Celastrol blocks LeTx-mediated cytolysis of RAW264.7 cells subsequent to MAPKK1 cleavage.

<p>(A) RAW264.7 cells were treated with 3 µM celastrol and/or LeTx (10⁻⁸ M PA and 5×10⁻¹⁰ M LF) as indicated for 4 h. Cell viability was assessed using the MTS assay. The means of three experiments±SEM are reported. (B) RAW264.7 cells were treated with LeTx and/or 10 µM celastrol as indicated for 1 h. Cell lysates were subjected to Western blotting using antibodies that detect MAPKK1 or α-tubulin. A representative result of three independent experiments is shown. (C) RAW264.7 cells were exposed to LeTx for indicated amounts of time and viability was assessed using the MTS assay. The means of three experiments±SEM are reported. (D) Celastrol (10 µM) was added to RAW264.7 cells at the indicated times after cells were treated with LeTx (black bars) at t = 0 h or were not treated with toxin (white bars). Cell viability was assessed 4 h after LeTx addition by the MTS assay. The means of three experiments±SEM are reported.