The antioxidant N-acetyl cysteine suppresses lidocaine-induced intracellular reactive oxygen species production and cell death in neuronal SH-SY5Y cells

Dose-dependent multi-organ injury following lipopolysaccharide gas inhalation

Lipopolysaccharide (LPS) is widely used to establish various animal models, including models of acute lung injury, cardiomyocyte damage, and acute kidney injury. Currently, there is no consensus on the diagnosis and treatment of LPS-induced disease. We herein present a case series of four patients who developed dose-dependent multi-organ injury, including acute lung injury and acute kidney injury, after inhaling LPS gas in a sealed room. These patients exhibited varying degrees of multi-organ injury characterized by inflammatory cell infiltration and secretion of proinflammatory cytokines. One patient showed progressive symptoms even with active treatment, leading to mild pulmonary fibrosis. This study emphasizes the importance of early diagnosis and treatment of significant LPS exposure and suggests personalized treatment approaches for managing LPS poisoning.

Trial watch: local anesthetics in cancer therapy

Preclinical evidence indicates potent antitumor properties of local anesthetics. Numerous underlying mechanisms explaining such anticancer effects have been identified, suggesting direct cytotoxic as well as indirect immunemediated effects that together reduce the proliferative, invasive and migratory potential of malignant cells. Although some retrospective and correlative studies support these findings, prospective randomized controlled trials have not yet fully confirmed the antineoplastic activity of local anesthetics, likely due to the intricate methodology required for mitigating confounding factors. This trial watch aims at compiling all published preclinical and clinical research, along with completed and ongoing trials, that explore the potential antitumor effects of local anesthetics.

Effect of N-Acetylcysteine on Cisplatin Toxicity: A Review of the Literature

N-acetylcysteine (NAC) is a membrane-permeable cysteine precursor capable of enhancing the intracellular cysteine pool, enhancing cellular glutathione (GSH) synthesis, and thus potentiating the endogenous antioxidant mechanism. Late administration of NAC after cisplatin has been shown in different in vivo studies to reduce the side effects caused by various toxicities at different levels without affecting the antitumor efficacy of platinum, improving total and enzymatic antioxidant capacity and decreasing oxidative stress markers. These characteristics provide NAC with a rationale as a potentially effective chemo protectant in cisplatin-based therapeutic cycles. NAC represents a potential candidate as a chemoprotective agent to decrease toxicities secondary to cisplatin treatment. It suggests that it could be used in clinical trials, whereby the effective dose, timing, and route should be adjusted to optimize chemoprotection. This review provides an overview of the effect of NAC on cisplatin toxicity, a drug widely used in the clinic in adults and children.

Effect of lidocaine on cognitively impaired rats: Anti-inflammatory and antioxidant mechanisms in combination with CRMP2 antiphosphorylation

OBJECTIVE

Studies have shown that lidocaine has antioxidative stress, anti-inflammatory, and nerve-protective effects. The current study investigated the effects of lidocaine on cognitive function in rats with cognitive dysfunction.

METHODS

A total of 48 rats were randomly assigned to four groups of 12 rats each: control group; L (lidocaine) + D (d-galactose) group, d-galactose group (D group); and D + L group. We assessed cognitive function using a Morris water maze (MWM) and pathologic changes of hippocampal sections. An enzyme-linked immunosorbent assay (ELIZA) was used to detect serum malondialdehyde (MDA) and superoxide dismutase (SOD) levels in rats, and protein immunoblotting (western blot) was used to detect brain tissue proteins (collapsing response mediator protein-2 [CRMP2], phosphorylated-collapsing response mediator protein-2 [P-CRMP2], and β-amyloid protein [Aβ]).

RESULTS

The MWM showed that the d-gal group (284.09 ± 20.46, 5.20 ± 0.793) performed worse than the L + D (265.37 ± 22.34, 4.170 ± 0.577; p = .000) and D + L groups (254.72 ± 27.87, 3.750; p = .000) in escape latency and number of platform crossings, respectively. The L + D group (44.94 ± 2.92 pg/mL, 6.22 ± 0.50 pg/mL, and 460.02 ± 8.26 nmol/mL) and D + L group (46.88 ± 2.63 pg/mL, 5.90 ± 0.38 pg/mL, and 465.6 ± 16.07 nmol/mL) had significantly lower serum inflammatory levels of interleukin-6, tumor necrosis factor-α, and MDA than the d-gal group (57.79 ± 3.96 pg/mL, 11.25 ± 1.70 pg/mL, and 564.9 ± 15.90 nmol/mL), respectively. The L + D group (3.17 ± 0.41 μg/mL) and D + L group (3.08 ± 0.09 μg/mL) had significantly higher serum inflammatory levels of SOD than the d-gal group (2.20 ± 0.13 μg/mL) (all p = .000). The levels of CRMP2, P-CRMP2, and Aβ in the brain tissue homogenates of the L + D group (0.87 ± 0.04, 0.57 ± 0.0, and 0.16 ± 0.02) and the D + L group (0.82 ± 0.05, 0.58 ± 0.09, and 0.15 ± 0.02) were significantly different than the d-gal group (0.67 ± 0.03, 0.96 ± 0.040, and 0.29 ± 0.05).

