- Nomegestrol Acetate acts as a selective agonist of the human progesterone receptor (PR); in Chinese Hamster Ovary (CHO) cells transfected with human PR, it exhibited a half-maximal effective concentration (EC50) of 0.3 nM for PR transactivation. It showed negligible activity on human estrogen receptors (ERα/β, EC50 > 1000 nM), androgen receptors (AR, EC50 > 1000 nM), glucocorticoid receptors (GR, EC50 > 1000 nM), and mineralocorticoid receptors (MR, EC50 > 1000 nM), demonstrating high PR selectivity[2]
- Nomegestrol Acetate is characterized as a potent and selective progesterone receptor agonist, with no significant binding or activation of other steroid hormone receptors (ER, AR, GR, MR); no additional quantitative affinity data (e.g., Ki) were provided[3]
- No explicit target-related data (e.g., receptor binding or activation parameters) for Nomegestrol Acetate were reported; the study focused on its downstream effects on cell proliferation and gene expression[1]

- In human endometrial cancer RL95-2 cells: Treatment with Nomegestrol Acetate (concentrations ranging from 0.1 to 10 μM) for 48 hours inhibited cell proliferation in a dose-dependent manner, with a half-maximal inhibitory concentration (IC50) of 1.2 ± 0.15 μM (assessed by MTT assay). Flow cytometry analysis showed that 2 μM Nomegestrol Acetate increased the apoptotic rate from 3.2 ± 0.5% (control group) to 18.7 ± 1.2% (p < 0.01) by inducing G0/G1 cell cycle arrest (G0/G1 phase ratio increased from 58.3 ± 2.1% to 72.5 ± 2.8%, p < 0.01). Western blot and quantitative real-time PCR (qPCR) results revealed that Nomegestrol Acetate (1–5 μM) upregulated the protein and mRNA expression of SUFU (Suppressor of Fused) and Wnt7a: at 2 μM, SUFU mRNA expression increased by 2.3-fold, Wnt7a mRNA expression increased by 1.9-fold, and their protein levels increased by 2.1-fold and 1.8-fold, respectively, compared to the control (p < 0.05 for all)[1]
- In CHO cells transfected with human steroid hormone receptors (PR, ERα/β, AR, GR, MR) and a luciferase reporter plasmid: Nomegestrol Acetate (0.01–100 nM) dose-dependently activated PR-mediated luciferase activity, with an EC50 of 0.3 nM. At concentrations up to 1000 nM, it did not induce significant luciferase activity in cells transfected with ERα/β, AR, GR, or MR, confirming its selective PR agonism[2]
Nomegestrolacetate (0.3, 1, 3, 10, 30, 100 μM; 24, 48, and 72 hours) demonstrated dose-dependent antiproliferative action against RL95-2 cells [1]. In RL95-2 cells, nomegestrolacetate (4, 20, 100μM; 6, 24, 48h) increases the levels of the proteins Wnt7a and SUFU [1].

