Effect of mifepristone on the transcriptomic signature of endometrial receptivity.

STUDY QUESTION

How does a single dose of mifepristone on Day 2 after the LH peak (LH + 2) affect the endometrial receptivity transcriptome as assessed by the receptive signature established by the endometrial receptivity analysis (ERA)?

SUMMARY ANSWER

A single dose of mifepristone on day LH + 2 renders the endometrium non-receptive by altering the transcriptome associated with endometrial receptivity.

WHAT IS KNOWN ALREADY

Mifepristone is a progesterone receptor modulator that has been shown to alter endometrial receptivity. The ERA is a computational predictor that utilizes gene expression data of 248 genes from next generation sequencing to identify endometrial receptivity status.

STUDY DESIGN, SIZE, DURATION: Endometrial biopsies were collected on day LH + 7 from controls (n = 11) and from women treated with mifepristone (n = 7). For further comparative analysis, samples were also obtained from women in the proliferative phase (n = 7).

PARTICIPANTS/MATERIALS, SETTING, METHODS: Mifepristone treatment consisted of 200 mg administered on day LH + 2. Endometrial biopsies were treated for RNA isolation and cDNA conversion and sequencing. Endometrial receptivity status was assessed by the ERA computational predictor. Differential gene expression between groups was also assessed. Ingenuity Pathway Analysis was used for network analysis. Validation of gene expression results was done by qPCR.

MAIN RESULTS AND THE ROLE OF CHANCE

Control samples were all staged around 'receptive' as would be clinically expected for LH + 7. Treatment samples were all staged as non-receptive (all but one was classified as 'proliferative' and the last as 'pre-receptive'). Differential gene expression analysis yielded 60 differentially expressed genes between the control and treatment groups. Bioinformatic pathway analysis for differential expression showed inactivation of the progesterone and glucocorticoid receptors, consistent with mifepristone action.

LIMITATIONS, REASONS FOR CAUTION: The primary limitations are the relative small number of subjects and the use of a limited gene panel.

WIDER IMPLICATIONS OF THE FINDINGS

This study sheds further light on the endometrial receptivity altering effects of mifepristone and on progesterone action. It further shows the capacity of the ERA to identify pharmacologically induced non-receptive endometrium, which expands its possible use clinically and in research.

STUDY FUNDING/COMPETING INTEREST(S): C.v.G. and N.R.B. have no conflicts of interest. P.G.L. reports honorarium from University of HK/Shenzhen, other from NIF, India, outside the submitted work. K.G.D. reports consultancy for Bayer AG, Exelgyn, HRA-Pharma, Gedeon Richter, MSD, Mithra, Exeltis and Natural cycles, payment for lectures from Bayer AG, NSD, Ferring, HRA-Pharma, Exelgyn and Exeltis and clinical trials for Bayer AG, MSD, Exeltis, Mithra, HRA-Pharma and Sun Pharma. C.S. has a patent gene expression profile (ERA) issued to Igenomix and is scientific director of Igenomix S.L. M.R., R.N. and J.M.V. are employees of Igenomix S.L.

TRIAL REGISTRATION NUMBER

N/A.