*4.6. ELISA Assays*

The Saos-2 or HOS cells (3.3 <sup>×</sup> <sup>10</sup><sup>5</sup> cells/mL) were incubated for 72 h without or with AKG (5, 10, 25, 50 mM) in 24-well plates containing appropriate culture medium with 2% FBS at 37 ◦C in an atmosphere of 5% CO2. Enzyme-linked immunosorbent assay (ELISA) kits were used to measure the levels of TGF-β (DRG International Inc., Springfield, NJ, USA) and VEGF (Diaclone Besançon, France) in the culture media according to the manufacturer's instructions.
