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ID: ALA1148694

Journal: Bioorg Med Chem

Title: Calcitriol derivatives with two different side-chains at C-20. Part 4: further chain modifications that alter VDR-dependent monocytic differentiation potency in human leukemia cells.

Authors: Garay E, Jankowski P, Lizano P, Marczak S, Maehr H, Adorini L, Uskokovic MR, Studzinski GP.

Abstract: Signaling of cell differentiation is one of the important physiological functions of the activated vitamin D receptor (VDR). Activation of the VDR can be achieved not only by 1alpha,25-dihydroxyvitamin D(3) (1,25D), the natural ligand, but also by a large number of its analogs. These include a category containing two side chains emanating at C-20, generally referred to as Gemini. The introduction of a cyclopropyl moiety as part of the pro-R side chain provides modified Gemini compounds with increased steric requirement and decreased chain flexibility; the biological consequences of this novel structural variant are subject of this investigation. In general, the resulting 1alpha,25-dihydroxy-(4-hydroxy-4-methyl-pentyl)-21,22-cis-cyclo-cholecalciferols reduced had differentiation and transcriptional potency and induced cell cycle arrest less efficiently, as shown by a decrease in G1/S ratio, when compared to 1,25D. Modifying their calcitriol side chain in the form of a 4-hydroxy-4-trifluoromethyl-5,5,5-trifluoropent-2-ynyl moiety, however, resulted in pronounced induction of differentiation in 1,25D-sensitive and moderate level of differentiation in 1,25D-resistant leukemia cells.

CiteXplore: 17485214

DOI: 10.1016/j.bmc.2007.04.034