The
GDP dissociation inhibitors (
GDIs) are pivotal regulators of
Rho GTPases, which are essential for
tumor progression, particularly in the area of
metastasis. One member of
GDIs was identified as
RhoGDI (Rho
GDP-dissociation inhibitor alpha, or
RhoGDIalpha), but little is known about this
protein in
tumors. In this study, we used comparative proteomic analysis to show that
RhoGDI is markedly up-regulated in metastatic
colorectal cancer (CRC). The elevated level of
RhoGDI protein in metastatic CRC was confirmed by Western blot at the tissue ( n = 24) and cell ( n = 6) levels. Further, we analyzed
RhoGDI protein expression in 126 clinicopathologically characterized CRC cases by immunohistochemistry. Statistical analysis showed that there were significant differences of
RhoGDI overexpression in patients categorized according to
tumor invasion ( p = 0.018),
lymph node metastasis ( p = 0.001) and clinical stage ( p = 0.009). A trend was also identified between high expression of
RhoGDI and shorter overall survival ( p = 0.013). In the present work, we also analyzed the effect of
RhoGDI on CRC cell line. Gene transfection-mediated overexpression of
RhoGDI in HT29 cells, containing a low detectable level of endogenous
RhoGDI, resulted in a significant increase in cell proliferation and motility in vitro. These data suggest that
RhoGDI may promote CRC progression and
metastasis by stimulating
tumor cell growth and migration.