Treatment of Pheochromocytoma Cells with Recurrent Cycles of Hypoxia: A New Pseudohypoxic In Vitro Model

• Published in: Cells (Basel, Switzerland) Vol. 11; no. 3; p. 560
• Main Authors: Helm, Jana, Drukewitz, Stephan, Poser, Isabel, Richter, Susan, Friedemann, Markus, William, Doreen, Mohr, Hermine, Nölting, Svenja, Robledo, Mercedes, Bornstein, Stefan R, Eisenhofer, Graeme, Bechmann, Nicole
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 05.02.2022; MDPI
• Subjects: Adrenal Gland Neoplasms - pathology; Adrenal Gland Neoplasms - therapy; Animals; Cell culture; Cell Hypoxia; Cell Proliferation; Dehydrogenases; Disease Models, Animal; DNA methylation; drug resistance; Experiments; Genotype & phenotype; Growth rate; Humans; Hypoxia; hypoxia resistance; Hypoxia-inducible factors; Metastasis; Mutation; Neoplasm Invasiveness; Neoplasm Metastasis; Paraganglioma; pheochromocytoma; Pheochromocytoma - pathology; Pheochromocytoma - therapy; Pheochromocytoma cells; pseudohypoxia; Rats; Tumors; United States > US; Switzerland; Germany; epigenetic; metastasis; hypermethylation; pheochromocytoma; pseudohypoxia; hypoxia resistance; drug resistance; paraganglioma
• ISSN: 2073-4409; 2073-4409
• DOI: 10.3390/cells11030560

Continuous activation of hypoxia pathways in pheochromocytomas and paragangliomas (PPGLs) is associated with higher disease aggressiveness, for which effective treatment strategies are still missing. Most of the commonly used in vitro models lack characteristics of these pseudohypoxic tumors, including elevated expression of hypoxia-inducible factor (HIF) 2α. To address this shortcoming, we investigated whether recurrent hypoxia cycles lead to continuous activation of hypoxia pathways under normoxic conditions and whether this pseudohypoxia is associated with increased cellular aggressiveness. Rat pheochromocytoma cells (PC12) were incubated under hypoxia for 24 h every 3-4 days, up to 20 hypoxia-reoxygenation cycles, resulting in PC12 Z20 cells. PC12 Z20 control cells were obtained by synchronous cultivation under normoxia. RNA sequencing revealed upregulation of in PC12 Z20 cells and a pseudohypoxic gene signature that overlapped with the gene signature of pseudohypoxic PPGLs. PC12 Z20 cells showed a higher growth rate, and the migration and adhesion capacity were significantly increased compared with control cells. Changes in global methylation, together with the pseudohypoxic conditions, may be responsible for the increased aggressiveness of this new model. The established sub-cell line with characteristics of pseudohypoxic PPGLs represent a complementary model for further investigations, for example, with regard to new therapeutic approaches.