Radiation induction of drug resistance in RIF-1 tumors and tumor cells. Radiat Res 1989 Nov;120(2):251-66
Date
11/01/1989Pubmed ID
2616741Scopus ID
2-s2.0-0024330331 (requires institutional sign-in at Scopus site) 17 CitationsAbstract
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.
Author List
Hopwood LE, Moulder JEMESH terms used to index this publication - Major topics in bold
AnimalsAntineoplastic Agents
Cell Line
Combined Modality Therapy
Drug Resistance
In Vitro Techniques
Mice
Mice, Inbred C3H
Neoplasm Transplantation
Neoplasms, Experimental
Tumor Cells, Cultured
