Imaging recognition of inhibition of multidrug resistance in human breast cancer xenografts using 99mTc-labeled sestamibi and tetrofosmin

Zhonglin Liu, Gail D. Stevenson, Harrison H. Barrett, Lars R. Furenlid, Donald W. Wilson, George A. Kastis, Michael Bettan, James M. Woolfenden

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


Background: 99mTc-sestamibi (MIBI) and 99mTc- tetrofosmin (TF) are avid transport substrates recognized by the multidrug resistance (MDR) P-glycoprotein (Pgp). This study was designed to compare the properties of MIBI and TF in assessing the inhibition of Pgp by PSC833 in severe combined immunodeficient mice bearing MCF7 human breast tumors using SPECT imaging. Methods: Animals with drug-sensitive (MCF/WT) and drug-resistant (MCF7/AdrR) tumors were treated by PSC833 and by carrier vehicle 1 h before imaging, respectively. Dynamic images were acquired for 30 min after intravenous injection of MIBI/TF using a SPECT system, FastSPECT. The biodistribution of MIBI and TF was determined at the end of the imaging session. Results: MCF7/WT in the absence and presence of PSC833 could be visualized by MIBI and TF imaging within 5 min and remained detectable for 30 min postinjection. MCF7/AdrR could be visualized only 2-5 min without PSC833 treatment but could be detected for 30 min with PSC833, very similar to MCF7/WT. MCF7/AdrR without PSC833 showed significantly greater radioactive washout than MCF7/WT and MCF7/AdrR with PSC833 treatment. PSC833 increased the accumulation (%ID/g) in MCF7/AdrR 3.0-fold (1.62±0.15 vs. 0.55±0.05, P<.05) for TF and 1.9-fold (1.21±0.04 vs. 0.64±0.05, P<.05) for MIBI but did not affect MCF7/WT. Conclusions: The feasibility of MIBI and TF for assessment of MDR expression and inhibition was demonstrated in mice through FastSPECT imaging. The results indicate that TF may be at least comparable with MIBI in recognizing Pgp expression and modulation.

Original languageEnglish (US)
Pages (from-to)573-583
Number of pages11
JournalNuclear Medicine and Biology
Issue number6
StatePublished - Aug 2005


  • Tc-sestamibi
  • Tc-tetrofosmin
  • Human breast cancer
  • Multidrug resistance
  • P-glycoprotein modulation

ASJC Scopus subject areas

  • Molecular Medicine
  • Radiology Nuclear Medicine and imaging
  • Cancer Research


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