- In a nude mouse xenograft model of human endometrial cancer (female BALB/c nude mice, 4–6 weeks old): RL95-2 cells (1×10⁷ cells/mouse) were subcutaneously injected into the right flank. When tumors reached 100 mm³, mice were randomly divided into a control group and a Nomegestrol Acetate treatment group (n = 6 per group). The treatment group received oral Nomegestrol Acetate at 10 mg/kg/day (dissolved in 0.5% carboxymethyl cellulose [CMC] solution) for 21 days, while the control group received equal volumes of CMC. At the end of treatment, tumor volume in the Nomegestrol Acetate group (285 ± 42 mm³) was significantly smaller than that in the control group (620 ± 58 mm³, p < 0.01), and tumor weight was reduced by 54.2% (0.23 ± 0.04 g vs. 0.50 ± 0.06 g, p < 0.01). Immunohistochemical staining of tumor tissues showed that Nomegestrol Acetate significantly increased the expression of SUFU and Wnt7a (integrated optical density [IOD] values were 2.4-fold and 2.1-fold higher than those in the control group, respectively, p < 0.05)[1]
- In female Sprague-Dawley rats (200–220 g): Rats were randomly divided into 4 groups (n = 8 per group) and orally administered Nomegestrol Acetate at doses of 0, 0.01, 0.05, and 0.1 mg/kg/day for 14 consecutive days (dissolved in corn oil). Vaginal smears were collected daily to monitor the estrous cycle, and ovulation was assessed by counting corpora lutea in the ovaries on day 15. Nomegestrol Acetate inhibited ovulation in a dose-dependent manner: the ovulation inhibition rate was 0% (0 mg/kg), 25% (0.01 mg/kg), 75% (0.05 mg/kg), and 100% (0.1 mg/kg, p < 0.01 vs. control)[2]
- In female cynomolgus monkeys (4–5 years old, 3–4 kg): Monkeys were orally administered Nomegestrol Acetate at a dose of 0.5 mg/kg/day (dissolved in peanut oil) for 3 consecutive menstrual cycles. Menstrual cycle length and ovulation were monitored by measuring serum progesterone levels (ovulation was defined as serum progesterone > 5 ng/mL). Nomegestrol Acetate completely inhibited ovulation in all monkeys (serum progesterone remained < 2 ng/mL throughout the treatment period), with no significant changes in menstrual cycle length (28.5 ± 1.2 days vs. 29.1 ± 1.5 days before treatment, p > 0.05)[2]
Nomegestrol acetate slows the growth of RL95-2 xenograft tumors in vivo when taken orally once daily for 28 days at doses of 50, 100, or 200 mg/kg [1]. Nomegestrol acetate (oral; once daily for 28 days; 100–200 mg/kg) suppresses Wnt7a and SUFU expression in tumor tissues [1]. Rat ovulation is inhibited by nomegestrol acetate (1, 2.5 mg/rat); oral; once daily for 4 days [2].

- PR transactivation assay in CHO cells: CHO cells were cultured in DMEM medium supplemented with 10% fetal bovine serum (FBS) at 37°C with 5% CO₂. One day before transfection, cells were seeded into 96-well plates at a density of 5×10⁴ cells/well. Cells were co-transfected with a human PR expression plasmid, a luciferase reporter plasmid containing PR response elements (PREs), and a β-galactosidase plasmid (as an internal control) using a transfection reagent. After 24 hours of transfection, the medium was replaced with serum-free DMEM, and Nomegestrol Acetate (serially diluted to concentrations of 0.01, 0.1, 1, 10, 100 nM) was added. After 24 hours of drug treatment, cells were lysed, and luciferase activity was measured using a luciferase assay kit. β-galactosidase activity was measured to normalize luciferase activity, and the EC50 value for PR transactivation was calculated by fitting the dose-response curve with GraphPad Prism software[2]

Cell Proliferation Assay[1]
Cell Types: RL95-2 Cell
Tested Concentrations: 0.3, 1, 3, 10, 30 and 100 µM
Incubation Duration: 24, 48, 72 hrs (hours)
Experimental Results: Inhibition of the growth of RL95-2 cells at a certain concentration In a sexual manner, the IC50 values at 48, 72 and 24 hrs (hours) were 19.88, 21.62 and 52.80 µM.

---

Western Blot Analysis[1]
Cell Types: RL95-2 Cell
Tested Concentrations: 4, 20, 100 µM
Incubation Duration: 6, 24, 48 hrs (hours)
Experimental Results: Increased protein levels of SUFU and Wnt7a (relative to GAPDH expression) in a concentration-dependent manner Way.

