Figure 1. Senescent cells upregulate NKG2D ligands. RT-PCR analysis demonstrates a consistent up-regulation of MICA, ULBP1, and ULBP2 in DNA damage-induced senescent (DIS) (A), replicative senescent (RS) (B), and H-RASv12-mediated oncogene-induced senescent (OIS) (C) IMR-90 fibroblasts compared to growing (control) cells. Similarly, DIS WI38 (D) and BJ (E) fibroblasts and DIS hepatic stellate cells (HSCs) (F) also show an up-regulation of NKG2D ligands. The graphs represent the mean and the S.E.M of at least triplicate measurements from at least four independent experiments. Two-tailed t-test *P<0.05, **P<0.001, ***P<0.0001.