Radiation induction of drug resistance in RIF-1 tumors and tumor cells

Journal Article · Wed Nov 01 00:00:00 EST 1989 · Radiation Research; (USA)

DOI:https://doi.org/10.2307/3577712· OSTI ID:6992663

Hopwood, L E; Moulder, J E ^[1]

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1. Medical College of Wisconsin, Milwaukee (USA)

The RIF-1 tumor cell line contains a small number of cells (1-20 per 10(6) cells) that are resistant to various single antineoplastic drugs, including 5-fluorouracil (5FU), methotrexate (MTX), and adriamycin (ADR). For 5FU the frequency of drug resistance is lower for tumor-derived cells than for cells from cell culture; for MTX the reverse is true, and for ADR there is no difference. In vitro irradiation at 5 Gy significantly increased the frequency of drug-resistant cells for 5FU, MTX, and ADR. In vivo irradiation at 3 Gy significantly increased the frequency of drug-resistant cells for 5FU and MTX, but not for ADR. The absolute risk for in vitro induction of MTX, 5FU, and ADR resistance, and for in vivo induction of 5FU resistance, was 1-3 per 10(6) cells per Gy; but the absolute risk for in vivo induction of MTX resistance was 54 per 10(6) cells per Gy. The frequency of drug-resistant cells among individual untreated tumors was highly variable; among individual irradiated tumors the frequency of drug-resistant cells was significantly less variable. These studies provide supporting data for models of the development of tumor drug resistance, and imply that some of the drug resistance seen when chemotherapy follows radiotherapy may be due to radiation-induced drug resistance.

• OSTI ID: 6992663
• Journal Information: Radiation Research; (USA), Vol. 120:2; ISSN 0033-7587
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANTINEOPLASTIC DRUGS
BIOLOGICAL EFFECTS
TUMOR CELLS
BIOLOGICAL RADIATION EFFECTS
COMBINED THERAPY
EXPERIMENTAL NEOPLASMS
IN VITRO
MICE
ANIMAL CELLS
ANIMALS
DRUGS
MAMMALS
RADIATION EFFECTS
RODENTS
THERAPY
VERTEBRATES
560120* - Radiation Effects on Biochemicals
Cells
& Tissue Culture