Promegestone

Promegestone (R-5020), a progestin, is a potent progesterone receptor (PR) agonist. Promegestone has the potential for endocrine regulation and cancer research.

Promegestone (R-5020; 1 nM) is efficient ligand with a full agonist response profile and a low EC₅₀ of 0.33 nM) in HELN-hPR while it only partially induced luciferase activity in U2OS-zfPR (EC₅₀=1.93 nM)^[1].
Promegestone is inactive in HELN cells that express luciferase but no functional receptor^[1].
Promegestone (10 nM) robustly stimulates SLC37A2 expression in cells expressing SUMO-deficient PR, but not in cells expressing WT PR in T47D cell models^[3].

Promegestone (R-5020; 8 mg/kg; intramuscularly)-treated pregnant mice on day 18 postbreeding has the least deterioration in extracellular collagen (lowest OD) and highest cell density compared to other groups on the day before birth^[2].

References:
[1]. Clémentine Garoche, et al. Human and Zebrafish Nuclear Progesterone Receptors Are Differently Activated by Manifold Progestins. Environ Sci Technol. 2020 Aug 4;54(15):9510-9518.
[2]. Michael A Kirby, et al. Progesterone Receptor-Mediated Actions Regulate Remodeling of the Cervix in Preparation for Preterm Parturition. Reprod Sci. 2016 Nov;23(11):1473-1483.
[3]. Todd P Knutson, et al. Posttranslationally modified progesterone receptors direct ligand-specific expression of breast cancer stem cell-associated gene programs. J Hematol Oncol. 2017 Apr 17;10(1):89.