[Synthesis and binding affinity of 3-aryl-7-hydroxycoumarins to human alpha and beta estrogen receptors]

The synthesis of a set of substituted 3-aryl-7-hydroxycoumarins was performed. The study of the relations between their structure and their relative binding affinity (RBA) to human alpha and B estrogen receptors was achieved.

Biphenyls as surrogates of the steroidal backbone. Part 1: synthesis and estrogen receptor affinity of an original series of polysubstituted biphenyls

In the course of a programme aimed at discovering new ligands of the estrogen receptor, we explored a series of substituted biphenyls. Their synthesis and binding affinity are described.

Synthesis and relative binding affinity to steroid receptors and antiproliferative activity on MCF-7 cells of 2,3-disubstituted indenes

The study of the relative binding affinity of a set of 2,3-disubstituted indenes to the receptors of steroid hormones indicates a weak effect of some derivatives on estrogen, progesterone and androgen receptors. The antiproliferative effect on human MCF-7 cells also shows a weak activity for three derivatives.

The pharmacological profile of a novel norpregnance progestin (trimegestone)

Trimegestone is a novel norpregnane progestin that is being developed, in combination with estradiol, for the treatment of menopausal symptoms. The pharmacological characteristics of trimegestone have been evaluated in both in vitro and in vivo test systems, and compared with reference progestins. Interaction with hormonal steroid receptors from animal tissues and with human recombinant receptors in vitro has demonstrated that trimegestone has a high specificity and potency for the progesterone receptor, no affinity for the estrogen receptor, and weak affinity for androgen, glucocorticoid and mineralocorticoid receptors. With respect to progestomimetic activity in vivo, trimegestone was more potent than reference progestins in the endometrial transformation test in the rabbit, preventing the uterotrophic effect of estradiol in the immature mouse bioassay, and had more effect on traumatic deciduoma formation and greater oral antiovulatory activity in the rat. In vivo, trimegestone effectively maintained pregnancy in the rat, but was devoid of any uterotrophic activity. Trimegestone showed no androgenic, glucocorticoid, antiglucocorticoid or mineralocorticoid activity, but did show some antiandrogenic and antimineralocorticoid activity at higher doses. Administration of trimegestone to ovariectomized rats, in combination with estradiol, inhibited the uterotrophic effects of estradiol. At doses up to 1 mg/kg intravenously and 30 mg/kg orally, trimegestone was not associated with any unwanted pharmacological effects. Overall, the results show trimegestone to have a favorable pharmacological profile with potent progestomimetic activity.

[Binding affinity to steroid hormone receptors and antiproliferative action on MCF-7 cells of coumarin derivatives and isoflavonoids]

The study of the relative binding affinity to steroïd hormonal receptors and of the antiproliferative action on MCF-7 cells of 3-arylcoumarines, 3-aryl-4-hydroxycoumarines, isoflavanones, isoflavan-4-ols and isoflavones, indicates a weak activity in the case of some representatives of coumarines.

Pharmacological profile of RU 58642, a potent systemic antiandrogen for the treatment of androgen-dependent disorders

The pharmacological profile of RU 58642, a new non-steroidal antiandrogen was investigated both in vitro and in vivo. In vitro, the compound displays a strong and specific affinity for androgen receptor. In vivo, its antiandrogenic activity was evaluated in castrated rat supplemented with testosterone propionate and in intact animals on prostate, seminal vesicles weight and serum levels of testosterone by oral and subcutaneous route. In castrated rats RU 58642 induced a significant decrease in prostate weight at a dose as low as 0.3 mg/kg whatever the route of administration. In intact rats its activity was compared to that of other non-steroidal antiandrogens such as flutamide, nilutamide and bicalutamide. RU 58642 proved to be significantly more potent than the reference compounds in reducing prostate weight: 3-30 times orally and 3-100 times subcutaneously, and thus the most potent antiandrogen to date to our knowledge. These results suggest that this compound may be very useful in the treatment of systemic androgen-dependent diseases.

