Whole transcriptome analysis of canine pheochromocytoma and paraganglioma

Marit F van den Berg; Hans S Kooistra; Guy C M Grinwis; Stefano Nicoli; Stefania Golinelli; Lisa Stammeleer; Monique E van Wolferen; Elpetra P M Timmermans-Sprang; Maurice M J M Zandvliet; Frank G van Steenbeek; Sara Galac

doi:10.3389/fvets.2023.1155804

Whole transcriptome analysis of canine pheochromocytoma and paraganglioma

Front Vet Sci. 2023 Aug 24:10:1155804. doi: 10.3389/fvets.2023.1155804. eCollection 2023.

Affiliations

¹ Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands.
² Department of Biomolecular Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands.
³ Anicura Veterinary Clinic Roma Sud, Rome, Italy.
⁴ Department of Veterinary Medical Science, Faculty of Veterinary Medicine, University of Bologna, Bologna, Italy.
⁵ Small Animal Department, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
⁶ Department of Cardiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands.

Abstract

Pheochromocytomas and paragangliomas (PPGLs) are neuroendocrine tumors arising from the chromaffin cells in the adrenal medulla and extra-adrenal paraganglia, respectively. Local invasion, concurrent disorders, and metastases prevent surgical removal, which is the most effective treatment to date. Given the current lack of effective medical treatment, there is a need for novel therapeutic strategies. To identify druggable pathways driving PPGL development, we performed RNA sequencing on PPGLs (n = 19) and normal adrenal medullas (NAMs; n = 10) of dogs. Principal component analysis (PCA) revealed that PPGLs clearly clustered apart from NAMs. In total, 4,218 genes were differentially expressed between PPGLs and NAMs. Of these, 232 had a log₂ fold change of >3 or < -3, of which 149 were upregulated in PPGLs, and 83 were downregulated. Compared with NAMs, PPGLs had increased expression of genes related to the cell cycle, tumor development, progression and metastasis, hypoxia and angiogenesis, and the Wnt signaling pathway, and decreased expression of genes related to adrenal steroidogenesis. Our data revealed several overexpressed genes that could provide targets for novel therapeutics, such as Ret Proto-Oncogene (RET), Dopamine Receptor D2 (DRD2), and Secreted Frizzled Related Protein 2 (SFRP2). Based on the PCA, PPGLs were classified into 2 groups, of which group 1 had significantly higher Ki67 scores (p = 0.035) and shorter survival times (p = 0.04) than group 2. Increased expression of 1 of the differentially expressed genes between group 1 and 2, pleiotrophin (PTN), appeared to correlate with a more aggressive tumor phenotype. This study has shed light on the transcriptomic profile of canine PPGL, yielding new insights into the pathogenesis of these tumors in dogs, and revealed potential novel targets for therapy. In addition, we identified 2 transcriptionally distinct groups of PPGLs that had significantly different survival times.

Keywords: RNA sequencing; adrenal; dog; paraganglioma; pheochromocytoma; prognostic marker; therapeutic target; transcriptome.