CONCLUSIONS

Lidocaine was shown to reduce cognitive impairment in rats with cognitive dysfunction through anti-inflammatory and antioxidative stress mechanisms in combination with CRMP2 antiphosphorylation.

Toxicologic pathological mechanism of acute lung injury induced by oral administration of benzalkonium chloride in mice

Benzalkonium chloride (BAC) intoxication causes fatal lung injuries, such as acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). However, the pathogenesis of ALI/ARDS induced by BAC ingestion is poorly understood. This study aimed to clarify the mechanism of lung toxicity after BAC ingestion in a mouse model. BAC was orally administered to C57BL/6 mice at doses of 100, 250, and 1250 mg/kg. After administration, BAC concentrations in the blood and lungs were evaluated via liquid chromatography with tandem mass spectrometry. Lung tissue injury was evaluated via histological and protein analyses. Blood and lung BAC concentration levels after oral administration increased in a dose-dependent manner, with the concentrations directly proportional to the dose administered. The severity of lung injury worsened over time after the oral administration of 1250 mg/kg BAC. An increase in the terminal transferase dUTP nick end labeling-positive cells and cleaved caspase-3 levels was observed in the lungs after 1250 mg/kg BAC administration. In addition, increased cleaved caspase-9 levels and mitochondrial cytochrome c release into the cytosol were observed. These results suggest that lung tissue injury with excessive apoptosis contributes to BAC-induced ALI development and exacerbation. Our findings provide useful information for developing an effective treatment for ALI/ARDS induced by BAC ingestion.

Mitochondrial Effects of Common Cardiovascular Medications: The Good, the Bad and the Mixed

Mitochondria are central organelles in the homeostasis of the cardiovascular system via the integration of several physiological processes, such as ATP generation via oxidative phosphorylation, synthesis/exchange of metabolites, calcium sequestration, reactive oxygen species (ROS) production/buffering and control of cellular survival/death. Mitochondrial impairment has been widely recognized as a central pathomechanism of almost all cardiovascular diseases, rendering these organelles important therapeutic targets. Mitochondrial dysfunction has been reported to occur in the setting of drug-induced toxicity in several tissues and organs, including the heart. Members of the drug classes currently used in the therapeutics of cardiovascular pathologies have been reported to both support and undermine mitochondrial function. For the latter case, mitochondrial toxicity is the consequence of drug interference (direct or off-target effects) with mitochondrial respiration/energy conversion, DNA replication, ROS production and detoxification, cell death signaling and mitochondrial dynamics. The present narrative review aims to summarize the beneficial and deleterious mitochondrial effects of common cardiovascular medications as described in various experimental models and identify those for which evidence for both types of effects is available in the literature.

Comparative Metabolomics Study of the Impact of Articaine and Lidocaine on the Metabolism of SH-SY5Y Neuronal Cells

Articaine (ATC) and lidocaine (LDC) are the local anesthetics (LAs) currently most employed in dentistry. Cases of paresthesia, reported more frequently for ATC, have raised concerns about their potential neurotoxicity, calling for further investigation of their biological effects in neuronal cells. In this work, the impact of ATC and LDC on the metabolism of SH-SY5Y cells was investigated through 1H NMR metabolomics. For each LA, in vitro cultured cells were exposed to concentrations causing 10 and 50% reductions in cell viability, and their metabolic intracellular and extracellular profiles were characterized. Most effects were common to ATC and LDC, although with varying magnitudes. The metabolic variations elicited by the two LAs suggested (i) downregulation of glycolysis and of glucose-dependent pathways (e.g., one-carbon metabolism and hexosamine biosynthetic pathway), (ii) disturbance of branched chain amino acids (BCAA) catabolism, (iii) downregulation of TCA cycle anaplerotic fueling and activation of alternative energy producing pathways, (iv) interference with choline metabolism and (v) lipid droplet build-up. Interestingly, LDC had a greater impact on membrane phospholipid turnover, as suggested by higher phosphatidylcholine to phosphocholine conversion. Moreover, LDC elicited an increase in triglycerides, whereas cholesteryl esters accumulated in ATC-exposed cells, suggesting a different composition and handling of lipid droplets.

