Expressions of SLPI in various cell lines after SLPI-siRNA transduction. A, the protein expressions of SLPI were evaluated by Western blot following SLPI knockdown by siRNA transfection. B, C and D, the quantities analysis of relative protein levels of SLPI after SLPI-siRNA treatment in three PDAC cell lines. GAPDH was used as the control. Considering the highest expressional inhibition rates in SLPI, si-3 was chosen as the target siRNA for followed investigation. E, relative SLPI mRNA levels detected by qRT-PCR were significantly lower in SLPI-siRNA expressed AsPC-1, BxPC-3 and PANC-1cells than the matched control (PDAC-WT or PDAC-Non), respectively (P < 0.05). F, the immunoblotting analysis of SLPI following SLPI knockdown. G, the quantities analysis of relative protein levels of SLPI after SLPI-siRNA treatment in three PDAC cell lines. Values plotted are means ± SD (n=3). * vs PDAC-WT cell lines, P < 0.05. # vs PDAC-Non cell lines, P < 0.05.