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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2006-9-13
pubmed:abstractText
Single high dose rate irradiation of 4 Gy in SW-1573 cells, derived from non-small cell lung cancer, led to increased activities of deoxycytidine kinase (dCK) and thymidine kinase 1 and 2 (TK1 and 2). The activity of dCK increased by approximately 30% between 1 and 5 h after irradiation, after which the activity returned to the level of control cells by 8 h after irradiation. TK1 activity also increased by 30-50% between 1 and 6 h after irradiation. The decline to normal levels of dCK concurred with a further increase in the activity of TK1, 8 h after irradiation. TK2 activity was below control levels during the first 4 h after irradiation but rose 3-fold at 8 and 16 h after treatment. The activities of TK1 and TK2 had returned to approximate control levels 24 h after irradiation. The observation that mitochondrial TK2 activity increased to a very high level after irradiation may indicate that the activity of this enzyme is not only important for the damage to mitochondrial DNA, the increased activity may also be instrumental for repair of damage to nuclear DNA. We presume that the increase in activity of TK1 after irradiation is limited to cells in S-phase. Recruitment of cells into S-phase, to replace cells killed by irradiation, is probably too slow to offer an explanation for the enhanced activity of TK1 8 h after irradiation. The increase in activity of both dCK, and TK1 and 2 might be involved in an adaptive response of the cells to radiation by facilitation of DNA repair. The expression of protein kinase C (PKC) decreased during the first 5 h after irradiation. At 5 h after irradiation the level of expression had decreased by >50%. The decrease in PKC expression is concurrent with the increase in dCK activity. This suggests a role of PKC in the signal transduction from DNA damage to the increase in activity of enzymes instrumental in DNA repair.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
1021-335X
pubmed:author
pubmed:issnType
Print
pubmed:volume
16
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
901-5
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Time course of enhanced activity of deoxycytidine kinase and thymidine kinase 1 and 2 in cultured human squamous lung carcinoma cells, SW-1573, induced by gamma-irradiation.
pubmed:affiliation
Department of Radiotherapy, Academic Medical Center, University of Amsterdam, P.O. Box 22700, 1100 DE Amsterdam, The Netherlands. j.haveman@amc.uva.nl
pubmed:publicationType
Journal Article