Monitoring tumor glucose utilization by positron emission tomography for the prediction of treatment response to epidermal growth factor receptor kinase inhibitors.
OBJECTIVE
The mechanisms underlying the sensitivity of non-small cell lung cancer to epidermal growth factor receptor (EGFR) kinase inhibitors are complex, and there are no established markers to accurately predict treatment outcome in individual patients.


METHODS
We investigated whether tumors responding to EGFR inhibitors can be identified by measuring treatment-induced changes in glucose utilization by positron emission tomography with the glucose analogue fluorodeoxyglucose (FDG-PET). We studied a panel of cell lines with a spectrum of sensitivity to EGFR kinase inhibitors. After incubation with the EGFR kinase inhibitor gefitinib for various time points, FDG uptake, glucose transport rates, and hexokinase activity were determined. FDG uptake in vivo was assessed by microPET imaging of tumor xenografts in mice.


RESULTS
In gefitinib-sensitive cell lines, there was a dramatic decrease in FDG uptake as early as 2 hours after treatment. Immunoblots showed the translocation of glucose transporters (GLUT3) from the plasma membrane to the cytosol; glucose transport rates were reduced 2.6-fold at this time. There was also a modest reduction of hexokinase activity. These metabolic alterations preceded changes in cell cycle distribution, thymidine uptake, and apoptosis. MicroPET studies showed an up to 55% decrease of tumor FDG uptake in sensitive xenografts within 48 hours. In contrast, gefitinib-resistant cells exhibited no measurable changes in FDG uptake, either in cell culture or in vivo.


CONCLUSIONS
Glucose metabolic activity closely reflects response to gefitinib therapy. FDG-PET may be a valuable clinical predictor, early in the course of treatment, for therapeutic responses to EGFR kinase inhibitors.
Su
Helen
H
Department of Molecular Medicine and Pharmacology, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California at Los Angeles, 650 Charles Young Drive, Los Angeles, CA 90095, USA.
Bodenstein
Claudia
C
Dumont
Rebecca A
RA
Seimbille
Yann
Y
Dubinett
Steven
S
Phelps
Michael E
ME
Herschman
Harvey
H
Czernin
Johannes
J
Weber
Wolfgang
W
D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging* / Q000188:drug therapy; D066246:ErbB Receptors / Q000037:antagonists & inhibitors*; D019788:Fluorodeoxyglucose F18; D000077156:Gefitinib; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy; D051379:Mice; D016513:Mice, SCID; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D011799:Quinazolines / Q000627:therapeutic use*; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D014407:Tumor Cells, Cultured
D000970:Antineoplastic Agents; D011799:Quinazolines; D019788:Fluorodeoxyglucose F18; D066246:ErbB Receptors; D005947:Glucose; D000077156:Gefitinib