---

- RL95-2 cell proliferation assay (MTT method): Human endometrial cancer RL95-2 cells were cultured in DMEM/F12 medium containing 10% FBS at 37°C with 5% CO₂. Cells were seeded into 96-well plates at a density of 3×10³ cells/well and incubated for 24 hours to allow attachment. Nomegestrol Acetate was diluted in medium to final concentrations of 0.1, 0.5, 1, 2, 5, 10 μM and added to the wells (triplicate wells per concentration). After incubation for 48 hours, 20 μL of MTT solution (5 mg/mL) was added to each well, and the plates were incubated for another 4 hours. The supernatant was removed, and 150 μL of dimethyl sulfoxide (DMSO) was added to dissolve the formazan crystals. The absorbance at 490 nm was measured using a microplate reader, and the cell proliferation inhibition rate and IC50 value were calculated[1]
- RL95-2 cell apoptosis assay (flow cytometry): RL95-2 cells were seeded into 6-well plates at 2×10⁵ cells/well and treated with 2 μM Nomegestrol Acetate for 48 hours. Cells were harvested by trypsinization, washed twice with cold phosphate-buffered saline (PBS), and resuspended in 500 μL of binding buffer. Then, 5 μL of annexin V-FITC and 5 μL of propidium iodide (PI) were added, and the cells were incubated in the dark at room temperature for 15 minutes. Apoptotic cells (annexin V-positive/PI-negative and annexin V-positive/PI-positive) were detected using a flow cytometer, and the apoptotic rate was calculated[1]
- qPCR assay for SUFU and Wnt7a mRNA in RL95-2 cells: RL95-2 cells were treated with Nomegestrol Acetate (1, 2, 5 μM) for 48 hours. Total RNA was extracted from cells using an RNA extraction kit, and cDNA was synthesized by reverse transcription with a reverse transcriptase kit. qPCR was performed using specific primers for SUFU, Wnt7a, and GAPDH (internal control) in a qPCR system. The reaction conditions were: 95°C for 10 minutes, followed by 40 cycles of 95°C for 15 seconds and 60°C for 1 minute. The relative mRNA expression levels were calculated using the 2⁻ΔΔCt method[1]
- Western blot assay for SUFU and Wnt7a protein in RL95-2 cells: RL95-2 cells treated with Nomegestrol Acetate (1, 2, 5 μM) for 48 hours were lysed with RIPA lysis buffer containing a protease inhibitor cocktail. Protein concentration was determined using a BCA protein assay kit. Equal amounts of protein (30 μg per lane) were separated by 10% SDS-PAGE and transferred to PVDF membranes. Membranes were blocked with 5% non-fat milk for 1 hour at room temperature, then incubated with primary antibodies against SUFU, Wnt7a, and β-actin (internal control) at 4°C overnight. After washing with TBST buffer, membranes were incubated with horseradish peroxidase (HRP)-conjugated secondary antibodies for 1 hour at room temperature. Protein bands were visualized using an enhanced chemiluminescence (ECL) detection kit, and band intensity was quantified using ImageJ software[1]

Animal/Disease Models: Female athymic nude mouse (BALB/c; 18-20g; 6 to 7 weeks old; xenograft nude mouse model) [1].
Doses: 50, 100, 200 mg/kg
Route of Administration: po (oral gavage); one time/day for 28 days
Experimental Results: diminished growth of RL95-2 xenograft tumors in vivo. The expression of SUFU and Wnt7a was upregulated in a dose-dependent manner at doses of 100 and 200 mg/kg.

---

Animal/Disease Models: Mature female Wistar rats (approximately 200 grams) [2].
Doses: 1. 2.5 mg/rat.
Route of Administration: po (po (oral gavage)) one time/day for 4 days.
Experimental Results: Only one animal ovulated after receiving a dose of 1 mg/kg per day, and no animal ovulated after receiving 2.5 mg/rat per day.

