Pantoprazole Induces Mitochondrial Apoptosis and Attenuates NF-κB Signaling in Glioma Cells.

Gastric H+/K+-ATPase or vacuolar-ATPases (V-ATPases) are critical for the cancer cells survival and growth in the ischemic microenvironment by extruding protons from the cell. The drugs which inhibit V-ATPases are known as proton pump inhibitors (PPIs). In the present study, we aimed to evaluate the anticancer efficacy of pantoprazole (PPZ) and its consequences on NF-κB signaling in glioma cells. We have used MTT and clonogenic assay to show PPZ effect on glioma cell growth. Propidium iodide and rhodamine 123 staining were performed to demonstrate cell cycle arrest and mitochondrial depolarization. TUNEL staining was used to evidence apoptosis after PPZ treatment. Immunoblotting and immunofluorescence microscopy were performed to depict protein levels and localization, respectively. Luciferase assay was performed to confirm NF-κB suppression by PPZ. Our results revealed PPZ treatment inhibits cell viability or growth and induced cell death in a dose- and time-dependent manner. PPZ exposure arrested G0/G1 cyclic phase and increased TUNEL positivity, caspase-3 and PARP cleavage with altered pro and anti-apoptotic proteins. PPZ also induced ROS levels and depolarized mitochondria (Δψm) with increased cytosolic cytochrome c level. Further, PPZ suppressed TNF-α stimulated NF-κB signaling by repressing p65 nuclear translocation. NF-κB luciferase reporter assays revealed significant inhibition of NF-κB gene upon PPZ treatment. PPZ exposure also reduced the expression of NF-κB-associated genes, such as cyclin-D1, iNOS, and COX-2, which indicate NF-κB inhibition. Altogether, the present study disclosed that PPZ exerts mitochondrial apoptosis and attenuates NF-κB signaling suggesting PPZ can be an effective and safe anticancer drug for glioma.

Increased ß-catenin/Tcf signaling in pilocytic astrocytomas: a comparative study to distinguish pilocytic astrocytomas from low-grade diffuse astrocytomas.

Although pilocytic and diffuse grade II astrocytomas considered as low-grade tumors, the distinction between them is still a major clinical problem. Previously we reported the activation of Wnt/ß-catenin/Tcf signaling pathway in diffuse astrocytomas, however its role in pilocytic astrocytomas is not well understood. In this study, we investigated the Wnt/ß-catenin/Tcf pathway in pilocytic astrocytomas and compared with diffuse astrocytomas. We observed the differential expression of ß-catenin, Tcf4, Lef1 and c-Myc in astrocytomas particularly higher levels were observed in pilocytic astrocytomas and GBM while very little expression was documented in grade II tumors. Further, immunohistochemical analysis revealed the strong positivity of ß-catenin, Tcf4, Lef1 and c-Myc in pilocytic astrocytomas than that of grade II tumors and also exhibited the strong positivity in vascular endothelial cells of pilocytic astrocytomas and GBM. Hence, Wnt/ß-catenin/Tcf signaling pathway is differentially expressed in astrocytomas, activation of this pathway might be helpful in separating pilocytic astrocytomas from low-grade diffuse astrocytomas.

The nonsteroidal anti-inflammatory drug celecoxib suppresses the growth and induces apoptosis of human glioblastoma cells via the NF-κB pathway.

Gliomas are devastating primary tumors of the central nervous system and tend to recur even after standard therapy. Celecoxib, the selective COX-2 nonsteroidal anti-inflammatory drug, has anti-neoplastic activity against several malignancies. Accumulating evidence suggests that several COX-2-independent mechanisms may also be involved in the anti-tumor effects of celecoxib. Deregulation of the NF-κB signaling pathway contributes to enhanced glioma cell survival, proliferation, and chemoresistance. In this study, we examined the efficacy of celecoxib in suppressing the growth of glioblastoma cell lines. We observed that treatment with celecoxib significantly reduced the proliferation of a variety of GBM cell lines in a dose-dependent manner and also induced apoptosis, which was evident from enhanced caspase-3 and 8 activity, PARP cleavage, and TUNEL positive cells. Celecoxib treatment significantly down-regulated TNF-α induced NF-κB nuclear translocation, NF-κB DNA binding activity, and NF-κB-dependent reporter gene expression in U373 and T98G cells in a dose-dependent manner. Furthermore, celecoxib suppressed IκBα degradation and phosphorylation and reduced IKK activity in a dose-dependent manner. This study provides evidence that celecoxib suppresses the growth of GBM cell lines partly by inhibiting the NF-κB signaling pathway.