Metabolome Profiling by HRMAS NMR Spectroscopy of Pheochromocytomas and Paragangliomas Detects SDH Deficiency: Clinical and Pathophysiological Implications

Abstract

Succinate dehydrogenase gene (SDHx) mutations increase susceptibility to develop pheochromocytomas/paragangliomas (PHEOs/PGLs). In the present study, we evaluate the performance and clinical applications of 1H high-resolution magic angle spinning (HRMAS) nuclear magnetic resonance (NMR) spectroscopy–based global metabolomic profiling in a large series of PHEOs/PGLs of different genetic backgrounds. Eighty-seven PHEOs/PGLs (48 sporadic/23 SDHx/7 von Hippel-Lindau/5 REarranged during Transfection/3 neurofibromatosis type 1/1 hypoxia-inducible factor 2α), one SDHD variant of unknown significance, and two Carney triad (CTr)–related tumors were analyzed by HRMAS-NMR spectroscopy. Compared to sporadic, SDHx-related PHEOs/PGLs exhibit a specific metabolic signature characterized by increased levels of succinate (P < .0001), methionine (P = .002), glutamine (P = .002), and myoinositol (P < .0007) and decreased levels of glutamate (P < .0007), regardless of their location and catecholamine levels. Uniquely, ATP/ascorbate/glutathione was found to be associated with the secretory phenotype of PHEOs/PGLs, regardless of their genotype (P < .0007). The use of succinate as a single screening test retained excellent accuracy in distinguishing SDHx versus non–SDHx-related tumors (sensitivity/specificity: 100/100%). Moreover, the quantification of succinate could be considered a diagnostic alternative for assessing SDHx-related mutations of unknown pathogenicity. We were also able, for the first time, to uncover an SDH-like pattern in the two CTr-related PGLs. The present study demonstrates that HRMAS-NMR provides important information for SDHx-related PHEO/PGL characterization. Besides the high succinate–low glutamate hallmark, SDHx tumors also exhibit high values of methionine, a finding consistent with the hypermethylation pattern of these tumors. We also found important levels of glutamine, suggesting that glutamine metabolism might be involved in the pathogenesis of SDHx-related PHEOs/PGLs.

In Vivo Detection of Succinate by Magnetic Resonance Spectroscopy as a Hallmark of SDHx Mutations in Paraganglioma

“…Interestingly, in an Sdhb À/À mouse tumor model, this succinate peak is correlated with the concentrations of succinate measured in the resected tumors by GC-MS. Demonstration of SDH inactivation is currently based on in vitro analyses of tissue samples: immunohistochemical analyses of SDHB, SDHA, and SDHD expression in FFPE tissues (16,18,22), direct succinate measurements on frozen tumor samples by nuclear magnetic resonance (NMR) spectroscopy (15,19,20,23), GC-MS, or liquid chromatography mass spectroscopy (LC-MS; refs. 13,17,21).…”

“…Biomarkers could serve as surrogate markers in the assessment of tumor response to specific treatments. Until now, no in vivo method to assess the functional consequences of SDHx mutations was available, and all existing tests were performed on surgical resected specimens (15)(16)(17)(18)(19)(20)(21)(22).…”

New Insights into the Nuclear Imaging Phenotypes of Cluster 1 Pheochromocytoma and Paraganglioma

“…SDHx -related PPGLs dramatically accumulate succinate as a result of a TCA blockade that is detectable by ex vivo [49–51] and in vivo proton MR spectroscopy [52, 53]. …”

15 YEARS OF PARAGANGLIOMA: Metabolism and pheochromocytoma/paraganglioma

“…A consequence of the enzymatic loss of function is the accumulation in the cytoplasm of the corresponding substrate. Two different groups demonstrated that in SDHx mutated pheochromocytoma/paraganglioma tumor tissues succinate levels are significantly higher than in WT tumors (Pollard et al 2005, Lendvai et al 2014, Imperiale et al 2015. The defect of enzymatic activity is associated not only with an impairment of the TCA cycle but also to changes in the structure of mitochondria that appear increased in number, swollen, and with a significant reduction of the internal cristae (Fig.…”