Fig. 2.

Downregulation of HSF1 by HSF1-specific small interfering RNA (siRNA) sequences. Transfection of pancreatobiliary cancer cells lines with 2 different specific siRNA sequences for HSF1 (HSF siRNA #1 and #2) led to a marked decrease in HSF1 mRNA levels at 24 h (A) and HSF1 protein levels at 48 h (B). Nonsilencing siRNA did not influence HSF1 levels, suggesting specificity of the effect. Also, inhibition of HSF1 expression by siRNA is associated with reduced levels of HSP70 protein (B), one of the many downstream proteins regulated by HSF1, suggesting that inhibition of HSF1 expression is influencing downstream pathways. C, control; NS, nonsilencing.