Biomedical subjects

Andrew Fensome

Publications and source records attributed to Andrew Fensome.

11 recordsLinked to original sources

PubMed2006

SAR studies of 6-(arylamino)-4,4-disubstituted-1-methyl-1,4-dihydro-benzo[d][1,3]oxazin-2-ones as progesterone receptor antagonists.

We previously disclosed that 6-aryl benzoxazin-2-ones were PR modulators. In a continuation of this work we examined the SAR of new 6-arylamino benzoxazinones and found the targets 1-25, with an extra amino linker between the pendent 6-aryl groups and benzoxazinone or benzoxazine-2-thione core, were PR antagonists. A series of compounds with substituents at the 1- and 4-positions as well as different 6-aryl groups were prepared and tested in the T47D cell alkaline phosphatase assay. Interestingly, the SAR unveiled from the 6-arylamino benzoxazinones was quite different from those of their parent compounds. For example, in contrast to the 6-aryl benzoxazinones, methyl substitution at the 1-position significantly increased the potency of 6-arylamino benzoxazinones. Several 6-arylamino benzoxazinones (e.g., 12, IC(50)=5.0 nM) had low nanomolar in vitro potency as PR antagonists in the T47D cell alkaline phosphatase assay.

Benzoxazines↗

PubMed2005

Synthesis and structure-activity relationship of novel 6-aryl-1,4-dihydrobenzo[d][1,3]oxazine-2-thiones as progesterone receptor modulators leading to the potent and selective nonsteroidal progesterone receptor agonist tanaproget.

Tanaproget represents a potential first-in-class nonsteroidal PR agonist for contraception with improved safety and side effect profiles versus currently available steroidal oral contraceptives. Additional SAR, biological activity, and structural information from a tanaproget/hPR-LBD (hPR-LBD = human progesterone receptor ligand binding domain) cocrystal structure will also be presented.

Alkaline Phosphatase↗

PubMed2005

SAR studies of 6-aryl-1,3-dihydrobenzimidazol-2-ones as progesterone receptor antagonists.

We have previously reported that the aryl substituted benzimidazolones, benzoxazinones, and oxindoles (e.g., 1-3) are progesterone receptor (PR) antagonists and have recently disclosed that the nature of 5- and 6-aryl moieties played a critical role in PR functional activity in the oxindole and benzoxazinone templates. For example, replacing the phenyl group of PR antagonists 2 and 3 with a 5'-cyanopyrrol-2'-yl moiety switched their functional activity to PR agonist activity (2a and 3a). These findings prompted us to examine if there is a similar effect of the 6-aryl moieties on the PR functional activity for the benzimidazolone template. Numerous analogs, such as 5, showed potent PR antagonist activity with about a 10-fold increase in potency as compared to those reported earlier in the same series. More interestingly, pyrrole-containing benzimidazolones 24-27 remained as PR antagonists in contrast to the PR agonist activity switch for oxindole and benzoxazinone scaffolds when a 5'-cyanopyrrol-2'-yl group was installed as a pendant aryl group.

Benzimidazoles↗

PubMed2005

Molecular and pharmacological properties of a potent and selective novel nonsteroidal progesterone receptor agonist tanaproget.

Progesterone receptor (PR) agonists have several important applications in women's health, such as in oral contraception and post-menopausal hormone therapy. Currently, all PR agonists used clinically are steroids. Because of their interactions with other steroid receptors, steroid-metabolizing enzymes, or other steroid-signaling pathways, these drugs can pose significant side effects in some women. Efforts to discover novel nonsteroidal PR agonists with improved biological properties led to the discovery of tanaproget (TNPR). TNPR binds to the PR from various species with a higher relative affinity than reference steroidal progestins. In T47D cells, TNPR induces alkaline phosphatase activity with an EC(50) value of 0.1 nm, comparable with potent steroidal progestins such as medroxyprogesterone acetate (MPA) and trimegestone (TMG), albeit with a reduced efficacy ( approximately 60%). In a mammalian two-hybrid assay to measure PR agonist-induced interaction between steroid receptor co-activator-1 and PR, TNPR showed similar potency (EC(50) value of 0.02 nm) and efficacy to MPA and TMG. Importantly, in key animal models such as the rat ovulation inhibition assay, TNPR demonstrates full efficacy and an enhanced progestational potency (30-fold) when compared with MPA and TMG. Furthermore, TNPR has relatively weak interactions with other steroid receptors and binding proteins and little effect on cytochrome P450 metabolic pathways. Finally, the three-dimensional crystal structure of the PR ligand binding domain with TNPR has been delineated to demonstrate how this nonsteroidal ligand achieves its high binding affinity. Therefore, TNPR is a structurally novel and very selective PR agonist with an improved preclinical pharmacological profile.

Alkaline Phosphatase↗

PubMed2005

Nonsteroidal progesterone receptor modulators: structure activity relationships.

