Induction of ARC by activated Ras. A, phase contrast micrographs demonstrating transformation of benign MCF-10A breast epithelial cells by H-Ras(V12). Cells were stably transduced with retroviruses encoding empty vector (left) and H-Ras(V12) (right). B and C, activated Ras isoforms induce ARC in MCF-10A benign breast epithelial cells (B) and MDA-MB-231 breast cancer epithelial cells (C). Cells were stably transduced with retroviruses encoding empty vector, H-Ras(V12), or N-Ras(K61) (top). Densitometric quantification of ARC protein levels normalized to those of GAPDH (bottom). Quantitative data presented as means + S.E. from three independent experiments. *, p < 0.01 (Ras compared with empty vector; one-way ANOVA followed by Dunnett test).