title: p53 enhances gefitinib-induced growth inhibition and apoptosis by regulation of Fas in non-small cell lung cancer.
abstract: Treatment with gefitinib, a specific inhibitor of epidermal growth factor receptor tyrosine kinase (EGFR-TK), has resulted in dramatic responses in some patients with non-small cell lung cancer (NSCLC). Most patients who respond to gefitinib have EGFR-TK mutations; however, >10% of patients with EGFR-TK mutations do not respond. Similarly, some patients without EGFR-TK mutations respond to this drug, suggesting that other factors determine sensitivity to gefitinib. Aberrations of the tumor suppressor gene p53 are frequently associated with drug resistance. In this study, we investigated the role of p53 in growth-inhibitory and apoptotic effects of gefitinib in the human NSCLC cell lines NCI-H1299 and A549, which have no EGFR-TK mutations. NCI-H1299 cells, which had a p53-null genotype, were more resistant to gefitinib compared with A549 cells, which were wild-type p53 (IC(50), 40 micromol/L in NCI-H1299 and 5 micromol/L in A549). Treatment of A549 with gefitinib resulted in the translocation of p53 from cytosol to nucleus and the up-regulation of Fas, which was localized to the plasma membrane. In the stable H1299 cell line with tetracycline-inducible p53 expression, induced p53 enhanced growth inhibition and apoptosis by gefitinib through the up-regulation of Fas and restoration of caspase activation. A caspase inhibitor, Z-VAD-fmk, reduced these effects. Conversely, inhibition of p53 using antisense oligonucleotide in A549 caused a significant decrease in apoptosis by gefitinib and down-regulation of Fas under the same conditions. In conclusion, p53 may play a role in determining gefitinib sensitivity by regulating Fas expression in NSCLC.
authors.affiliation: Department of Internal Medicine, Korea Institute of Radiological and Medical Science, 215-4 Gongneung-dong, Nowon-gu, Seoul 139-706, Korea.
authors.forename: Jin Kyung
authors.initials: JK
authors.lastname: Rho
authors.forename: Yun Jung
authors.initials: YJ
authors.lastname: Choi
authors.forename: Baek-Yeol
authors.initials: BY
authors.lastname: Ryoo
authors.forename: Im I I
authors.initials: II
authors.lastname: Na
authors.forename: Sung Hyun
authors.initials: SH
authors.lastname: Yang
authors.forename: Cheol Hyeon
authors.initials: CH
authors.lastname: Kim
authors.forename: Jae Cheol
authors.initials: JC
authors.lastname: Lee
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D048708:Cell Growth Processes / Q000187:drug effects / Q000502:physiology; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism; D000077156:Gefitinib; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D016376:Oligonucleotides, Antisense / Q000235:genetics; D011799:Quinazolines / Q000494:pharmacology*; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D019014:fas Receptor / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D000970:Antineoplastic Agents; D016376:Oligonucleotides, Antisense; D011799:Quinazolines; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D019014:fas Receptor; D066246:ErbB Receptors; D000077156:Gefitinib