The effect of P-glycoprotein on 18F-FDG uptake in tumor-bearing nude mice

Abstract

Objective To evaluate the relationship between 18F-FDG uptake and P-gp expression in Bcap37 or Bcap37/MDR1 tumor-bearing BALB/c nude mice. Methods Bcap37 or Bcap37/MDR1 cells were injected into BALB/c nude mice (1×107 cells/ml, 0.2 ml/mouse) to construct mice models. Bcap37(n=5) or Bcap37/MDR1 (n=5) tumor-bearing mice fasted for 6 h before imaging. After anesthesia, the mice were injected with 7.4 MBq of 18F-FDG via tail vein. The dynamic microPET scans were carried out for 90 min. On the microPET images, the ROI was drawn and the TAC was obtained. The next day, those 10 mice underwent dynamic microPET scans after injected with elacridar (GF120918) and 18F-FDG. Another 10 mice, 5 with Bcap37 tumors and 5 with Bcap37/MDR1 tumors, were used. After 7.4 MBq 18F-FDG with or without 2.0 mg/kg GF120918 was administered via tail vein, microPET images were acquired at 60 min. ROI was drawn over the tumors and SUVmean was obtained. Two-sample t test was used to analyze the data. Results GF120918 did not significantly alter the 18F-FDG accumulation curve in Bcap37 tumors, but significantly enhanced the 18F-FDG accumulation in Bcap37/MDR1 tumors. GF120918 did not influence 18F-FDG uptake (SUVmean) in Bcap37 tumors (1.052±0.028, 1.028±0.045, t=1.792, P>0.05), but significantly increased the SUVmean in Bcap37/MDR1 tumors (1.015±0.043, 0.712±0.031, t=3.365, P 0.05). Conclusions 18F-FDG is a substrate of P-gp. 18F-FDG imaging combined with GF120918 injection may be an effective noninvasive method for the detection of tumor's MDR. Key words: Breast neoplasms; Fluorine radioisotopes; Deoxyglucose; P-glycoprotein; Mice, nude