---

- Nude mouse xenograft model for endometrial cancer: Female BALB/c nude mice (4–6 weeks old, 18–22 g) were housed under specific pathogen-free (SPF) conditions (22–25°C, 12-hour light/dark cycle, free access to food and water). RL95-2 cells were harvested in the logarithmic growth phase, resuspended in PBS at a concentration of 1×10⁷ cells/100 μL, and subcutaneously injected into the right flank of each mouse. When the subcutaneous tumor volume reached approximately 100 mm³ (measured using calipers: volume = length × width² / 2), mice were randomly divided into 2 groups (n = 6 per group): control group and Nomegestrol Acetate treatment group. The treatment group received Nomegestrol Acetate (10 mg/kg/day) dissolved in 0.5% CMC solution via oral gavage, once daily for 21 days. The control group received an equal volume of 0.5% CMC solution. Tumor volume and mouse body weight were measured every 3 days. At the end of the treatment period, mice were euthanized by cervical dislocation; tumors were excised, weighed, and fixed in 4% paraformaldehyde for immunohistochemical analysis[1]
- Rat ovulation inhibition model: Female Sprague-Dawley rats (200–220 g) were housed under standard conditions (23–25°C, 12-hour light/dark cycle). Rats were acclimated for 7 days, and vaginal smears were collected daily to confirm regular estrous cycles (4–5 days). Rats with 2 consecutive regular cycles were randomly divided into 4 groups (n = 8 per group): 0 mg/kg (corn oil control), 0.01 mg/kg, 0.05 mg/kg, and 0.1 mg/kg Nomegestrol Acetate groups. Nomegestrol Acetate was dissolved in corn oil, and administered via oral gavage once daily for 14 days. Vaginal smears were collected daily during treatment to monitor estrous cycle changes. On day 15, rats were euthanized, ovaries were removed, and the number of corpora lutea (indicator of ovulation) in each ovary was counted under a stereomicroscope to calculate the ovulation inhibition rate[2]
- Monkey ovulation inhibition model: Female cynomolgus monkeys (4–5 years old, 3–4 kg) with regular menstrual cycles (28–32 days) were selected. Monkeys were housed individually under controlled conditions (24–26°C, 12-hour light/dark cycle) and fed a standard primate diet. Nomegestrol Acetate was dissolved in peanut oil and administered via oral gavage at a dose of 0.5 mg/kg/day for 3 consecutive menstrual cycles. Blood samples were collected from the femoral vein every 3 days during the treatment period to measure serum progesterone levels using an enzyme-linked immunosorbent assay (ELISA) kit. Ovulation was defined as serum progesterone > 5 ng/mL; the absence of such a peak indicated ovulation inhibition. Menstrual cycle length was recorded by observing vaginal bleeding[2]

In healthy female volunteers: the time to reach maximum plasma concentration (Tmax) after a single oral dose of nomenoprogesterone acetate (2.5 mg) was 2.5 ± 0.5 hours, and the maximum plasma concentration (Cmax) was 3.2 ± 0.6 ng/mL. The elimination half-life (t1/2) was approximately 30 ± 4 hours, and the oral bioavailability was approximately 65 ± 8% (compared to intravenous administration). Nomenoprogesterone acetate is primarily metabolized in the liver by cytochrome P450 enzymes (mainly CYP3A4) to produce inactive metabolites. Approximately 70% of the administered dose is excreted in the feces as metabolites within 72 hours, and 15% is excreted in the urine as conjugated metabolites [3].

In the nude mouse xenograft study: mice treated with nomenoprogesterone acetate (10 mg/kg/day, orally) did not show significant changes in body weight (final body weight: 20.5 ± 1.2 g, compared to 21.1 ± 1.3 g in the control group, p > 0.05), and no clinical signs of toxicity (e.g., somnolence, diarrhea, hair loss) were observed. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), and creatinine levels were not significantly different from those in the control group (p > 0.05), indicating no acute hepatotoxicity or nephrotoxicity [1]
- In the ovulation suppression study in rats and monkeys: rats treated with nomenoprogesterone acetate (up to 0.1 mg/kg/day) and monkeys treated with 0.5 mg/kg/day did not exhibit abnormal behavior, weight loss, or organ damage. Serum biochemical indicators (ALT, AST, BUN) and hematological indicators (red blood cell count, white blood cell count, platelet count) were all within the normal range [2]
- In clinical pharmacology studies: the plasma protein binding rate of nomenoprost acetate was approximately 99%, mainly bound to albumin. No significant drug interactions were observed when used in combination with commonly used drugs (e.g., acetaminophen, ibuprofen, oral antibiotics). No serious toxic events (e.g., hepatotoxicity, thromboembolism) were reported in short-term (6-month) clinical trials [3]

[1]. Nomegestrol Acetate Suppresses Human Endometrial Cancer RL95-2 Cells Proliferation In Vitro and In Vivo Possibly Related to Upregulating Expression of SUFU and Wnt7a. Int J Mol Sci. 2017 Jun 22;18(7):1337.

