Transcriptional Inhibition of Manganese Superoxide Dismutase (SOD2) Gene Expression by DNA Methylation of the 5′ CpG Island

Huang, Yuanhui; Peng, Jiexin; Oberley, Larry W.; Domann, Frederick E.

doi:10.1016/s0891-5849(97)00095-6

Cited by 50 publications

(39 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Total protein extracts were prepared as previously described from logarithmically growing cells. 13 Protein extracts were resolved 4-20% SDS-polyacrylamide gels (Bio-Rad) at 125 V for 95 min at room temperature using SDS Tris-Glycine running buffer (40 mM Tris pH 8.8, 1.8 mM EDTA 400 mM glycine and 1% SDS). Western transfer onto a nitrocellulose membrane was performed at 100 V for two hours at 4˚C using nitrocellulose membrane with SDS transfer buffer (25 mM Tris, 200 mM glycine and 20% methanol).…”

Section: Methodsmentioning

confidence: 99%

“…Nuclear extracts were prepared from MDA-MB-435 cells as previously described. 13 Two probes for the SOD2 promoter were synthesized with an unmethylated (SOD2U1: 5'-TACATTCTTCTGACGTCTGTAAACAAG-3', SOD2U2: 5'-CTTGTTTACAGACGTCAGAAGAATGTA-3'), or methylated (SOD2M1: 5'-TACATTCTTCTGAC(Me)GTCTGTAAACAAG-5', SOD2M2: 5'-CTTGTTTACAGAC(Me)GTCAGAAGAATGTA-5') CpG within the previously characterized CREB consensus site (underlined). Complementary oligos were and annealed to create the unlabeled SOD2 competitor probes.…”

Section: Methodsmentioning

confidence: 99%

“…SOD2 transcription is mediated trough a TATA-less proximal promoter containing several transcriptional cis-elements. 11 Analysis of the proximal promoter has revealed numerous transcription factor binding sites including those for AP-1, 12 AP-2, 13 …”

Section: Introductionmentioning

confidence: 99%

“…25,26 This is facilitated by DNA methylation inhibiting transcription factor binding at the SOD2 promoter. 13 Furthermore, a causal link between DNA methylation and SOD2 gene silencing is also being developed through the use of pharmacological inhibitors of DNA methyltransferase activity. 26 While these models demonstrate that DNA methylation appears to participate in the regulation of SOD2 expression, its role in repressing MnSOD expression in breast cancer remains undefined.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Epigenetic Regulation of Manganese Superoxide Dismutase Expression in Human Breast Cancer Cells

Hitchler¹,

Wikainapakul²,

Yu³

et al. 2006

Epigenetics

View full text Add to dashboard Cite

Malignant breast cancer cells often exhibit lower expression and activity of manganese superoxide dismutase (MnSOD) than their normal cell counterparts; however, the mechanism(s) responsible for this change remains unclear. We examined whether SOD2, the gene encoding MnSOD, was epigenetically repressed in breast cancer cell lines by DNA methylation and histone acetylation. RT-PCR analysis of SOD2 mRNA showed the nontumorigenic breast epithelial cell line MCF-10A to have two to three fold higher expression levels than either UACC-893 or MDA-MB-435 breast carcinoma cells. Analysis of a region in the SOD2 promoter by sodium bisulfite genomic sequencing demonstrated significantly higher levels of CpG methylation in both human breast carcinoma cell lines assessed than in MCF-10A cells. CREB binding in vitro to a cognate site derived from this region was repressed by DNA methylation, and CREB binding to the 5' regulatory region of the SOD2 gene in vivo as determined by ChIP was significantly lower in breast carcinoma cells than in MCF-10A. Increased cytosine methylation was also accompanied by a significant decrease in the level of acetylated histones in the same region of the SOD2 promoter. Finally, a causal link between cytosine methylation and transcriptional repression was established by increasing MnSOD mRNA, protein and activity in breast carcinoma cells using the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine. These findings indicate that epigenetic silencing of SOD2 constitutes one mechanism leading to the decreased expression of MnSOD observed in many breast cancers.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Epigenetic Regulation of Manganese Superoxide Dismutase Expression in Human Breast Cancer Cells

