Fig. 5: Characterization of patient-derived PPGL cell models.

a Representative brightfield images showing culture morphology of the tumor-derived PPGL cell models at different stages of adaptation in vitro. PGLa (vagal paraganglioma), PCC (adrenal pheochromocytoma), and PGLb (carotid body paraganglioma). Cells were initially maintained in suspension to promote spheroid formation and subsequently plated for adherent growth prior to characterization. Scale bars, 100 μm. b Immunofluorescence analysis confirming preservation of key chromaffin/neuroendocrine features in the three PPGL models. Upper panels show expression of nestin (green) and tyrosine hydroxylase (TH, red); lower panels show nestin (green) and synaptophysin (red). Merged images include nuclear counterstaining (DAPI, blue). Boxed regions indicate areas shown at higher magnification to highlight punctate synaptophysin staining consistent with neurosecretory granules. c Immunofluorescence staining showing co-expression of nestin (green) and HIF2α (red) in PCC, PGLa, and PGLb cells, indicating retention of hypoxia-related signaling features characteristic of PPGLs. Nuclei are counterstained with DAPI (blue). d Quantification of the average doubling time (in days) of the three patient-derived cell lines. Cells were passaged at confluence, and doubling times were calculated based on the interval between passages over multiple consecutive passages (minimum of five passages per cell line). Bars represent mean values, and error bars indicate standard deviation, reflecting variability in proliferation rates.