Relationship between radiosensitivity and metallothionein content in clones from a mouse squamous cell carcinoma
- Tokyo Medical and Dental Univ. (Japan)
The relationship between intrinsic radiosensitivity and metallothionein (MT) level in several clones isolated from a mouse squamous cell carcinoma was studied. Dose-survival curves for exponentially growing cells assayed by the soft-agar colony method were fitted to the linear-quadratic model by the least-squares method. Intrinsic radiosensitivity was expressed as the mean inactivation dose (D) calculated by the parameters alpha and beta. The D of the clones ranged from 1.6 to 3.9 Gy. A significant negative correlation was obtained between individual D and MT levels determined by the 203Hg-binding assay when expressed as MT content per cell; however, no correlation was obtained when the levels were expressed as MT content per unit cellular volume. The D of the parent cell line MSCC was 2.0 Gy, and that of the most radioresistant clone R1 was 3.9 Gy. Metallothionein content was 315 and 37 Hg-bound pmol/10(6) cells for MSCC and R1 cells, respectively, and thus D was not positively correlated with the level of MT. Metallothionein content of MSCC and R1 cells was elevated to 2304 and 854 Hg-bound pmol/10(6) cells, respectively, by cadmium treatment. Both MSCC and R1 cells with elevated MT content became more resistant to cadmium toxicity. However, the D's of the two cell lines were identical to those of the untreated controls despite the elevated MT content. These results suggest that, at least in this tumor, the endogenous MT level is not a major factor in determining intrinsic radiosensitivity of aerated cells.
- OSTI ID:
- 6616239
- Journal Information:
- Radiation Research; (USA), Journal Name: Radiation Research; (USA) Vol. 123:2; ISSN RAREA; ISSN 0033-7587
- Country of Publication:
- United States
- Language:
- English
Similar Records
Intracellular metallothionein concentration and the rate of zinc or cadmium influx and MT mRNA accumulation in a CHO Cd sup r variant
Metallothionein gene expression in peripheral lymphocytes and renal dysfunction in a population environmentally exposed to cadmium
Related Subjects
560120* -- Radiation Effects on Biochemicals
Cells
& Tissue Culture
560300 -- Chemicals Metabolism & Toxicology
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOASSAY
BIOSYNTHESIS
CADMIUM
CARCINOMAS
CELL CULTURES
CLONE CELLS
DAYS LIVING RADIOISOTOPES
DISEASES
DOSE-RESPONSE RELATIONSHIPS
ELEMENTS
EVEN-ODD NUCLEI
HEAVY NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
MERCURY 203
MERCURY ISOTOPES
METALLOPROTEINS
METALLOTHIONEIN
METALS
MICE
NEOPLASMS
NUCLEI
ORGANIC COMPOUNDS
PROTEINS
RADIOISOTOPES
RADIOSENSITIVITY
RODENTS
SURVIVAL CURVES
SYNTHESIS
TOXICITY
TRACER TECHNIQUES
TUMOR CELLS
VERTEBRATES