The effect of single versus double-strand substitution on halogenated pyrimidine-induced radiosensitization and DNA strand breakage in human tumor cells. 1990

T S Lawrence, and M A Davis, and J Maybaum, and P L Stetson, and W D Ensminger
Department of Radiation Oncology, University of Michigan Medical Center, Ann Arbor 48109.

To better understand the mechanism underlying halogenated pyrimidine-mediated cytotoxicity and radiosensitization in human tumor cells, a study was undertaken to determine the influence of unifilar (one DNA strand) versus bifilar (both DNA strands) substitution of thymidine by the halogenated bases 5-iodo-2'-deoxyuridine (IdUrd) and 5-bromo-2'-deoxyuridine (BrdUrd) in HT29 human colon cancer cells. Unifilar labeling was obtained by incubating cells with IdUrd or BrdUrd for one doubling time. Cells were incubated for at least three doublings to approximate bifilar substitution. Only IdUrd caused significant cytotoxicity, which correlated with incorporation into DNA. Both BrdUrd and IdUrd were potent radiosensitizers. Radiosensitization was linearly correlated with incorporation of both bases regardless of the number of strands in which thymidine was substituted. In contrast, the relationship between radiosensitization and DNA double-strand breakage was critically dependent in the case of IdUrd, but not for BrdUrd, on whether substitution was unifilar or bifilar. These findings suggest that incorporation is the best predictor of radiation sensitivity, and that the induction of DNA double-strand breaks alone does not account for radiosensitization mediated by halogenated pyrimidines in these human tumor cells.

