Figure 6. ERK activity regulates MICA and ULBP2 expression in DIS cells. Western blot analysis was performed on lysates from DIS IMR-90 cells and growing cells to evaluate ERK1/2 phosphorylation in senescent cells and to assess the effect of PD184352 (10μM, 48 hours) on ERK1/2 phosphorylation (A). Total ERK and tubulin expression were evaluated as controls. (B,C) The expression level of MICA and ULBP2 was determined following inhibition of ERK activity for 48 hours on DIS (B) and OIS (C) cells. Two additional inhibitors of MEK (AZD6244 and GSK1120212) also reduced ERK1/2 phosphorylation (D and E) and significantly reduced the expression of MICA and ULBP2 over indicated incubation periods as assessed by RT-PCR (F and G). PD184352 also significantly reduced the expression of indicated cytokines as assessed by RT-PCR (H). Data presented as mean with S.E.M of three independent experiments. Two-tailed t-test *P<0.05, **P<0.001, ***P<0.0001.