XPC is essential for nucleotide excision repair of zidovudine-induced DNA damage in human hepatoma cells
- Division of Biochemical Toxicology, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR 72079 (United States)
- Division of Personalized Nutrition and Medicine, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR 72079 (United States)
Zidovudine (3'-azido-3'-dexoythymidine, AZT), a nucleoside reverse transcriptase inhibitor, can be incorporated into DNA and cause DNA damage. The mechanisms underlying the repair of AZT-induced DNA damage are unknown. To investigate the pathways involved in the recognition and repair of AZT-induced DNA damage, human hepatoma HepG2 cells were incubated with AZT for 2 weeks and the expression of DNA damage signaling pathways was determined using a pathway-based real-time PCR array. Compared to control cultures, damaged DNA binding and nucleotide excision repair (NER) pathways showed significantly increased gene expression. Further analysis indicated that AZT treatment increased the expression of genes associated with NER, including XPC, XPA, RPA1, GTF2H1, and ERCC1. Western blot analysis demonstrated that the protein levels of XPC and GTF2H1 were also significantly up-regulated. To explore further the function of XPC in the repair of AZT-induced DNA damage, XPC expression was stably knocked down by 71% using short hairpin RNA interference. In the XPC knocked-down cells, 100 {mu}M AZT treatment significantly increased [{sup 3}H]AZT incorporation into DNA, decreased the total number of viable cells, increased the release of lactate dehydrogenase, induced apoptosis, and caused a more extensive G2/M cell cycle arrest when compared to non-transfected HepG2 cells or HepG2 cells transfected with a scrambled short hairpin RNA sequence. Overall, these data indicate that XPC plays an essential role in the NER repair of AZT-induced DNA damage.
- OSTI ID:
- 21535249
- Journal Information:
- Toxicology and Applied Pharmacology, Vol. 251, Issue 2; Other Information: DOI: 10.1016/j.taap.2010.12.009; PII: S0041-008X(10)00466-7; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0041-008X
- Country of Publication:
- United States
- Language:
- English
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APOPTOSIS
CELL CYCLE
DNA
DNA DAMAGES
EXCISION REPAIR
GENES
HEPATOMAS
HUMAN POPULATIONS
LACTATE DEHYDROGENASE
NUCLEOSIDES
POLYMERASE CHAIN REACTION
RNA
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CARCINOMAS
DISEASES
DNA REPAIR
ENZYMES
GENE AMPLIFICATION
HEMIACETAL DEHYDROGENASES
NEOPLASMS
NUCLEIC ACIDS
NUCLEOTIDES
ORGANIC COMPOUNDS
OXIDOREDUCTASES
POPULATIONS
PROTEINS
REPAIR
RIBOSIDES