Histological endpoints and oxidative stress transcriptional responses in the Mediterranean mussel Mytilus galloprovincialis exposed to realistic doses of salicylic acid

Despite the availability of analytic data, little is known about the toxicity of salicylic acid (SA) on aquatic non-target organisms. The present study aimed at evaluating the impact of SA through a short-term exposure of the Mediterranean mussel Mytilus galloprovincialis to five environmentally relevant concentrations of SA. A set of suitable biomarkers was applied at selected time-points on mussel digestive glands, including histological observations and expression of oxidative stress related genes. The obtained results showed a conspicuous hemocytic infiltration among mussel digestive tubules, as confirmed also by a flow cytometric approach that revealed an increase of halinocytes and granulocytes. Interestingly, a significant dose and time dependent decrease in the expression levels of oxidative stress related genes was found in mussels exposed to SA except for the glutathione S-transferase gene that was significantly up-regulated in a time-dependent manner confirming its important role against oxidant species and in the metabolism of pharmaceuticals.

Activation of transcription factor HIF inhibits IL-1β-induced NO production in primary cultured rat hepatocytes

Roxadustat and other hypoxia-inducible factor-prolyl hydroxylase inhibitors (HIF-PHIs) have recently been approved for the treatment of chronic renal anemia. In macrophages and monocytes, the activation of HIF-1 by pro-inflammatory cytokines induces iNOS expression and activity through the NF-κB pathway to produce nitric oxide (NO), which causes liver injury when excessively produced. Few studies have reported a relationship between HIF activity and iNOS induction in hepatocytes. We investigated the effect of drug- and hypoxia-induced HIF activations on NO production in primary cultured rat hepatocytes. Roxadustat treatment and hypoxic conditions activated HIF. Contrary to expectations, HIF-PHI treatment and hypoxia inhibited IL-1β-induced NO production. RNA-Seq analysis of mRNA expression in rat hepatocytes showed that roxadustat treatment decreased the expression of genes related to inflammation, and genes in the NF-κB signaling pathway were induced by IL-1β. Moreover, roxadustat suppressed IL-1β-activated signaling pathways in an HIF-dependent manner. GalN/LPS-treated rats were used as in vivo models of hepatic injury, and roxadustat treatment showed a tendency to suppress the death of rats. Therefore, exogenous HIF-1 activation, including HIF-PHI and hypoxia exposures, suppressed IL-1β-induced iNOS mRNA expression and subsequent NO production in hepatocytes, by suppressing the NF-κB signaling pathway. Roxadustat treatment suppresses the expression of pro-inflammatory genes by activating HIF, and thus may exhibit hepatoprotective effects.

Direct Cytotoxic and Indirect, Immune-Mediated Effects of Local Anesthetics Against Cancer

Local anesthetics are frequently employed during surgery in order to control peri- and postoperative pain. Retrospective studies have revealed an unexpected correlation between increased long-term survival and the use of local anesthetics during oncological surgery. This effect of local anesthetics might rely on direct cytotoxic effects on malignant cells or on indirect, immune-mediated effects. It is tempting to speculate, yet needs to be formally proven, that the combination of local anesthetics with oncological surgery and conventional anticancer therapy would offer an opportunity to control residual cancer cells. This review summarizes findings from fundamental research together with clinical data on the use of local anesthetics as anticancer standalone drugs or their combination with conventional treatments. We suggest that a better comprehension of the anticancer effects of local anesthetics at the preclinical and clinical levels may broadly improve the surgical treatment of cancer.

Ethanol Extract of Maclura tricuspidata Fruit Protects SH-SY5Y Neuroblastoma Cells against H2O2-Induced Oxidative Damage via Inhibiting MAPK and NF-κB Signaling

