Makoto Yoshihama

Aromatase activity and the effect of estradiol and testosterone on DNA synthesis in endometrial carcinoma cell lines

Human endometrial and breast carcinoma cell lines were examined for aromatase activity and the effects of sex steroids (estradiol and testosterone) on DNA synthesis. Aromatase activity was high (greater than 500 fmol/10(7) cells/24 h) in the cell lines MCF-7 and OMC-2, moderate (100-499 fmol/10(7) cells/24 h) in the cell lines HEC-59 and Ishikawa, and low (less than 100 fmol/10(7) cells/24 h) in the HHUA cell line. A substantial stimulation of DNA synthesis by estradiol (10(-9)M) was observed in cell lines HEC-59, OMC-2, and MCF-7, with an increase in [3H]thymidine uptake of over 250%. The Ishikawa cell line was stimulated moderately (115-249%). No estradiol-induced increase in DNA synthesis was observed in HHUA. Responsiveness of DNA synthesis to testosterone was observed in cell lines that showed the greatest response to estradiol, namely HEC-59, OMC-2, and MCF-7. Otherwise, estrogen-responsiveness did not always correlated with a significant aromatase activity. These data suggest that some but not all endometrial carcinomas may possess an aromatase-dependent growth stimulating system.

Microbial production of two new dihydroxylated androstenedione derivatives by acremonium strictum

Abstract We found that Acremonium strictum NN106 converted 4-androstene-3, 17-dione (androstenedione) to 12 compounds. Among them, five products were isolated and found to be hydroxylated at the 11α-, 14α-, 7α, 11α-, 6β, 11α- or 6β, 14α-positions of androstenedione. 6β, 11α-Dihydroxy and 6β, 14α-dihydroxy derivatives of androstenedione have been obtained for the first time. From the time course profile of this transformation, sequential hydroxylation at the 6β-position followed by 11α- or 14α-monohydroxylation was observed. The oxidative product of the 6β, 14α-dihydroxy derivative was found to be the most potent inhibitor of human placentral aromatase.

Microbial Polyhydroxylation of Progesterone by Acremonium strictum

Abstract Acremonium strictum NN106, which has been shown to have a unique hydroxylating ability on androstenedione, also transformed progesterone into a mixture of various products. Six products were isolated in sufficient amounts for structural analysis. Three products were found to have two hydroxy moieties on axial and equatorial positions at 7β, 15β-, 6β, 11α- and 11α, 15β-sites. The other three products had an extra 17α-hydroxyl on the above dihydroxy derivatives to give trihydroxy progesterone. This type of microbial polyhydroxylation of a steroid caused by a fungal strain has not been reported so far and 7β, 15β, 17α-trihydroxy-4-pregnene-3,20-dione is a hitherto unknown compound which was obtained for the first time in the course of this experiment. The 6β, 11α-dihydroxylation has been found in the transformation of androstenedione, but the other positions of hydroxyl introduction are different. The hydroxylating events caused by this strain were greatly influenced by the 17β side chain, especially by C20 keto moiety in the steroidal skeleton.

Microbial production of hydroxy-C19-steroids as estrogen synthetase (P-450 · aromatase) inhibitors

Abstract Four monohydroxy derivatives of androst-4-ene-3,17-dione (4AD) and two of androst-4-ene-3,6,17-trione (4AT), derived from microbial transformation of 4AD and 4AT, were purified and identified by UV, IR, mass, 13 C-NMR, and 1 H-NMR spectroanalyses. These derivatives were evaluated as inhibitors of human placental aromatase. They showed dose-dependent inactivation of aromatase in the presence of reduced nicotinamide adenine dinucleotide phosphate. Among them, 6α-hydroxyandrost-4-ene-3,17-dione (6α-OH-4AD) was the most potent, exhibiting 97.8% inhibition at 100 μM; this value was 1.04-fold higher than the inhibition shown by 4AT (93.6%). The other derivatives, 16β-OH-4AT, 15α-OH-4AD, 15β-OH-4AD, 6β-OH-4AD and 12α-OH-4AT, inhibited the aromatase 80.4%, 63.6%, 61.8%, 30.1%, and 9.6%, respectively, at the same concentration.

Inhibition of 17α-Hydroxylase/C17,20-Lyase (CYP17) from Rat Testis by Green Tea Catechins and Black Tea Theaflavins

In the course of screening for 17α-hydroxylase/C17,20-lyase inhibitors from food ingredients, the methanol soluble fraction of green tea and black tea, which were expected to be rich in catechin and theaflavin content, showed potent inhibitory activity. (−)-Epigallocathechin gallate and theaflavin 3-O-gallate with a pirogallol moiety significantly inhibited C17,20-lyase activity on IC50 values of 24.5 μM and 11.5 μM respectively. They had potent cytotoxicity against human prostate cancer LNCaP cells (IC50=28.1 μM and 37.4 μM).