Fig. 3. FRA-1 is required for the survival of colon carcinoma cells in suspension. (A) Immunoblot analysis of FRA-1 protein expression in HCT-116 and BE cells 48 hours after transfection of the FRA-1 specific or scrambled siRNAs. (B) Cell-cycle distribution in HCT-116 and BE cells after inhibition of the ERK-MAPK pathway with the synthetic MEK inhibitor PD184352 (or DMSO in control experiments) or after transfection of FRA-1 specific or scrambled siRNAs. Cell-cycle analyses were done either with adherent cells or with cells maintained in suspension for 24 hours. (C) Cell-cycle distribution in HCT-116-RAF:ER cells after activation of RAF:ER with 1 µM tamoxifen (4-OHT) for 24 hours, or ethanol in control experiments, and/or after transfection of FRA-1 specific or scrambled siRNAs. Cell-cycle analyses were done with cells maintained in suspension for 24 hours. Experiments were repeated three times; one representative experiment is shown.