4-(5-benzo(1-3)dioxol-5-yl-4-pyridin-2-yl-1h-imidazol-2-yl)benzamide and Glioma

Studies have shown that the abnormal expression of leucine-rich α2 glycoprotein 1 (LRG1) is associated with multiple malignancies, yet its role in glioma pathology remains to be elucidated. In this study, we investigated the role of LRG1 in regulating proliferation, migration and invasion of glioma cells by establishing glioma cell strains with constitutively silenced or elevated LRG1 expression. LRG1 overexpression and silenced cell lines demonstrated modulation of glioma cellular proliferation, migration and invasion through MTT, cell scratching and Transwell assays. Furthermore, overexpression of LRG1 led to augmented activation of transforming growth factor-β (TGF-β) signaling pathway as well as downregulation of E-cadherin and resultant enhanced invasiveness, which was reversed by TGF-β signaling pathway inhibitor SB431542. In summary, our findings suggest that LRG1 promotes invasion and migration of glioma cells through TGF-β signaling pathway.

Topics: Benzamides; Cell Line, Tumor; Cell Movement; Dioxoles; Glioma; Glycoproteins; Humans; Neoplasm Invasiveness; Receptors, Transforming Growth Factor beta; Signal Transduction; Transforming Growth Factor beta

Angiogenesis is the hallmark of malignant gliomas positively correlated with the vascular endothelial growth factor (VEGF) expression. We previously reported that expression levels of Nodal, a member of transforming growth factor-β super family, correlate with the malignant invasive behavior of human glioma cells. In this study, we show that knockdown of Nodal suppresses glioma angiogenesis by inhibition of VEGF. In human primary glioma specimens, expression of Nodal positively correlates with WHO glioma tumor grades and expression of VEGF in the corresponding glioma specimens. In human U87MG glioma cells, knockdown of endogenous Nodal by RNA interference (RNAi) significantly decreases colony formation and secretion of VEGF. In vivo, cellular depletion of Nodal in U87MG inhibited brain glioma growth and prolonged the survival of mice with U87MG/shNodal glioma compared with controls. Inhibition of Nodal suppressed tumor vessel growth in U87MG gliomas. Using Nodal inhibitor (SB431542), silencing Nodal, or overexpressing Nodal in the U87MG, GBM8401, and GBM glioma cells, our further experiments revealed that Nodal-induced VEGF expression might, at least in part, mediate through the ERK1/2-HIF-1α-mediated signaling pathway. Taken together, our data revealed that alteration of Nodal expression in glioma cells resulted in changes to VEGF secretion, and subsequent colony formation, in vivo tumor growth, and angiogenesis, all of which are consistent with the regulation of VEGF through the ERK1/2-HIF-1α-mediated signaling, suggesting that Nodal may serve as a potential therapeutic target for the treatment of human gliomas.

Topics: Analysis of Variance; Animals; Benzamides; Brain Neoplasms; Cell Line, Transformed; Cell Proliferation; Computational Biology; Dioxoles; Dose-Response Relationship, Drug; Enzyme Inhibitors; Enzyme-Linked Immunosorbent Assay; Flavonoids; Gene Expression Regulation, Neoplastic; Glioma; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Magnetic Resonance Imaging; Mice; Neovascularization, Pathologic; Nodal Protein; Platelet Endothelial Cell Adhesion Molecule-1; RNA Interference; Signal Transduction; Time Factors; Vascular Endothelial Growth Factor A; Xenograft Model Antitumor Assays

The transforming growth factor β1 (TGF-β1) belongs to a family of structurally related polypeptide factors. TGF-beta plays an important role in the pathobiology of invasion of malignant gliomas. The objective of the present study was to investigate the impact of TNF-α converting enzyme (TACE/ADAM17) signaling on the process of TGF-β1-stimulated migration and invasion of T98G glioma cells. We found that TGF-β1 increased migration and invasiveness in glioma cells. Addition of the TGF-β1 receptor inhibitor, SB431542, reduced the TGF-β1-stimulated migration and invasiveness of glioma cells. In addition, TGF-β1-induced migration and invasiveness were also blocked by exposure to an ADAM17 inhibitor, TAPI-2. Furthermore, ADAM17 mRNA and protein expression were up-regulated by TGF-β1. Treatment with SB431542 and TAPI-2 blocked TGF-β1-induced ADAM17 protein expression. In summary, these results indicate that TGF-β1 promotes cell migration and invasiveness of glioma cells through stimulation of ADAM17.

Topics: ADAM Proteins; ADAM17 Protein; Benzamides; Cell Line, Tumor; Cell Movement; Dioxoles; Enzyme Activation; Gene Expression Regulation, Neoplastic; Glioma; Humans; Neoplasm Invasiveness; RNA, Messenger; Signal Transduction; Transforming Growth Factor beta1

Transforming growth factor-beta (TGF-beta) is a multifunctional cytokine that promotes malignant glioma invasion, angiogenesis, and immunosuppression. Antisense oligonucleotide suppression of TGF-beta(2) ligand expression has shown promise in preclinical and clinical studies but at least two ligands mediate the effects of TGF-beta in gliomas. Therefore, we examined the effects of SB-431542, a novel, small molecule inhibitor of the type I TGF-beta receptor, on a panel of human malignant glioma cell lines. SB-431542 blocked the phosphorylation and nuclear translocation of the SMADs, intracellular mediators of TGF-beta signaling, with decreased TGF-beta-mediated transcription. Furthermore, SB-431542 inhibited the expression of two critical effectors of TGF-beta-vascular endothelial growth factor and plasminogen activator inhibitor-1. SB-431542 treatment of glioma cultures inhibited proliferation, TGF-beta-mediated morphologic changes, and cellular motility. Together, our results suggest that small molecule inhibitors of TGF-beta receptors may offer a novel therapy for malignant gliomas by reducing cell proliferation, angiogenesis, and motility.

Topics: Active Transport, Cell Nucleus; Activin Receptors, Type I; Benzamides; Cell Line, Tumor; Cell Movement; Cell Proliferation; Dioxoles; DNA-Binding Proteins; Gene Expression Regulation, Neoplastic; Glioma; Humans; Phosphorylation; Protein Serine-Threonine Kinases; Receptor, Transforming Growth Factor-beta Type I; Receptors, Transforming Growth Factor beta; Smad Proteins; Trans-Activators; Transcription, Genetic; Transforming Growth Factor beta