High-throughput screening for growth inhibitors using a yeast model of familial paraganglioma.

Irina Bancos,Defeng Tian,John Paul Bida,Yeng F Her,Derek Hook,L James Maher,Kristen John,Gunda Georg,Molly Nelson Holte,Debra Evans,Mary Bundrick,Eric M Poeschla,Dyana T Saenz,Yanchang Wang

doi:10.1371/journal.pone.0056827

Abstract

Classical tumor suppressor genes block neoplasia by regulating cell growth and death. A remarkable puzzle is therefore presented by familial paraganglioma (PGL), a neuroendocrine cancer where the tumor suppressor genes encode subunits of succinate dehydrogenase (SDH), an enzyme of the tricarboxylic acid (TCA) cycle of central metabolism. Loss of SDH initiates PGL through mechanisms that remain unclear. Could this metabolic defect provide a novel opportunity for chemotherapy of PGL? We report the results of high throughput screening to identify compounds differentially toxic to SDH mutant cells using a powerful S. cerevisiae (yeast) model of PGL. Screening more than 200,000 compounds identifies 12 compounds that are differentially toxic to SDH-mutant yeast. Interestingly, two of the agents, dequalinium and tetraethylthiuram disulfide (disulfiram), are anti-malarials with the latter reported to be a glycolysis inhibitor. We show that four of the additional hits are potent inhibitors of yeast alcohol dehydrogenase. Because alcohol dehydrogenase regenerates NAD+ in glycolytic cells that lack TCA cycle function, this result raises the possibility that lactate dehydrogenase, which plays the equivalent role in human cells, might be a target of interest for PGL therapy. We confirm that human cells deficient in SDH are differentially sensitive to a lactate dehydrogenase inhibitor.

Highlights

Cancer Focus Paraganglioma/pheochromocytoma (PGL) is a rare neuroendocrine tumor derived from paraganglia, a diffuse neuroendocrine system present from the pelvic floor to the base of the skull [1]
Yeast Strain Construction Three yeast strains (Table 1 and Fig. 1B) were created for the purpose of identifying compounds that act as selective growth inhibitors of sdh2D mutant yeast
The ‘‘wild-type’’ (WT) yeast strain is derived from BY4741 (MATa) with the PDR5 gene gene disrupted by homologous recombination with DNA fragments carrying a G418 resistance marker

Summary

Introduction

Cancer Focus Paraganglioma/pheochromocytoma (PGL) is a rare neuroendocrine tumor derived from paraganglia, a diffuse neuroendocrine system present from the pelvic floor to the base of the skull [1]. PGL patients may display catecholamine excess with symptoms including headache, sweating, palpitations, and flushing. The penetrance of familial PGL appears to be greater than 40%, depending on genotype. Some PGLs are initially benign and curable by resection. Malignancy is defined by the appearance of distant metastases, commonly to bone, liver, lung, and lymph nodes [4]. Extra-adrenal pheochromocytomas are estimated to be malignant in 15–50% of cases, depending on subtype [5,6]. There is currently no effective cure for malignant PGL

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Results

Conclusion