Free radical generation and oxidative stress push forward an immense influence on the pathogenesis of neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease. Maclura tricuspidata fruit (MT) contains many biologically active substances, including compounds with antioxidant properties. The current study aimed to investigate the neuroprotective effects of MT fruit on hydrogen peroxide (H₂O₂)-induced neurotoxicity in SH-SY5Y cells. SH-SY5Y cells were pretreated with MT, and cell damage was induced by H₂O₂. First, the chemical composition and free radical scavenging properties of MT were analyzed. MT attenuated oxidative stress-induced damage in cells based on the assessment of cell viability. The H₂O₂-induced toxicity caused by ROS production and lactate dehydrogenase (LDH) release was ameliorated by MT pretreatment. MT also promoted an increase in the expression of genes encoding the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT). MT pretreatment was associated with an increase in the expression of neuronal genes downregulated by H₂O₂. Mechanistically, MT dramatically suppressed H₂O₂-induced Bcl-2 downregulation, Bax upregulation, apoptotic factor caspase-3 activation, Mitogen-activated protein kinase (MAPK) (JNK, ERK, and p38), and Nuclear factor-κB (NF-κB) activation, thereby preventing H₂O₂-induced neurotoxicity. These results indicate that MT has protective effects against H₂O₂-induced oxidative damage in SH-SY5Y cells and can be used to prevent and protect against neurodegeneration.

Long Noncoding RNA LINC01347 Modulated Lidocaine-Induced Cytotoxicity in SH-SY5Y Cells by Interacting with hsa-miR-145-5p

Local anesthetics, including lidocaine (Lid), are widely used in clinical settings but new evidence suggested that they may induce strong neurological side-effects in human brains. In this work, we used an in vitro model to examine the functional modulations of a long non-coding RNA (lncRNA), LINC01347 on Lid-induced cytotoxicity in SH-SY5Y cells. SH-SY5Y cells were maintained in vitro and treated with Lid to induce cytotoxicity. Dynamic expression of LINC01347, in response to Lid treatment or lentivirus-mediated overexpression, was examined by quantitative real-time PCR. The effects of LINC01347 overexpression on Lid-induced cell death, LDH, caspase, and autophagy activities were evaluated. A potential downstream target of LINC01347, human microRNA-145-5p (hsa-miR-145-5p), was evaluated in SH-SY5Y cells. Hsa-miR-145-5p was subsequently upregulated to explore its functional correlation with LINC01347 in modulating Lid-induced SH-SY5Y cytotoxicity. Lid caused cell death and downregulated LINC01347 expression in SH-SY5Y cells in vitro. LINC01347 overexpression reduced Lid-induced cell death, LDH and caspase augmentation, and LC3B accumulation. Hsa-miR-145-5p was discovered to be closely affiliated with LINC01347. Its upregulation partially restored Lid-induced cytotoxic effects in LINC01347-overexpressed SH-SY5Y cells. Our study presented strong evidence showing lncRNA LINC01347 modulated lidocaine-induced cytotoxicity in SH-SY5Y cells by interacting with hsa-miR-145-5p.

Do Autophagy Enhancers/ROS Scavengers Alleviate Consequences of Mild Mitochondrial Dysfunction Induced in Neuronal-Derived Cells?

Mitochondrial function is at the nexus of pathways regulating synaptic-plasticity and cellular resilience. The involvement of brain mitochondrial dysfunction along with increased reactive oxygen species (ROS) levels, accumulating mtDNA mutations, and attenuated autophagy is implicated in psychiatric and neurodegenerative diseases. We have previously modeled mild mitochondrial dysfunction assumed to occur in bipolar disorder (BPD) using exposure of human neuronal cells (SH-SY5Y) to rotenone (an inhibitor of mitochondrial-respiration complex-I) for 72 and 96 h, which exhibited up- and down-regulation of mitochondrial respiration, respectively. In this study, we aimed to find out whether autophagy enhancers (lithium, trehalose, rapamycin, and resveratrol) and/or ROS scavengers [resveratrol, N-acetylcysteine (NAC), and Mn-Tbap) can ameliorate neuronal mild mitochondrial dysfunction. Only lithium (added for the last 24/48 h of the exposure to rotenone for 72/96 h, respectively) counteracted the effect of rotenone on most of the mitochondrial respiration parameters (measured as oxygen consumption rate (OCR)). Rapamycin, resveratrol, NAC, and Mn-Tbap counteracted most of rotenone's effects on OCR parameters after 72 h, possibly via different mechanisms, which are not necessarily related to their ROS scavenging and/or autophagy enhancement effects. The effect of lithium reversing rotenone's effect on OCR parameters is compatible with lithium's known positive effects on mitochondrial function and is possibly mediated via its effect on autophagy. By-and-large it may be summarized that some autophagy enhancers/ROS scavengers alleviate some rotenone-induced mild mitochondrial changes in SH-SY5Y cells.

