GBM cell lines capable of forming caveolae expressed more uPA and matrix metalloproteinase-2 (MMP-2) and/or -9 (MMP-9) and were more invasive than GBM cells devoid of caveola-forming proteins.
The expression of these MMPs was markedly increased in most GBMs with excellent correlation between mRNA and protein levels; activated forms of MMP-2 and MMP-9 were present in 8/18 and 7/18 of GBMs.
This prospective, case control study was aimed to find out an association of MMP-2 gene polymorphism with susceptibility to develop glioblastoma in Indian population.
We find that MMP-2 activity in human U251 GBM xenografts increases (*P=0.03) and collagen IV content decreases (*P=0.01) during vascular endothelial growth factor (VEGF-A) antibody neutralization.
We analysed the transcript expression of CLEC5A in glioblastoma by accessing The Cancer Genome Atlas (TCGA). qRT-PCR was performed to detect the RNA expression of genes in cells and tissues, and Western blot was used to measure the protein levels (Cyclin D1, Bcl-2, BAX, PCNA, MMP2, MMP9, Akt and Akt phosphorylation) in tissues and cells.
This cannabinoid-induced inhibition of MMP-2 expression in gliomas (a) was MMP-2-selective, as levels of other MMP family members were unaffected; (b) was mimicked by JWH-133, a CB(2) cannabinoid receptor-selective agonist that is devoid of psychoactive side effects; (c) was abrogated by fumonisin B1, a selective inhibitor of ceramide biosynthesis; and (d) was also evident in two patients with recurrent glioblastoma multiforme.
Moreover, the expression of MMP-2, its inhibitor TIMP-2 and the tumour invasiveness-related protein SPARC were effectively inhibited by TRAIL in glioblastoma cell lines.
Consistent with this idea, 39% less extracellular MMP2 was measured from knockdown cells identifying one mechanism by which calpain 2 mediates glioblastoma cell invasion.
A significant decline of MMP-9 and MMP-2 secretion in cultured U87MG was detected after incubation with EBB (42.9% and 73.0%, respectively) and EBB + TMZ (38.4% and 68.5%, respectively).
Tumor growth rate and final tumor weight were significantly increased in the animals with the glioblastoma derived from transfected U87-H4645 cells, compared to untransfected and vector control (p<0.01). mRNA expression of β-catenin, CD44, ICAM-1, and MMP-2 in the glioblastoma derived from the transfected U87-H4645 tumors was significantly increased compared with tumors derived from untransfected and vector-control U87 cells (p<0.01).
Immunohistochemically, MT1-MMP and MT2-MMP are localized to the neoplastic astrocytes in glioblastoma samples (17/17 cases and 12/17 cases, respectively), which are also positive for MMP-2.
Further research into the underlying mechanism demonstrated that the effects of miR-125b on the invasion of glioblastoma CD133-positive cells were associated with the alteration of the expression of MMPs (MMP-2 and MMP-9) and corresponding inhibitors (RECK and TIMP3).
Similarly, U87MG cells engineered to overexpress TIMP-2 at the same levels as U87-C1 cells also demonstrated increased MMP-2 activation, indicating that an increase in physiological levels of TIMP-2 can promote MMP-2 activation and invasion in glioblastoma cells.
Activation of PI3K/AKT signaling prevented the suppressive effects of RWDD3 downregulation on glioblastoma cell proliferation and migration, concurrent with increased protein levels of MMP2 and MMP9.
By virtue of its restricted expression in GBM and its role in invasion, Necl-5 may be an attractive target for limiting MMP-2 production in glioblastoma, and therefore limiting dispersal.
Finally, tissue microarray analysis of 68 GBM tissue specimens showed a significant correlation between the overexpression of IGFBP2 and elevated MMP-2 expression.
Measurements of MMP-2 intensity increased with tumor grade, and MMP-2 expression was found to be significantly higher in glioblastomas compared to normal brain tissue (p<0.001), diffuse astrocytomas (p<0.001) and anaplastic astrocytomas (p<0.05).
In medulloblastomas, the expression of mt1-MMP, mt2-MMP, and gelatinase A were also increased, but to a lesser extent than that observed in glioblastomas.