The effect of the mTOR inhibitor rapamycin on glucoCEST signal in a preclinical model of glioblastoma

Research output: Contribution to journalArticle

Abstract

Purpose: The mammalian target of rapamycin is an enzyme that regulates cell metabolism and proliferation. It is up-regulated in aggressive tumors, such as glioblastoma, leading to increased glucose uptake and consumption. It has been suggested that glucose CEST signals reflect the delivery and tumor uptake of glucose. The inhibitor rapamycin (sirolimus) has been applied as a glucose deprivation treatment; thus, glucose CEST MRI could potentially be useful for monitoring the tumor responses to inhibitor treatment. Methods: A human U87-EGFRvIII xenograft model in mice was studied. The mice were treated with a mammalian target of Rapamycin inhibitor, rapamycin. The effect of the treatment was evaluated in vivo with dynamic glucose CEST MRI. Results: Rapamycin treatment led to significant increases (P < 0.001) in dynamic glucose-enhanced signal in both the tumor and contralateral brain as compared to the no-treatment group, namely a maximum enhancement of 3.7% ± 2.3% (tumor, treatment) versus 1.9% ± 0.4% (tumor, no-treatment), 1.7% ± 1.1% (contralateral, treatment), and 1.0% ± 0.4% (contralateral, no treatment). Dynamic glucose-enhanced contrast remained consistently higher in treatment versus no-treatment groups for the duration of the experiment (17 min). This was confirmed with area-under-curve analysis. Conclusion: Increased glucose CEST signal was found after mammalian target of Rapamycin inhibition treatment, indicating potential for dynamic glucose-enhanced MRI to study tumor response to glucose deprivation treatment.

Details

Authors
  • Xiang Xu
  • Jiadi Xu
  • Linda Knutsson
  • Jing Liu
  • Huanling Liu
  • Yuguo Li
  • Bachchu Lal
  • John Laterra
  • Dmitri Artemov
  • Guanshu Liu
  • Peter C.M. van Zijl
  • Kannie W.Y. Chan
Organisations
External organisations
  • Johns Hopkins University
  • Guangzhou Panyu Central Hospital
  • Kennedy Krieger Institute
  • Affiliated Hospital of Guizhou Medical University
  • University of Hong Kong
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Cancer and Oncology
  • Radiology, Nuclear Medicine and Medical Imaging

Keywords

  • DGE MRI, glioblastoma, glucoCEST, mTOR inhibitor, preclinical imaging, rapamycin
Original languageEnglish
JournalMagnetic Resonance in Medicine
Publication statusE-pub ahead of print - 2019 Feb 22
Publication categoryResearch
Peer-reviewedYes