Neurotoxic Effects of Local Anesthetics on Developing Motor Neurons in a Rat Model

Neurotoxic effects of local anesthetics (LAs) on developing motor neurons have not been documented. We investigated the neurotoxic effects of LAs on developing motor neurons in terms of cell viability, cytotoxicity, reactive oxygen species (ROS), and apoptosis. Embryonic spinal cord motor neurons were isolated from Sprague-Dawley rat fetuses and exposed to one of the three LAs-lidocaine, bupivacaine, or ropivacaine-at concentrations of 1, 10, 100, or 1000 µM. The exposure duration was set to 1 or 24 h. The neurotoxic effects of LAs were determined by evaluating the following: cell viability, cytotoxicity, ROS production, and apoptosis. In the 1-h exposure group, the motor neurons exposed to lidocaine and bupivacaine had reduced cell viability and increased cytotoxicity, ROS, and apoptosis in a concentration-dependent manner. Lidocaine showed the highest toxicity, followed by bupivacaine. In the 24-h exposure group, all three LAs showed significant effects (decreased cell viability and increased cytotoxicity, ROS, and apoptosis) on the motor neurons in a concentration-dependent manner. The neurotoxic effects of lidocaine were greater than those of bupivacaine and ropivacaine. Ropivacaine appeared to have the least effect on motor neurons. This study identified the neurotoxic effects of lidocaine and bupivacaine on developing spinal cord motor neurons.

Evaluation of toxicity of gadolinium-based contrast agents on neuronal cells

BACKGROUND

Gadolinium-based contrast agents (GBCAs) are widely used in magnetic resonance imaging (MRI). Recently, increased signal intensity has been reported in specific brain areas after repeated administrations of GBCAs.

PURPOSE

To investigate the toxic effects of GBCAs on neuronal cells by using SH-SY5Y neuroblastoma cell cultures.

MATERIAL AND METHODS

For toxicity assays, SH-SY5Y cells were incubated with different doses (0-1000 µM) of several macrocyclic (gadoterate meglumine and gadobutrol) and linear GBCAs (gadoversetamide, gadopentetate dimeglumine, gadodiamide, and gadoxetate disodium) for 48 h. Cell viability and proliferation capacity were evaluated by using MTS assay, LDH assay, and colony-forming assay. In addition, Western blotting of Bcl-2 and Bax proteins and nuclear Hoechst 33258 staining were performed to evaluate apoptotic cell death. The results were expressed as mean ± SEM. The data were analyzed using Student's t-test. A P value < 0.05 was accepted as statistically significant.

RESULTS

Both macrocyclic and linear GBCAs significantly and dose-dependently reduced cell viability in neuronal cells compared to control. Cell viability was measured between 89.5% ± 4% and 61% ± 0.7% in GBCA-treated groups. In addition, neurotoxicity was more prominent in linear GBCA-treated cultures (P < 0.0005). Bax protein levels were increased in GBCA-treated cells particularly with linear agents whereas Bcl-2 expression was decreased concomitantly.

CONCLUSION

The results of the present study indicated that exposure to specific GBCAs, even at low micro-molar concentrations, may have detrimental effects on neuronal survival. Further investigations are required to clarify the molecular mechanism underlying GBCA-induced cell death.

Mir-141-3p Regulates Apoptosis and Mitochondrial Membrane Potential via Targeting Sirtuin1 in a 1-Methyl-4-Phenylpyridinium in vitro Model of Parkinson's Disease

Objectives

Parkinson's disease (PD) is a common neurodegenerative disease characterized by the loss of midbrain dopaminergic neurons in the substantia nigra. The present study investigated miR-141-3p/sirtuin1 (SIRT1) activity in a 1-methyl-4-phenylpyridinium- (MPP+-) induced PC12-cell model of PD.

Methods

PC12 cells were exposed to MMP+ following induction of differentiation by nerve growth factor (NGF). miR-141-3p and SIRT1 expressions were examined using RT-qPCR and western blot. Cell viability was evaluated using the MTT assay. Apoptosis percentage, reactive oxygen species (ROS) production, and mitochondrial membrane potential (Δψm) were evaluated using flow cytometry. Expression of Nuclear factor-kappa B- (NF-κB-) related proteins was determined by western blot. Bioinformatic analysis, RT-qPCR, and luciferase reporter assay were used to confirm the interaction between miR-141-3p and SIRT1.

