Selective inhibition of COX Vb expression by A549 cells suppresses anchorage-independent growth in soft agar. A. 105 A549 cells transfected with COX Vb or control siRNA were cultured for 48 hours and viable cells were enumerated using light microscopy. B. After the 48 hour transfection, A549 cells were plated on 6 cm dishes containing DMEM with 0.6% agar. Cells were fed with 0.2% agar in media every three days. After 21 days, soft agar colonies were enumerated. C. Representative photomicrographs of the soft agar colonies. Data are expressed as the mean ± SD of five (A) and three (B) experiments. * p value <0.05.