title: Biological Evaluation of Double Point Modified Analogues of 1,25-Dihydroxyvitamin D₂ as Potential Anti-Leukemic Agents.
abstract: Structurally similar double-point modified analogues of 1,25-dihydroxyvitamin D₂ (1,25D₂) were screened in vitro for their pro-differentiating activity against the promyeloid cell line HL60. Their affinities towards human full length vitamin D receptor (VDR) and metabolic stability against human vitamin D 24-hydroxylase (CYP24A1) were also tested. The analogues (PRI-1730, PRI-1731, PRI-1732, PRI-1733 and PRI-1734) contained 5,6-trans modification of the A-ring and of the triene system, additional hydroxyl or unsaturation at C-22 in the side chain and reversed absolute configuration (24-epi) at C-24 of 1,25D₂. As presented in this paper, introduction of selected structural modifications simultaneously in two distinct parts of the vitamin D molecule resulted in a divergent group of analogues. Analogues showed lower VDR affinity in comparison to that of the parent hormones, 1,25D₂ and 1,25D₃, and they caused effective HL60 cell differentiation only at high concentrations of 100 nM and above. Unexpectedly, introducing of a 5,6-trans modification combined with C-22 hydroxyl and 24-epi configuration switched off entirely the cell differentiation activity of the analogue (PRI-1734). However, this analogue remained a moderate substrate for CYP24A1, as it was metabolized at 22%, compared to 35% for 1,25D₂. Other analogues from this series were either less (12% for PRI-1731 and PRI-1733) or more (52% for PRI-1732) resistant to the enzymatic deactivation. Although the inactive analogue PRI-1734 failed to show VDR antagonism, when tested in HL60 cells, its structure might be a good starting point for our design of a vitamin D antagonist.
authors: Faculty of Biotechnology, University of Wroclaw, 14a Joliot-Curie, Wroclaw 50-383, Poland. aoifecorkie@hotmail.com.
authors: Aoife
authors: A
authors: Corcoran
authors: Pharmaceutical Research Institute, 8 Rydygiera, Warsaw 01-793, Poland. s.nadkarni@ifarm.eu.
authors: Sharmin
authors: S
authors: Nadkarni
authors: Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan. z02232@mail.pu-toyama.ac.jp.
authors: Kaori
authors: K
authors: Yasuda
authors: Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan. tsakaki@pu-toyama.ac.jp.
authors: Toshiyuki
authors: T
authors: Sakaki
authors: School of Immunity and Infection, University of Birmingham, Vincent Drive, Edgbaston, Birmingham, West Midlands B15 2TT, UK. G.BROWN@bham.ac.uk.
authors: Geoffrey
authors: G
authors: Brown
authors: Pharmaceutical Research Institute, 8 Rydygiera, Warsaw 01-793, Poland. a.kutner@ifarm.eu.
authors: Andrzej
authors: A
authors: Kutner
authors: Faculty of Biotechnology, University of Wroclaw, 14a Joliot-Curie, Wroclaw 50-383, Poland. ema@cs.uni.wroc.pl.
authors: Ewa
authors: E
authors: Marcinkowska
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor / Q000379:methods*; D004872:Ergocalciferols / Q000737:chemistry / Q000494:pharmacology*; D018922:HL-60 Cells; D006801:Humans; D007938:Leukemia / Q000188:drug therapy / Q000201:enzymology* / Q000378:metabolism; D015394:Molecular Structure; D018167:Receptors, Calcitriol / Q000378:metabolism; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D065668:Vitamin D3 24-Hydroxylase / Q000037:antagonists & inhibitors
chemical_list: D000970:Antineoplastic Agents; D004872:Ergocalciferols; D018167:Receptors, Calcitriol; C579457:VDR protein, human; C003564:1,25-dihydroxyergocalciferol; C585549:CYP24A1 protein, human; D065668:Vitamin D3 24-Hydroxylase
keywords: leukemia; receptor; vitamin D analogues