Results

miR-141-3p was upregulated, and SIRT1 was downregulated in MPP+-treated PC12 cells. MPP+ treatment also upregulated nitric oxide synthase 1 (Nos1) and α-synuclein. miR-141-3p induced apoptosis, oxidative stress, mitochondrial dysfunction, and downregulated the SIRT1 mRNA expression. The luciferase reporter assay showed that SIRT1 was the target of miR-141-3p. SIRT1 transfection attenuated apoptosis, ROS production and maintained Δψm. SIRT1 also downregulated Nos1, tumor necrosis factor-α (TNF-α), interleukin 1 beta (IL-1β), interleukin 6(IL-6) and upregulated B cell lymphoma 2 (Bcl-2) protein. In addition, SIRT1 activator resveratrol blocked the effects of miR-141-3p mimic on Nos1, α-synuclein, and mitochondrial membrane potential. SIRT1 inhibitor sirtinol reversed the biological effects of miR-141-3p.

Conclusion

Increased miR-141-3p induced apoptosis, oxidative stress, and mitochondrial dysfunction in MPP+-treated PC12 cells by directly targeting the SIRT1 expression. Our study provided a potential therapeutic strategy for PD.

N-acetylcysteine prevents olanzapine-induced oxidative stress in mHypoA-59 hypothalamic neurons

Olanzapine is a second-generation antipsychotic (AP) drug commonly prescribed for the treatment of schizophrenia. Recently, olanzapine has been found to cause brain tissue volume loss in rodent and primate studies; however, the underlying mechanism remains unknown. Abnormal autophagy and oxidative stress have been implicated to have a role in AP-induced neurodegeneration, while N-acetylcysteine (NAC) is a potent antioxidant, shown to be beneficial in the treatment of schizophrenia. Here, we investigate the role of olanzapine and NAC on cell viability, oxidative stress, mitochondrial mass and mitophagy in hypothalamic cells. Firstly, cell viability was assessed in mHypoA-59 and mHypoA NPY/GFP cells using an MTS assay and flow cytometric analyses. Olanzapine treated mHypoA-59 cells were then assessed for mitophagy markers and oxidative stress; including quantification of lysosomes, autophagosomes, LC3B-II, p62, superoxide anion (O₂^–) and mitochondrial mass. NAC (10 mM) was used to reverse the effects of olanzapine (100 µM) on O₂⁻, mitochondrial mass and LC3B-II. We found that olanzapine significantly impacted cell viability in mHypoA-59 hypothalamic cells in a dose and time-dependent manner. Olanzapine inhibited mitophagy, instigated oxidative stress and prompted mitochondrial abnormalities. NAC was able to mitigate olanzapine-induced effects. These findings suggest that high doses of olanzapine may cause neurotoxicity of hypothalamic neurons via increased production of reactive oxygen species (ROS), mitochondrial damage and mitophagy inhibition. This could in part explain data suggesting that APs may reduce brain volume.

Repositioning Lidocaine as an Anticancer Drug: The Role Beyond Anesthesia

While cancer treatment has improved dramatically, it has also encountered many critical challenges, such as disease recurrence, metastasis, and drug resistance, making new drugs with novel mechanisms an urgent clinical need. The term “drug repositioning,” also known as old drugs for new uses, has emerged as one practical strategy to develop new anticancer drugs. Anesthetics have been widely used in surgical procedures to reduce the excruciating pain. Lidocaine, one of the most-used local anesthetics in clinical settings, has been found to show multi-activities, including potential in cancer treatment. Growing evidence shows that lidocaine may not only work as a chemosensitizer that sensitizes other conventional chemotherapeutics to certain resistant cancer cells, but also could suppress cancer cells growth by single use at different doses or concentrations. Lidocaine could suppress cancer cell growth in vitro and in vivo via multiple mechanisms, such as regulating epigenetic changes and promoting pro-apoptosis pathways, as well as regulating ABC transporters, metastasis, and angiogenesis, etc., providing valuable information for its further application in cancer treatment and for new drug discovery. In addition, lidocaine is now under clinical trials to treat certain types of cancer. In the current review, we summarize the research and analyze the underlying mechanisms, and address key issues in this area.

Propofol inhibits stromatoxin-1-sensitive voltage-dependent K+ channels in pancreatic β-cells and enhances insulin secretion

Background

Proper glycemic control is an important goal of critical care medicine, including perioperative patient care that can influence patients’ prognosis. Insulin secretion from pancreatic β-cells is generally assumed to play a critical role in glycemic control in response to an elevated blood glucose concentration. Many animal and human studies have demonstrated that perioperative drugs, including volatile anesthetics, have an impact on glucose-stimulated insulin secretion (GSIS). However, the effects of the intravenous anesthetic propofol on glucose metabolism and insulin sensitivity are largely unknown at present.

