Endothelin A Receptor Antagonism Enhances Inhibitory Effects of Anti-Ganglioside GD2 Monoclonal Antibody on Invasiveness and Viability of Human Osteosarcoma Cells
Figure 8
Effects of anti-ganglioside GD2 14G2a monoclonal antibody (mAb) alone or in combination with ET A receptor (ETAR) antagonist on phosphorylated Akt (P-Akt) level in osteosarcoma (OS) cells.
Levels of total Akt and P-Akt at serine 473 (ser473) were determined by Western blot analyses 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. Density of the P-Akt (ser473) blot was normalized against that of total Akt to obtain a relative blot density, which was expressed as fold changes to the relative P-Akt (ser473) 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.