Cooperative effect of antisense-Rb and antisense-p53 oligomers on the extension of life span in human diploid fibroblasts, TIG-1.

Normal human diploid fibroblasts, TIG-1, which have a replicative life span of about 62 population doublings (PD), tended to senesce after about 50 PD with a gradual decrease in sensitivity to serum. Treatment of TIG-1 cells with the antisense-Rb oligomer, which completely depleted the retinoblastoma susceptibility gene product (RB), extended life span by about 10 PD. Treatment with the antisense-p53 oligomer alone had no effect; however, cotreatment with the antisense-Rb oligomer further potentiated the extension and the increased sensitivity to serum caused by the antisense-Rb oligomer alone, suggesting that p53 and RB function in separate, yet complementary pathways in signal transduction to senescence. The c-fos expression, which is presumed to be regulated negatively by RB, was not stimulated in partially senescent TIG-1 cells by treatment with the antisense-Rb oligomer.