FIG. 7.

mDia1-deficient cells are impaired in tumorigenesis and invasion in vivo. (A) Tumor formation in nude mice. Nude mice underwent subcutaneous injection of either WT-NY72 cells or KO-NY72 cells (3 × 10⁵ per site) in the flank, three mice per group and two sites per mouse. Nineteen days after inoculation, tumor formation at the injected sites was photographed. Inoculation of KO-NY72 cells developed no or very small tumors compared to those from WT-NY72 cells (arrowheads). (B) Time course of tumor development. WT-NY72 and KO-NY72 cells were injected into nude mice as described above, and the tumor volumes were measured as described in Materials and Methods. Each point represents a mean ± SEM (n = 6). (C) Histological analysis. Tumors from WT-NY72 and KO-NY72 cells were taken at day 22 after inoculation, sectioned, and stained with hematoxylin and eosin. Photomicrographs of a representative tumor from WT-NY72 cells and a sole tumor formed from six injections of KO-NY72 cells are shown. Boxed areas are magnified below. Note that the tumor from WT-NY72 cells expands to both sides of the muscle layer (arrowheads). Bar, 5 mm.