Figure 2

ERK1 and/or ERK2 shRNA treatment of A375 cells reduces clonogenic expansion and growth of colonies. A. Colony formation in soft agar after 21 days using A375 cells exposed to shRNAs (upper panel-phase contrast microscopic appearance after crystal violet staining). Quantification of clone number per 10x microscopic field for cells exposed to shRNAs for duplicate experiments performed with triplicate wells. (lower panel; all values using ERK1 and/or ERK2 shRNA compared to SC shRNA, p < 0.001). B. Appearance of A375 cells after exposure (9 days) to indicated shRNAs revealing crystal violet stained clones readily visible in the SC shRNA treated cultures, but rare to absent in the other wells (upper panel). Quantitation of clone number per well for A375 cells exposed for 9 days to indicated shRNAs for duplicate experiments performed with triplicate wells (lower panel; all values using ERK1 and/or ERK2 shRNA compared to SC shRNA, p < 0.001).