genistein and Prostatic-Neoplasms

A 14-step biomimetic synthetic route to glyceollin I (1.5% overall yield) was developed and deployed to produce the natural enantiomeric form in soy, its unnatural stereoisomer, and a racemic mixture. Enantiomeric excess was assessed by asymmetric NMR shift reagents and chiral HPLC. Antiproliferative effects were measured in human breast, ovarian, and prostate cancer cell lines, with all three chiral forms exhibiting growth inhibition (GI) in the low to mid μM range for all cells. The natural enantiomer, and in some cases the racemate, gave significantly greater GI than the unnatural stereoisomer for estrogen receptor positive (ER(+)) versus ER(-) breast/ovarian cell lines as well as for androgen receptor positive (AR(+)) versus AR(-) prostate cancer cells. Surprisingly, differences between ER(+) and ER(-) cell lines were not altered by media estrogen conditions. These results suggest the antiproliferative mechanism of glyceollin I stereoisomers may be more complicated than strictly ER interactions.

Topics: Antineoplastic Agents; Biomimetics; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Chromatography, High Pressure Liquid; Drug Screening Assays, Antitumor; Female; Humans; Magnetic Resonance Spectroscopy; Male; Models, Chemical; Ovarian Neoplasms; Prostatic Neoplasms; Pterocarpans; Receptors, Estrogen; Stereoisomerism

Chemical investigation of a soybean phytochemical concentrate resulted in the isolation and identification of two new isoflavanones, dihydrodaidzin (1) and dihydrogenistin (2), a new isoflavone, 2' ',6' '-O-diacetyloninin (3), and two new triterpenoid saponins (13 and 14). Nine known isoflavonoids (4-12) and three known saponins (15-17) were also identified. Structures of the new compounds were established by a combination of extensive NMR (DEPT, DQF-COSY, HMBC, HMQC, and ROESY) studies and chemical degradation. Cytotoxic activities (ED(50)) of various extracts and selected isoflavonoids and saponins were measured against human stomach carcinoma (Hs 740.T, Hs 756 T), breast adenocarcinoma (Hs 578 T, Hs 742.T), and prostate carcinoma (DU 145, LNCaP-FGC) cell lines. Isoflavonoids 3 and 5 were more active than 1 and 2 versus at least one of the three cell lines examined, indicating the importance of the 2,3-double bond in cytotoxicity. Saponins 13, 14, and 15 were slightly more active than saponins 16 and 17, indicating that sugar attachments at position-22 enhance cytotoxic activity.

Topics: Breast Neoplasms; Drug Screening Assays, Antitumor; Female; Glycine max; Humans; Hydrolysis; Inhibitory Concentration 50; Isoflavones; Male; Nuclear Magnetic Resonance, Biomolecular; Plants, Medicinal; Prostatic Neoplasms; Saponins; Stereoisomerism; Stomach Neoplasms; Structure-Activity Relationship; Triterpenes; Tumor Cells, Cultured

In a screening programme for inhibitors of human testis 17beta-hydroxysteroid dehydrogenase (17beta-HSD type 3), as potential agents for the treatment of hormone-dependent prostatic cancer, we have used crude human testis microsomal 17beta-hydroxysteroid dehydrogenase as a convenient source of the enzyme. Crude human enzyme was shown to have a similar substrate profile to recombinant Type 3 17beta-HSD from the same source as determined by the low Km/Vmax ratio for the reduction of androstenedione compared to the oxidation of testosterone, and a low level of activity in reduction of oestrone. Screening of a wide range of compounds of different structural types as potential inhibitors of the microsomal enzyme in the reduction step revealed that certain p-benzoquinones and flavones/isoflavones were potent inhibitors of the enzyme, diphenyl-p-benzoquinone (2.7 microM), phenyl-p-benzoquinone (5.7 microM), 7-hydroxyflavone (9.0 microM), baicalein (9.3 microM) and biochanin A (10.8 microM). Some structure-activity relationships within the flavone/isoflavone series are discussed. Studies with rat testis microsomal 17beta-HSD showed that it differed from the human enzyme mainly in its greater ability to accept oestrone as substrate and the pH-optimum for oxidation of testosterone. It was found to be much less sensitive to inhibition by the compounds studied so negating it use as a more readily available tissue for the screening of potential inhibitors.

Topics: 17-Hydroxysteroid Dehydrogenases; Androstenedione; Animals; Benzoquinones; Drug Evaluation, Preclinical; Enzyme Inhibitors; Estradiol; Estrone; Flavanones; Flavonoids; Genistein; Humans; Hydrogen-Ion Concentration; Inhibitory Concentration 50; Kinetics; Male; Microsomes; Prostatic Neoplasms; Rats; Structure-Activity Relationship; Testis; Testosterone