Knockdown of S100A7 in NCI-H520 cells. Short-hairpin RNA (shRNA) sequence S4 obtains most robust knockdown of S100A7 messenger RNA and protein. ANCI-H520 cells were stably transduced with green fluorescent protein (GFP)-tagged pUSE shRNA, (A) to determine the optimal conditions for transduction, before transducing cells with vector particles containing nontargeted shRNA as a control, or shRNA targetingS100A7. Growth selection for transduced cells was with puromycin. Four distinct shRNA sequences (S1 to S4) targeting groupS100A7 were used to create 4 different knockdown cell lines. (B). Knockdown was confirmed by messenger RNA and (C) protein analysis. The most robust knockdown in protein was with sequence S4.