A novel fluorometric oligonucleotide assay to measure O( 6)-methylguanine DNA methyltransferase, methylpurine DNA glycosylase, 8-oxoguanine DNA glycosylase and abasic endonuclease activities: DNA repair status in human breast carcinoma cells overexpressing methylpurine DNA glycosylase.

DNA repair status plays a major role in mutagenesis, carcinogenesis and resistance to genotoxic agents. Because DNA repair processes involve multiple enzymatic steps, understanding cellular DNA repair status has required several assay procedures. We have developed a novel in vitro assay that allows quantitative measurement of alkylation repair via O(6)-methylguanine DNA methyltransferase (MGMT) and base excision repair (BER) involving methylpurine DNA glycosylase (MPG), human 8-oxoguanine DNA glycosylase (hOGG1) and yeast and human abasic endonuclease (APN1 and APE/ref-1, respectively) from a single cell extract.

Protection of mammalian cells against chemotherapeutic agents thiotepa, 1,3-N,N'-bis(2-chloroethyl)-N-nitrosourea, and mafosfamide using the DNA base excision repair genes Fpg and alpha-hOgg1: implications for protective gene therapy applications.

Chemotherapeutic agents used in the treatment of cancer often lead to dose-limiting bone marrow suppression and may initiate secondary leukemia. N,N',N"-triethylenethiophosphoramide (thiotepa), a polyfunctional alkylating agent, is used in the treatment of breast, ovarian, and bladder carcinomas and is also being tested for efficacy in the treatment of central nervous system tumors. Thiotepa produces ring-opened bases such as formamidopyrimidine and 7-methyl-formamidopyrimidine, which can be recognized and repaired by the formamidopyrimidine glycosylase/AP lyase (Fpg) enzyme of Escherichia coli.

Going APE over ref-1.

The DNA base excision repair (BER) pathway is responsible for the repair of cellular alkylation and oxidative DNA damage. A crucial and the second step in the BER pathway involves the cleavage of baseless sites in DNA by an AP endonuclease. The major AP endonuclease in mammalian cells is Ape1/ref-1.

DNA repair and gene therapy: implications for translational uses.

Gene therapy has been proposed to have implications in the treatment of cancer. By genetically manipulating the hematopoietic stem cell compartment with genes that confer resistance to chemotherapeutic agents, the dose escalation that is necessary to effectively treat the cancers could potentially be achieved. DNA repair genes are some of the potential candidates to confer increased resistance to chemotherapeutic agents.