Inhibition of 12-O-tetradecanoylphorbol-13-acetate-promoted skin tumor formation in mice by 16 alpha-fluoro-5-androsten-17-one and its reversal by deoxyribonucleosides

The work of ourselves and others has demonstrated that dehydroepiandrosterone (DHEA) dispalys a broad spectrum of cancer preventive action in laboratory rodents, with little toxicity. In the two-stage skin tumorigenesis model in mice, topical application of the synthetic DHEA analog 16 alpha-fluoro-5-androsten-17-one, a more potent preventive agent than DHEA without the sex-hormonal side-effects of the parent steroid, markedly inhibited promotion of 7,12-dimethylbenz[a]anthracene (DMBA)-initiated tumor development by 12-O-tetradecanoylphorbol-13-acetate (TPA). DHEA is a powerful inhibitor of glucose-6-phosphate dehydrogenase (G6PDH), suggesting that its inhibiting effect in carcinogenesis may be due to a lack of NADPH and ribose-5-phosphate production for deoxyribonucleotide synthesis and subsequent DNA replication. Further evidence of a reduced NADPH and ribose-5-phosphate pool on the lowering of intracellular deoxyribonucleotide levels has been demonstrated in this paper by completely reversing the 16 alpha-fluoro-5-androsten-17-one-induced inhibition of tumor promotion by the addition of the four deoxyribonucleosides-deoxyadenosine, deoxycytidine, deoxyguanosine and thymidine--to the drinking water during the promotion period of tumorigenesis.

Detailed study of oxidative esterification and elimination reactions undergone by a steroidal 17 alpha-benzoyloxy-20-oxo-21-aldehyde

The reaction of 17 alpha-benzoyloxy-11 beta-hydroxy-3,20-dioxo-1, 4-pregnadien-21-al as the hemiacetal (1) with methanol:acetic acid:potassium cyanide:manganese dioxide followed by acetylation and preparative HPLC of the reaction mixture afforded 11 crystalline products. These products can be conveniently divided into three categories representing side-chain cleavage and oxidative esterification with or without elimination of the benzoyloxy group. Of special interest was the stereospecific formation of the C-17 cyanohydrin acetate 4a and the cis delta 17(20) enol acetate methyl ester 5. On the other hand, nonstereospecific addition of HCN to the side chain gave the C-20 epimeric cyanohydrin acetates 7a and 7b. The use of activated versus nonactivated MnO2 plays a major role in determining the quantitative distribution of the products. It was also discovered that even in the absence of MnO2, the reaction goes to completion. A proposed mechanism which explains the formation of all products is presented.

Inhibition of 7,12-dimethylbenz[a]anthracene-initiated and 12-O-tetradecanoylphorbol-13-acetate-promoted skin papilloma formation in mice by dehydroepiandrosterone and two synthetic analogs

Previous work has demonstrated that the adrenal steroid, dehydroepiandrosterone (3-beta-hydroxy-5-androsten-17-one, DHEA), has broad spectrum tumor chemopreventive activity in laboratory mice and rats, inhibiting the development of spontaneous breast cancer and chemically induced tumors of the lung, colon, skin, thyroid and liver. DHEA treatment produces specific side-effects, including estrogenic and androgenic action and an increase in liver weight, which could limit its use as a cancer chemopreventive drug. It is now shown that oral administration of the synthetic steroid 16 alpha-fluoro-5-androsten-17-one, which lacks the side-effects of DHEA treatment, to CD-1 mice inhibits 7,12-dimethylbenz[a]anthracene-initiated and 12-O-tetradecanoylphorbol-13-acetate-promoted skin papilloma formation at both the initiation and promotion stage. The synthetic steroid is more potent as an inhibitor of papilloma formation than comparably administered DHEA.

