anisomycin and Neuroblastoma

Sorafenib, a multiple kinase inhibitor, is widely used in cancer patients. Recently, clinical studies highlighted the relationship between cognitive deficits and sorafenib exposure. Zinc abundant in the body has been reported to exert neuroprotective activities. However, the effects of zinc supplementation on sorafenib-induced cognitive impairment are still unknown. In the current study, we verified that mice challenged with sorafenib displayed characteristic features of cognitive impairment. However, zinc treatment effectively improved these changes. Histopathological staining also showed that zinc significantly alleviated hippocampal microstructural and ultrastructural damages induced by sorafenib. Meanwhile, zinc significantly reduced sorafenib-induced ROS production and neuronal cells apoptosis in vivo and vitro. Additionally, we also investigated whether zinc protected against sorafenib-induced neuronal cells apoptosis via ROS/JNK pathway through treating SH-SY5Y cells with the NAC or the specific JNK activator anisomycin. The results indicated that NAC performed the same protective effects as zinc in sorafenib-challenged SH-SY5Y cells and activation of JNK by anisomycin partly abolished the protective effects of zinc. Collectively, the present study suggested that inhibition of oxidative stress and the JNK pathway might contribute to the protective effects of zinc against sorafenib-caused cognitive impairment in vivo and vitro.

Topics: Animals; Anisomycin; Apoptosis; Cell Line, Tumor; Cognitive Dysfunction; Dietary Supplements; Humans; MAP Kinase Signaling System; Mice; Neuroblastoma; Oxidative Stress; Reactive Oxygen Species; Sorafenib; Zinc

Necroptosis is an essential pathophysiological process in cerebral ischemia-related diseases. Therefore, targeting necroptosis may prevent cell death and provide a much-needed therapy. Ansiomycin is an inhibitor of protein synthesis which can also activate c-Jun N-terminal kinases. The present study demonstrated that anisomycin attenuated necroptosis by upregulating CHIP (carboxyl terminus of Hsc70-interacting protein) leading to the reduced levels of receptor-interacting protein kinase 1 (RIPK1) and receptor-interacting protein kinase 3 (RIPK3) proteins in two in vitro models of cerebral ischemia. Further exploration in this research revealed that losing neither the co-chaperone nor the ubiquitin E3 ligase function of CHIP could abolish its ability to reduce necroptosis. Collectively, this study identifies a novel means of preventing necroptosis in two in vitro models of cerebral ischemia injury through activating the expression of CHIP, and it may provide a potential target for the further study of the disease.

Topics: Animals; Anisomycin; Anti-Bacterial Agents; Apoptosis; Cell Hypoxia; Female; Gene Expression Regulation, Enzymologic; Glucose; Mice; Necrosis; Neuroblastoma; Oxygen; Rats; Rats, Sprague-Dawley; Ubiquitin; Ubiquitin-Protein Ligases

Oxidative stress and inflammation as the pathological components of Alzheimer's disease (AD) have been well understood. Among a diversity of mitogen-activated protein kinase (MAPK) family members, JNK and p38 MAPK subfamilies are relevant to the response of environmental stress, inflammatory stimuli, or other insults. Recent studies have demonstrated that epigenetic mechanisms may play a pivotal role in AD pathogenesis and development. In the present study, we have investigated epigenetic mechanisms such as DNA methylation and histone acetylation involved in the activation of stress-related signaling pathways for amyloid-β (Aβ) production. Human neuroblastoma SH-SY5Y cells were treated by anisomycin, an activator of stress-related MAPKs (JNK and p38 MAPK). A significant increase of intracellular Aβ level in anisomycin-treated SH-SY5Y cells was observed. The expression of amyloid-β precursor protein (APP), β-site APP-cleaving enzyme 1 (BACE1), and presenilin 1 (PS1) was upregulated by demethylation in three gene promoters associated with the reduction of methyltransferases (DNMTs). Meanwhile, an enhanced level of global histone H3 acetylation accompanied with upregulation of histone acetyltransferases p300/CREB-binding protein (CBP) and downregulation of histone deacetylases (HDACs) was also observed. These findings indicated that the activation of stress-related signaling pathways could result in the increased transcription of APP, BACE1, and PS1 genes through DNMT-dependent hypomethylation and histone H3 hyperacetylation, thus leading to Aβ overproduction. Moreover, our findings provided a novel insight into epigenetic mechanisms by which oxidative stress contributes to the pathogenesis of AD.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Anisomycin; Cell Line, Tumor; Epigenesis, Genetic; Humans; Neuroblastoma; Oxidative Stress; Protein Synthesis Inhibitors

