The comparison of apoptosis-related protein expressions in neurotoxin-based in vitroParkinson’s Disease models

Programmed cell death (apoptosis) is mainly responsible for neuronal damage in neurodegenerative diseases. Thus, inhibition of apoptosis could represent an effective strategy in the prevention of these diseases. in this study, we aimed to compare the apoptotic responses of neurotoxins that are widely used to induce neuronal damage incell culture studies and help to decide the most suitable experimental model for drug studies that target apoptosis. Cell viability analyses were performed by MTT assay following 1-methyl-4-phenylpyridinium (MPP+), 6-hydroxydopamine (6-OHDA), rotenone andparaquat treatments at three different time points(12, 24, 48h). Pro-apoptotic (Bax, Bad, Bak), anti-apoptotic (Bcl-2, Bcl-xl) protein levels and total caspase-3 protein levels were determined by Western Blotting technique following treatments. As expected, all neurotoxins managed to trigger cell death and apoptotic pathway. on the other hand, each neurotoxin was found to enhance and/or reduce the levels of different proteins that are associated with apoptosis. Due to different responses of apoptosis related proteins to neurotoxins, it can be concluded that the determination of target proteins with a number of protein-binding assays prior to cell culture studies and then deciding an in vitro model are essential while screening newly synthesized drugs that target apoptosis

Potential Cytotoxic Activity of Psephellus pyrrhoblepharus Extracts

Many species of Psephellus and Centaurea genuses have pharmacological activities including antiinflamatory, antipyretic, cytotoxic etc. Psephellus pyrrhoblepharus (Boiss.) Wagenitz (Centaurea pyrrhoblephara), an endemic plant, was collected from Elazığ, Turkey. Liver cancer is affecting millions of people all over the world. Recent days interest in use of plant-derived compounds for therapeutic purposes in cancer is increasing. So any approach to treat liver cancer is extremely valuable. We aimed to evaluate the cytotoxic potential of extracts (methanol:water 1:1, chloroform and n-hexane) of aerial parts of P. pyrrhoblepharus using human liver cancer cell (HepG2) by utilizing the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) assay in different concentrations (50,100,200 µg/mL) and time points (6, 12, 24 h). Regarding the cytotoxicity, cell viability was decreased following extract exposures at different time points. However, the highest cytotoxic activity was observed in 100 µg/mL concentrations of chloroform extract at 24 h. Chloroform extract of plant showed the highest cytotoxic activity in 200 µg/mL concentrations when compared to methanol:water and n-hexane extracts at 12 h. It can be suggested that used extracts of P. pyrrhoblepharus exert cytotoxic effect in HepG2 carcinoma cells in a dose- and time-dependent manner. Generally, results provide information regarding the threshold concentrations of P. pyrrhoblepharus extracts that might be used in different applications without toxicity hazards

Design, synthesis, cytotoxic activity, and apoptosis inducing effects of 4- and N-substituted benzoyltaurinamide derivatives

In this study, a group of 4-substituted benzoyltaurinamide derivatives were designed, synthesized, and investigated for their anticancer activity against three cancer cell lines and one nontumorigenic cell line by MTT assay. Among the final compounds, methoxyphenyl derivatives 14, 15, 16 were found to be effective against all the tested cancerous cell lines with promising selectivity. The most active compounds were further evaluated to determine the molecular mechanism of their anticancer activity by using western blot assay and the Annexin V-FITC/PI test. Compound 14 (in SH-SY5Y and MDA-MB-231 cell lines) and 15 (in SH-SY5Y cell line) were found to induce intrinsic apoptotic pathway by upregulating BAX, caspase-3, and caspase-9, while downregulating Bcl-2 and Bcl-xL expression levels. According to mechanistic studies, compounds displayed their anticancer activity via three different mechanisms: a. caspase-dependent, b. caspase-independent, and c. caspase-dependent pathway that excluded caspase-9 activation. As a result, this study provides interesting data which can be used to design new taurine-based anticancer derivatives

Regulation of the Nrf2 Pathway by Glycogen Synthase Kinase-3β in MPP⁺-Induced Cell Damage

Recently, nuclear translocation and stability of nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2) have gained increasing attention in the prevention of oxidative stress. The present study was aimed to evaluate the regulatory role of glycogen synthase kinase-3β (GSK-3β) inhibition by tideglusib through the Nrf2 pathway in a cellular damage model. Gene silencing (siRNA-mediated) was performed to examine the responses of Nrf2-target genes (i.e., heme oxygenase-1, NAD(P)H:quinone oxidoreductase1) to siRNA depletion of Nrf2 in MPP+-induced dopaminergic cell death. Nrf2 and its downstream regulated genes/proteins were analyzed using Real-time PCR and Western Blotting techniques, respectively. Moreover, free radical production, the changes in mitochondrial membrane potential, total glutathione, and glutathione-S-transferase were examined. The possible contribution of peroxisome proliferator-activated receptor gamma (PPARγ) to tideglusib-mediated neuroprotection was evaluated. The number of viable cells and mitochondrial membrane potential were increased following GSK-3β enzyme inhibition against MPP+. HO-1, NQO1 mRNA/protein expressions and Nrf2 nuclear translocation significantly triggered by tideglusib. Moreover, the neuroprotection by tideglusib was not observed in the presence of siRNA Nrf2. Our study supports the idea that GSK-3β enzyme inhibition may modulate the Nrf2/ARE pathway in cellular damage and the inhibitory role of tideglusib on GSK-3β along with PPARγ activation may be responsible for neuroprotection

Efficient synthesis and first regioselective C-6 direct arylation of imidazo[2,1-c][1,2,4]triazine scaffold and their evaluation in H2O2-induced oxidative stress

Oxidative stress and apoptosis are both associated with various acute and chronic disorders. Thus, the aim of the present study is to synthesize imidazo[2,1-c][1,2,4]triazines derivatives and to evaluate their effects in H2O2-induced oxidative stress in human neuroblastoma cell line (SH-SY5Y cells). The effects of the compounds on cell viability were measured by MTT assay and the changes in stress and apoptosis-related proteins were investigated by PathScan® Stress and Apoptosis Signaling Antibody Array kit and Western Blot technique. In particular, four compounds were found to protect SH-SY5Y cells from H2O2-induced toxicity by increasing Bcl-2/Bax ratio, regulating PI3-K/Akt cascade and inhibiting the ERK pathway

Evaluation of the cellular protection by novel spiropyrazole compounds in dopaminergic cell death

The loss of neurons is strongly correlated with aging and aging-associated disorders. In this study, cell viability assays and mitochondrial function were performed to evaluate the effect of new spiro-pyrazole derivatives, prepared from aldehydes and 3-amino-1-phenyl-2-pyrazolin-5-one, on neuroprotection in an in vitro model of dopaminergic cell death induced by 1-methyl-4-phenylpyridinium (MPP+). The percentages of neuroprotection by derivatives were found between 21.26% and 52.67% at selected concentrations (10-50 μM) with compound 4d exerting the best neuroprotective effect. The results show that the studied spiropyrazolones perform important roles in dopaminergic neuroprotection and can be used for potential new therapies in the treatment of neurodegenerative disorders including Parkinson's disease