Effects of anti-ganglioside GD2 14G2a monoclonal antibody (mAb) alone or in combination with ET A receptor (ETAR) antagonist on matrix metalloproteinase-2 (MMP-2) protein levels in osteosarcoma (OS) cells.
MMP-2 protein levels were determined by Western blot analyses in in Saos-2 (A), MG-63 (B) and SJSA-1 (C) cells treated with control IgG (50 µg/mL, lane 2), selective ETAR antagonist BQ123 (5 µM, lane 3), stably-transduced ETAR-shRNA (lane 4), 14G2a mAb (50 µg/mL, lane 5), 14G2a+BQ123 (lane 6), 14G2a+ETAR-shRNA (lane 7), and selective phosphatidylinositide 3-kinase (PI3K) inhibitor BKM120 (50 µM, lane 8). The untreated control was in lane 1. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) blotting was used as a loading control. Density of the MMP-2 blot was normalized against that of GAPDH to obtain a relative blot density, which was expressed as fold changes to the relative MMP-2 blot density of the untreated control cells (designated as 1). Three independent experiments were performed for each Western blot analysis. Data values were expressed as Mean+SD. ap<0.05 vs. control or control IgG; bp<0.05 vs. BQ123; cp<0.05 vs. ETAR-shRNA; dp<0.05 vs. 14G2a; ep<0.05 vs. 14G2a+BQ123; fp<0.05 vs. 14G2a+ETAR-shRNA.