Yuan Zhu

Design, Synthesis, and SAR of New Pyrrole-Oxindole Progesterone Receptor Modulators Leading to 5-(7-Fluoro-3,3-dimethyl-2-oxo-2,3-dihydro-1H-indol-5-yl)-1-methyl-1H-pyrrole-2-carbonitrile (WAY-255348)

We have continued to explore the 3,3-dialkyl-5-aryloxindole series of progesterone receptor (PR) modulators looking for new agents to be used in female healthcare: contraception, fibroids, endometriosis, and certain breast cancers. Previously we reported that subtle structural changes with this and related templates produced functional switches between agonist and antagonist properties ( Fensome et al. Biorg. Med. Chem. Lett. 2002, 12, 3487; 2003, 13, 1317 ). We herein report a new functional switch within the 5-(2-oxoindolin-5-yl)-1 H-pyrrole-2-carbonitrile class of compounds. We found that the size of the 3,3-dialkyl substituent is important for controlling the functional response; thus small groups (dimethyl) afford potent PR antagonists, whereas larger groups (spirocyclohexyl) are PR agonists. The product from our optimization activities in cell-based systems and also for kinetic properties in rodents and nonhuman primates was 5-(7-fluoro-3,3-dimethyl-2-oxo-2,3-dihydro-1 H-indol-5-yl)-1-methyl-1 H-pyrrole-2-carbonitrile 27 (WAY-255348), which demonstrated potent and robust activity on PR antagonist and contraceptive end points in the rat and also in cynomolgus and rhesus monkeys including ovulation inhibition, menses induction, and reproductive tract morphology.

In vitro characterization of trimegestone: a new potent and selective progestin

Trimegestone (TMG) is a novel 19-norpregnane progestin under development for hormone replacement therapy and oral contraception. The objective of the current study was to characterize the potency and steroid receptor selectivity of TMG in several in vitro assays and to compare its activity to that of medroxyprogesterone acetate (MPA). TMG and MPA had a similar competitive binding affinity for human and rabbit progesterone receptor (PR). However, TMG had a significantly higher affinity for rat PR (IC(50) = 3.3 nM) than MPA (IC(50) = 53.3 nM). In T47D cells, both compounds increased alkaline phosphatase activity and cell proliferation with comparable potencies (EC(50s) of 0.1 nM and of 0.02 nM, respectively). To further characterize the progestational activity and steroid receptor selectivity, we established an immortalized human endometrial stromal cell line (HESC-T). This cell line lacks endogenous estrogen receptor (ER) and PR but does have functional glucocorticoid receptors (GR). When ER is transiently expressed in the cells, 17beta-estradiol (E(2)) induces PR, allowing the study of PR-regulated genes. In HESC-T cells expressing exogenous ER, and therefore PR, both TMG and MPA increased HRE-tk-luciferase activity tenfold with an EC(50) of 0.2 nM. In HESC-T cells without exogenous ER, and therefore no PR, TMG did not induce HRE-tk-luciferase activity, whereas MPA induced the reporter activity with an EC(50) of about 10 nM. This MPA-induced reporter activity is believed to be mediated through GR. The steroid receptor selectivity of TMG was further evaluated using the HRE-tk-luciferase assay in the human lung carcinoma cell line A549, which contains GR but no PR. In these cells TMG had no effect on luciferase activity, whereas MPA increased the reporter activity in a dose-dependent manner with an EC(50) of approximately 30 nM. Furthermore, HRE-tk-luciferase assay in mouse fibroblast cell line L929, which expresses androgen receptor (AR) but no PR, showed that TMG had weak antiandrogenic activity whereas MPA had androgenic activity. In summary, data from several in vitro assays demonstrate that TMG is a potent progestin with a better receptor selectivity profile than MPA.

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).

Rat uterine complement C3 expression as a model for progesterone receptor modulators: characterization of the new progestin trimegestone.

Progestins have a wide variety of activities in female reproduction. There are also pharmacological applications for progestins, including hormone replacement therapy and contraception. Here we report the development and characterization of the rat uterine complement component C3 mRNA as a molecular target for the evaluation of the antiestrogenic activity of progestins in the uterus. In this assay, ethinyl estradiol (EE) is used to stimulate C3 expression and progestins are then evaluated for their ability to inhibit this expression. The three reference progestins, progesterone (P4), levonorgestrel (LNG), and medroxyprogesterone acetate (MPA) blocked the increase in C3 mRNA levels induced by EE. Dexamethasone (DEX) and 17alpha-methyl testosterone did not inhibit the estrogen induced C3 mRNA levels; in fact, DEX caused a further increase in C3 mRNA levels. Finally, the antiprogestin RU486 was able to block the MPA inhibition of C3 message. RU486, like DEX, caused an increase in C3 mRNA levels above that of estrogen treatment alone. The model was also used to evaluate trimegestone (TMG), a new steroidal progestin, that has been shown to be a potent and selective progesterone receptor agonist. The activity of TMG in the rat uterine decidualization and ovulation inhibition assays was similar to MPA. However, in the C3 model, TMG caused a dose-dependent inhibition of the EE induced C3 message and was approximately five-fold more potent in this model than MPA (EC(50) of 4.7 microg/kg and 26.5 microg/kg, respectively). Therefore, TMG was a more potent antagonist of estrogenic activity in the uterine endometrium than any of the reference progestins tested and therefore may be more effective in protecting the endometrium in hormone replacement therapy.

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.

Synthesis and progesterone receptor antagonist activities of 6-aryl benzimidazolones and benzothiazolones.

Novel 6-aryl benzimidazolones and benzothiazolones were prepared and examined as bioisosteres of the recently reported 6-aryl dihydroquinolines (1) for progesterone receptor (PR) antagonist activities. PR antagonist activities increased when compounds 9c-f possessed a more lipophilic group at position-1 and pendent aryl moiety para to NH moiety. Furthermore, conversion of carbonyl moiety of 9e,f to the thio-carbonyl led to benzoimidazolethiones 15a,b with significantly improved potency and binding affinity.

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.

1-Methyl-1H-pyrrole-2-carbonitrile containing tetrahydronaphthalene derivatives as non-steroidal progesterone receptor antagonists

Non-steroidal 1-methyl-1H-pyrrole-2-carbonitrile containing tetrahydronaphthalenes and acyclic derivatives were evaluated as novel series of progesterone receptor (PR) antagonists using the T47D cell alkaline phosphatase assay. Moderate to potent PR antagonists were achieved with these scaffolds. Several compounds (e.g., 15 and 20) demonstrated low nanomolar PR antagonist potency and good selectivity versus other steroid receptors.

5-Aryl indanones and derivatives as non-steroidal progesterone receptor modulators.

Novel 5-aryl indanones, inden-1-one oximes, and inden-1-ols were synthesized and evaluated as progesterone receptor (PR) modulators using the T47D cell alkaline phosphatase assay. Both PR agonists and antagonists were achieved with appropriate 3- and 5-substitution from indanones and inden-1-ols while inden-1-one oximes provided only PR antagonists. Several compounds such as 10 and 11 demonstrated potent in vitro PR agonist potency similar to that of steroidal progesterone (1). In addition, a number of compounds (e.g., 12, 13, 17, 18) showed potent PR antagonist activity indicating the indanones and derivatives are promising PR modulator templates.