Endometriosis is a very common disease that is characterized by increased formation of estradiol and disturbed progesterone action. This latter is usually explained by a lack of progesterone receptor B (PR-B) expression, while the role of pre-receptor metabolism of progesterone is not yet fully understood. In normal endometrium, progesterone is metabolized by reductive 20alpha-hydroxysteroid dehydrogenases (20alpha-HSDs), 3alpha/beta-HSDs and 5alpha/beta-reductases. The aldo-keto reductases 1C1 and 1C3 (AKR1C1 and AKR1C3) are the major reductive 20alpha-HSDs, while the oxidative reaction is catalyzed by 17beta-HSD type 2 (HSD17B2). Also, 3alpha-HSD and 3beta-HSD activities have been associated with the AKR1C isozymes. Additionally, 5alpha-reductase types 1 and 2 (SRD5A1, SRD5A2) and 5beta-reductase (AKR1D1) are responsible for the formation of 5alpha- and 5beta-reduced pregnanes. In this study, we examined the expression of PR-AB and the progesterone metabolizing enzymes in 31 specimens of ovarian endometriosis and 28 specimensof normal endometrium. Real-time PCR analysis revealed significantly decreased mRNA levels of PR-AB, HSD17B2 and SRD5A2, significantly increased mRNA levels of AKR1C1, AKR1C2, AKR1C3 and SRD5A1, and negligible mRNA levels of AKR1D1. Immunohistochemistry staining of endometriotic tissue compared to control endometrium showed significantly lower PR-B levels in epithelial cellsand no significant differences in stromal cells, there were no significant differences in the expression of AKR1C3 and significantly higher AKR1C2 levels were seen only in stromal cells. Our expression analysis data atthe mRNA level and partially at the cellular level thus suggest enhanced metabolism of progesterone by SRD5A1 and the 20alpha-HSD and 3alpha/beta-HSD activities of AKR1C1, AKR1C2 and AKR1C3.
COBISS.SI-ID: 27920857
In the search for novel biomarkers of endometriosis, we selected 152 genes from the GeneLogic database based on results of genome-wide expression analysis of ovarian endometriosis, plus 20 genes related to estrogen metabolism and action. We then performed low-density array analysis of these 172 genes on 11 ovarian endometriosis samples and 9 control endometrium samples. Principal component analysis of the gene expression levels showed clear separation between the endometriosis and control groups. We identified 78 genes as differentially expressed. Based on Ingenuity pathway analysis, these differentially expressed genes were arranged into groups according to biological function. These analyses revealed that 32 differentially expressedgenes are estrogen related, 23 of which have not been reported previously in connection with endometriosis. Functional annotation showed that 25 and 22 genes are associated with the biological terms "secreted" and "extracellular region", respectively. Differential expression of 4 out of 5 genes related to estrogen metabolism and action (ESR1, ESR2, PGR and BGN) was also confirmed by immunohistochemistry. Our study thus reveals differential expression of several genes that have not previously been associated with endometriosis and that encode potential novel biomarkers and drug targets.
COBISS.SI-ID: 28170457
Expression levels of genes encoding phases I and II estrogen-metabolizing enzymes: CYP1A1, CYP1A2, CYP1B1, CYP3A5, CYP3A7, SULT1A1, SULT1E1, SULT2B1, COMT, UGT2B7, and GSTP1 were studied by real-time PCR in 38 samples of cancerous and adjacent control endometrium. We found significantly lower levels of CYP1B1 and CYP3A7, higher levels of SULT2B1, UGT2B7 and GSTP1, and no differences in expression of COMT, CYP1A1, CYP3A5, SULT1E1 and SULT2A1 in the endometrial cancers. The CYP1B1 and COMT proteins were also examined by Western blotting and immunohistochemical staining, supporting the real-time PCR analysis. Lower levels of CYP1B1 detected in cancerous endometrium suggest its important role in control, precancerous tissue. Additionally, we showed for the first time higher protein levels of soluble COMT in cancerous endometrium, and higher levels of membrane-bound COMT in control, precancerousendometrium. The importance of the changed ratio between soluble and membrane-bound COMT still needs to be evaluated in further studies.
COBISS.SI-ID: 27490009