Effect of si-RNA transfection on parental cells. (A) Proliferation assay. Cell proliferation was measured by the [3H]thymidine uptake assay after 24 h or 48 h of incubation. Proliferation curve was plotted as radioactivity versus incubation time of cancer cells. No differences in proliferation were seen between si-SW1990 and p-SW1990. Shown data are means ± SD. (B) Detection of MUC5AC mRNA by RT-PCR. mRNA expression of MUC5AC decreased in si-SW1990 and si-BxPC3 compared with parental cells. PCI-64 has no MUC5AC endogeneously.