Wnt factors are a large family of signaling molecules that play important roles in the regulation of cell fate specification, tissue polarity and cell movement. In the nervous system, Wnts also regulates the formation of neuronal connection acting as retrograde signals that regulate the remodeling of the axons prior to the assembly of the presynaptic apparatus. The scaffold protein Dishevelled (Dvl) mimics the effect of Wnt on the neuronal cytoskeleton by increasing the number of stable microtubule along the axon shaft and inducing the formation of looped microtubules (MT) at enlarged growth cones. A divergent Wnt-Dvl canonical pathway which bifurcates downstream of Gsk3beta regulates MT dynamics.. Here we show that the Wnt pathway also activates c-Jun N-terminal kinase (JNK) to regulate MT stabilization. Although in the Wnt planar cell polarity (PCP) pathway, JNK lays downstream of Rho GTPases, these GTPases are not required for Wnt-mediated MTs stability. Epistatic analyses and pharmacological studies suggest that the Wnt-Dvl signalling regulates the dynamic of the cytoskeleton through two different pathways that lead to inhibition of Gsk3beta and activation of JNK in the same cell.. We demonstrate a novel role for JNK in Wnt-mediated MT stability. Wnt-Dvl pathway increases MT stability through a transcription independent mechanism that requires the concomitant inhibition of Gsk3beta and activation of JNK. These studies demonstrate that Wnts can simultaneously activate different signalling pathways to modulate cytoskeleton dynamics.

Topics: Adaptor Proteins, Signal Transducing; Animals; Animals, Newborn; Anisomycin; Anthracenes; Bucladesine; Cell Differentiation; Cell Line, Tumor; Cells, Cultured; Cerebellum; Dishevelled Proteins; Enzyme Activation; Enzyme Inhibitors; Gene Expression Regulation, Neoplastic; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; JNK Mitogen-Activated Protein Kinases; Mice; Microtubules; Neuroblastoma; Neurons; Nocodazole; Phosphoproteins; Time Factors; Transfection; Wnt Proteins

Tau is a microtubule-associated protein that is functionally modulated by phosphorylation and hyperphosphorylated in several neurodegenerative diseases. Because phosphorylation regulates both normal and pathological tau functioning, it is of great interest to identify the signalling pathways and enzymes capable of modulating tau phosphorylation in vivo. The present study examined changes in tau phosphorylation and localization in response to osmotic stress, which activates the stress-activated protein kinases (SAPKs), a family of proline-directed protein kinases shown to phosphorylate tau in vitro and hypothesized to phosphorylate tau in Alzheimer's disease. Immunoblot analysis with phosphorylation-dependent antibodies revealed that osmotic stress increased tau phosphorylation at the non-Ser/Thr-Pro sites Ser-262/356, within the microtubule-binding domain, as well as Ser/Thr-Pro sites outside of tau's microtubule-binding domain. Although all SAPKs examined were activated by osmotic stress, none of the endogenous SAPKs mediated the increase in tau phosphorylation. However, when transfected into SH-SY5Y cells, SAPK3, but not the other SAPKs examined, phosphorylated tau in situ in response to activation by osmotic stress. Osmotic-stress-induced tau phosphorylation correlated with a decrease in the amount of tau associated with the cytoskeleton and an increase in the amount of soluble tau. This stress-induced alteration in tau localization was only partially due to phosphorylation at Ser-262/356 by a staurosporine-sensitive, non-proline-directed, protein kinase. Taken together, these results suggest that osmotic stress activates at least two tau-directed protein kinases, one proline-directed and one non-proline-directed, that SAPK3 can phosphorylate tau on Ser/Thr-Pro residues in situ, and that Ser-262/356 phosphorylation only partially regulates tau localization in the cell.

Topics: Anisomycin; Binding Sites; Cell Compartmentation; Cytoskeleton; Enzyme Activation; Epitopes; Humans; Mitogen-Activated Protein Kinase 12; Mitogen-Activated Protein Kinases; Nerve Tissue Proteins; Neuroblastoma; Osmotic Pressure; Phosphorylation; Protein Kinase Inhibitors; Recombinant Proteins; Sorbitol; Staurosporine; tau Proteins; Tumor Cells, Cultured

The effects of protein synthesis inhibitors (cycloheximide, anisomycin, puromycin and emetine) on the growth of human brain tumor cells were investigated using U-373 MG human astrocytoma and SK-N-MC human neuroblastoma cell lines. These agents inhibited the growth of the tumor cells in a dose-dependent manner. However, these agents did not affect cell viability evaluated by the trypan blue exclusion method, indicating that growth inhibition was due to the inhibition of cell proliferation rather than the induction of cytotoxicity. Anti-proliferation induced by these agents was significantly blocked by the treatments with either free radical scavengers or antioxidants. These results suggest that enhanced oxidative stress may be involved in the anti-proliferation induced by the protein synthesis inhibitors in human brain tumor cells.

Topics: Anisomycin; Astrocytoma; Brain Neoplasms; Cell Division; Cycloheximide; Drug Screening Assays, Antitumor; Emetine; Humans; Neuroblastoma; Protein Synthesis Inhibitors; Puromycin; Tumor Cells, Cultured