Synthesis and Evaluation of Azole-Substituted Tetrahydronaphthalenes as Inhibitors of P450 arom,P450 17, and P450 TxA2

In search of potential drugs for the treatment of estrogen- and androgen-dependent cancer as well as the prophylaxis of metastases, tetralones, tetralins, and dihydronaphthalenes bearing a OCH₃ substituent at the benzene nucleus and an imidazol-4-yl, imidazol-1-yl, or 1,2,4-triazol-1-yl substituent in 2-position were synthesized with and without C₁-spacer between the rings (compounds 2 – 26 ). The compounds were tested in vitro for inhibition of the three target enzymes P450 arom (human placental microsomes), P450 17 (rat testicular microsomes), and P450 TxA₂ (citrated human whole blood). To examine selectivity, some compounds were further tested in vitro for inhibition of P450 18 (bovine adrenal mitochondria), P450 see (bovine adrenal mitochondria) and corticoid formation (aldosterone, corticosterone; ACTH stimulated rat adrenal tissue). In vivo, selected compounds were examined in Sprague Dawley rats regarding P450 TxA₂ inhibition, reduction of plasma testosterone concentration, antiuterotrophic activity (inhibition of the uterotrophic activity of androstenedione), reduction of plasma estradiol concentration (pregnant mares' serum gonadotropin-primed rats), and mammary tumor inhibiting activity (dimethylbenzanthracene-induced tumor; pre- and postmenopausal model). In the series of imidazol-4-yl compounds, which represent a novelty in the field of azole inhibitors of steroidogenic P450 enzymes, strong inhibitors of P450 arom and/or P450 17 were found: 7-OCH₃-2-(imidazol-4-ylmethylene)-1-tetralone ( 4 ) and 7-OCH₃-2-(imidazol-4-ylmethyl)-tetralin ( 12 ) are among the most potent inhibitors of P450 arom in vitro known so far. Compound 4 is a selective inhibitor, whereas 12 shows in addition strong inhibition of P450 17. In contrast to 12 , the 6-OCH₃ derivative (compound 11 ) is a selective inhibitor of P450 17, being 50 times more potent than ketoconazole. Some imidazol-1-yl compounds show a marked inhibition of P450 TxA₂: 2-(imidazol-1-ylmethyl)-1-tetralone ( 13 ) is a selective inhibitor of P450 TxA₂, whereas 7-OCH₃-2-(imidazol-1-ylmethyl)-tetralin ( 17 ) as well as 2-(imidazol-1-ylmethyl)-tetralin ( 16 ) and 7-OCH₃-2-imidazol-1-yl-3,4-dihydronaphthalene ( 25 ) additionally show strong inhibition of P450 arom and P450 17. Regarding the other steroidogenic P450 enzymes as well as corticosterone formation, the compounds show only little inhibitory activity. Aldosterone formation, however, is inhibited at low concentrations. Nevertheless, 4 and 12 are more selective, i.e. inhibit aldosterone synthesis less than the well known inhibitor of P450 arom fadrozole. The compounds show activity in the aforementioned in vivo tests.     

Aromatase and its inhibitors in breast cancer treatment — overview and perspective

Summary Estrogen has an important role in stimulating the growth of breast carcinomas. Inhibition of estrogen production is therefore a logical treatment strategy. A number of selective inhibitors have been developed against aromatase, a cytochrome P-450 enzyme which catalyzes the rate limiting step in the biosynthesis of estrogens. The mechanisms of the aromatase reaction, current knowledge of the enzyme, and regulation of its expression are discussed as the basis for inhibitor development. Two classes of aromatase inhibitors, steroidal and non-steroidal compounds, are now coming into use. Among the steroid substrate analogues, 4-hydroxyandrostenedione (4-OHA) has been shown to be effective in breast cancer patients with advanced disease and was recently approved for treatment in the United Kingdom. Several different classes of compounds which act as aromatase inhibitors are currently in clinical trials and should provide breast cancer patients with a number of treatment options. Among these are highly potent and selective non-steroidal inhibitors which have recently been found to suppress plasma and urinary estrogens over 95% in breast cancer patients. The potency of these newer aromatase inhibitors provides the opportunity to determine whether complete suppression of estrogen production and action will result in enhanced tumor regression.     

胰岛素增敏剂曲格列酮对人卵巢颗粒细胞芳香化酶活性的抑制作用

为探讨曲格列酮(troglitazone,TGZ)对人卵巢颗粒细胞芳香化酶(P450arom)活性的调节作用，以不同剂量的TGZ和(或)维甲酸类X受体(RXR)激动剂(LG100268，LG)处理来源于体外受精患者的卵巢颗粒细胞24h，然后测定细胞的芳香化酶活性和P450arom mRNA水平。结果发现，TGZ处理颗粒细胞24h可引起剂量依赖性的芳香化酶活性下降；LG单独作用可以抑制芳香化酶活性，但与TGZ合用对芳香化酶的抑制作用更明显；RT-PCR结果显示，随着芳香化酶活性的下降，P450arom mRNA表达水平也降低。表明TGZ可能是通过过氧化物酶体增殖物激活受体γ(PPARγ)：RXR异二聚体组成的核受体系统直接抑制卵巢颗粒细胞芳香化酶活性。     

Influence of aminoglutethimide on plasma oestrogen levels in breast cancer patients on 4-hydroxyandrostenedione treatment

Summary The clinical and biochemical effects of combined treatment with the two aromatase inhibitors aminoglutethimide and 4-hydroxyandrostenedione were evaluated in 10 patients suffering from advanced breast cancer. All patients had become resistant to treatment with one of the drugs before having combined treatment. Seven patients progressing on 4-hydroxyandrostenedione who had aminoglutethimide added to their treatment and achieved a further suppression of plasma oestradiol by a mean of 40.0% (p<0.05). Plasma oestrone was suppressed by a mean of 40.6% (p<0.025) and plasma oestrone sulphate was suppressed by a mean of 63.6% (p<0.025). Two of the patients, neither of whom had responded to 4-hydroxyandrostenedione alone, experienced objective tumour regression when aminoglutethimide was given in concert. Three patients progressing on aminoglutethimide who had 4-hydroxyandrostenedione added showed no further suppression of their plasma oestrogen levels, and no tumour regression was observed. These findings suggest a dose-response relationship between plasma oestrogen suppression at low postmenopausal levels and objective tumour response in breast cancer.     

