title: Effects of cisplatin, 5-fluorouracil, and radiation on cell cycle regulation and apoptosis in the hypopharyngeal carcinoma cell line.
abstract: In head and neck cancer including hypopharyngeal cancer, cisplatin and 5-fluorouracil (5-FU) usually have been used as neoadjuvant chemotherapeutic agents. We investigated the effects of cisplatin, 5-FU and radiation on p53 protein expression and cell responses (cell cycle arrest and/or apoptosis) in the hypopharyngeal carcinoma cell line (PNUH-12; mutant type p53). PNUH-12 cells were treated with cisplatin, 5-FU and radiation. The changes in the cells were assessed by a cell cytotoxicity assay, Western blotting (p53 and p21(WAF1/CIP1) proteins), a DNA fragmentation assay, propidium iodide (PI) staining and DNA flow cytometry. The expression of p53 protein was increased after treatment with cisplatin and 5-FU, but not radiation. The expression of p21(WAF1/CIP1) protein was increased only after treatment with 5-FU, not cisplatin or radiation. With cisplatin and radiation, we observed apoptosis both by DNA fragmentation and PI staining and increased S phase in cisplatin and G2 phase in radiation by DNA flow cytometry. But, with 5-FU, we could not observe apoptosis by DNA fragmentation and PI stain but only an increased G1 phase by DNA flow cytometry. In PNUH-12, radiation induced p53-independent apoptosis and p21(WAF1/CIP1)-independent G2-phase cell cycle arrest. Cisplatin induced p53-dependent apoptosis and p21(WAF1/CIP1)-independent S-phase cell cycle arrest and 5-FU induced p53 and p21(WAF1/CIP1)-dependent G1-phase cell cycle arrest, not apoptosis. Cisplatin and 5-FU induced p53-dependent pathways, but radiation p53-independent pathway. The cell responses by cisplatin, 5-FU and radiation were all different pathways.
authors.affiliation: Department of Otolaryngology, College of Medicine, Pusan National University, Pusan, South Korea.
authors.forename: Byung-Joo
authors.initials: BJ
authors.lastname: Lee
authors.forename: Kyong-Myong
authors.initials: KM
authors.lastname: Chon
authors.forename: You-Sun
authors.initials: YS
authors.lastname: Kim
authors.forename: Won G
authors.initials: WG
authors.lastname: An
authors.forename: Hwan-Jung
authors.initials: HJ
authors.lastname: Roh
authors.forename: Eui-Kyung
authors.initials: EK
authors.lastname: Goh
authors.forename: Soo-Geun
authors.initials: SG
authors.lastname: Wang
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D002294:Carcinoma, Squamous Cell; D002453:Cell Cycle / Q000187:drug effects / Q000528:radiation effects; D018797:Cell Cycle Proteins / Q000378:metabolism; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000494:pharmacology*; D050759:Cyclin-Dependent Kinase Inhibitor p21; D005472:Fluorouracil / Q000494:pharmacology*; D006801:Humans; D007012:Hypopharyngeal Neoplasms; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; C493956:CDKN1A protein, human; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016159:Tumor Suppressor Protein p53; D002945:Cisplatin; D005472:Fluorouracil