skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Inhibition of topoisomerase II[alpha] activity in CHO K1 cells by 2-[(aminopropyl)amino]ethanethiol (WR-1065)

Abstract

The aminothiol 2-[(aminopropyl)amino]ethanethiol (WR-1065) is the active thiol of the clinically studied radioprotective agent S-2-(3-aminopropylamino)ethylphosphorothioic acid (WR-2721). WR-1065 is an effective radiation protector when it is administered 30 min prior to exposure of Chinese hamster ovary K1 cells to radiation (i.e., a dose modification factor of 1.4) at a concentration of 4 mM. Under these exposure conditions, topoisomerase (Topo) I and II[alpha] activities and associated protein contents were measured in cells of the K1 cell line using the DNA relaxation assay, the P4 unknotting assay and immunoblotting, respectively. WR-1065 was ineffective in modifying Topo I activity, but it did not reduce Topo II[alpha] activity by an average of 50%. The magnitude of Topo II[alpha] protein content however, was not affected by these exposure conditions. The effects on the cell cycle were monitored by the method of flow cytometry. Exposure of cells to 4 mM WR-1065 for up to 6 h resulted in a build-up of cells in the g[sub 2]/M-phase compartment. However, under these conditions and in contrast to Topo II inhibitors used in chemotherapy, WR-1065 is an effective radioprotective agent capable of protecting against both radiation-induced cell lethality and mutagenesis. One of several mechanisms of action attributed to aminothiolmore » compounds such as WR-1065 has been their ability to affect endogenous enzymatic reactions involved in DNA synthesis and repair and progression of cells through the phases of the cell cycle. These results are consistent with such a proposed mechanism and demonstrate in particular a modifying effect by WR-1065 on Topo II, which is involved in DNA synthesis. 54 refs., 5 figs., 2 tabs.« less

Authors:
 [1];  [2]; ;  [3]
  1. Argonne National Lab., IL (United States) Univ. of Chicago, IL (United States)
  2. Univ. of Illinois, Chicago, IL (United States)
  3. Argonne National Lab., IL (United States)
Publication Date:
OSTI Identifier:
6758717
DOE Contract Number:  
W-31109-ENG-38
Resource Type:
Journal Article
Journal Name:
Radiation Research; (United States)
Additional Journal Information:
Journal Volume: 138:1; Journal ID: ISSN 0033-7587
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.; CHO CELLS; BIOLOGICAL REPAIR; RADIATION INDUCED MUTANTS; RADIOPROTECTIVE SUBSTANCES; RESPONSE MODIFYING FACTORS; THIOLS; BIOCHEMICAL REACTION KINETICS; CELL CYCLE; CHEMOTHERAPY; DNA REPLICATION; ENZYME ACTIVITY; ANIMAL CELLS; BIOLOGICAL RECOVERY; DRUGS; KINETICS; MUTANTS; NUCLEIC ACID REPLICATION; ORGANIC COMPOUNDS; ORGANIC SULFUR COMPOUNDS; REACTION KINETICS; REPAIR; THERAPY; 550200* - Biochemistry; 560160 - Radionuclide Effects, Kinetics, & Toxicology

Citation Formats

Grdina, D J, Constantinou, A, Shigematsu, N, and Murley, J S. Inhibition of topoisomerase II[alpha] activity in CHO K1 cells by 2-[(aminopropyl)amino]ethanethiol (WR-1065). United States: N. p., 1994. Web. doi:10.2307/3578845.
Grdina, D J, Constantinou, A, Shigematsu, N, & Murley, J S. Inhibition of topoisomerase II[alpha] activity in CHO K1 cells by 2-[(aminopropyl)amino]ethanethiol (WR-1065). United States. https://doi.org/10.2307/3578845
Grdina, D J, Constantinou, A, Shigematsu, N, and Murley, J S. 1994. "Inhibition of topoisomerase II[alpha] activity in CHO K1 cells by 2-[(aminopropyl)amino]ethanethiol (WR-1065)". United States. https://doi.org/10.2307/3578845.
@article{osti_6758717,
title = {Inhibition of topoisomerase II[alpha] activity in CHO K1 cells by 2-[(aminopropyl)amino]ethanethiol (WR-1065)},
author = {Grdina, D J and Constantinou, A and Shigematsu, N and Murley, J S},
abstractNote = {The aminothiol 2-[(aminopropyl)amino]ethanethiol (WR-1065) is the active thiol of the clinically studied radioprotective agent S-2-(3-aminopropylamino)ethylphosphorothioic acid (WR-2721). WR-1065 is an effective radiation protector when it is administered 30 min prior to exposure of Chinese hamster ovary K1 cells to radiation (i.e., a dose modification factor of 1.4) at a concentration of 4 mM. Under these exposure conditions, topoisomerase (Topo) I and II[alpha] activities and associated protein contents were measured in cells of the K1 cell line using the DNA relaxation assay, the P4 unknotting assay and immunoblotting, respectively. WR-1065 was ineffective in modifying Topo I activity, but it did not reduce Topo II[alpha] activity by an average of 50%. The magnitude of Topo II[alpha] protein content however, was not affected by these exposure conditions. The effects on the cell cycle were monitored by the method of flow cytometry. Exposure of cells to 4 mM WR-1065 for up to 6 h resulted in a build-up of cells in the g[sub 2]/M-phase compartment. However, under these conditions and in contrast to Topo II inhibitors used in chemotherapy, WR-1065 is an effective radioprotective agent capable of protecting against both radiation-induced cell lethality and mutagenesis. One of several mechanisms of action attributed to aminothiol compounds such as WR-1065 has been their ability to affect endogenous enzymatic reactions involved in DNA synthesis and repair and progression of cells through the phases of the cell cycle. These results are consistent with such a proposed mechanism and demonstrate in particular a modifying effect by WR-1065 on Topo II, which is involved in DNA synthesis. 54 refs., 5 figs., 2 tabs.},
doi = {10.2307/3578845},
url = {https://www.osti.gov/biblio/6758717}, journal = {Radiation Research; (United States)},
issn = {0033-7587},
number = ,
volume = 138:1,
place = {United States},
year = {Fri Apr 01 00:00:00 EST 1994},
month = {Fri Apr 01 00:00:00 EST 1994}
}