title: Molecular portrait of the progestagenic and estrogenic actions of tibolone: behavior of cellular networks in response to tibolone.
abstract: Tibolone is a synthetic steroid with estrogenic effects on brain, vagina, and bone without stimulating the endometrium. During tibolone treatment, it is thought that the progestagenic properties of tibolone stimulate cell differentiation, which effectively counterbalances the growth-stimulating effects of the estrogenic properties of tibolone. The objective of this study was to characterize the expression profile that reflects the endometrial responses to the separated estrogenic (growth-inducing) and progestagenic (growth-inhibiting) actions of tibolone, thus gaining insight into the counteracting effect of these properties of tibolone on the endometrium. The estrogenic action of tibolone was studied in the estrogen-responsive ECC1 cell line (expressing estrogen receptor alpha), and the progestagenic action was studied in the progesterone-responsive cell line Ishikawa PRAB-36 (expressing PRA and PRB). The data showed that the progestagenic and estrogenic effects of tibolone produce different expression profiles with a narrow overlap in genes; however, both properties modulate the same biological processes. The final genetic network analysis indicated that the estrogenic effect of tibolone is potentially counterbalanced by the progestagenic metabolite of tibolone via differential regulation of similar cellular processes. For example, both progestagenic and estrogenic properties stimulate proliferation, but they exert the opposite effect on apoptosis. The apoptosis network was stimulated by the progestagenic properties of tibolone; in contrast, the estrogenic effect of tibolone suppressed the apoptosis network. The current results indicate that this differential regulation is realized through modulation of a different group of genes and rarely via contraregulation of the same set of genes.
authors.affiliation: Department of Reproduction and Development, Erasmus Medical Center, P.O. Box 1738, 3000 DR Rotterdam, The Netherlands. p.hanifi_moghaddam@erasmusmc.nl
authors.forename: P
authors.initials: P
authors.lastname: Hanifi-Moghaddam
authors.forename: S C J P
authors.initials: SC
authors.lastname: Gielen
authors.forename: H J
authors.initials: HJ
authors.lastname: Kloosterboer
authors.forename: M E
authors.initials: ME
authors.lastname: De Gooyer
authors.forename: A M
authors.initials: AM
authors.lastname: Sijbers
authors.forename: A J
authors.initials: AJ
authors.lastname: van Gool
authors.forename: M
authors.initials: M
authors.lastname: Smid
authors.forename: M
authors.initials: M
authors.lastname: Moorhouse
authors.forename: F H
authors.initials: FH
authors.lastname: van Wijk
authors.forename: C W
authors.initials: CW
authors.lastname: Burger
authors.forename: L J
authors.initials: LJ
authors.lastname: Blok
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics / Q000473:pathology; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D016889:Endometrial Neoplasms / Q000235:genetics / Q000473:pathology; D004958:Estradiol / Q000494:pharmacology; D020847:Estrogen Receptor Modulators / Q000494:pharmacology*; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006801:Humans; D009415:Nerve Net; D009652:Norpregnenes / Q000494:pharmacology*; D011372:Progestins / Q000037:antagonists & inhibitors*; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D020847:Estrogen Receptor Modulators; D009652:Norpregnenes; D011372:Progestins; D004958:Estradiol; C027385:tibolone