Targeting pheochromocytoma/paraganglioma with polyamine inhibitors

Area of Science:

• Biochemistry
• Oncology
• Genetics

Background:

• Pheochromocytomas (PCCs) and paragangliomas (PGLs) are neuroendocrine tumors, often benign, but metastatic disease occurs in 10-25% of cases.
• Metastatic PCCs/PGLs lack effective therapies, particularly in patients with succinate dehydrogenase subunit B (SDHB) gene mutations.
• SDHB mutations are hypothesized to alter cellular metabolism, presenting a potential therapeutic target.

Purpose of the Study:

• To investigate the metabolic changes in PCCs/PGLs with SDHB mutations.
• To explore the therapeutic potential of targeting the polyamine pathway in these tumors.

Main Methods:

• Metabolomic analysis of human hPheo1 cells with and without SDHB knockdown.
• Analysis of 115 human fresh-frozen PCC/PGL tissue samples.
• In vitro and in vivo studies using polyamine pathway inhibitors (DENSPM, DESPM) in cell lines and mouse xenografts.

Main Results:

• SDHB knockdown cells and SDHx-mutated PCC/PGL tissues showed elevated polyamine pathway components, including spermidine and spermine.
• Polyamine pathway inhibitors DENSPM and DESPM significantly inhibited hPheo1 cell growth in vitro.
• DENSPM treatment suppressed tumor growth in mouse xenografts.

Conclusions:

• The polyamine pathway is significantly overactive in PCCs/PGLs with SDHB mutations.
• Polyamine pathway inhibitors demonstrate therapeutic potential for malignant PCCs/PGLs.
• Further research into polyamine analogue inhibitors for metastatic PCC/PGL is warranted.