The objectives of this project are to investigate the role of DNA methylation on the regulation of the SOD2 gene, a putative tumor suppressor gene, which encodes the antioxidant enzyme manganese superoxide dismutase (MnSOD). While it is generally accepted that in malignant cells SOD2 is expressed at lower levels than in normal cells, the mechanisms underlying this differential expression are not known. However, numerous studies have pointed to the participation of tumor suppression genes whose expression is modulated by genomic methylation patterns, and which are believed to contribute to differentiation and carcinogenesis. The central hypothesis of this project is that cytosine methylation in the CpG islands surrounding the SOD2 gene transcription start site can adversely influence the expression of SOD2.
Specific aim #1 is to map the human SOD2 gene for cis-acting regulatory elements that participate in governing its expression.
In specific aim #2, the hypothesis will be tested that hypermethylation of CpG island in the human SOD gene promoter can block the expression of a reporter gene in a non-malignant cell line known to express SOD2 (the WI-38 human lung fibroblast cell line).
I specific aim #3 the hypothesis will be tested that a decreased SOD2 expression in cancer cells relative to their normal cell counterparts is due to differential methylation of the SOD2 promoter.
Specific aim #4 is to determine the effects of methylation and transcription factor availability on the transcriptional activation of the SOD2 promoter in malignant and non-malignant cells. A better understanding of the mechanisms of regulation of the expressio of SOD2 during carcinogenesis and differentiation may lead to new strategies for the treatment of diseases in which aberrant SOD2 expression plays a key role.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29CA073612-04
Application #
6376351
Study Section
Chemical Pathology Study Section (CPA)
Project Start
1998-04-06
Project End
2003-03-31
Budget Start
2001-04-01
Budget End
2002-03-31
Support Year
4
Fiscal Year
2001
Total Cost
$106,845
Indirect Cost
Name
University of Iowa
Department
Radiation-Diagnostic/Oncology
Type
Schools of Medicine
DUNS #
041294109
City
Iowa City
State
IA
Country
United States
Zip Code
52242
Khoo, Nicholas K H; Hebbar, Sachin; Zhao, Weiling et al. (2013) Differential activation of catalase expression and activity by PPAR agonists: implications for astrocyte protection in anti-glioma therapy. Redox Biol 1:70-9
Zhao, Rui; Xiang, Nong; Domann, Fredrick E et al. (2009) Effects of selenite and genistein on G2/M cell cycle arrest and apoptosis in human prostate cancer cells. Nutr Cancer 61:397-407
Hitchler, Michael J; Domann, Frederick E (2009) Metabolic defects provide a spark for the epigenetic switch in cancer. Free Radic Biol Med 47:115-27
Teoh, Melissa L T; Fitzgerald, Matthew P; Oberley, Larry W et al. (2009) Overexpression of extracellular superoxide dismutase attenuates heparanase expression and inhibits breast carcinoma cell growth and invasion. Cancer Res 69:6355-63