Gefitinib and Erlotinib Lead to Phosphorylation of Eukaryotic Initiation Factor 2 Alpha Independent of Epidermal Growth Factor Receptor in A549 Cells.
Gefitinib and erlotinib are anticancer agents, which inhibit epidermal growth factor receptor (EGFR) tyrosine kinase. Interstitial lung disease (ILD) occurs in patients with non-small cell lung cancer receiving EGFR inhibitors. In the present study, we examined whether gefitinib- and erlotinib-induced lung injury related to ILD through endoplasmic reticulum (ER) stress, which is a causative intracellular mechanism in cytotoxicity caused by various chemicals in adenocarcinomic human alveolar basal epithelial cells. These two EGFR inhibitors increased Parkinson juvenile disease protein 2 and C/EBP homologous protein mRNA expressions, and activated the eukaryotic initiation factor (eIF) 2α/activating transcription factor 4 pathway without protein kinase R-like ER kinase activation in A549 cells. Gefitinib and erlotinib caused neither ER stress nor cell death; however, these agents inhibited cell growth via the reduction of cyclin-D1 expression. Tauroursodeoxycholic acid, which is known to suppress eIF2α phosphorylation, cancelled the effects of EGFR inhibitors on cyclin-D1 expression and cell proliferation in a concentration-dependent manner. The results of an EGFR-silencing study using siRNA showed that gefitinib and erlotinib affected eIF2α phosphorylation and cyclin-D1 expression independent of EGFR inhibition. Therefore, the inhibition of cell growth by these EGFR inhibitors might equate to impairment of the alveolar epithelial cell repair system via eIF2α phosphorylation and reduced cyclin-D1 expression.
Department of Clinical Pharmacology and Therapeutics, Kyoto University Hospital, Kyoto, Japan.
Satoshi
S
Koyama
Department of Clinical Pharmacology and Therapeutics, Kyoto University Hospital, Kyoto, Japan.
Tomohiro
T
Omura
Department of Clinical Pharmacology and Therapeutics, Kyoto University Hospital, Kyoto, Japan.
Atsushi
A
Yonezawa
Department of Clinical Pharmacology and Therapeutics, Kyoto University Hospital, Kyoto, Japan.
Satoshi
S
Imai
Department of Clinical Pharmacology and Therapeutics, Kyoto University Hospital, Kyoto, Japan.
Shunsaku
S
Nakagawa
Department of Clinical Pharmacology and Therapeutics, Kyoto University Hospital, Kyoto, Japan.
Takayuki
T
Nakagawa
Department of Clinical Pharmacology and Therapeutics, Kyoto University Hospital, Kyoto, Japan.
Ikuko
I
Yano
Department of Clinical Pharmacology and Therapeutics, Kyoto University Hospital, Kyoto, Japan.
Kazuo
K
Matsubara
D000970:Antineoplastic Agents / Q000009:adverse effects; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D019938:Cyclin D1 / Q000378:metabolism; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects; D066246:ErbB Receptors / Q000037:antagonists & inhibitors*; D000069347:Erlotinib Hydrochloride / Q000009:adverse effects*; D015852:Eukaryotic Initiation Factor-2 / Q000378:metabolism*; D000077156:Gefitinib; D006801:Humans; D017563:Lung Diseases, Interstitial / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology; D010766:Phosphorylation / Q000187:drug effects; D011650:Pulmonary Alveoli / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D011799:Quinazolines / Q000009:adverse effects*; D015398:Signal Transduction / Q000187:drug effects; D013655:Taurochenodeoxycholic Acid / Q000494:pharmacology
D000970:Antineoplastic Agents; C530104:CCND1 protein, human; D015852:Eukaryotic Initiation Factor-2; D011799:Quinazolines; D019938:Cyclin D1; D013655:Taurochenodeoxycholic Acid; C031655:ursodoxicoltaurine; D000069347:Erlotinib Hydrochloride; D066246:ErbB Receptors; D000077156:Gefitinib