title: Functional characterization of gefitinib uptake in non-small cell lung cancer cell lines.
abstract: Gefitinib, an inhibitor of epidermal growth factor receptor tyrosine kinase, has been developed and approved for treatment of advanced non-small cell lung cancer (NSCLC). In this study, we investigated the uptake of gefitinib in gefitinib-sensitive and -resistant NSCLC cell lines. The transport system was temperature-dependent, indicative of an active process and sodium- and potential-independent. Moreover, high cell densities and low extracellular pH significantly reduced the uptake of gefitinib. Inhibitors of the human organic cation transporter 1 (hOCT1) significantly decreased gefitinib uptake; however, gefitinib was not a substrate for hOCT1 or hOCT2 in overexpressing HEK293 cells. Interestingly, gefitinib significantly reduced uptake of the hOCT prototypical substrate MPP suggesting that gefitinib may exert an inhibitory effect on the intracellular accumulation of drugs transported by hOCT1 and hOCT2. After 15min of treatment at 1microM (the maximum plasma concentration of gefitinib obtained at the clinically relevant dose) gefitinib accumulated within the cell in resistant-cell lines at concentrations similar or even higher than in gefitinib-sensitive cells tending to rule out an alteration in drug uptake as a mechanism of resistance to gefitinib treatment. Moreover, our results suggest that the extrusion of lactate by crowded cells may contribute in decreasing the pH, which in turn can influence the uptake of gefinitib and as a result the inhibition of EGFR autophosphorylation.
authors.affiliation: Department of Experimental Medicine, University of Parma, Italy.
authors.forename: Maricla
authors.initials: M
authors.lastname: Galetti
authors.forename: Roberta R
authors.initials: RR
authors.lastname: Alfieri
authors.forename: Andrea
authors.initials: A
authors.lastname: Cavazzoni
authors.forename: Silvia
authors.initials: S
authors.lastname: La Monica
authors.forename: Mara
authors.initials: M
authors.lastname: Bonelli
authors.forename: Claudia
authors.initials: C
authors.lastname: Fumarola
authors.forename: Paola
authors.initials: P
authors.lastname: Mozzoni
authors.forename: Giuseppe
authors.initials: G
authors.lastname: De Palma
authors.forename: Roberta
authors.initials: R
authors.lastname: Andreoli
authors.forename: Antonio
authors.initials: A
authors.lastname: Mutti
authors.forename: Marco
authors.initials: M
authors.lastname: Mor
authors.forename: Marcello
authors.initials: M
authors.lastname: Tiseo
authors.forename: Andrea
authors.initials: A
authors.lastname: Ardizzoni
authors.forename: Pier Giorgio
authors.initials: PG
authors.lastname: Petronini
mesh_terms: D019138:Antibodies, Blocking / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000378:metabolism* / Q000494:pharmacology; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy / Q000378:metabolism*; D045744:Cell Line, Tumor; D019008:Drug Resistance, Neoplasm / Q000187:drug effects / Q000502:physiology; D004354:Drug Screening Assays, Antitumor; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism; D000077156:Gefitinib; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007668:Kidney / Q000187:drug effects / Q000378:metabolism; D008175:Lung Neoplasms / Q000188:drug therapy / Q000378:metabolism*; D050811:Octamer Transcription Factor-1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D027701:Organic Cation Transport Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D000075102:Organic Cation Transporter 2; D010766:Phosphorylation / Q000187:drug effects; D011799:Quinazolines / Q000378:metabolism* / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D019138:Antibodies, Blocking; D000970:Antineoplastic Agents; D050811:Octamer Transcription Factor-1; D027701:Organic Cation Transport Proteins; D000075102:Organic Cation Transporter 2; C494165:POU2F1 protein, human; D011799:Quinazolines; D012333:RNA, Messenger; C491013:SLC22A2 protein, human; D066246:ErbB Receptors; D000077156:Gefitinib