Figure 2. Overexpression of both nucleolin and ErbB2 increases cell tumorigenicity.

A. Colony formation was tested in either naïve MDCK cells or MDCK stable clones expressing ErbB2 and nucleolin, either separately or in combination. Upper panel, representative images. Lower panel, total colonies area presented as fold induction of control (means ±SD). B. MDCK cells overexpressing nucleolin, ErbB2, nucleolin and ErbB2 or none were plated and grown in soft agar, as described in Materials and Methods. Upper panel, photomicrographs of typical wells. Lower panel, number of colonies (size>0.01 mm²; means ±SD). *** (p-value<0.005) - ErbB2 and nucleolin clone compared to the controls; ^^^ (p-value<0.005) - ErbB2/nucleolin clones compared to naïve control.