Elf5 modulates cell adhesion and proliferation of breast cancer cells.

T47D (circles) and MCF7 (squares) cells were permanently transduced with DOX-inducible ELF5-V5 or empty retroviral vectors. Pooled cells were grown with puromycin. Representative experiments are shown. Bars, standard error of the mean (SEM). (A) Control cells transduced with empty vector grown in the absence of DOX (−D, open symbols) or presence of DOX from 0 h (+D0 h, closed symbols). (B) Cells transduced with the DOX-inducible ELF5-V5 expression vector grown in the presence of DOX (+D0 h, closed symbols) or absence of DOX (−D, open symbols). Inset Western blot of ELF5-V5 induction. (C) T47D-ELF5-V5 cells were grown as xenografts in nude mice, with (+D) or without (−D) DOX supplementation of food. Inset shows induction of ELF5-V5 expression. (D and E) Basal breast cancer cells HCC1937 (circles, dashed lines) or HCC1187 (squares, solid lines) were transfected with siRNA against ELF5 mRNA (siELF5, solid symbols), or were mock transfected (open symbols) before quantification of cell number with time. Insets, The degree of ELF5 mRNA knockdown was measured by qPCR at 72 h. (F) Cells were arrested at G1-S phase by treatment with hydroxyurea, then released. Histograms show the subsequent distribution of cells within the cell cycle phases by PI staining at the indicated times post release, green +DOX, red –DOX, and Western blots show the expression of key cell cycle regulatory proteins.