Downregulation of the RECK-tumor and metastasis suppressor gene in glioma invasiveness.
Invasive behavior is the pathological hallmark of malignant gliomas, being responsible for the failure of surgery, radiation, and chemotherapy. Matrix metalloproteinases (MMPs) are essential for proper ECM remodeling and invasion. The tumor and metastasis suppressor RECK protein regulates at least three members of the MMPs family: MMP-2, MMP-9, and MT1-MMP. In order to mimic the in vivo invasion process, A172 and T98G, respectively, non-invasive and invasive human glioblastoma cell lines, were cultured onto uncoated (control) or type I collagen gel-coated surface, and maintained for up to 7 days to allow establishment of the invasive process. We show that the collagen substrate causes decreased growth rates and morphological alterations correlated with the invasive phenotype. Electronic transmission microscopy of T98G cells revealed membrane invaginations resembling podosomes, which are typically found in cells in the process of crossing tissue boundaries, since they constitute sites of ECM degradation. Real time PCR revealed higher RECK mRNA expression in A172 cells, when compared to T98G cells and, also, in samples obtained from cultures where the invasive process was fully established. Interestingly, the collagen substrate increases RECK expression in A172 cells and the same tendency is displayed by T98G cells. MMPs-2 and -9 displayed higher levels of expression and activity in T98G cells, and their activities are also upregulated by collagen. Therefore, we suggest that: (1) RECK downregulation is critical for the invasiveness process displayed by T98G cells; (2) type 1 collagen could be employed to modulate RECK expression in glioblastoma cell lines. Since a positive correlation between RECK expression and patients survival has been noted in several types of tumors, our results may contribute to elucidate the complex mechanisms of malignant gliomas invasiveness.
Correa
Tatiana C Silveira
TC
Department of Clinical Chemistry and Toxicology, School of Pharmaceutical Sciences, University of São Paulo, Brazil.
Brohem
Carla Abdo
CA
Winnischofer
Sheila Maria Brochado
SM
da Silva Cardeal
Laura Beatriz
LB
Sasahara
Regina Maki
RM
Taboga
Sebastião Roberto
SR
Sogayar
Mari Cleide
MC
Maria-Engler
Silvya Stuchi
SS
D045744:Cell Line, Tumor; D049109:Cell Proliferation; D016543:Central Nervous System Neoplasms / Q000235:genetics / Q000473:pathology*; D015536:Down-Regulation; D058851:GPI-Linked Proteins; D015972:Gene Expression Regulation, Neoplastic; D016147:Genes, Tumor Suppressor; D005910:Glioma / Q000235:genetics / Q000473:pathology*; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000235:genetics; D020780:Matrix Metalloproteinase 9 / Q000235:genetics; D020782:Matrix Metalloproteinases / Q000235:genetics; D053504:Matrix Metalloproteinases, Membrane-Associated; D008562:Membrane Glycoproteins / Q000235:genetics*; D046529:Microscopy, Electron, Transmission; D009361:Neoplasm Invasiveness; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000235:genetics
D058851:GPI-Linked Proteins; D008562:Membrane Glycoproteins; C115460:RECK protein, human; D019716:Tissue Inhibitor of Metalloproteinase-2; D020782:Matrix Metalloproteinases; D053504:Matrix Metalloproteinases, Membrane-Associated; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9