Morphology of IGFBP-rP1 expressed cells and the control cells . Three colon cancer cell lines (RKO, SW620, CW2) were cultured in DMEM medium. Phase-contrast micrographs of various cells were photographed. A, Parental blank cells (-bl). B, Cells transfected with PcDNA3.1 empty vector (-ev). C, Cells transfected with PcDNA3.1(IGFBP-rP1) (-rp). D, Cells treated with recombinant IGFBP-rP1 protein for 48 hr (-pr, 4 μg/ml for SW620 and CW2, 10 μg/ml for RKO,). RKO cells, Magnification: 100. SW620, CW2 cells, Magnification: 200.