Stem Cell-Like Properties of CK2 beta-down Regulated Mammary Cells

The ubiquitous protein kinase CK2 has been demonstrated to be overexpressed in a number of human tumours. This enzyme is composed of two catalytic alpha or alpha' subunits and a dimer of beta regulatory subunits whose expression levels are probably implicated in CK2 regulation. Several recent papers reported that unbalanced expression of CK2 subunits is sufficient to drive epithelial to mesenchymal transition, a process involved in cancer invasion and metastasis. Herein, through transcriptomic and miRNA analysis together with comparison of cellular properties between wild type and CK2 beta-knock-down MCF10A cells, we show that down-regulation of CK2 beta subunit in mammary epithelial cells induces the acquisition of stem cell-like properties associated with perturbed polarity, CD44(high)/CD24(low) antigenic phenotype and the ability to grow under anchorage-independent conditions. These data demonstrate that a CK2 beta level establishes a critical cell fate threshold in the control of epithelial cell plasticity. Thus, this regulatory subunit functions as a nodal protein to maintain an epithelial phenotype and its depletion drives breast cell stemness.