Production of stably transfected K562, RL and HL60 cells by sonoporation.

K562 and RL cell lines were transfected with pEGFP-C1 plasmid and cultured in selection medium containing 1.2 and 1.5 mg/ml of G418, respectively. The microscopy pictures (objective 10×) correspond to light transmission (A1 and B1) and fluorescence images of RL-pEGFP-C1 (A2) and K562-pEGFP-C1 (B2) stable clones. (C) The GFP channel histograms obtained from flow cytometry are shown. Grey indicates non-transfected cell lines and black indicates GFP-transfected cell lines. Flow cytometry analysis revealed 98% GFP positive cells in the stable clones. (D) HL-60 cell line transfected with expression vectors coding for shRNA against cN-II (pScN-II) and control sequence (pScont) were selected with continuous exposure to 1 mg/ml (HL60-pScN-II and HL60-pScont cells) of G418. Western blot analysis clearly showed strong inhibition of cN-II expression in HL60-pScN-II cells compared with cells expressing a non-silencing shRNA. Results are representative of three independent western blot analyses.