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Antitumor properties of (5E,7E) analogs of vitamin D3
B Filip1, M Milczarek, J Wietrzyk
1Department of Experimental Oncology, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 12 Rudolf Weigl Street, 53-114 Wroclaw, Poland.
Abstract:
Geometric isomers (5E,7E) of major active metabolites of vitamin D3 [1alpha,25(OH)2D3 and (24R)-1,24(OH)2D3] were synthesized by a new convenient procedure. Vitamin D triene system of the metabolites was first derivatized as a Diels-Alder adduct. Removal of the triene protecting group, in a key synthetic step, yielded the title compounds PRI-2208 and PRI-2209, respectively. The analogs were examined for their antiproliferative activity in vitro against human breast cancer cells (MCF-7) and promyelocytic leukemia (HL-60) cells. The activity was compared with one of the parent compounds. Both analogs examined revealed similar or higher antiproliferative activity compared to 1alpha,25(OH)2D3 or to (24R)-1,24(OH)2D3. The studies of calcemic activity in vivo showed that analogs PRI-2208 and PRI-2209 did not influence the serum calcium level in doses, in which 1alpha,25(OH)2D3 or (24R)-1,24(OH)2D3 significantly increased this level. The antitumor activity of these analogs in the LLC mice tumor model was studied. Analog PRI-2208 was found to be more active in inhibiting LLC tumor growth than 1alpha,25(OH)2D3, as well as than PRI-2191 and PRI-2209.
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