Metabolic Shifts Induced by Fatty Acid Synthase Inhibitor Orlistat in Non-small Cell Lung Carcinoma Cells Provide Novel Pharmacodynamic Biomarkers for Positron Emission Tomography and Magnetic Resonance Spectroscopy
Open Access
- 11 August 2012
- journal article
- research article
- Published by Springer Science and Business Media LLC in Molecular Imaging & Biology
- Vol. 15 (2), 136-147
- https://doi.org/10.1007/s11307-012-0587-6
Abstract
Abnormal fatty acid (FA) synthesis is one of the common features of cancer. Fatty acid synthase (FASN), a multifunctional enzyme playing a key role in biosynthesis of FA, is up-regulated in prostate, breast, and lung carcinomas. Orlistat is a FDA-approved anti-obesity drug that inhibits the thioesterase domain of FASN, interferes with cellular FA synthesis, can arrest tumor cell proliferation, and induces tumor cell apoptosis. The current study was aimed to investigate the metabolic changes associated with FASN inhibition by orlistat and to understand the molecular mechanisms behind the observed metabolic changes in non-small cell lung carcinoma (NSCLC) cell lines. Changes in metabolite pools in four NSCLC cell lines (H441, H1975, H3255, and PC14) with different mutational profiles were studied using NMR spectroscopy before and after in vitro incubation with sub-toxic concentration of orlistat and [1-13C]d-glucose or [1,2-13C2]choline. In vitro radiotracer accumulation assays in cells were performed with [3H]acetate, [14C]fluoroacetate, and 2-deoxy-2-[18F]fluoro-d-glucose. In parallel, microarray profiling of genes involved in the regulation of carbohydrate and lipid metabolism was performed. In orlistat-treated NSCLC cells, FASN inhibition results in characteristic changes in intermediary metabolites (FAs, choline, phospholipids, and TCA cycle metabolites) as observed by magnetic resonance spectroscopy. Further, FASN inhibition by orlistat induces multiple adaptive changes in FA synthetic pathway and associated metabolic pathways, including induction of ketone metabolism and glutaminolysis, as well as the up-regulation of 5' adenosine monophosphate-activated protein kinase. These observed changes in metabolic pools in orlistat-treated cells demonstrate the critical role of fatty acid de novo synthesis and metabolism for cellular energy production, especially in tumor cells with low glycolytic activity, which goes beyond the widely accepted concept that FA synthesis is important for cell membrane biosynthesis in rapidly proliferating tumor cells. The online version of this article (doi:10.1007/s11307-012-0587-6) contains supplementary material, which is available to authorized users.Keywords
This publication has 31 references indexed in Scilit:
- Molecular imaging of active mutant L858R EGF receptor (EGFR) kinase-expressing nonsmall cell lung carcinomas using PET/CTProceedings of the National Academy of Sciences of the United States of America, 2011
- Fatty acid synthase phosphorylation: a novel therapeutic target in HER2-overexpressing breast cancer cellsBreast Cancer Research, 2010
- []Fluoro-2-Deoxy-D-Glucose Incorporation by MCF-7 Breast Tumour Cells In Vitro Is Modulated by Treatment with Tamoxifen, Doxorubicin, and Docetaxel: Relationship to Chemotherapy-Induced Changes in ATP Content, Hexokinase Activity, and Glucose TransportInternational Journal of Molecular Imaging, 2010
- New Strategies in Prostate Cancer: Targeting Lipogenic Pathways and the Energy Sensor AMPKClinical Cancer Research, 2010
- Extracellular Fatty Acid Synthase: A Possible Surrogate Biomarker of Insulin ResistanceDiabetes, 2010
- 18F-FDG Uptake in Lung, Breast, and Colon Cancers: Molecular Biology Correlates and Disease CharacterizationJournal of Nuclear Medicine, 2009
- De novo fatty-acid synthesis and related pathways as molecular targets for cancer therapyBritish Journal of Cancer, 2009
- Fatty acid synthase inhibition results in a magnetic resonance–detectable drop in phosphocholineMolecular Cancer Therapeutics, 2008
- Genome-wide changes accompanying knockdown of fatty acid synthase in breast cancerBMC Genomics, 2007
- FDG uptake, tumor proliferation and expression of glycolysis associated genes in animal tumor modelsNuclear Medicine and Biology, 1994