OR29-5 Genotype–specific Differences in the Tumor Metabolite Profile of Pheochromocytoma and Paraganglioma: a Metabolomics Study

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: OR29-Adrenal Tumors & Pheochromocytoma
Translational
Monday, June 17, 2013: 11:15 AM-12:45 PM
Presentation Start Time: 12:15 PM
Room 134 (Moscone Center)
Jyotsna Upendra Rao*1, Udo Engelke2, Fred CG J Sweep1, Karel Pacak3, Benno Kusters2, Angelina Goudswaard2, Jacques W.M. Lenders4, Ad R.M.M. Hermus5, Arjen Mensenkamp6, Graeme Eisenhofer7, Nan Qin8, Susan Richter8, Henricus PM Kunst9, Henri JLM Timmers2 and Ron Wevers2
1Radboud Univ Nijmegen Med Ctr, Nijmegen, Netherlands, 2Radboud University Nijmegen Medical Center, Nijmegen, Netherlands, 3National Institutes of Health (NIH), Bethesda, MD, 4Rabound University Nijmegen, Nijmegen, Netherlands, 5Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands, 6Radboud University Nijmegen Medical Center, 7University Hospital Carl Gustav Carus, Dresden, Germany, 8University of Dresden, Dresden, Germany, 9Radboud University Nijmegen Medical Centre, Nijmegen
Background: Metabolomics may provide insight on the impact of genetic alterations on metabolic pathways leading to tumor formation. Tumors that are more commonly associated with inherited mutations than any other cancer type are pheochromocytomas and paragangliomas (PGLs). At least, 30% of these neuroendocrine tumors of sympathetic and parasympathetic paraganglia are caused by germline mutations of ten identified tumor susceptibility genes. These include RET, NF1, VHL, SDHA/B/C/D/AF-2, TMEM127 and MAX. Studies on the impact of these genetic alterations on metabolic networks in these tumors could help in improved understanding of their pathophysiology.

Objective: The aim of the study was to examine genotype-specific differences in the concentrations of various metabolites in PGLs using 1H-NMR spectroscopy.

Methods: 80 primary PGL tissues collected from patients with hereditary mutations in SDHB (n=11), SDHD (n=8), SDHAF-2 (n=1) VHL (n=7), RET (n=14), NF1 (n=7) and from sporadic patients (n=32) were investigated. Patients whose genotype was tested negative for RET, VHL and SDHA/B/C/D/AF-2 were considered as sporadics. Tumor homogenates were prepared in MilliQ water (10% w/v) and deproteinized by ultrafiltration using a 10 kDa filter. The ultrafiltrates were analyzed using 500 MHz 1H-NMR spectrometer. Validation of various metabolites identified by 1H-NMR spectroscopy was performed using HPLC and LC-MS. HPLC tandem MS was used to further investigate the levels of various purines and pyrimidines.

Results: 1H-NMR spectroscopy identified 29 different metabolites. SDH tumors showed high succinate levels, while VHL tumors showed low N-Acetylaspartate and creatine levels in comparison with other genotypes. In sporadic, RET and NF1 tumors, N-acetylaspartate and ATP/ADP/AMP were detectable while they were below detection limit in SDH tumors. Epinephrine was detectable in RET, NF-1 and some of the sporadic tumors while it was undetectable in SDH and VHL tumors. Further investigations on purines and pyrimidines in PGLs showed that adenine and adenosine in SDH and guanosine in RET tumors were below detection limit while these metabolites were detected in other genotypes. Levels of inosine and hypoxanthine were low in SDH and RET tumors respectively in comparison with the other genotypes.

Conclusion: Genotype specific differences in the levels of various metabolites were observed. Some of the metabolites detected could potentially serve as biomarkers for these tumors.

Nothing to Disclose: JU, UE, FCJS, KP, BK, AG, JWML, ARMMH, AM, GE, NQ, SR, HPK, HJT, RW

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 259735 (ENSAT CANCER)