Epigenetic-mediated upregulation of progesterone receptor B gene in endometrial cancer cell lines.
OBJECTIVE
To determine if epigenetic interference can restore progesterone receptor-B (PR-B) expression in PR-B negative endometrial adenocarcinoma cell lines, and to characterize the kinetics of PR-B induction mediated by DNA methyltransferase and histone deacetylase inhibitors.


METHODS
The PR-B negative endometrioid cancer cell lines KLE and HEC-1B were used as study models. PR-B mRNA and protein expression levels were measured using real-time PCR and Western blot analysis, respectively. DNA methylation levels of the PR-B promoter were determined by methylation-specific PCR. Dose-response correlations and the duration of response to aza-deoxycytidine (ADC) and trichostatin A (TSA) were characterized. Cell responses to prolonged and repeated drug treatment were also examined.


RESULTS
Relatively low concentrations of ADC and TSA over a 24-h period induced PR-B expression. Furthermore, ADC and TSA acted synergistically to reactivate PR-B expression. Depending on the cell line used, PR-B mRNA was induced 10-110 fold. This elevated PR-B expression continued for 48 h after drug withdrawal. Sustained upregulation of PR-B mRNA and protein was observed during prolonged and repeated drug treatment.


CONCLUSIONS
The epigenetically silenced PR-B gene remains sensitive to changes in DNA demethylation and histone acetylation in uterine adenocarcinoma cell lines. Treatment with ADC and/or TSA results in a robust and sustainable PR-B upregulation. These small molecule epigenetic modifying agents may be used to sensitize poorly differentiated, PR-B negative endometrial cancers to progestational therapy.
Xiong
Yuning
Y
Department of Obstetrics and Gynecology, Mayo Clinic and Foundation, 200 First Street SW, Rochester, MN 55905, USA.
Dowdy
Sean C
SC
Gonzalez Bosquet
Jesus
J
Zhao
Ying
Y
Eberhardt
Norman L
NL
Podratz
Karl C
KC
Jiang
Shi-Wen
SW
D000230:Adenocarcinoma / Q000235:genetics* / Q000378:metabolism; D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D045744:Cell Line, Tumor; D019175:DNA Methylation; D000077209:Decitabine; D016889:Endometrial Neoplasms / Q000235:genetics* / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D044127:Epigenesis, Genetic; D005260:Female; D056572:Histone Deacetylase Inhibitors; D006655:Histone Deacetylases / Q000378:metabolism; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011980:Receptors, Progesterone / Q000096:biosynthesis / Q000235:genetics*; D015854:Up-Regulation / Q000187:drug effects
D004791:Enzyme Inhibitors; D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; D012333:RNA, Messenger; D011980:Receptors, Progesterone; C097314:progesterone receptor B; C012589:trichostatin A; D000077209:Decitabine; D006655:Histone Deacetylases; D001374:Azacitidine