Methods

The effect of propofol on insulin secretion under low glucose or high glucose was examined in mouse MIN6 cells, rat INS-1 cells, and mouse pancreatic β-cells/islets. Cellular oxygen or energy metabolism was measured by Extracellular Flux Analyzer. Expression of glucose transporter 2 (GLUT2), potassium channels, and insulin mRNA was assessed by qRT-PCR. Protein expression of voltage-dependent potassium channels (Kv2) was also assessed by immunoblot. Propofol’s effects on potassium channels including stromatoxin-1-sensitive Kv channels and cellular oxygen and energy metabolisms were also examined.

Results

We showed that propofol, at clinically relevant doses, facilitates insulin secretion under low glucose conditions and GSIS in MIN6, INS-1 cells, and pancreatic β-cells/islets. Propofol did not affect intracellular ATP or ADP concentrations and cellular oxygen or energy metabolism. The mRNA expression of GLUT2 and channels including the voltage-dependent calcium channels Cav1.2, Kir6.2, and SUR1 subunit of K_ATP, and Kv2 were not affected by glucose or propofol. Finally, we demonstrated that propofol specifically blocks Kv currents in β-cells, resulting in insulin secretion in the presence of glucose.

Conclusions

Our data support the hypothesis that glucose induces membrane depolarization at the distal site, leading to K_ATP channel closure, and that the closure of Kv channels by propofol depolarization in β-cells enhances Ca²⁺ entry, leading to insulin secretion. Because its activity is dependent on GSIS, propofol and its derivatives are potential compounds that enhance and initiate β-cell electrical activity.

Infectious stress triggers a POLG-related mitochondrial disease

A 3-year-old girl presented with severe epilepsy in the context of Borrelia infection. After ceftriaxone/lidocaine administration, she showed secondarily generalized focal crises that led to neurological and motor sequelae. Genetic studies identified in the patient two heterozygous POLG mutations (c.2591A>G; p.Asn864Ser and c.3649G>C; p.Ala1217Pro). Through analysis of POLG activity in cultured fibroblasts, we confirmed that the mutations altered the mtDNA turnover. Moreover, patient fibroblasts were more sensitive than controls in the presence of a mitochondrial replication-affecting drug, the antiretroviral azidothymidine. To test if ceftriaxone treatment could worsen the deleterious effect of the patient mutations, toxicity assays were performed. Cell toxicity, without direct effect on mitochondrial respiratory function, was detected at different antibiotic concentrations. The clinical outcome, together with the different in vitro sensitivity to ceftriaxone among patient and control cells, suggested that the mitochondrial disease symptoms were hastened by the infection and were possibly worsened by the pharmacological treatment. This study underscores the benefit of early genetic diagnosis of the patients with mitochondrial diseases, since they may be a target group of patients especially vulnerable to environmental factors.

Dexmedetomidine protects PC12 cells from lidocaine-induced cytotoxicity via downregulation of Stathmin 1

Background: Understanding of lidocaine-induced neurotoxicity is not complete, resulting in the unsuccessful treatment in some clinical settings. Dexmedetomidine (DEX) has been shown to alleviate lidocaine-induced neurotoxicity in our previous cell model. However, the rationale for DEX combined with lidocaine to reduce lidocaine-induced neurotoxicity in the clinical setting remains to be further clarified in the detailed molecular mechanism. Methods: In this study, we established a cellular injury model by lidocaine preconditioning. Cell Counting Kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EdU) proliferation assay kit were used to analyze cell proliferation. Cell apoptosis was measured by flow cytometry and Hoechst 33342 staining. Cell cycle progression was detected by flow cytometry. The protein expression levels were detected by Western blotting and immunofluorescence staining. Results: Our results showed that DEX dose-dependently restored impaired proliferation of PC12 cells induced by lidocaine，as reflected by the increased cell viability and EdU positive cells, which were consistent with the decreased expression of tumor suppressor protein p21 and increased expression of cell cycle-related cyclin D1 and CDK1. In addition, DEX dose-dependently reduced apoptotic PC12 cells induced by lidocaine，as reflected by the decreased expression of apoptosis-related Bax, caspase-3 and caspase-9 and increased expression of anti-apoptotic Bcl-2 compared to the cells only treated with lidocaine. Mechanistically, with gain-or-loss-of-function of STMN1, we showed that DEX-mediated neuroprotection by lidocaine-induced damage is associated with downregulation of STMN1 which might be an upstream molecule involved in regulation of mitochondria death pathway. Conclusion: Our results reveal that DEX is likely to be an effective adjunct to alleviate chronic neurotoxicity induced by lidocaine.