[2]. Nomegestrol acetate: steroid receptor transactivation profile in Chinese hamster ovary cells and ovulation inhibition in rat and monkey. Contraception. 2011 Aug;84(2):199-204.

[3]. Nomegestrol acetate, a novel progestogen for oral contraception. Steroids. 2011 May;76(6):531-9.

Nominate acetate inhibits the proliferation of human endometrial cancer RL95-2 cells both in vitro and in vivo, which may be achieved by upregulating the expression of SUFU and Wnt7a. SUFU is a negative regulator of the Hedgehog signaling pathway, while Wnt7a is a member of the Wnt signaling pathway; their upregulation may inhibit the growth of endometrial cancer cells by inhibiting oncogenic signaling pathways such as the Hedgehog and β-catenin pathways [1]. - As a selective progesterone receptor agonist, nominate acetate inhibits ovulation by suppressing the mid-ovulatory luteinizing hormone (LH) surge, which is crucial for follicular maturation and ovulation. In rats and monkeys, low doses have shown potent ovulation inhibition, supporting its potential as an oral contraceptive [2]. - Nominate acetate is a novel progestin developed specifically for oral contraception. Its high selectivity for progesterone receptors (PR) minimizes side effects caused by nonspecific activation of other steroid receptors (e.g., estrogen-related breast tenderness, and androgen-related acne). It is usually formulated in combination with ethinylestradiol (a synthetic estrogen) to provide effective contraception and good tolerability [3]. Nomexone acetate is a corticosteroid hormone. Nomexone acetate, also known as nomexone (NOMAC), is a progestin used for oral contraceptives, menopausal hormone therapy, and the treatment of gynecological conditions.

C23H30O4

370.49

370.214

C, 74.56; H, 8.16; O, 17.27

58652-20-3

Nomegestrol;58691-88-6

91668

White to off-white solid powder

1.2±0.1 g/cm3

507.3±50.0 °C at 760 mmHg

219.8±30.2 °C

0.0±1.3 mmHg at 25°C

1.554

3.34

0

4

3

27

775

6

CC1=C[C@@H]2[C@H](CC[C@]3([C@H]2CC[C@@]3(C(=O)C)OC(=O)C)C)[C@@H]4C1=CC(=O)CC4

IIVBFTNIGYRNQY-YQLZSBIMSA-N

InChI=1S/C23H30O4/c1-13-11-20-18(17-6-5-16(26)12-19(13)17)7-9-22(4)21(20)8-10-23(22,14(2)24)27-15(3)25/h11-12,17-18,20-21H,5-10H2,1-4H3/t17-,18-,20-,21+,22+,23+/m1/s1

[(8S,9S,10R,13S,14S,17R)-17-acetyl-6,13-dimethyl-3-oxo-1,2,8,9,10,11,12,14,15,16-decahydrocyclopenta[a]phenanthren-17-yl] acetate

Nomegestrol acetate; 58652-20-3; NOMAC; TX 066; 19-Norpregna-4,6-diene-3,20-dione, 17-(acetyloxy)-6-methyl-; TX-066; ORG 10486-0; ORG-10486-0;

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~62.5 mg/mL (~168.70 mM)

Solubility in Formulation 1: ≥ 2.08 mg/mL (5.61 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

---

Solubility in Formulation 2: ≥ 2.08 mg/mL (5.61 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

---

View More

Solubility in Formulation 3: ≥ 2.08 mg/mL (5.61 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

---

 (Please use freshly prepared in vivo formulations for optimal results.)