Effects of peptide D2A and its shorter version GEEG on cell proliferation. Effects of increasing doses of peptide: D2A (a, b), GEEG (c, d) and scrambled D2A (e, f) on proliferation of HT-29 (a, c, e) and HT-1080 (b, d, f) cells. Cell numbers were determined at day 4. Values are the mean ± SD from three experiments. Control corresponds to the number of cells cultured in serum-free media without peptide (100% proliferation). *p < 0.01 compared to control