DNA damage in the form of apurinic/apyrimidinic (AP) sites is induced by cytotoxic agents resulting in base substitution mutations and blocks to DNA replication. The DNA base excision repair (BER) enzyme, AP endonuclease (APE), is a multifunctional protein involved in DNA base excision repair, oxidative signaling, transcription factor regulation, cell cycle control, and apoptosis. APE is essential for the repair of AP sites thus maintaining cellular and genetic integrity. Deficient expression of APE results in a heightened sensitivity to radiation and alkylating agents with resultant tissue damage. Logically it follows that APE may also play a role in the sensitivity to malignant cells to DNA damaging therapeutic agents. Many cancer therapeutic agents will induce apoptosis or programmed cell death, however little is known about the relationship of DNA repair enzymes (particularly BER) and apoptosis. Preliminary observations indicating that APE expression can be suppressed in myeloid leukemia cells by retinoic acid or DMSO while inducing apoptosis, has led to the hypothesis that: Decreased expression of APE is functionally related to apoptosis in myeloid leukemia cells.
The specific aims are:
Specific Aim #1 What is the relationship of APE expression to myeloid leukemia cell differentiation and apoptosis? Specific Aim 2: What is the role of APE protein phosphorylation in APE expression, function and apoptosis.
Specific Aim #3 : Determination of the molecular mechanisms that are responsible for down-regulation of APE expression upon induction of apoptosis. We propose to initiate studies on the relationship of APE expression and phosphorylation to cell differentiation, apoptosis, and sensitivity to cytotoxic agents, with the long-term goal of developing ways to enhance the chemo/radio sensitivity of leukemia cells by manipulating expression of APE.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA076643-03
Application #
6173169
Study Section
Radiation Study Section (RAD)
Program Officer
Stone, Helen B
Project Start
1998-08-01
Project End
2002-05-31
Budget Start
2000-06-01
Budget End
2001-05-31
Support Year
3
Fiscal Year
2000
Total Cost
$258,571
Indirect Cost
Name
Indiana University-Purdue University at Indianapolis
Department
Pediatrics
Type
Schools of Medicine
DUNS #
005436803
City
Indianapolis
State
IN
Country
United States
Zip Code
46202
Fishel, Melissa L; Colvin, E Scott; Luo, Meihua et al. (2010) Inhibition of the redox function of APE1/Ref-1 in myeloid leukemia cell lines results in a hypersensitive response to retinoic acid-induced differentiation and apoptosis. Exp Hematol 38:1178-88
Fishel, Melissa L; Seo, Young R; Smith, Martin L et al. (2003) Imbalancing the DNA base excision repair pathway in the mitochondria; targeting and overexpressing N-methylpurine DNA glycosylase in mitochondria leads to enhanced cell killing. Cancer Res 63:608-15
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Roth, Timothy J; Xu, Yi; Luo, Meihua et al. (2003) Human-yeast chimeric repair protein protects mammalian cells against alkylating agents: enhancement of MGMT protection. Cancer Gene Ther 10:603-10
Dobson, Allison W; Grishko, Valentina; LeDoux, Susan P et al. (2002) Enhanced mtDNA repair capacity protects pulmonary artery endothelial cells from oxidant-mediated death. Am J Physiol Lung Cell Mol Physiol 283:L205-10
Kelley, M R; Cheng, L; Foster, R et al. (2001) Elevated and altered expression of the multifunctional DNA base excision repair and redox enzyme Ape1/ref-1 in prostate cancer. Clin Cancer Res 7:824-30
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Robertson, K A; Bullock, H A; Xu, Y et al. (2001) Altered expression of Ape1/ref-1 in germ cell tumors and overexpression in NT2 cells confers resistance to bleomycin and radiation. Cancer Res 61:2220-5
Tell, G; Crivellato, E; Pines, A et al. (2001) Mitochondrial localization of APE/Ref-1 in thyroid cells. Mutat Res 485:143-52
Schindl, M; Oberhuber, G; Pichlbauer, E G et al. (2001) DNA repair-redox enzyme apurinic endonuclease in cervical cancer: evaluation of redox control of HIF-1alpha and prognostic significance. Int J Oncol 19:799-802

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