Fig. 1

Overexpression of KITENIN causes an induction of aerobic glycolysis but no change in mitochondrial respiration. A The GEPIA web tool was used to analyze the relationship between the expression of KITENIN and that of PKM mRNA levels in COAD samples. B Overall survival curve of between KITENIN-PKM, according to the GEPIA database. C Disease-specific survival curve of between among the KITENIN high expression and high vs low PKM2 patients. D–E Oxygen consumption rate (OCR) was measured using a Cell Mito Stress Test Kit on a Seahorse XF96 extracellular flux analyzer. OCR was measured, and then oligomycin (1 μM), FCCP (0.5 μM), rotenone (1 μM), and antimycin A (1 μM) were added sequentially to assess basal respiration, spare respiratory capacity, proton leak, and ATP production, respectively. F–G CaCo2/EV and CaCo2/KITENIN cells were incubated for 48 h and then their metabolism was studied. The extracellular acidification rate (ECAR) and oxygen consumption rate (OCR) were assessed using a Glycolytic Rate Assay Kit on a Seahorse XF96 extracellular flux analyzer. The assay utilizes both ECAR and OCR measurements to determine the glycolytic proton efflux rate (glycoPER). GlycoPER was measured at two time points, and then rotenone (1 μM)/antimycin A (1 μM) and 2-DG (50 mM) were added in sequence. H–I Transwell invasion assays were performed using CaCo2/EV and CaCo2/KITENIN cells. Representative images and the relative number of invaded cells are shown. J To elucidate the mechanism by which KITENIN affects glycolysis, the relative mRNA expression of molecules mediating the Warburg effect (GLUT1, HK2, PKM1, PKM2, and LDHA) was measured in CaCo2/EV and CaCo2/KITENIN cells incubated for 48 h. K–L Protein expression of GLUT1, HK2, PKM1, PKM2, and LDHA. α-Tubulin or actin served as the loading control. M The PKM2/PKM1 ratio was calculated using the relative mRNA expression and protein level of PKM1 and PKM2 after 48 h. Data are the mean ± standard deviation. * p < 0.05; ** p < 0.01; *** p < 0.001