하인두암 세포주에서 Cisplatin, 5-Fluorouracil, 방사선조사가 세포주기 및 세포고사에 미치는 영향

Objectives and Background: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 difference of the influences 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). Method:PNUH-12 cells were treated with cisplatin, 5-FU and radiation. The changes in the cells were assessed by acell cytotoxicity assay, Western blotting (p53 and p21^WAFI/CIPI proteins), DNA fragmentation assay, pro- pidium iodide (PI) stain and DNA flow cytometry. Results:The expression of p53 protein was increased after treatment with cisplatin and 5-FU, but not radiation. The expression of p21^WAF1/CIPI protein was increased only after treatment with 5-FU, not cisplatin or radiation. With cisplatin and radiation, we observed apoptosis in both by DNA fragmentation and PI stain and increased the S phase in cisplatin and the G2 phase in radiation by DNA flow cytometry. But, with 5-FU, we couldn’t observe apoptosis by DNA fragmentation and PI stain but only an increased G1 phase by DNA flow cytometry. Conclustions:In PNUH-12, radiation induced p53- independent apoptosis and p21^WAFI/CIPI-mdependent G2 phase cell-cycle arrest. Cisplatin induced p53-depen- dent apoptosis and p21^WAF1/C1P1-independent S phase cell-cycle arrest and 5-FU induced p53 and p21^WAF1/CIPI- 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. Our results suggest that combined treatmentwith radiation and cisplatin or 5-FU may be effect because these have different molecular mechanism of cell damage. (J Clinical Otolaryngol 2005;16:45-53)