title: Cigarette smoke condensate-induced oxidative DNA damage and its removal in human cervical cancer cells.
abstract: Exposure to cigarette smoke is well documented to increase oxidative stress and could account for higher risk of cervical cancer in smokers. Cervical pre-cancerous lesions that are initiated by human papillomavirus (HPV) infection generally regress in the absence of known risk factors such as smoking. 8-oxodeoxyguanosine (8-oxodG) is a highly mutagenic oxidative DNA lesion that is formed by the oxidation of deoxyguanosine. In the present study, we examined: a) the effect of cigarette smoke condensate (CSC) on 8-oxodG formation in and its removal from HPV-transfected (ECT1/E6 E7), HPV-positive (CaSki) and HPV-negative (C33A) human cervical cancer cells, and b) the cell cycle progression and apoptosis in CSC-treated ECT1/E6 E7 cells. CSC induced 8-oxodG in a dose- (p=0.03) and time (p=0.002)-dependent fashion in ECT1/E6 E7 cells as determined by flow cytometry. A 2.4-fold higher level of 8-oxodG was observed in HPV-positive compared with HPV-negative cells. However, 8-oxodG lesions were almost completely removed 72 h post-exposure in all cell lines as determined by ImageStream analysis. This observation correlates with the 2- and 5-fold increase in the p53 levels in ECT1/E6 E7 and CaSki cells with no significant change in C33A cells. We conclude that: a) cigarette smoke constituents induce oxidative stress with higher burden in HPV-positive cervical cancer cells and b) the significant increase observed in p53 levels in wild-type cervical cells (ECT1/E6 E7 and CaSki) may be attributed to the p53-dependent DNA repair pathway while a p53-independent pathway in C33A cells cannot be ruled out.
authors: Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY 40202 , USA.
authors: Afsoon
authors: A
authors: Moktar
authors: Rajesh
authors: R
authors: Singh
authors: Manicka V
authors: MV
authors: Vadhanam
authors: Srivani
authors: S
authors: Ravoori
authors: James W
authors: JW
authors: Lillard
authors: C Gary
authors: CG
authors: Gairola
authors: Ramesh C
authors: RC
authors: Gupta
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D017209:Apoptosis / Q000235:genetics; D002453:Cell Cycle / Q000235:genetics; D002461:Cell Line, Transformed; D045744:Cell Line, Tumor; D002472:Cell Transformation, Viral; D004249:DNA Damage; D004260:DNA Repair / Q000235:genetics; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000096:biosynthesis; D005260:Female; D016158:Genes, p53 / Q000235:genetics; D052162:Human papillomavirus 16 / Q000502:physiology; D006801:Humans; D018384:Oxidative Stress / Q000235:genetics*; D030361:Papillomavirus Infections / Q000150:complications / Q000378:metabolism; D012307:Risk Factors; D012906:Smoke / Q000009:adverse effects*; D014026:Nicotiana; D002583:Uterine Cervical Neoplasms / Q000209:etiology* / Q000235:genetics / Q000473:pathology / Q000821:virology
chemical_list: D012906:Smoke; D000080242:8-Hydroxy-2'-Deoxyguanosine; D003849:Deoxyguanosine