Dual-function 2-nitroimidazoles as hypoxic cell radiosensitizers and bioreductive cytotoxins: In vivo evaluation in KHT murine sarcomas

Journal Article · Mon Oct 01 00:00:00 EDT 1990 · Radiation Research; (USA)

DOI:https://doi.org/10.2307/3577675· OSTI ID:6167404

Cole, S; Stratford, I J; Adams, G E; Fielden, E M; Jenkins, T C ^[1]

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1. Medical Research Council, Didcot, Oxon (England)

The efficacies of a series of potential prodrugs of RSU-1069 and its alkyl-aziridine analogues were assessed. These 1-(2-haloethylamino)-3-(2-nitro-1-imidazolyl)-2-propanol compounds were designed to cyclize in vivo to generate 2-nitro-imidazoles with aziridine (RSU-1069) or alkyl-substituted aziridine (RSU-1164, RB-7040, or RSU-1150) functions. Maximum tolerated single, intraperitoneal doses (MTD) were determined in C3H/He mice bearing subcutaneous KHT sarcomas, and a drug dose-response relationship for radiosensitization was established for each compound administered at the optimum time (45-60 min) before local irradiation of tumors with a 10-Gy dose of X-rays. The potentials of the compounds as bioreductive cytotoxins were studied by administering them immediately after irradiation. Tumor cell survival was measured 18-24 h after treatment in an in vitro soft agar clonogenic assay. Results of toxicity, radiosensitization, and bioreductive cytotoxicity assays for each of the prodrugs (RB-6171, RB-6172, RB-6173, RB-6174, and RB-6175) of the alkyl-substituted aziridines were entirely consistent with complete conversion to their respective target compounds. For example, RB-6171 (the prodrug form of RSU-1164) was only about four times less efficient than RSU-1069 as a radiosensitizer and bioreductive cytotoxin but had an MTD 7.5 times higher. In contrast, prodrugs of RSU-1069 (RB-6144 and RB-6145) were two- to threefold less toxic than their expected product. RB-6144 was a poor radiosensitizer and bioreductive agent compared with RSU-1069 and was similar to RB-6170, a nonalkylating nitroimidazole. This is consistent with the observation that there is limited conversion of RB-6144 to RSU-1069 in vitro. However, radiosensitization and bioreductive cytotoxicity produced by RB-6145 were only slightly less than the effects produced by RSU-1069.

• OSTI ID: 6167404
• Journal Information: Radiation Research; (USA), Vol. 124:1 Suppl; 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.
62 RADIOLOGY AND NUCLEAR MEDICINE
RADIOSENSITIZERS
TOXICITY
SARCOMAS
COMBINED THERAPY
ANTINEOPLASTIC DRUGS
DOSE-RESPONSE RELATIONSHIPS
EXPERIMENTAL NEOPLASMS
MICE
RADIATION DOSES
RADIOSENSITIVITY EFFECTS
X RADIATION
ANIMALS
DISEASES
DOSES
DRUGS
ELECTROMAGNETIC RADIATION
IONIZING RADIATIONS
MAMMALS
NEOPLASMS
RADIATIONS
RODENTS
THERAPY
VERTEBRATES
560152* - Radiation Effects on Animals- Animals
550603 - Medicine- External Radiation in Therapy- (1980-)