Figure 3.

Glycolysis inhibition in oncocytomas contributed to mitochondrial biogenesis in an in vitro model. (A) Oncocytomas did not have elevated HIF-1α expression as compared with normal pituitaries (n = 3 and n = 5 for normal pituitaries and oncocytomas, respectively). (B) With the exception of LDHA, HIF-1α downstream targets were not upregulated in oncocytomas (n = 3 and n = 5 for the normal pituitaries and oncocytomas, respectively). (C) LDHA expression was significantly inhibited in oncocytomas as compared with normal glands (n = 3 and n = 9 for normal pituitaries and oncocytomas, respectively). (D) As compared with normal tissue (n = 3), oncocytomas (n = 4) showed decreased LDH activity, unlike null-cell adenomas (n = 4) and follicle-stimulating hormone (FSH)/adrenocorticotropic hormone (ACTH)-secreting adenomas (n = 4). (E) HEK293T cells were treated with rotenone (100 nM) and oxamate (50 mM) for >48 h, and stained with MitoTracker Orange probes. Flow cytometry showed higher intensity in the same number of cells. Numbers show the area under the curve of each sample. (F) HEK293T cells treated with rotenone and oxamate or 2-DG (5 mM) showed enhanced transcription of PPARGC1A and PPARGC1B. *p < 0.05; **p < 0.01; ***p < 0.001. CAIX, carbonic anhydrase IX; GLUT1, glucose transporter 1; ns, not significant; PDHB, pyruvate dehydrogenase-β; PKM2, pyruvate kinase muscle isozyme M2; VEGF, vascular endothelial growth factor.