RU 58,668, a new pure antiestrogen inducing a regression of human mammary carcinoma implanted in nude mice

RU 58,668, a new steroidal antiestrogen, has been synthesized. Its in vitro and in vivo pharmacological activities have been compared to those of tamoxifen and ICI 182,780. In vitro, it displayed affinities for human and murine estrogen receptors equivalent to those of 4-hydroxy-tamoxifen, along with moderate affinities for progestin and glucocorticoid receptors. RU 58,668 proved to be a potent antiproliferative agent on MCF-7 cells stimulated by estradiol, or by exogenous or endogenous growth factors (IC50, 0.01 nM). It also inhibited the growth of the insulin-stimulated T47D cell line. In vivo, RU 58,668 displayed a total anti-uterotrophic activity in mice or rats without exhibiting any agonistic effect. Moreover, RU 58,668 was the only antiestrogenic compound tested so far to be able to induce a long term regression of human mammary MCF-7 tumors implanted in nude mice, suggesting its potential use for the treatment of advanced breast cancer.

Synthesis of a fluorescent steroid derivative with high affinities for the glucocorticoid and progesterone receptors

The synthesis of RU 45196, an 11 beta-substituted 19-norsteroid of the estra-4,9-diene series, incorporating the nitrobenzoxadiazole (NBD) fluorophore, is reported. The highly fluorescent target compound displayed remarkable affinity for both the progesterone and glucocorticoid receptors. The present work demonstrates for the first time that it is indeed possible to design fluorescent steroid conjugates which maintain very high affinities for their cognate receptors and which are potentially useful for mechanistic and diagnostic purposes.

Non-steroidal antiandrogens: synthesis and biological profile of high-affinity ligands for the androgen receptor

New N-substituted arylthiohydantoin antiandrogens were synthesized. These compounds presented exceptionally high relative binding affinities (RBAs) for the rat androgen receptor (AR): up to 3 times that of testosterone (T) and 100 times the RBAs of non-steroidal antiandrogens such as flutamide, Casodex and Anandron. Furthermore, unlike available markers for AR, they were totally devoid of any binding to the other steroid receptors. RU 59063, the molecule with the highest RBA, was tritiated. When it was compared to [3H]T for the assay of rat, mouse, hamster and human AR, it gave rise to the same number of binding sites but its K alpha (6 x 10(9) M-1) for rat and human AR were, respectively 3 and 8 times higher than that of T. Moreover RU 59063, unlike T, was devoid of any specific binding to human plasma. In vivo, these compounds displayed antiandrogenic activity while being devoid of any agonistic effect. Thus, RU 56187, given orally in castrated male animals, prevented in a dose-dependent manner the effects of 3 mg/kg testosterone propionate (TP) on mouse renal ornithine decarboxylase (acute test) and of 0.5 mg/kg TP on rat prostate weight (chronic test). In these two models, its ED50 was 0.6 and 1 mg/kg, respectively. In the intact rat, when given alone, it inhibited dose-dependently the effect of endogenous androgens on the seminal vesicles (ED50 approximately 1 mg/kg) and prostate (ED50 approximately 3 mg/kg) weights. These results suggest that these new compounds may be useful as specific markers for the androgen receptor as well as for the treatment of androgen-dependent diseases or disorders such as prostate cancer, acne, hirsutism and male pattern baldness.

[Pharmacologic study of the glucocorticoid activity of flunisolide compared with other steroids in the rat]

Flunisolide (FLU), beclomethasone dipropionate (BDP) and its pulmonary metabolites beclomethasone monopropionate (BMP) and beclomethasone (B) were studied in rat for: their relative binding affinity (RBA) for the 5 classes of steroid receptors, their in vitro glucocorticoid activity on rat thymocytes, their in vivo glucocorticoid activity by oral route. These compounds displayed a strong RBA for rat lung, thymus and liver glucocorticoid receptors (FLU > or = BMP > BDP > or = B). They were also shown to have a moderate RBA for both mineralocorticoid and progestin receptors, while being devoid of any binding to androgen and oestrogen receptors. On rat thymocytes FLU exhibited the highest glucocorticoid activity (FLU > B > or = BMP > BDP). In rat oral FLU displayed a strong glucocorticoid activity with a slight first-pass metabolism as opposed to what has been reported in human.