Cancer prevention with dehydroepiandrosterone and non-androgenic structural analogs.

There is increasing evidence that the adrenocortical steroid, dehydroepiandrosterone (DHEA), is an important mammalian hormone. Administration of DHEA to laboratory mice and rats inhibits development of experimental tumors of the breast, lung, colon, liver, skin and lymphatic tissue. In the two-stage skin tumorigenesis model in mice, DHEA treatment inhibits tumor initiation, as well as tumor promoter-induced epidermal hyperplasia and promotion of papillomas. There is much evidence that DHEA produces its antiproliferative and tumor preventive effects by inhibiting glucose-6-phosphate dehydrogenase and the pentose phosphate pathway. This pathway is an important source of NADPH, a critical reductant for many biochemical reactions that generate oxygen free radicals, which may act as second messengers in stimulating hyperplasia. The therapeutic use of DHEA in humans may be limited by its sex hormonal side effects. DHEA is metabolized in vivo to both testosterone and estrone, producing both androgenic and estrogenic effects in laboratory animals. We have developed a synthetic steroid, 16 alpha-fluoro-5-androsten-17-one, which does not demonstrate the androgenic or estrogenic activity of DHEA, yet retains the antiproliferative and cancer preventive activity of the native steroid.