FIGURE 6.
miR-205 overexpression induces senescence that is reversed by E2F1. A, senescence associated-β-galactosidase activity was increased significantly in cells overexpressing miR-205 as compared with cells expressing control vector. The bar graph shows quantification of stained cells. *, p < 0.05. B, Western blot analysis showing up-regulation in p16INK4a, down-regulation in Rb phosphorylation (Ser-807/811), MCM3 and PCNA in miR-205-expressing cells. *, p < 0.05. C, E2F1 overexpression in miR-205-expressing cells significantly increased cell proliferation. Western blot showing expression of E2F1 in miR-205-expressing cells. D, colony formation assay of melanoma cells expressing miR-205 following transfection with plasmid encoding vector only or vector expressing E2F1 cDNA. E, senescence associated-β-galactosidase activity was decreased in miR-205-expressing cells following transfection with vector expressing E2F1 cDNA. *, p < 0.05. (Experiments depicted in A, C, D, and E were performed in triplicate.).