Excision and postreplication DNA repair capacities, enhanced transformation, and survival of Syrian hamster embryo cells irradiated by ultraviolet light

Journal Article · Sat Mar 01 04:00:00 EST 1980 · Cancer Res.; (United States)

OSTI ID:5871474

Doniger, J; DiPaolo, J A

The frequency of ultraviolet light induced neoplastic transformation of Syrian hamster embryo cells is enhanced 3- to 10-fold when the cells are first treated with either x-irradiation or with methyl methanesulfonate. Maximum enhancement occurs when the interval between the two treatments is 48 h. The relevance of uv-induced transformation to neoplasia is confirmed because the transformation to neoplasia is confirmed because the transformants produce tumors when injected into nude mice. Excision and postreplication DNA repair were studied to determine whether the enhanced transformations were associated with either of these repair mechanisms. Independent of x-ray or of methyl methanesulfonate pretreatment, approximately 25% of the pyrimidine dimers are excised within 24 h in cells irradiated with uv with 3 J/sq m. During this period, more than 70% of the genome of cells irradiated with uv has been replicated. Postreplication repair is measured by the time required to chase pulse-labeled nascent DNA strands to parental-sided DNA. Regardless of pretreatment, 1 and 3 h are required for pulse-labeled DNA in control and irradiated cells, respectively, to reach parental size. Therefore, no correlation is found between a change in the rate of excision or postreplication repair and enhancement of transformation. Relative to control cloning efficiency, the survival of HEC contain more than 10(5) pyrimidine dimers/genome. The level of survival is similar to the survival of human skin fibroblasts which excise pyrimidine dimers four to five times as efficiently. Moreover, postreplication repair cannot account for the ability of these cells to survive because it is three times slower than in human fibroblasts. Therefore, other repair mechanisms must be responsible for HEC survival and transformation.

• OSTI ID: 5871474
• Journal Information: Cancer Res.; (United States), Journal Name: Cancer Res.; (United States) Vol. 40:3; ISSN CNREA
• Country of Publication: United States
• Language: English

Related Subjects

560111* -- Radiation Effects on Biochemicals-- In Vitro-- (-1987)
560121 -- Radiation Effects on Cells-- External Source-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CELL CULTURES
COMPARATIVE EVALUATIONS
DNA
DNA REPLICATION
ELECTROMAGNETIC RADIATION
EMBRYOS
ESTERS
HAMSTERS
IONIZING RADIATIONS
MAMMALS
METHYL METHANESULFONATE
MUTAGENS
NUCLEIC ACID REPLICATION
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
RADIATION EFFECTS
RADIATIONS
RADIOSENSITIVITY EFFECTS
RECOVERY
REPAIR
RODENTS
SULFONIC ACID ESTERS
SURVIVAL CURVES
TIME DEPENDENCE
ULTRAVIOLET RADIATION
VERTEBRATES
X RADIATION