RESUMO
The formal C-20 methylation of 1,25-dihydroxy vitamin D3 (calcitriol) and bridging of two methyl groups produces spiro[cyclopropane-1, 20'-calcitriol], colloquially referred to as C-20 cyclopropylcalcitriol, which is much more active in MLR for suppression of interferon-gamma release than calcitriol, and hypercalcemia in mice is elicited at a ten-fold lower dose when compared to calcitriol. Introduction of the Delta16,17-double bond, modification of the side chain by 23-unsaturation and replacement of the methyl groups at C-26 and C-27 with trifluoromethyl moieties create a highly active series of vitamin D analogs. As previously observed in the calcitriol series, the presence of the C-16 double bond in the cyclopropyl analogs also arrests metabolic side-chain oxidation in the at the C-24 oxo level in UMR 106 cells. The enhanced biological activity is ascribed, at least in part, to the improved resistance toward metabolic degradation.
Assuntos
Antineoplásicos/uso terapêutico , Colecalciferol/análogos & derivados , Animais , Antineoplásicos/química , Linhagem Celular Tumoral , Colecalciferol/química , Colecalciferol/uso terapêutico , Humanos , Masculino , Camundongos , Camundongos Nus , Estrutura Molecular , Neoplasias Experimentais , Neoplasias da Próstata/tratamento farmacológico , Ratos , Relação Estrutura-AtividadeRESUMO
The steroid hormone 1alpha,25(OH)(2)-Vitamin D(3) [1alpha,25(OH)(2)D(3)] exerts a wide variety of biological actions through one or more receptors/binding proteins. The nuclear Vitamin D receptor (VDR) when bound to its natural ligand, 1alpha,25(OH)(2)D(3), can stimulate transcription of a wide variety of genes. The synthesis of 1alpha,25(OH)(2)D(3) analogs allows the study of structure-function relationships between ligand and the VDR. 1alpha,25(OH)(2)D(3) is a conformationally flexible molecule; specifically the side-chain of the hormone can display a large variety of shapes for its receptor. Here, we describe and analyze the properties of 10 1alpha,25(OH)(2)D(3) analogs modified at the side-chain of which five lack carbon-19 (19-nor) but have a novel 20-cyclopropyl functionality. Analog NG [20,21-methylene-23-yne-26,27-F(6)-19-nor-1alpha,25(OH)(2)D(3)] possesses a respectable binding affinity for the VDR and exhibits a high transcriptional activity (EC(50) approximately 10pM), while retaining low induction of hypercalcemia in vivo in the mouse, making it a primary candidate for further analyses of its anti-proliferative and/or cell differentiating properties.