The apoptosis-resistance in t-AUCB-treated glioblastoma cells depends on activation of Hsp27.

We previously reported that sEH inhibitor t-AUCB suppresses the growth of human glioblastoma U251 and U87 cell lines and induces cell-cycle G0/G1 phase arrest. In present study, we found even 96 h-treatment of 200 μM t-AUCB can not induce apoptosis in U251 and U87 cells. We also revealed that 200 μM t-AUCB significantly elevates the activation of p38 MAPK, MAPKAPK2 and Hsp27. The p38 MAPK inhibitor SB203580 and the inhibitor of Hsp27 phosphorylation, KRIBB3, were used to investigate the mechanism of the apoptosis-resistance. The results showed that, after blocking the activation of Hsp27 by SB203580 or KRIBB3, 200 μM t-AUCB significantly induces apoptosis and increases caspase-3 activities in U251 and U87 cells. Our data demonstrated that t-AUCB induces cell apoptosis after blocking itself-induced activation of Hsp27, and that the activation of Hsp27 may confer chemoresistance in GBM cells. The combination of t-AUCB and the inhibitor of Hsp27 phosphorylation may be a potential strategy for treatment of glioblastoma.