Progesterone, acting primarily via the progesterone receptor (PR), plays an essential role in the regulation of female reproduction. Steroidal progestins (i.e., PR agonists) are commonly used in women's health, such as in contraception and hormone therapy and for the treatment of gynecological disorders. Recent studies in women and in nonhuman primates also indicate that PR antagonists may have potential applications in contraception and for the treatment of reproductive disorders such as fibroids and endometriosis. Currently, all clinically available PR agonists and antagonists are steroidal compounds. They often cause various side effects due to their functional interactions with other steroid receptors or because of effects associated with their steroidal metabolites. In an effort to identify more receptor-selective and structurally diverse compounds that may render clinical advantages over steroidal PR ligands, numerous receptor-selective novel nonsteroidal PR agonists and antagonists have been discovered. This review focuses on the structure activity relationships and the biological profile of the nonsteroidal PR modulators discovered in the last decade.

Animals↗

PubMed2004

Novel pyrrole-containing progesterone receptor modulators.

A series of 1,4-dihydro-2H-[d][3,1]-benzoxazin-2-one and 1,3-dihydro-[3H]-indol-2-one containing 6- or 5-, respectively, appended substituted pyrrole moieties were synthesized and evaluated for their ability to modulate the activity of the progesterone receptor (PR). Key structural changes to the pyrrole moieties of these molecules were shown to have a predictive influence as to whether the compounds behaved as PR agonists or antagonists. Compounds with the 5(')-cyano-2(')-pyrrole moiety (e.g., 32, 33, and 38) were shown to be potent PR agonists (EC(50)'s of 1.1, 1.8, and 2.8 nM, respectively). Compounds with the 5(')-nitro-2(')-pyrrole moiety (e.g., 34 and 36) were shown to be PR antagonists (IC(50)'s of 180 and 36 nM, respectively).

Benzoxazines↗

PubMed2003

Novel 6-aryl-1,4-dihydrobenzo[d]oxazine-2-thiones as potent, selective, and orally active nonsteroidal progesterone receptor agonists.

The functional activity of 6-aryl benzoxazinone-based progesterone (PR) antagonists changed to PR agonism when the 2-carbonyl group was replaced by a 2-thiocarbonyl moiety. Based on this finding novel 6-aryl benzoxazine-2-thiones were synthesized and evaluated as PR agonists in various in vitro and in vivo assays. Several analogues had sub-nanomolar in vitro potency and showed excellent oral activities in rats. Compounds 15 and 29 had similar potencies to medroxyprogesterone acetate (MPA) in the in vitro T47D alkaline phosphatase assay and in vivo rat decidualization model. In contrast to MPA, 29 was highly selective (>500-fold) for PR over glucocorticoid and androgen receptors.

Alkaline Phosphatase↗

PubMed2003

Novel 5-aryl-1,3-dihydro-indole-2-thiones. potent, orally active progesterone receptor agonists.

During the course of our studies on 3,3-disubstituted-5-aryloxindoles derived progesterone receptor (PR) antagonists we discovered that changing the amide funtionality to a thio-amide resulted in compounds displaying potent PR agonist activity. In this communication, the synthesis, structure activity relationships (SAR) and in vivo activity of various 5-arylthio-oxindoles will be discussed.

Alkaline Phosphatase↗

PubMed2002

New progesterone receptor antagonists: 3,3-disubstituted-5-aryloxindoles.

A new series of 3,3-disubstituted-5-aryloxindoles has been synthesized and evaluated for progesterone receptor antagonist (PR) activity in a T47D cell alkaline phosphatase assay and for their ability to bind PR in competition binding studies. In this communication, the synthesis and structure-activity relationships (SARs) of various 3,3-substituents are discussed where it is clear that small alkyl and spiroalkyl groups are required to achieve better PR antagonist activity.

Alkaline Phosphatase↗

PubMed2002

6-Aryl-1,4-dihydro-benzo[d][1,3]oxazin- 2-ones: a novel class of potent, selective, and orally active nonsteroidal progesterone receptor antagonists.

Novel 6-aryl-1,4-dihydro-benzo[d][1,3]oxazin-2-ones were synthesized and tested as progesterone receptor (PR) antagonists. These compounds were potent and showed good selectivity for PR over other steroid receptors such as the glucocorticoid and androgen receptors (e.g., greater than 80-fold selectivity at PR for 4h). Numerous 6-aryl benzoxazinones (e.g., 4h-j) were active orally in the uterine decidualization and component C3 assays in the rats. In these in vivo models,4h had potencies comparable to mifepristone.

Administration, Oral↗

PubMed2002

Potent nonsteroidal progesterone receptor agonists: synthesis and SAR study of 6-aryl benzoxazines.

Novel 6-aryl benzoxazines were prepared and examined as progesterone receptor (PR) modulators. In contrast to the structurally related 6-aryl dihydroquinoline PR antagonists, the 6-aryl benzoxazines were potent PR agonists. Compounds 4e, 5b, and 6a with the 2,4,4-trimethyl-1,4-dihydro-2H-benzo[d][1,3]oxazine core were the most potent PR agonists in the series with sub-nanomolar activities (EC(50) 0.20-0.35nM). Compound 6a was more potent than progesterone (P4) in the in vivo decidualization assay in an ovariectomized female rat model by subcutaneous administration with an ED(50) of 1.5mg/kg (vs 5.62mg/kg for P4).

Animals↗