Effect of tumor type, size, and endpoint on tumor radioprotection by WR-2721. [Mice]

Journal Article · Sun Jan 01 04:00:00 EST 1984 · Int. J. Radiat. Oncol., Biol. Phys.; (United States)

DOI:https://doi.org/10.1016/0360-3016(84)90410-3· OSTI ID:6847473

Milas, L; Hunter, N; Ito, H; Peters, L J

Experiments are reported showing that the degree of tumor radioprotection afforded by WR-2721 varies with the type of tumor and assay endpoint, and that for a given tumor system, microaggregates are protected better than larger cell masses. The tumors used were a methylcholanthrene-induced fibrosarcoma (FSa), and two tumors of spontaneous origin, another fibrosarcoma (NFSa), and a mammary carcinoma (MCa-4), all syngeneic to C/sub 3/Hf/Kam mice. WR-2721 was given in a dose of 400 mg/kg 30 minutes before irradiation in all experiments. In TCD/sub 50/ assays, WR-2721 protected 5 mm diameter and impalpable 3 day-old transplants of 5 x 10/sup 5/ FSa cells growing in the leg by factors of 1.11 and 1.13, respectively. Using the tumor latency endpoint, 3 day-old s.c. transplants of 10/sup 3/FSa in the abdominal wall were protected by a factor of 1.27, a degree of protection similar to that reported earlier for sterilization of lung micrometastases of the same tumor. MCa-4 tumors growing in the leg were protected better than FSa in TCD/sub 50/ assays with protection factors of 1.3 for 4 day-old transplants, 1.24 for 5mm tumors, and 1.23 for 8mm tumors. Using the lung micrometastasis assay, NFSa was protected by a factor of 1.22. This variability in protection with different tumor types, sizes, and assay endpoints is discussed in terms of drug delivery and uptake, and also in relation to the influence of tumor hypoxia on the radioprotective ability of WR-2721.

• Research Organization: Univ. of Texas, Houston
• OSTI ID: 6847473
• Journal Information: Int. J. Radiat. Oncol., Biol. Phys.; (United States), Journal Name: Int. J. Radiat. Oncol., Biol. Phys.; (United States) Vol. 12:1; ISSN IOBPD
• Country of Publication: United States
• Language: English

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62 RADIOLOGY AND NUCLEAR MEDICINE
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
ANOXIA
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
CARCINOMAS
DISEASES
EXPERIMENTAL NEOPLASMS
MAMMALS
MEDICINE
MICE
NEOPLASMS
NUCLEAR MEDICINE
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
RADIATION EFFECTS
RADIOLOGY
RADIOSENSITIVITY EFFECTS
RADIOTHERAPY
RODENTS
SARCOMAS
SIZE
THERAPY
THIOLS
VERTEBRATES