Figure 4.

ActRII signaling regulates cell proliferation, viability, morphology, and attachment of M17 neuroblastoma cells. (A) Human M17 neuroblastoma cells cultured in OPTI-MEM medium were plated in 0.5% FBS at 40% confluence. After 24 hours, wells were treated with the antihuman ActRII mouse monoclonal antibody (0, 10, or 20 µg/ml). Cell proliferation was assessed using the MTS assay after 3 days. Results are presented as percentage change from the control (mean ± SEM; n = 3; *significantly different from control, P < .001). Ab = antibody. (B) M17 cells were plated in 10% serum at 40% confluence for 24 hours, after which cells were either collected (day 0 control) or treated every day for 3 days with 1) medium containing 10% serum plus lipofectamine (control), plus 2) sense-P oligonucleotide to ActRIIA (sense A), 3) antisense-P oligonucleotide to ActRIIA (antisense A), 4) sense-P oligonucleotide to ActRIIB (sense B), or 5) antisense-P oligonucleotides to ActRIIB (antisense B; final concentration of 0.4 µM each). M17 cell viability was measured using the trypan blue staining assay. Results are presented as number of cells (mean ± SEM; n = 4; *significantly different from day 3 control, P < .005). (C) M17 neuroblastoma cells cultured in OPTI-MEM medium were plated in 0.5% FBS for 1 day before treatment ± antihuman ActRII antibody (20 µg/ml) for 3 days. Original magnification, x 100. Scale, 400 µm. (D) M17 cells were plated exactly as in Figure 4B, and immunoblot analysis was performed for ADAM-15 as in Figure 3C. Quantitation of blot is shown on the right.