S100B-p53 disengagement by pentamidine promotes apoptosis and inhibits cellular migration via aquaporin-4 and metalloproteinase-2 inhibition in C6 glioma cells

Abstract

Abstract. S100 calcium-binding protein B (S100B) is highly expressed in glioma cells and promotes cancer cell survival via inhibition of the p53 protein. In melanoma cells, this S100B-p53 interaction is known to be inhibited by pentamidine isethionate, an antiprotozoal agent. Thus, the aim of the present study was to evaluate the effect of pentamidine on rat C6 glioma cell proliferation, migration and apoptosis in vitro. The change in C6 cell proliferation following treatment with pentamidine was determined by performing a 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyltetrazolium bromide-formazan assay. Significant dose-dependent decreases in proliferation were observed at pentamidine concentrations of 0.05 µM (58.5±5%; P<0.05), 0.5 µM (40.6±7%; P<0.01) and 5 µM (13±4%; P<0.001) compared with the control (100% viability). Furthermore, treatment with 0.05, 0.5 and 5 µM pentamidine was associated with a significant increase in apoptosis versus the untreated cells, as determined by DNA fragmentation assays, immunofluorescence analysis of C6 chromatin using Hoechst staining, and immunoblot analysis of B-cell lymphoma-2 (Bcl-2)-associated X protein (100%, P<0.05; 453%, P<0.01; and 1000%, P<0.001, respectively) and Bcl-2 (-60%, P<0.001; -80.13%, P<0.001; -95%, P<0.001, respectively). In addition, the administration of 0.05, 0.5 and 5 µM pentamidine significantly upregulated the protein expression levels of p53 (681±87.5%, P<0.05; 1244±94.3%, P<0.01; and 2244±111%, P<0.001, respectively), and significantly downregulated the expression levels of matrix metalloproteinase-2 (42±2.3%, P<0.05; 71±2.5%, P<0.01; and 95.8±3.3%, P<0.001, respectively) and aquaporin 4 (38±2.5%, P<0.05; 69±2.6%, P<0.01; and 88±3.0%, P<0.001, respectively), compared with the untreated cells. The wound healing assay demonstrated that cell migration was significantly impaired by treatment with 0.05, 0.5 and 5 µM pentamidine compared with untreated cells (88±4.2%, P<0.05; 64±2%, P<0.01; and 42±3.1%, P<0.001, respectively). Although additional in vivo studies are required to clarify the current in vitro data, the present study indicates that pentamidine and S100B-p53 inhibitors may represent a novel approach for the treatment of glioma.

A transcribed ultraconserved noncoding RNA, Uc.173, is a key molecule for the inhibition of lead-induced neuronal apoptosis

“…Cell apoptosis is regulated by a set of genes and is accompanied by changes in the expression of associated proteins [ 22 ], so we further investigated the anti-apoptotic function of Uc.173 at the protein level. The cascade reaction induced by the caspase cysteine protease family is the key event in the process of cell apoptosis.…”

Chitosan Glutamate-Coated Niosomes: A Proposal for Nose-to-Brain Delivery

“…There is a renewed interest in pentamidine, an antiprotozoal drug discovered in 1938 for treatment of Pneumocystis jirovecii pneumonia, due to the recent discovery of its anti-inflammatory and neuroprotective effect in Alzheimer’s disease (AD) [ 14 , 15 , 16 ]. It is suggested that pentamidine inhibits S100 calcium-binding protein B (S100B) in glial cells by blocking interaction between S100B and tumor suppressor p53.…”

“…It is suggested that pentamidine inhibits S100 calcium-binding protein B (S100B) in glial cells by blocking interaction between S100B and tumor suppressor p53. Overexpression of S100B protein is responsible for upregulation of cell apoptosis and neuroinflammation, which is a key feature of AD [ 15 , 16 ]. The progression of AD could be delayed with anti-inflammatory and antiproliferative effects of pentamidine.…”

S100B Inhibitor Pentamidine Attenuates Reactive Gliosis and Reduces Neuronal Loss in a Mouse Model of Alzheimer’s Disease

“…Moreover, we demonstrated that pentamidine inhibited other proinflammatory events like lipid peroxidation and nitric oxide release. According to our previous observations [ 29 ], S100B protein release was upregulated by A β injection but its level was not affected by pentamidine treatment. To prove that all the above discussed anti-inflammatory effects, together with the reduction of reactive gliosis, were due to the inhibition of S100B/p53 binding, we evaluated p53 expression in the different experimental conditions.…”

“…Here we show that pentamidine, an ancient antiprotozoal drug that inhibits S100B protein, ameliorates gliosis and neuroinflammation in a mouse model of A β -induced AD. Many studies have been addressed in the attempt to enlarge the pharmacological knowledge on pentamidine and its novel therapeutic effects in disorders characterized by S100B upregulation, such as melanoma [ 28 ], glioblastoma [ 29 ], and colitis [ 19 ]. This has led to the discovery that, besides being an antiprotozoal drug, pentamidine also inhibits S100B activity by blocking the interaction at the Ca ++ /p53 site of the protein.…”