In vitro and in vivo effects of DDHD1 overexpression on colon cancer cell growth. a Cell viability was measured by MTT assay on SW480 cell lines after 24, 48, 72 or 96 h of transfection with mock or DDHD1 plasmid DNA. The values were plotted as % of growth vs Ctrl (cells transfected with mock plasmid). Each point represents the mean ± SD of three independent experiments. Asterisks indicate statistically significant values in comparison to control (mock) (**p ≤ 0.01). b Levels of DDHD1, ERK 1/2, phospho-ERK 1/2 were determined in the cell lysate of SW480 cells transfected with mock or DDHD1 plasmid DNA. Blots were probed with an antibody against GAPDH to ensure equal loading. c SW480 cells, transfected with mock or DDHD1 plasmid DNA were injected subcutaneously in nude mice as described. Comparison of the mean tumor volume was an index of the pro-tumor effect of DDHD1. A significant interaction was found between (group) and within (experimental time)-subject factors for volumetric data (F = 6.92, p = 0.028). Significant differences in terms of tumor volume were observed between the two groups (8 days p = 0.009; 12 days p = 0.010; 15 days p = 0.024) and within the experimental time (mock at 8 days versus starting point a,p = 0.025; over DDHD1 at 8 days versus starting point b,p = 0.0001; over DDHD1 at 12 days versus 8 days c,p = 0.003; over DDHD1 at 15 days versus 12 days d,p = 0.002). d IL8 and Survivin mRNA levels were evaluated in tumor biopsies by Real-time PCR. e Protein levels of ERK 1/2, phospho-ERK 1/2 and SURVIVIN were analyzed in the mice tumor biopsies