title: Vitamin C augments chemotherapeutic response of cervical carcinoma HeLa cells by stabilizing P53.
abstract: Human Papilloma Virus (HPV) is associated in most instances with cervical cancer. The HPV oncoproteins target P53 protein for degradation, leading to deregulation of cell cycle. We investigated whether stabilization of P53 in cervical cancer cells, by downregulating HPV transcription would restore the apoptotic ability of these cells. Our findings show that vitamin C downregulates the redox sensitive transcription factor AP-1 and decreases one of its transcription targets HPV E6, and stabilizes P53. This was associated with an increase in Bax and decrease in Bcl-2 and telomerase activity. Accumulation of P53 and its target gene bax then sensitized HeLa cells to cell-cycle arrest, cell death/apoptosis induced by cisplatin, and etoposide. Increasing drug sensitivity of cervical carcinoma cells by stabilizing P53 using vitamin C is a novel approach and has potential clinical relevance.
authors.affiliation: Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: V G
authors.initials: VG
authors.lastname: Reddy
authors.forename: N
authors.initials: N
authors.lastname: Khanna
authors.forename: N
authors.initials: N
authors.lastname: Singh
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage*; D017209:Apoptosis / Q000187:drug effects; D001205:Ascorbic Acid / Q000008:administration & dosage*; D002453:Cell Cycle / Q000187:drug effects; D002945:Cisplatin / Q000008:administration & dosage; D015536:Down-Regulation / Q000187:drug effects; D004355:Drug Stability; D004357:Drug Synergism; D005047:Etoposide / Q000008:administration & dosage; D005260:Female; D006367:HeLa Cells; D006801:Humans; D009856:Oncogene Proteins, Viral / Q000235:genetics / Q000378:metabolism; D027383:Papillomaviridae / Q000187:drug effects / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D019098:Telomerase / Q000037:antagonists & inhibitors; D014158:Transcription, Genetic / Q000187:drug effects; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D002583:Uterine Cervical Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism* / Q000821:virology; D051028:bcl-2-Associated X Protein
chemical_list: C494826:BAX protein, human; D009856:Oncogene Proteins, Viral; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D005047:Etoposide; D019098:Telomerase; D001205:Ascorbic Acid; D002945:Cisplatin