Evaluation of C-2-substituted 19-nor-1alpha,25-dihydroxyvitamin D3 analogs as therapeutic agents for prostate cancer.

1alpha,25-Dihydroxyvitamin D(3) (1alpha,25(OH)(2)D(3)) is known to inhibit the proliferation and invasiveness of prostate cancer cells. However, 1alpha,25(OH)(2)D(3) can cause hypercalcemia and is not suitable as a therapeutic agent. 19-Nor-vitamin D derivatives are known to be less calcemic when administered systemically. In order to develop more potent anti-cancer agents with less calcemic side effect, we therefore utilized (3)H-thymidine incorporation as an index for cell proliferation and examined the antiproliferative activities of nine C-2-substituted 19-nor-1alpha,25(OH)(2)D(3) analogs in the immortalized PZ-HPV-7 normal prostate cell line. Among the nine analogs we observed that the substitution with 2alpha- or 2beta-hydroxypropyl group produced two analogs having antiproliferative potency that is approximately 500- to 1000-fold higher than 1alpha,25(OH)(2)D(3). The (3)H-thymidine incorporation data were supported by the cell counting data after cells were treated with 1alpha,25(OH)(2)D(3), 19-nor-2alpha-(3-hydroxypropyl)-1alpha,25(OH)(2)D(3) or 19-nor-2beta-(3-hydroxypropyl)-1alpha,25(OH)(2)D(3) for 7 days. 19-Nor-2alpha-(3-hydroxypropyl)-1alpha,25(OH)(2)D(3) and 19-nor-2beta-(3-hydroxypropyl)-1alpha,25(OH)(2)D(3) were also shown to be about 10-fold more active than 1alpha,25(OH)(2)D(3) in cell invasion studies using prostate cancer cells. In conclusion, a substitution at the C-2 position of 19-nor-1alpha,25(OH)(2)D(3) molecule with a hydroxypropyl group greatly increased the antiproliferative and anti-invasion potencies. Thus, these two analogs could be developed to be effective therapeutic agents for treating early and late stages of prostate cancer.

Efficient and versatile synthesis of novel 2alpha-substituted 1alpha,25-dihydroxyvitamin D(3) analogues and their docking to vitamin D receptors.

Novel 2alpha-substituted 1alpha,25-dihydroxyvitamin D(3) analogues with 2alpha-alkyl and 2alpha-hydroxyalkyl groups were systematically synthesized from D-xylose. Their conformation on binding to the ligand binding domain (LBD) of the vitamin D receptor was analyzed. It has been found that the 2alpha-hydroxypropyl group best fits the cavity of the LBD, and the binding activity is three times higher than that for the natural hormone.

Chemical cross-linking of peptides derived from RecA with single-stranded oligonucleotides containing 5-formyl-2'-deoxyuridine.

We report the first example of chemical cross-linking of 5-formyl-2'-deoxyuridine containing oligonucleotides with oligopeptides through a Schiff base formation. Twenty amino acid residue peptides investigated here were derived from the DNA binding site of RecA protein. We have demonstrated that the lysine residue placed at the 6th or 8th position from the N-terminus of the peptide directly contacts with DNA.

DNA sequence recognition by NF kappa B p50 homodimer: strict and obscure recognition sites in the binding sequence.

5-Formyl- and 5-(formylmethyl)-2'-deoxyuridines are introduced into a kappa B site instead of thymidine(s) in order to understand target sequence specificity of NF kappa B. It was found that one thymidine in the kappa B site is particularly important for the sequence specific recognition by NF kappa B.

Evidence for a Schiff base formation of peptides derived from RecA with single-stranded oligonucleotides containing 5-formyl-2'-deoxyuridine.

We report some evidence for a Schiff base formation of 5-formyl-2'-deoxyuridine containing oligonucleotides with oligopeptide derived from the DNA binding site of RecA protein. We have demonstrated that cross-linked products were successfully detected by lowering the peptide concentrations. This is probably due to the reduced formation of large aggregates.

A concise and efficient route to 2alpha-(omega-hydroxyalkoxy)-1alpha,25-dihydroxyvi tam in D3: remarkably high affinity to vitamin D receptor.

[reaction: see text]A convenient and potentially valuable synthetic approach to the novel 2alpha-functionalized 1alpha,25-dihydroxyvitamin D3 [1alpha,25(OH)2D3] derivatives (1a-c), which are the C2-epimer of ED-71 and its analogues, has been developed. The C2alpha-modified ring A precursors (1,7-enynes 16, n = 0, 1, and 2) were constructed stereoselectively starting from D-glucose in high yield. In the synthesized 2alpha-(omega-hydroxyalkoxy)-1alpha,25(OH)2D3 derivatives, 1a and 1b showed a greater binding affinity to vitamin D receptor (VDR), up to 1.8 times that of the native hormone.

Interaction of peptides derived from RecA with single-stranded oligonucleotides containing 5-formyl-2'-deoxyuridine.

We report the first example of chemical cross-linking of 5-formyl-2'-deoxyuridine containing oligonucleotides with oligopeptides through a Schiff base formation. Twenty amino acid residue peptides investigated here were derived from the DNA binding site of RecA protein. We have demonstrated that the lysine residue placed at the 6th or 8th position from the N-terminus of the peptide directly contacts with DNA.

Introduction of 6-formylcytidine into a Myb binding sequence.

Single 6-formylcytidine was introduced into a oligonucleotide duplex (23 mers) as a substitute for thymidine in the Myb binding sequence of 3'-TTGAC-5'. The modified duplex showed Tm of 67 degrees C, which was six degrees lower than the Tm of the native duplex. Binding affinity of the 23-mers to the Myb protein was estimated by electrophoretic mobility shift assays, and the binding was almost completely abolished.

Synthesis of oligonucleotides containing the oxidatively modified kappaB site: unique binding affinity to the NFkappaB p50 homodimer.

Synthesis of oligonucleotide 26-mers including single 5-formyl-2'-deoxyuridine (1) or 5-formyl-2'-O-methyluridine (2) in place of thymidine at the kappaB site has been accomplished. One of the 26-mers with 1 was critically discriminated by the NFkappaB p50 homodimer in binding.

Oligonucleotides bearing 5-formyl-2'-O-methyluridine: preference in binding affinity to the NF-kappa B (p50)2 homo- and p50/p65 heterodimers.

5-Formyl-2'-O-methyluridine was incorporated into the various positions of oligonucleotide 26-mers containing the NF-kappa B binding sequence. Some of them showed binding selectivity toward the homo- and heterodimers of subunits of NF-kappa B.

Stereocontrolled cyclization at the anomeric position of 6-(hydroxyalkyl)uridines using hypoiodite reaction.

Hypoiodite reaction of 6-(hydroxyalkyl)-2',3'-O-isopropylideneuridines (1-3) was found to yield a new class of spiro nucleosides having an anomeric orthoester structure. It appeared that the 6-hydroxyalkyl substituent and the 2',3'-O-isopropylidene group are working cooperatively to control the anomeric stereochemistry (beta/alpha = 35/1-2/1) of the cyclization.