Figure 2. Attenuation of TORC1 signaling in early-passage fibroblasts delays replicative senescence. (A) Cells treated over 70 d with either 1nM or 10 nM rapamycin, and duplication rate measured every 5 d in triplicate. Cumulative duplications displayed on the Y-axis. Rate of duplications is displayed as the slope of the curve. (B) SA-β-gal staining of cells passaged in the presence of rapamycin (1 nM or 10 nM) for 70 d (high passage) or control, unpassaged (low passage). (C) Western blot of high passage and low passage cells cultured in the presence of rapamycin (1 nM or 10 nM).