Cullin1 regulates proliferation, migration and invasion of glioma cells

This study was designed to explore the role of Cullin1 (Cul1) in the pathogenesis of human glioma and to investigate the role of Cul1 in the growth, migration and invasion of glioma cells. Expression of Cul1 in 191 glioma tissues, 8 normal brain tissues and 8 tumor adjacent normal brain tissues was analyzed by tissue microarray and immunohistochemistry. Cul1 expression in human glioblastoma cells was knocked down by specific siRNA to study the effect of down-regulation of Cul1 on proliferation, invasion and migration of glioma cells. Our results showed that Cul1 expression increased significantly in tissues from the benign tumor and malignant tumor in comparison with those from the tumor-adjacent normal brain (P<0.05 for both). We did not find any correlation between Cul1 expression and clinicopathological parameters. In addition, we found that knockdown of Cul1 by RNA interference markedly inhibited cell proliferation and caused cessation of cell cycle. This reduced cell proliferation was due to G1 phase arrest as cyclinA, cyclinD1 and cyclinE were diminished, whereas p21 and p27 were up-regulated. We further demonstrated that silencing of Cul1 in glioma cells inhibited the cell migration and invasion abilities, and down-regulation of MMP-2 and MMP-9 expression greatly contributed to the reduced cell invasion and migration abilities. Our data indicated that Cul1 expression significantly increased in human glioma, and it may be involved in proliferation, migration and invasion of glioma cells.