Fig. 5.

Antibody blocking of growth factor receptors. H7 human ES cells were differentiated for 20 days before Percoll separation, and fraction IV cells were cultured for an additional 4 days in serum-free media with various signaling inhibitors. The inhibitors were added for the final 48 hours of culture prior to fixation. Only the PI 3-kinase inhibitor (LY294002) and the IGF-1 receptor blocking antibody significantly inhibited human ES cell-derived cardiomyocyte proliferation (* = P < 0.05), whereas antibodies to the EPO ligand or receptor had no effect.