Molecular basis for treating endometriosis with aromatase inhibitors

Although treatment of one unusually aggressive case of postmenopausal endometriosis with an aromatase inhibitor has been strikingly successful, large clinical trials are required to establish whether aromatase inhibitors will have a significant role in the medical management of endometriosis. Introduction of aromatase inhibitors into the treatment of endometriosis underscores the importance of basic research leading to the development of novel strategies in reproductive disorders. It was shown earlier that aromatase activity was not detectable in normal endometrium. Aromatase, however, is expressed inappropriately in endometriosis and stimulated by prostaglandin E2. Aromatase activity gives rise to local biosynthesis of oestrogen, which, in turn, stimulates prostaglandin E2 production, thus establishing a positive feedback cycle. This favours accumulation of oestrogen and prostaglandins in endometriosis, which is an inflammatory disorder dependent on oestrogen for growth.     

Alteration of cytokine production in follicular cystic ovaries induced in mice by neonatal estradiol injection

PROBLEM: Neonatal estradiol injections in mice lead to follicular cystic ovaries that are similar to ovaries in patients with polycystic ovarian syndrome (PCOS). The present study examined ovarian cytokine production following neonatal estradiol injection. METHOD OF STUDY: Female (C3H,HeJ x 129/HeJ)F1 mice were injected daily with 20 microg 17beta-estradiol from 0-3 days postpartum. At intervals, animals were sacrificed to determine ovarian architecture, circulating levels of estradiol, ovarian and peritoneal macrophage cytokine production, and ovarian P450 aromatase enzyme mRNA levels. RESULTS: Similar to PCOS, our results show that neonatally estradiol-injected mice have lower levels of circulating estrogen that are correlated with decreased mRNA levels of P450 aromatase enzyme. Our data also show that follicular cystic ovaries have increased tumor necrosis factor (TNF)-alpha and interleukin (IL)-6 production. This increase in TNF-alpha and IL-6 production is also observed in peritoneal macrophages of estradiol-injected mice. CONCLUSION: The present study showed that neonatal estrogen injection in mice has an overall systemic effect on cytokine production. We speculate that increased cytokine production may alter certain important steps in follicular maturation, ultimately contributing to ovarian dysfunction.     

Immunolocalization of aromatase in human minor salivary glands of the lower lip with primary Sjogren's syndrome

The enzyme aromatase Is Involved In the conversion of androgens to estrogens and in the modulation of various androgenlc and estrogenlc actions. Abnormalities of estrogen metabolism have been postulated to play roles in the development and/or pathophyslology of Sjdgren's syndrome. In the present study, aromatase was immunolocal-ized In 75 cases of Inflammatory disorders of human minor salivary glands of the lower lip. These included cases of primary Sjögren's syndrome (19 cases), of chronic slaladenitis (34 cases) and of mucous extravasation cysts (22 cases), in order to clarify the possible involvement of in situ estrogen production in primary Sjögren's syndrome. Aromatase Immunoreactlvlty was detected In myoepithelial cells of acini and in interstitial cells adjacent to acini and ducts In 13/19 (68%) cases of primary Sjögren's syndrome. In contrast, aromatase expression was detected In only six of 34 (18%) cases of chronic sialadenttis and in seven of 22 (32%) cases of mucous extravasation cyst. These results suggest that Increased aromatase expression in minor salivary glands with primary Sjogren's syndrome in premenopausal women may be involved in the biological features of primary Sjogren's syndrome through the production of estrogens in situ and possibly through the aggravation of the inflammatory reaction.     

Effect of Chronic Aromatase Inhibition by Δ1 -Testolactone on Pituitary-Gonadal Function in Oligozoospermic Men

Aromatase inhibition by delta 1-testolactone (Teslac, 500 mg twice daily) for 6 months in 9 patients with idiopathic oligozoospermia lowered the levels of serum estradiol (E2) and thereby sex hormone binding globulin (SHBG) (rS = +0.40, p less than 0.025) to values -35 and -25%, respectively, below the pretreatment values (P less than 0.001 and less than 0.005). The E2 decrease was accompanied by a temporary increase (+50%) in the levels of follicle stimulating hormone (FSH), not of luteinizing hormone (LH), and of 17 alpha-hydroxyprogesterone (17 alpha-OHP), but less of testosterone (T) (+30%), which led to a transient rise in the 17 alpha-OHP/T ratio. The T/E2 ratio and "free T" index (T/SHBG) almost doubled until the end of the treatment period. During delta 1-testolactone treatment the mean sperm density gradually rose from 8.1 +/- 1.3 (SEM) before to 21.3 +/- 6.7 X 10(6)/ml after 6 months (P less than 0.01), whereas the total sperm count almost threefold increased (P less than 0.05). Sperm concentrations exceeding 20 X 10(6)/ml were achieved in 4 of the 9 patients. Two of these patients' wives became pregnant. Although the data point to a pivotal role of estrogens in the pathogenesis of the spermatogenic lesion in some patients with idiopathic oligozoospermia, the lack of a beneficial effect of estrogen lowering in others points to a multicausal nature of the disease entity.