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Abstract #4035

Quantitative 31P Magnetic Resonance Spectroscopy Stratifies Treatment Response to a PI3K/mTOR Inhibitor in Two Distinct Breast Cancer Xenografts

Morteza Esmaeili1, Tone Frost Bathen1, Olav Engebrthen2, 3, Gunhild Maelandsmo2, Ingrid Susann Gribbestad4, Siver A. Moestue1

1Department of Circulation and Medical Imaging, Norwegian University of Science and Technology (NTNU), Trondheim, Norway; 2Institute for Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway; 3Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital Radiumhospital, Oslo, Norway; 4Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway


The phosphatidylinositol-3-kinase (PI3K) signaling pathway promotes cell proliferation and survival of cancer cells. Inhibitors of this pathway are under investigation as targeted anticancer treatments. The aim of this study was to develop a phosphorus high resolution magic angle spinning (31P HR MAS) magnetic resonance spectroscopy (MRS) protocol for quantifying phosphorylated metabolites of importance in two distinct breast cancer xenografts, and to use this method for identifying biomarkers for response to PI3K inhibition. In basal-like xenografts, BEZ235 treatment induced a significant decrease in PE whilst PC and GPC were significantly increased. No significant metabolic changes were observed in luminal-like xenografts.