UI MeSH Term Description Entries
D007065 Idoxuridine An analog of DEOXYURIDINE that inhibits viral DNA synthesis. The drug is used as an antiviral agent. 5-Iodo-2'-deoxyuridine,IUdR,Iododeoxyuridine,5-Iododeoxyuridine,Allergan 211,Herplex Liquifilm,Idoxuridine, 123I-Labeled,Idoxuridine, 125I-Labeled,Idoxuridine, 131I-Labeled,Idoxuridine, 3H-Labeled,Idoxuridine, Radical Ion (+1),Idoxuridine, Radical Ion (1-),Kerecide,NSC-39661,Oftan-IDU,SK&F-14287,Stoxil,123I-Labeled Idoxuridine,125I-Labeled Idoxuridine,131I-Labeled Idoxuridine,3H-Labeled Idoxuridine,5 Iodo 2' deoxyuridine,5 Iododeoxyuridine,Idoxuridine, 123I Labeled,Idoxuridine, 125I Labeled,Idoxuridine, 131I Labeled,Idoxuridine, 3H Labeled,Liquifilm, Herplex,NSC 39661,NSC39661,Oftan IDU,OftanIDU
D011838 Radiation-Sensitizing Agents Drugs used to potentiate the effectiveness of radiation therapy in destroying unwanted cells. Radiation Sensitizer,Radiosensitizing Agent,Radiosensitizing Agents,Agents, Radiation-Sensitizing,Radiation Sensitizers,Radiation Sensitizing Agents,Radiation-Sensitizing Drugs,Radiation-Sensitizing Effect,Radiation-Sensitizing Effects,Radiosensitizing Drugs,Radiosensitizing Effect,Radiosensitizing Effects,Agent, Radiosensitizing,Agents, Radiation Sensitizing,Agents, Radiosensitizing,Drugs, Radiation-Sensitizing,Drugs, Radiosensitizing,Effect, Radiation-Sensitizing,Effect, Radiosensitizing,Effects, Radiation-Sensitizing,Effects, Radiosensitizing,Radiation Sensitizing Drugs,Radiation Sensitizing Effect,Radiation Sensitizing Effects,Sensitizer, Radiation,Sensitizers, Radiation,Sensitizing Agents, Radiation
D001973 Bromodeoxyuridine A nucleoside that substitutes for thymidine in DNA and thus acts as an antimetabolite. It causes breaks in chromosomes and has been proposed as an antiviral and antineoplastic agent. It has been given orphan drug status for use in the treatment of primary brain tumors. BUdR,BrdU,Bromouracil Deoxyriboside,Broxuridine,5-Bromo-2'-deoxyuridine,5-Bromodeoxyuridine,NSC-38297,5 Bromo 2' deoxyuridine,5 Bromodeoxyuridine,Deoxyriboside, Bromouracil
D002460 Cell Line Established cell cultures that have the potential to propagate indefinitely. Cell Lines,Line, Cell,Lines, Cell
D002470 Cell Survival The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability. Cell Viability,Cell Viabilities,Survival, Cell,Viabilities, Cell,Viability, Cell
D003110 Colonic Neoplasms Tumors or cancer of the COLON. Cancer of Colon,Colon Adenocarcinoma,Colon Cancer,Cancer of the Colon,Colon Neoplasms,Colonic Cancer,Neoplasms, Colonic,Adenocarcinoma, Colon,Adenocarcinomas, Colon,Cancer, Colon,Cancer, Colonic,Cancers, Colon,Cancers, Colonic,Colon Adenocarcinomas,Colon Cancers,Colon Neoplasm,Colonic Cancers,Colonic Neoplasm,Neoplasm, Colon,Neoplasm, Colonic,Neoplasms, Colon
D004247 DNA A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine). DNA, Double-Stranded,Deoxyribonucleic Acid,ds-DNA,DNA, Double Stranded,Double-Stranded DNA,ds DNA
D004249 DNA Damage Injuries to DNA that introduce deviations from its normal, intact structure and which may, if left unrepaired, result in a MUTATION or a block of DNA REPLICATION. These deviations may be caused by physical or chemical agents and occur by natural or unnatural, introduced circumstances. They include the introduction of illegitimate bases during replication or by deamination or other modification of bases; the loss of a base from the DNA backbone leaving an abasic site; single-strand breaks; double strand breaks; and intrastrand (PYRIMIDINE DIMERS) or interstrand crosslinking. Damage can often be repaired (DNA REPAIR). If the damage is extensive, it can induce APOPTOSIS. DNA Injury,DNA Lesion,DNA Lesions,Genotoxic Stress,Stress, Genotoxic,Injury, DNA,DNA Injuries
D004273 DNA, Neoplasm DNA present in neoplastic tissue. Neoplasm DNA
D004277 DNA, Single-Stranded A single chain of deoxyribonucleotides that occurs in some bacteria and viruses. It usually exists as a covalently closed circle. Single-Stranded DNA,DNA, Single Stranded,Single Stranded DNA

Related Publications

T S Lawrence, and M A Davis, and J Maybaum, and P L Stetson, and W D Ensminger
November 2002, International journal of radiation biology,
T S Lawrence, and M A Davis, and J Maybaum, and P L Stetson, and W D Ensminger
June 1993, Radiation research,
T S Lawrence, and M A Davis, and J Maybaum, and P L Stetson, and W D Ensminger
November 1993, International journal of radiation biology,
T S Lawrence, and M A Davis, and J Maybaum, and P L Stetson, and W D Ensminger
December 1990, International journal of radiation oncology, biology, physics,
T S Lawrence, and M A Davis, and J Maybaum, and P L Stetson, and W D Ensminger
January 1996, Cancer chemotherapy and pharmacology,
T S Lawrence, and M A Davis, and J Maybaum, and P L Stetson, and W D Ensminger
January 2011, Cell cycle (Georgetown, Tex.),
T S Lawrence, and M A Davis, and J Maybaum, and P L Stetson, and W D Ensminger
May 1994, Radiation research,
T S Lawrence, and M A Davis, and J Maybaum, and P L Stetson, and W D Ensminger
July 1985, Cancer research,
T S Lawrence, and M A Davis, and J Maybaum, and P L Stetson, and W D Ensminger
June 1997, Free radical research,
T S Lawrence, and M A Davis, and J Maybaum, and P L Stetson, and W D Ensminger
January 1992, Radiation and environmental biophysics,
Copied contents to your clipboard!