Western blot analysis of cleaved PARP and caspase 3 proteins

Cells were treated with riluzole (5 or 10 μM) and/or paclitaxel (5–10 nM) and collected by scraping in RIPA lysis buffer (Santa Cruz, CA). Protein (10–30 μg) was separated by SDS-PAGE and transferred to PVD membranes. Detection of PARP and caspase 3 cleavage products was performed using respective primary and secondary antibodies (Cell Signaling Technology, Danvers, MA) and detected by chemiluminescence. Primary blots were reprobed with anti-GAPDH antibody (Novus Biologicals, Littleton, CO).