Objective: To study the anti-invasion effect of SEPT7 gene on U251MG glioma cells and its possible molecular mechanism.
Methods: Recombinant adenovirus vector carrying SEPT7 gene (rAd5-SEPT7) was transduced to human glioma cell line U251MG, and empty adenovirus vector was used as control. Tumor invasion was examined by Transwell method and 3 D-Matrigel assay, and tumor cell migration by wound-healing method and 2 D-Matrigel assay. Three major molecular events associated with cell motility and migration, including changes of expression in MMP2, MMP9, MT1-MMP, TIMP1 and TIMP2, the alteration of integrin alpha(v)beta(3) expression, and the structural change of cytoskeleton protein, tubulin-alpha, in U251 cells transduced with rAd5-SEPT7 were studied by Western blotting, immunofluorescence and laser scanning confocal microscope, respectively.
Results: The invasive and migratory capabilities of cells transduced with rAd5-SEPT7 were inhibited. The expression of extracellular matrix metalloproteinases MMP-2, MMP-9, MT1-MMP and integrin alpha(v)beta(3) was significantly decreased, while the expression of matrix metalloproteinase inhibitor TIMP1, TIMP2 was upregulated. Intracellular cytoskeleton protein-tubulin-alpha in U251 cells exhibited prominent morphological changes which including the appearance of distortion and aggregation resulting from redistribution of tubulin-alpha, and this feature of alteration was similar to the tubulin-alpha structure in normal non-tumor cells.
Conclusion: SEPT7 gene can inhibit the invasion and migration ability of U251 glioma cells. Its molecular mechanism may include that SEPT7 gene reverses the imbalanced state of MMPs/TIMPs, downregulates the expression of integrin alpha(v)beta(3) and alters the structure of tubulin-alpha of U251MG glioma cells. It is suggested that SEPT7 gene could be a good candidate for gene therapy of gliomas.