Forced SPARC enhances the expression or activation of pro-survival and pro-death proteins but promotes death signaling in temozolomide (TMZ), whereas HSP27 inhibition promotes apoptotic signaling (SPARC-independent) and autophagic signaling (SPARC-dependent), but suppresses autophagic signaling in the presence of TMZ and SPARC. A-D. Representative Western blots are illustrated for n ≥ 3 experiments of C1.1 control GFP- or H2 SPARC-GFP-expressing cells treated with control siRNA (Csi) or HSP27 siRNA (HSP27si) for 72 hr. Equal numbers of siRNA-treated cells were plated overnight in growth serum, and then treated with 0 (0.1% DMSO control), 40, 80 or 100 μM TMZ for 2 days before lysing. Arrows indicate ≥ 2-fold increases or decreases due to ± SPARC expression and/or ± HSP27 siRNA treatment. Arrow with brackets indicates 30% reduction. # - Indicates a ≥ 2-fold increase in the ratio of LC-3II/LC-3I. Asterisks indicate ≥ 2-fold increases or decreases due to TMZ treatment.