Radiosensitization of GL261 glioma cells by tetraiodothyroacetic acid (tetrac).

Full Abstract

We studied effects of tetrac (tetraiodothyroacetic acid) on survival of GL261, a murine brain tumor cell line, following single doses of 250 kVp x-rays and on repair of damage (sublethal and potentially lethal damage repair; SLDR, PLDR) in both exponential and plateau phase cells. Cells were exposed to 2 muM tetrac (1 h at 37 degrees C) prior to x-irradiation. At varying times after irradiation, cells were re-plated in medium without tetrac. Two weeks later, colonies were counted and results analyzed using either the linear-quadratic (LQ) or single-hit, multitarget (SHMT) formalisms. Tetrac sensitized both exponential and plateau phase cells to x-irradiation, as shown by a decrease in the quasi-threshold dose (Dq), leading to an average tetrac enhancement factor (ratio of SF2 values) of 2.5. Tetrac reduced SLDR in exponential cells by a factor of 1.8. In plateau phase cells there was little expression of SLDR, but tetrac produced additional cell killing at 1-4 h after the first dose. For PLDR expression in exponential cells, tetrac inhibited PLDR by a factor of 1.9, and in plateau phase cells, tetrac decreased PLDR expression by a factor of 3.4. These data show that the decreased Dq value seen after single doses of x-rays with tetrac treatment is also accompanied by a significant decrease in recovery from sublethal and potentially lethal damage.

Author information

Author/s: Hercbergs, Aleck (A); Davis, Paul J (PJ); Davis, Faith B (FB); Ciesielski, Michael J (MJ); Leith, John T (JT);

Affiliation: The Cleveland Clinic, Department of Radiation Oncology, Cleveland, OH 44195, USA. hercbergs(-atsign-)gmail.com

Journal and publication information

Publication Type: Journal Article

Journal: Cell cycle (Georgetown, Tex.) (Cell Cycle), published in United States. (Language: eng)

Reference: 2009-Aug; vol 8 (issue 16) : pp 2586-91

Dates: Created 2009/08/17; Completed 2009/10/27;

PMID: 19597333, status: MEDLINE (last retrieval date: 10/27/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

External Links for this article
(including full text providers, if available):

Click Electronic Full-text Provider Links to see options for finding the electronic full text links to this article. Note there may be a subscription or fee required for access to the full text. See our FAQ for information on finding FREE full text articles.

This article may also be located in paper journal collections available in many libraries. Use the Journal and Publication Information above to find the full article.