Inhibition of stress-associated MAPK signaling attenuates SASP expression in CAFs. A, N-CAFs were treated with 100 nmol/L GEM plus DMSO or the above-listed small-molecule inhibitors for 48 hours, and SASP mediator expression was compared with that of untrea... Inhibition of stress-associated MAPK signaling attenuates SASP expression in CAFs. A, N-CAFs were treated with 100 nmol/L GEM plus DMSO or the above-listed small-molecule inhibitors for 48 hours, and SASP mediator expression was compared with that of untreated cells. Drug concentrations and targets: SB203580 10 μmol/L, P38 MAPK; SP600125 20 μmol/L, JNK; BEZ235 1 μmol/L, ATM/ATR/DNA-PK/PI3K/mTOR; AZD77622 200 nmol/L, Chk1/Chk2, VE821 2 μmol/L ATR; KU55933 20 μmol/L, ATM. B, cell lysates from N-CAFs treated with 100 nmol/L GEM and DMSO, SB203580, or SP600125 at the indicated concentrations (μmol/L) were blotted for P38 MAPK and JNK activation as well as their downstream targets, HSP27 and cJUN, respectively. Lysates from untreated N-CAFs were used as a control. Densitometry values are displayed below the blots. All values were normalized to GAPDH, and expression is displayed as the ratio of phospho- to total protein. For all experiments, data represent the composite of two separately performed experiments. The blots displayed in B are from one representative experiment. Paul A. Toste et al. Mol Cancer Res 2016;14:437-447 ©2016 by American Association for Cancer Research