Research Paper Volume 2, Issue 12 pp 924—935

DNA damaging agents and p53 do not cause senescence in quiescent cells, while consecutive re-activation of mTOR is associated with conversion to senescence


Figure 5. Effects of rapamycin and serum starvation on senescence caused by a higher concentration of etoposide. A. Immunoblot: WI-38t and RPE cells were treated with 0.5 μg/ml and 10 μg/ml etoposide (Et) or left untreated (-). The next day, cells were lysed and immunoblot was performed.

B-C: WI-38t and RPE cells were plated at 25000/well in 12 well plates, the next day cells were either pretreated with 10 nM rapamycin (Rapa), placed in serum free medium (no serum) or left in complete medium with 10% serum (control). The next day, 0.5 μg/ml and 10 μg/ml etoposide (Et) was added: in complete medium (control) or with 10 nM Rapamycin (Rapa) or in serum free medium (no serum). After 5 days, cells were washed and cultured in fresh, drug free medium for 11 days and then trypsinized and counted. (in panel C): Before trypsinization, cells treated with 10 μg/ml etoposide (under three conditions: control, Rapa and no serum) were microphotographed.