title: Antitumor impact of p14ARF on gefitinib-resistant non-small cell lung cancers.
abstract: Activation of the epidermal growth factor receptor (EGFR) has been observed in many malignant tumors and its constitutive signal transduction facilitates the proliferation of tumors. EGFR-tyrosine kinase inhibitors, such as gefitinib, are widely used as a molecular-targeting agent for the inactivation of EGFR signaling and show considerable therapeutic effect in non-small cell lung cancers harboring activating EGFR mutations. However, prolonged treatment inevitably produces tumors with additional gefitinib-resistant mutations in EGFR, which is a critical issue for current therapeutics. We aimed to characterize the distinct molecular response to gefitinib between the drug-resistant and drug-sensitive lung adenocarcinoma cells in order to learn about therapeutics based on the molecular information. From the quantitative PCR analysis, we found a specific increase in p14(ARF) expression in gefitinib-sensitive lung adenocarcinoma clones, which was absent in gefitinib-resistant clones. Moreover, mitochondria-targeted p14(ARF) triggered the most augmented apoptosis in both clones. We identified the amino acid residues spanning from 38 to 65 as a functional core of mitochondrial p14(ARF) (p14 38-65 a.a.), which reduced the mitochondrial membrane potential and caused caspase-9 activation. The synthesized peptide covering the p14 38-65 a.a. induced growth suppression of the gefitinib-resistant clones without affecting nonneoplastic cells. Notably, transduction of the minimized dose of the p14 38-65 peptide restored the response to gefitinib like that in the sensitive clones. These findings suggest that the region of p14(ARF) 38-65 a.a. is critical in the pharmacologic action of gefitinib against EGFR-mutated lung adenocarcinoma cells and has potential utility in the therapeutics of gefitinib-resistant cancers.
authors.affiliation: Division of Oncological Pathology, Aichi Cancer Center Research Institute, Chikusa-ku, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Saito
authors.forename: Nagio
authors.initials: N
authors.lastname: Takigawa
authors.forename: Naoko
authors.initials: N
authors.lastname: Ohtani
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Iioka
authors.forename: Yuki
authors.initials: Y
authors.lastname: Tomita
authors.forename: Ryuzo
authors.initials: R
authors.lastname: Ueda
authors.forename: Junya
authors.initials: J
authors.lastname: Fukuoka
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Kuwahara
authors.forename: Eiki
authors.initials: E
authors.lastname: Ichihara
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Kiura
authors.forename: Eisaku
authors.initials: E
authors.lastname: Kondo
mesh_terms: D000595:Amino Acid Sequence; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics* / Q000378:metabolism; D045744:Cell Line, Tumor; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D000077156:Gefitinib; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism; D008175:Lung Neoplasms / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D010455:Peptides / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D021381:Protein Transport; D011799:Quinazolines / Q000494:pharmacology*; D025803:Tumor Suppressor Protein p14ARF / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D010455:Peptides; D047428:Protein Kinase Inhibitors; D011799:Quinazolines; D025803:Tumor Suppressor Protein p14ARF; D066246:ErbB Receptors; D000077156:Gefitinib