The female sex hormone estradiol (1) has a variety of beneficial and detrimental effects in women.' The triphenylethylene class of non-steroidal estrogens (e.g., tamoxifen, 2) shows tissue-dependent expression of estrogen agonist and antagonist activity and may represent a significant advance over conventional hormone replacement therapy with 1 for prevention of osteoporosis and cardiovascular disease in postmenopausal women2 ( Figure 1). The estrogen receptor is a ligand-activated transcription factor that belongs to the steroidbetinoid family of DNA-binding intracellular receptors (ICR). Studies with deletion and point-mutated receptors have revealed two independent transcription activation domains (AF-1 and AF-2, Figure 2) within the receptor that allow the expression of cell-and promoter-specific agonist activity in transient cotransfection experiments in vitr0.3 The translation of these observations to the design of ligands for ICRs that show tissue-specific expression of functional activity is at the forefront of modern endo~rinology.~ For this purpose, we formulated the hypothesis that the tissueselective profile of 2 was due to induction of a unique receptor conformation5 in which the antagonist activity in some tissues was due to disruption of AF-2, mediated by a H-bond interaction6 with the receptor protein in the region of the putative AF-2 a -h e l i~,~~~~ and the agonist activity in other tissues was a result of a functional AF-1 domain.3bld Combining this hypothesis with analysis of the in vitro and in vivo pharmacology of non-steroidal estrogens: it was proposed that the stilbene portion of 2 was required for AF-1 activity leading to agonist activity in bone, and the ethanolamine side chain was responsible for blocking AF-2 activity leading to antagonism in the uterus. We report here on the use of this hypothesis to identify triphenylethylene estrogens that show full agonist activity in bone through inhibition of bone loss in ovariectomized rats but which are antagonists in the rat uterus with minimal residual agonist activity.We elected to synthesize analogs of the triphenylethylene 2 in which the ethanolamine side chain was replaced by alternate H-bond acceptor groups and the degree of conformational freedom was reduced. Following the general synthetic strategy of Millerg for synthesis of (2)-tamoxifen, bromide 3 was coupled with arylboronic acid

A variety of C17 amide-substituted 6-azaandrost-4-en-3-ones were prepared and tested versus human type 1 and 2 steroid 5 alpha-reductase (5AR) and human adrenal 3 beta-hydroxy-delta 5-steroid dehydrogenase/3-keto-delta 5-steroid isomerase (3BHSD) in order to optimize potency versus both isozymes of 5AR and selectivity versus 3BHSD. Two series of potent and selective C17 amides were discovered, 2,5-disubstituted anilides and (arylcycloalkyl)amides. Compounds from each series with picomolar IC50's versus human type 2 5AR and low nanomolar to picomolar IC50's versus human type 1 5AR possessing 100-500-fold selectivity versus 3BHSD were identified. A conformational model to predict 3BHSD potency was developed which could rationalize 3BHSD potency within three different series of compounds. Evaluation of some optimal compounds from this series in a chronic castrated rat model of 5AR inhibitor induced prostate involution, and pharmacokinetic measurements identified compounds (9, 12, 16, and 29) with good in vivo efficacy and half-life in the dog. An intact rat model of in vivo selectivity for 5AR versus 3BHSD inhibition was also developed. Dual inhibitors of both human 5AR's may show advantages over type 2 selective 5AR inhibitors, such as finasteride (1), in the treatment of disease states which depend upon dihydrotestosterone.

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BackgroundNT1014 is a novel biguanide and AMPK activator with a high affinity for the organic cation-specific transporters, OCT1 and OCT3. We sought to determine the anti-tumorigenic effects of NT1014 in human ovarian cancer cell lines as well as in a genetically engineered mouse model of high-grade serous ovarian cancer.MethodsThe effects of NT1014 and metformin on cell proliferation were assessed by MTT assay using the human ovarian cancer cell lines, SKOV3 and IGROV1, as well as in primary cultures. In addition, the impact of NT1014 on cell cycle progression, apoptosis, cellular stress, adhesion, invasion, glycolysis, and AMPK activation/mTOR pathway inhibition was also explored. The effects of NT1014 treatment in vivo was evaluated using the K18 − gT121+/−; p53fl/fl; Brca1fl/fl (KpB) mouse model of high-grade serous ovarian cancer.ResultsNT1014 significantly inhibited cell proliferation in both ovarian cancer cell lines as well as in primary cultures. In addition, NT1014 activated AMPK, inhibited downstream targets of the mTOR pathway, induced G1 cell cycle arrest/apoptosis/cellular stress, altered glycolysis, and reduced invasion/adhesion. Similar to its anti-tumorigenic effects in vitro, NT1014 decreased ovarian cancer growth in the KpB mouse model of ovarian cancer. NT1014 appeared to be more potent than metformin in both our in vitro and in vivo studies.ConclusionsNT1014 inhibited ovarian cancer cell growth in vitro and in vivo, with greater efficacy than the traditional biguanide, metformin. These results support further development of NT1014 as a useful therapeutic approach for the treatment of ovarian cancer.