Small interfering RNA-mediated downregulation of CDK11 and CK2 in breast cancer cells decreases cell viability and inhibits clonal survival. (A) Breast cancer cells were transfected with 30 nM single small interfering RNA (siRNA) or 15 nM each of the two siRNAs combined as indicated. After 96 hours, cell viability was determined relative to the untreated cells. Means ± standard errors (SEs) are presented. *P <0.05. **P <0.01, ***P <0.001 relative to untreated. ^
P = 0.055, #
P <0.05, ##
P <0.01, ###
P <0.001 relative to siCtrl. (B) Triple-negative breast cancer (TNBC) cells were transfected twice with 30 nM single siRNAs or 15 nM each of the two siRNAs combined as indicated and as described in Materials and methods. Seven days after the second transfection, cell colonies were stained and counted. Means ± SE are presented. $
P <0.0001 relative to siCtrl and untreated. (C) Representative crystal violet stained colonies on 35 mm plates 7 days after the second siRNA transfection as described in (B). Cell lines are indicated above the plate images and siRNA transfections are indicated to the left of the plate images. CDK, cyclin-dependent kinase; CK2, casein kinase 2; si, small interfering.