates were metabolized in animals, MMP-selective conjugates were given to mice with HT1080 xenografts and the distribution of doxorubicin was determined. These studies showed that MMP-selective conjugates were preferentially metabolized in HT1080 xenografts, relative to heart and plasma, leading to 10-fold increases in the tumor/heart ratio of doxorubicin. The doxorubicin deposited by a MMP-selective prodrug, compound 6, was more effective than doxorubicin at reducing HT1080 xenograft growth. In particular, compound 6 cured 8 of 10 mice with HT1080 xenografts at doses below the maximum tolerated dose, whereas doxorubicin cured 2 of 20 mice at its maximum tolerated dose. Compound 6 was less toxic than doxorubicin at this efficacious dose because mice treated with compound 6 had no detectable changes in body weight or reticulocytes, a marker for marrow toxicity. Hence, MMP-activated doxorubicin prodrugs have a much higher therapeutic index than doxorubicin using HT1080 xenografts as a preclinical model.
Assuntos
Doxorrubicina/análogos & derivados , Fibrossarcoma/tratamento farmacológico , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Metaloendopeptidases/metabolismo , Fragmentos de Peptídeos/farmacologia , Pró-Fármacos/farmacologia , Animais , Doxorrubicina/síntese química , Doxorrubicina/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Fibrossarcoma/metabolismo , Humanos , Metaloproteinases da Matriz Associadas à Membrana , Camundongos , Neprilisina/farmacologia , Fragmentos de Peptídeos/síntese química , Fragmentos de Peptídeos/química , Pró-Fármacos/síntese química , Pró-Fármacos/química , Reticulócitos/efeitos dos fármacos , Reticulócitos/metabolismo , Transplante Heterólogo , Células Tumorais CultivadasRESUMO
New indeno[1,2-c]pyrazol-4-one cyclin dependent kinase inhibitors have been disclosed. The most promising compounds are nanomolar enzyme inhibitors with excellent activity against tumor cells. The most advanced compound retains cell culture activity even in the presence of human serum proteins. The most advanced compound did not kill the normal fibroblast line AG1523.
Assuntos
Quinases Ciclina-Dependentes/antagonistas & inibidores , Inibidores Enzimáticos/síntese química , Compostos Heterocíclicos/síntese química , Pirazóis/síntese química , Linhagem Celular Tumoral , Quinases Ciclina-Dependentes/metabolismo , Avaliação Pré-Clínica de Medicamentos/métodos , Inibidores Enzimáticos/farmacologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/enzimologia , Compostos Heterocíclicos/farmacologia , Humanos , Pirazóis/farmacologiaRESUMO
The identification of indeno[1,2-c]pyrazol-4-ones as inhibitors of cyclin-dependent kinases (CDKs) has led to the discovery of a series of novel and potent compounds. Herein, we report the effects of substitutions at C3 of the indeno[1,2-c]pyrazol-4-one core with alkyls, heterocycles, and substituted phenyls. Substitutions at the para position of the phenyl ring at C3 were generally well-tolerated; however, larger groups were generally inactive. For alkyls directly attached to C3, longer chain substituents were not tolerated; however, shorter alkyl groups and cyclic alkyls were acceptable. In general, the heterocycles at C3 gave the most potent analogues. One such heterocycle, 24j, was examined in detail and was determined to have a biological profile consistent with CDK inhibition. An X-ray crystal structure of one of the alkyl compounds, 13q, complexed with CDK2 was determined and showed the inhibitor residing in the adenosine 5'-triphosphate pocket of the enzyme.