title: Cytosine-phosphoguanine methylation of estrogen receptors in endometrial cancer.
abstract: We hypothesize that estrogen receptors (ERs) are differentially expressed in endometrial cancer. To test this hypothesis, we investigated the expression profile of ERalpha (ERalpha-A, ERalpha-B, ERalpha-C) and ERbeta genes and CpG methylation status in endometrial cancer cell lines and tissues using reverse transcription-PCR and methylation-specific PCR and direct DNA sequencing. The results demonstrated that ERalpha-A, ERalpha-B, and ERbeta were normally expressed whereas ERalpha-C gene was inactivated in all endometrial cancer cell lines. We further investigated the mechanisms of ERalpha-C gene inactivation through CpG methylation pathways. The treatment with demethylating agent (5'-aza-2'-deoxycytidine) restored ERalpha-C gene expression in all endometrial cancer cell lines. We further confirmed these findings with methylation-specific PCR and direct DNA sequencing and found that only ERalpha-C was methylated on all five different CpG sites in all cell lines. We further analyzed 88 cancerous and 46 normal endometrial tissues. The results demonstrated that only ERalpha-C was inactivated and methylated in 94% of cancer tissues. In 32 pairs of cancerous and normal endometrial tissues from the same patient, ERalpha-C was methylated in 29 of 32 cancer tissues but unmethylated in all normal endometrial tissues. This is the first report that demonstrates selective ERalpha-C gene inactivation through CpG methylation pathway in uterine endometrial cancer.
authors: Department of Urology, University of California-San Francisco, and VA Medical Center, San Francisco, CA 94121, USA. urologylab@aol.com
authors: M
authors: M
authors: Sasaki
authors: L
authors: L
authors: Kotcherguina
authors: A
authors: A
authors: Dharia
authors: S
authors: S
authors: Fujimoto
authors: R
authors: R
authors: Dahiya
mesh_terms: D018899:CpG Islands; D019175:DNA Methylation; D016889:Endometrial Neoplasms / Q000235:genetics* / Q000378:metabolism; D004717:Endometrium / Q000378:metabolism / Q000502:physiology; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D005260:Female; D006801:Humans; D020033:Protein Isoforms; D011960:Receptors, Estrogen / Q000096:biosynthesis / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
chemical_list: D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D020033:Protein Isoforms; D011960:Receptors, Estrogen