Synthesis and evaluation of inhibitors against vitamin D3 and all-trans retinoic acid metabolising enzymes as potential therapy for androgen-independent prostate cancer

• Main Author: Yee, Sook Wah
• Published: Cardiff University 2005
• Subjects: 615
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.583588

1alpha25-Dihydroxyvitamin D3 (1alpha,25-(OH)2-D 3) and all-trans retinoic acid (ATRAA) have differentiating and anti-proliferative effects on prostate cancer cells. However, the use of 1alpha,25-(OH)2-D3 and ATRA is limited by the induction of the cytochrome P450 enzymes. A drug which can prolong the action of 1alpha,25-(OH) 2-D3 or ATRA by inhibiting the P450 enzymes could have potential use in the treatment of AIPC. Three series of novel compounds were synthesised in an attempt to probe for the key binding residues in the enzymes. The preparation of the rat kidney mitochondria and rat liver microsome enzymes were described herein to study the inhibition of the 25-hydroxyvitamin D 3 and ATRA metabolism respectively using the synthesised compounds. In addition, cancer cell-lines (MCF-7 and DU-145) were also used to study the inhibition of the 25-hydroxyvitamin D3 and ATRA metabolism using the synthesised compounds. Reverse-transcriptase-polymerase chain reaction (RT-PCR) analysis was carried out to demonstrate the presence of CYP24 and CYP26 mRNA in the cancer cell-lines. Some of the synthesised compounds described herein show improved activities compared with ketoconazole and/or liarozole in these in vitro assays. Molecular docking studies using the homology model of CYP26 was carried out to investigate the binding of the substrate, ATRA and the synthesised compounds at the active site. Furthermore, the anti-proliferative effects of some synthesised compounds, both alone and in combination with 1alpha25-(OH)2-D3 in human prostate cancer cells (DU-145 and PC-3) were examined. The effects of ketoconazole and one of the synthesised compounds were further investigated to examine their effects, both alone and in combination with 1alpha25-(OH)2-D 3 on the vitamin D3 target genes in DU-145 and PC-3 by real-time quantitative RT-PCR.