L-165041 protects H9c2 from doxorubicin-induced apoptosis through a Bcl6-independent mechanism.

<p>(A) Pre-treatment with L-165141decreases the number of doxorubicin-induced apoptotic cells. Bcl6 siRNA (siBcl6) does not modify the number of activated caspase-3 positive cells in any of the treatment groups i.e., untreated cells, 1 µM doxorubicin-treated cells, and in cells pretreated with L-165041 and then incubated with doxorubicin. 24 h after treatment, cells were assayed by immunocytochemistry for cleaved caspase-3. Bar graph illustrates the percentage of cleaved-caspase-3 positive cells. *<i>P</i><0.05 versus ct, §<i>P</i><0.05 versus doxorubicin. (B) Effects of L-165041(L-165) and 1 µM doxorubicin (Dox1) on PPARδ and Bcl6 protein expression and on PPARδ and Bcl6 protein interaction. Doxorubicin increases PPARδ levels and down-regulates the amount of total and PPARδ bound Bcl6 (IP-PPARδ WB-Bcl6). Pre-treatment with L-165041 does not modify the effects induced by doxorubicin. H9c2 cells were pre-treated with or without L-165041 for 2 h, then treated with or without 1 µM doxorubicin for 3 h and analyzed after 24 h by western blot. The bar graph shows the protein quantification expressed as a percentage. *<i>p</i><0.05 versus control (ct).