Hitchler¹,

Wikainapakul²,

Yu³

et al. 2006

Epigenetics

View full text Add to dashboard Cite

show abstract

“…Elafin is an elastase inhibitor, constitutively expressed in normal mammary epithelial cells, but downregulated in most tumor cell lines (Zhang et al, 1995). Manganese-containing superoxide dismutase functions as a tumor suppressor gene in breast cancer (Li et al, 2001a) and it is silenced by DNA methylation of the 5'-CpG island (Huang et al, 1997b).…”

Section: Ink4amentioning

confidence: 99%

DNA methylation and breast carcinogenesis

2002

View full text Add to dashboard Cite

Knowledge about breast carcinogenesis has accumulated during the last decades but has barely been translated into strategies for early detection or prevention of this common disease. Changes in DNA methylation have been recognized as one of the most common molecular alterations in human neoplasia and hypermethylation of gene-promoter regions is being revealed as one of the most frequent mechanisms of loss of gene function. The heritability of methylation states and the secondary nature of the decision to attract or exclude methylation support the idea that DNA methylation is adapted for a specific cellular memory. According to Hanahan and Weinberg, there are six novel capabilities a cell has to acquire to become a cancer cell: limitless replicative potential, self-sufficiency in growth signals, insensitivity to growth-inhibitory signals, evasion of programmed cell death, sustained angiogenesis and tissue invasion and metastasis. This review highlights how DNA-methylation contributes to these features and offers suggestions about how these changes could be prevented, reverted or used as a 'tag' for early detection of breast cancer or, preferably, for detection of premalignant changes.

show abstract

Modified expression of plasma glutathione peroxidase and manganese superoxide dismutase in human renal cell carcinoma

Sarto¹,

Frutiger

Cappellano³

et al. 1999

Electrophoresis

View full text Add to dashboard Cite

Two‐dimensional polyacrylamide gel electrophoresis (2‐D PAGE) is a powerful tool to separate thousands of polypeptides and to highlight the modification of protein expression in malignant diseases. By applying 2‐D PAGE to ten normal human kidney and ten homologous renal cell carcinoma (RCC) tissues, we found two peptides in all ten normal tissues but not in RCCs and, conversely, two peptides were detected in all RCCs but not in normal tissues. Using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF‐MS) and internal sequence analysis, the two first peptides were identified as two isoforms of plasma glutathione peroxidase (GPxP). The two other peptides isolated in all RCCs but not in normal tissues were identified by N‐terminal sequence analysis as multimeric forms of manganese superoxide dismutase (Mn‐SOD). No multimeric Mn‐SODs and only two monomeric forms were detected in normal tissues. GPxP and Mn‐SOD are metallo‐enzymes encoded on chromosome 5q32 and on chromosome 6p25, respectively. Their regions are within the locus 5q21 → qter and 6q21‐6q27 on which deletions and translocations are described in some cytogenetic studies of RCC transformation. Therefore, our results might suggest a correlation between the modified expression of GPxP and Mn‐SOD in tumor tissues and chromosomal modifications, and that the two proteins may be putative markers for diagnosis of RCC.*

show abstract

Transcriptional Inhibition of Manganese Superoxide Dismutase (SOD2) Gene Expression by DNA Methylation of the 5′ CpG Island

Cited by 50 publications

References 8 publications

Epigenetic Regulation of Manganese Superoxide Dismutase Expression in Human Breast Cancer Cells

Epigenetic Regulation of Manganese Superoxide Dismutase Expression in Human Breast Cancer Cells

DNA methylation and breast carcinogenesis

Modified expression of plasma glutathione peroxidase and manganese superoxide dismutase in human renal cell carcinoma

Contact Info

Product

Resources

About