Novel dehydroepiandrosterone analogues with enhanced biological activity and reduced side effects in mice and rats

Treatment of laboratory mice and rats with the adrenal steroid, dehydroepiandrosterone (DHEA), produces antiobesity and broad spectrum tumor chemopreventive activity. Certain side effects are associated with DHEA administration which could limit its usefulness as a drug. DHEA can be metabolized into both testosterone and estrone and also increases liver weight and liver catalase activity. We have developed two synthetic steroids, 16 alpha-fluoro-5-androstan-17-one and 16 alpha-fluoro-5 alpha-androstan-17-one, which, unlike DHEA, do not stimulate uterine weight in sexually immature female rats or seminal vesicle weight in castrated male rats, nor stimulate liver weight and liver catalase activity in mice. 16 alpha-Fluoro-5-androsten-17-one is also about three times as potent as DHEA as an antiobesity agent and is more active when administered p.o. in inhibiting [3H]-7,12-dimethylbenz(a)-anthracene binding to skin DNA and tetradecanoylphorbol-13-acetate stimulation of epidermal [3H]thymidine incorporation in the mouse, two effects believed to be important in the tumor preventive action of DHEA. 16 alpha-Fluoro-5 alpha-androstan-17-one is as active as 16 alpha-fluoro-5-androsten-17-one in inhibiting [3H]-7,12-dimethylbenz(a)anthracene binding to skin DNA and tetradecanoylphorbol-13-acetate stimulation in epidermal [3H]thymidine incorporation but, on the contrary, is not more active than DHEA as an antiobesity drug. Compounds such as 16 alpha-fluoro-5-androsten-17-one and 16 alpha-fluoro-5 alpha-androstan-17-one, which lack specific side-effects of DHEA treatment and demonstrate greater potency, may have therapeutic application as drugs for humans.

Dehydroepiandrosterone and two structural analogs inhibit 12-O-tetradecanoylphorbol-13-acetate stimulation of prostaglandin E2 content in mouse skin

Dehydroepiandrosterone, a naturally occurring adrenal steroid, is a highly effective tumor chemopreventive agent in laboratory mice and rats, inhibiting spontaneous breast cancer and chemically induced tumors of the lung, colon, skin, liver and thyroid. Dehydroepiandrosterone blocks three processes that have been implicated in experimental tumorigenesis: (i) carcinogen activation through the mixed-function oxidases, (ii) 12-O-tetradecanoylphorbol-13-acetate stimulation of superoxide anion production in neutrophils, and (iii) 12-O-tetradecanoylphorbol-13-acetate stimulation of [3H]thymidine incorporation in mouse epidermis. All of these effects of dehydroepiandrosterone very likely result from glucose-6-phosphate dehydrogenase inhibition and a lowering of the NADPH cellular pool. It is now reported that oral administration of dehydroepiandrosterone (0.2% in the diet) for two weeks inhibits the stimulation in prostaglandin E2 content in mouse epidermis produced by topical application of 12-O-tetradecanoylphorbol-13-acetate. Two synthetic steroids, 16 alpha-fluoro-5-androsten-17-one and 16 alpha-fluoro-5 alpha-androstan-17-one, which are more potent inhibitors of the above three processes in tumorigenesis and are also more effective than dehydroepiandrosterone in inhibiting skin papilloma development in the mouse, are more active in suppressing prostaglandin E2 induction by 12-O-tetradecanoyl-phorbol-13-acetate. These two structural analogs, which also lack specific side-effects associated with dehydroepiandrosterone treatment, may find application as cancer chemopreventive drugs in humans.

Determination of urinary free cortisol and cortisone by sequential thin layer and high-performance liquid chromatography

A specific, rapid and sensitive method for urinary free cortisol and cortisone utilizing sequential thin layer (TLC) and high-performance liquid chromatography (HPLC) was developed. After addition of prednisone as the internal standard to 1 ml of urine, extraction of the steroids was accomplished by automated sorption on and desorption from a styrenedivinylbenzene copolymeric resin cartridge. Further purification was carried out by TLC. Quantitation of the recovered steroids at 254 nm was achieved during HPLC in a reverse phase system with 21-deoxycortisone as the external standard. When the values of urinary free cortisol both from normal subjects and patients were compared with those obtained by a current RIA procedure, the greater specificity of the new method was clearly demonstrated. Simultaneous measurement of both urinary free cortisol and cortisone in various clinical states appears to offer a more complete index of adrenocortical function than urinary free cortisol alone.