RGD Reference Report - Opposite alterations of DNA methyltransferase gene expression in endometrioid and serous endometrial cancers. - Rat Genome Database

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Opposite alterations of DNA methyltransferase gene expression in endometrioid and serous endometrial cancers.

Authors: Xiong, Y  Dowdy, SC  Xue, A  Shujuan, J  Eberhardt, NL  Podratz, KC  Jiang, SW 
Citation: Xiong Y, etal., Gynecol Oncol. 2005 Mar;96(3):601-9.
RGD ID: 9588596
Pubmed: PMID:15721400   (View Abstract at PubMed)
DOI: DOI:10.1016/j.ygyno.2004.11.047   (Journal Full-text)

OBJECTIVE: To examine the DNA methyltransferase (DNMT) mRNA and protein levels in endometrioid and serous cancers and to study the relationship between DNA methyltransferase expression and endometrial cancer development. METHODS: Normal endometrium, Grade I and Grade III endometrioid carcinoma tissues and cell lines, as well as serous cancer tissues, were analyzed for DNMT expression. Real-time PCR and Western blot techniques were employed to measure the mRNA and protein levels of the four DNA methyltransferases, DNMT1, DNMT2, DNMT3A, and DNMT3B. Immunohistochemistry was performed to detect alterations in DNMT nuclear localization and spatial organization patterns. RESULTS: While DNMT2 and DNMT3A expression appear to be normal, two- to fourfold increase in DNMT1 and DNMT3B were found in both Grade I and Grade III endometrioid cancers. In addition, the poorly differentiated cell lines expressed relatively higher DNMT levels than well-differentiated cells. In contrast to endometrioid carcinomas, serous cancers expressed substantially lower levels of DNMT1 and DNMT3B than normal controls, with four- and twofold reduction observed in DNMT1 and DNMT3B mRNA levels, respectively. Western blot analysis confirmed opposite expression patterns of DNMT1 and DNMT3B protein in endometrioid and serous cancers. Immunohistochemistry showed normal nuclear localization of DNMT1 and DNMT3B in Type I and Type II cancer specimens as well as cell cultures. CONCLUSION: Two opposite DNMT expression patterns were identified in endometrioid and serous cancers. The concerted upregulation in maintenance and de novo DNA methyltransferases in endometrioid carcinomas is consistent with a tendency for gene-specific hypermethylation observed in this histologic subtype, and may be implicated in tumor suppressor silencing. In contrast, the downregulation of maintenance and de novo DNA methyltransferases in serous cancers suggests that these tumors may contain hypomethylated genomic DNA, which has been associated with a higher mutation rate and is consistent with the known pathogenesis of serous-specific phenotypes. Taken together, the data suggest that divergent DNA methylation pathways may be implicated in the development of Type I and Type II endometrial cancers.

RGD Manual Disease Annotations    Click to see Annotation Detail View
TermQualifierEvidenceWithReferenceNotesSourceOriginal Reference(s)
Endometrial Neoplasms  IEP 9588596; 9588596mRNA and protein:decreased expression:uterus:RGD 
Endometrial Neoplasms  ISODNMT1 (Homo sapiens)9588596; 9588596mRNA and protein:decreased expression:uterus:RGD 
Endometrial Neoplasms  ISODNMT3B (Homo sapiens)9588596; 9588596mRNA and protein:decreased expression:uterus:RGD 
Endometrioid Carcinomas  IEP 9588596; 9588596mRNA and protein:increased expression:uterus:RGD 
Endometrioid Carcinomas  ISODNMT1 (Homo sapiens)9588596; 9588596mRNA and protein:increased expression:uterus:RGD 
Endometrioid Carcinomas  ISODNMT3B (Homo sapiens)9588596; 9588596mRNA and protein:increased expression:uterus:RGD 

Objects Annotated

Genes (Rattus norvegicus)
Dnmt1  (DNA methyltransferase 1)
Dnmt3b  (DNA methyltransferase 3 beta)

Genes (Mus musculus)
Dnmt1  (DNA methyltransferase 1)
Dnmt3b  (DNA methyltransferase 3B)

Genes (Homo sapiens)
DNMT1  (DNA methyltransferase 1)
DNMT3B  (DNA methyltransferase 3 beta)


Additional Information