Effects of JNK inhibitors on the proliferation and morphology of WS cells. (a) immunoblot showing activation of JNK1/2 in AG03141 WS primary cells, MRC5 cells, and AG03141.tert cells ("y" and "s" are low PD and senescent cells respectively; p-JNK1/2 = activated JNK1/2). (b) Immunoblot showing inhibition of anisomycin-induced JNK1/2 activity by SP600125 as measured by c-Jun phosphorylation (p-c-Jun = activated c-Jun). (c) Effects of SP600125 on the proliferation of AG03141.tert cells (closed triangles represent SP600125 at 10, 25 or 50 μM). (d) Structure of the aminopyridine JNK inhibitors. (e) Titration inhibition of JNK1/2 profile by 1 and 2 as measured by c-Jun phosphorylation ELISA. (f) Immunoblot showing inhibition of JNK1/2 in AG03141.tert cells by 1 and 2 (p-c-Jun = activated c-Jun; arrow shows p-c-Jun). (g) Effects of 1 and 2 on the growth rate of AG03141.tert cells measured as percentage of DMSO control (SB = SB203580 treated cells). (h) Effects of 1 and 2 on the replicative lifespan of primary AG03141F cells. (i) Titration inhibition of the p38 pathway profile by 1 and 2 as measured by HSP27 phosphorylation. (j) F-actin stress fibre phenotype of primary AG03141F cells (left) and the effects of 1 at 25 μM (middle) and 2 at 10 μM (right). (j) Immunoblot showing inhibition of MK2 by 1 (p-p38 and p-HSP27 are activated p38 and HSP27; p-MK2 upper band is activated MK2).