RESUMEN

Transient treatment with small molecule CDK inhibitors is toxic to cancer cells and leads to depletion of anti-apoptotic proteins and Chk1, coupled with DNA damage and induction of apoptosis. Here we have examined, which of these phenomena are necessary for CDK inhibitors to have an anti-proliferative effect. We find that 24 hours treatment with either a primarily CDK2-specific, or a primarily CDK7/9-specific, antagonist eliminates proliferative potential even if apoptosis is blocked and the tendency of CDK inhibition to result in DNA damage is overcome by expression of recombinant Chk1. Loss of proliferative potential is correlated with irreversible suppression of biomarkers of cell cycle progression. CDK inhibitors dramatically reduced levels of the anti-apoptotic proteins, Mcl-1 and XIAP, but siRNA-mediated suppression of Mcl-1 and XIAP did not induce cell death in the osteosarcoma cells used in this study. Finally, we found that many literature CDK inhibitors do not effectively suppress the CDK/cyclin complexes responsible for cell cycle progression at the minimum doses required to block proliferation: some are only effective after a substantial delay and may act via inhibition of CDK7.

Asunto(s)

Antineoplásicos/farmacología , Quinasas Ciclina-Dependientes/antagonistas & inhibidores , Inhibidores de Proteínas Quinasas/farmacología , Apoptosis , Línea Celular Tumoral , Proliferación Celular , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1) , Quinasas Ciclina-Dependientes/metabolismo , Daño del ADN , Humanos , Proteína 1 de la Secuencia de Leucemia de Células Mieloides , Oxazoles/farmacología , Proteínas Quinasas/biosíntesis , Proteínas Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Pirazoles/farmacología , Pirimidinas/farmacología , ARN Interferente Pequeño , Tiazoles/farmacología , Proteína Inhibidora de la Apoptosis Ligada a X/metabolismo

RESUMEN

Inhibitors of the Hsp90 molecular chaperone are showing considerable promise as potential chemotherapeutic agents for cancer. Here, we describe the structure-based design, synthesis, structure-activity relationships and pharmacokinetics of potent small-molecule inhibitors of Hsp90 based on the 4,5-diarylisoxazole scaffold. Analogues from this series have high affinity for Hsp90, as measured in a fluorescence polarization (FP) competitive binding assay, and are active in cancer cell lines where they inhibit proliferation and exhibit a characteristic profile of depletion of oncogenic proteins and concomitant elevation of Hsp72. Compound 40f (VER-52296/NVP-AUY922) is potent in the Hsp90 FP binding assay (IC50 = 21 nM) and inhibits proliferation of various human cancer cell lines in vitro, with GI50 averaging 9 nM. Compound 40f is retained in tumors in vivo when administered i.p., as evaluated by cassette dosing in tumor-bearing mice. In a human colon cancer xenograft model, 40f inhibits tumor growth by approximately 50%.

Asunto(s)

Antineoplásicos/síntesis química , Proteínas HSP90 de Choque Térmico/antagonistas & inhibidores , Isoxazoles/síntesis química , Resorcinoles/síntesis química , Animales , Antineoplásicos/farmacocinética , Antineoplásicos/farmacología , Unión Competitiva , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Cristalografía por Rayos X , Ensayos de Selección de Medicamentos Antitumorales , Polarización de Fluorescencia , Proteínas HSP90 de Choque Térmico/metabolismo , Humanos , Isoxazoles/farmacocinética , Isoxazoles/farmacología , Ratones , Ratones Desnudos , Modelos Moleculares , Trasplante de Neoplasias , Resorcinoles/farmacocinética , Resorcinoles/farmacología , Relación Estructura-Actividad , Trasplante Heterólogo

RESUMEN

The protein structure guided design of a series of pyrazolo[1,5-a]pyrimidines with high potency for human cyclin-dependent kinase 2 (CDK2) is described. Some examples were shown to inhibit the growth of human colon tumour cells, were equipotent for CDK1 and were selective against GSK-3beta and other kinases.

Asunto(s)

Quinasas CDC2-CDC28/antagonistas & inhibidores , Pirimidinas/química , Pirimidinas/farmacología , Proteína Quinasa CDC2/antagonistas & inhibidores , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Quinasa 2 Dependiente de la Ciclina , Diseño de Fármacos , Humanos , Concentración 50 Inhibidora , Modelos Moleculares , Relación Estructura-Actividad

RESUMEN

A simple method for the derivatization of primary amines and carboxylic acids with tris(trimethoxyphenyl)phosphonium (TMPP) reagents to enhance their detection by electrospray mass spectrometry (ESI-MS) has been developed. The synthesis of novel TMPP reagents and their stable isotopically labelled analogues is described. Through the use of stable isotopically labelled TMPP "tags", incorporation of a doublet (1:1, (1)H/(2)H or (12)C/(13)C) into the target molecule can be achieved, enabling the use of isotopic target analysis to detect compounds of unknown molecular weight but with a characteristic isotope pattern and accurate mass difference.