N-Acetylcysteine Attenuates Cisplatin-Induced Acute Kidney Injury by Inhibiting the C5a Receptor

N-acetylcysteine has been widely used as a nutritional supplement and drug in humans for its antioxidant properties. The complement activation fragment C5a is a strong proinflammatory molecule that mediates cell adhesion, chemotaxis, and the complex biological functions. However, the effect of NAC on the C5a, and the relationship of those two with cisplatin-induced acute kidney injury are unknown. In cisplatin induced AKI mouse model, mice with NAC administration had a marked improvement in renal function (BUN and Cr), decreased pathological damage, reduced inflammation, and alleviated renal oxidative stress. Furthermore, C5a and C5aR expression in the cisplatin-treated group was notably increased compared with the control group, and this increase could be significantly inhibited by NAC. In addition, neutrophils coexpressed distinctly with C5aR, and the number of infiltrating neutrophils (MPO⁺ly6G⁺) and inflammatory factors decreased with NAC treatment in the cisplatin-treated group. Overall, these data demonstrate that NAC could ameliorate cisplatin-induced nephrotoxicity in mice and the protective effects may be conducted by inhibiting the activation of kidney inflammation and the complement system.

High Glucose Enhances Bupivacaine-Induced Neurotoxicity via MCU-Mediated Oxidative Stress in SH-SY5Y Cells

Bupivacaine, a typical local anesthetic, induces neurotoxicity via reactive oxygen species regulation of apoptosis. High glucose could enhance bupivacaine-induced neurotoxicity through regulating oxidative stress, but the mechanism of it is not clear. Mitochondrial calcium uniporter (MCU), a key channel for regulating the mitochondrial Ca2+ (mCa2+) influx, is closely related to oxidative stress via disruption of mCa2+ homeostasis. Whether MCU is involved in high glucose-sensitized bupivacaine-induced neurotoxicity remains unknown. In this study, human neuroblastoma (SH-SY5Y) cells were cultured with high glucose and/or bupivacaine, and the data showed that high glucose enhanced bupivacaine-induced MCU expression elevation, mCa2+ accumulation, and oxidative damage. Next, Ru360, an inhibitor of MCU, was employed to pretreated SH-SY5Y cells, and the results showed that it could decrease high glucose and bupivacaine-induced mCa2+ accumulation, oxidative stress, and apoptosis. Further, with the knockdown of MCU with a specific small interfering RNA (siRNA) in SH-SY5Y cells, we found that it also could inhibit high glucose and bupivacaine-induced mCa2+ accumulation, oxidative stress, and apoptosis. We propose that downregulation expression or activity inhibition of the MCU channel might be useful for restoring the mitochondrial function and combating high glucose and bupivacaine-induced neurotoxicity. In conclusion, our study demonstrated the crucial role of MCU in high glucose-mediated enhancement of bupivacaine-induced neurotoxicity, suggesting the possible use of this channel as a target for curing bupivacaine-induced neurotoxicity in diabetic patients.

Heteronemin Induces Anti-Proliferation in Cholangiocarcinoma Cells via Inhibiting TGF-β Pathway

A marine sesterterpenoid-type natural product, heteronemin, retains anticancer effects. In the current study, we investigate the antitumor mechanism of heteronemin in cholangiocarcinoma cells and further explore its molecular targets. Initially, heteronemin exhibited potent cytotoxic effects against cholangiocarcinoma HuccT1 and SSP-25 cells. In vitro, heteronemin altered the abilities of cell adhesion and cell migration in HuccT1 and SSP-25 cell lines. It repressed messenger ribonucleic acid (mRNA) expression levels of transforming growth factor (TGF)-β, mothers against decapentaplegic homolog (SMAD) and Myc, whose protein products play important roles in regulating cell growth, angiogenesis, and metastasis. In addition, heteronemin altered several signaling pathways. The results indicate that heteronemin was able to modulate cell adhesion, the expression of extracellular matrix (ECM) receptors, the TGF-β pathway, cell motility, the membrane integration, metastasis response, matrix metalloproteinase (MMP) remodeling, the regulation of metabolism, sprouting angiogenesis, transcription factors, and vasculogenesis in cholangiocarcinoma cell lines. The results also suggest that it activated multiple signal transduction pathways to induce an anti-proliferation effect and anti-metastasis in cholangiocarcinoma. In conclusion, heteronemin may be used as a potential medicine for anticancer therapy.

Restoration of skeletal muscle homeostasis by hydrogen sulfide during hyperhomocysteinemia-mediated oxidative/ER stress condition 1

Elevated homocysteine (Hcy), i.e., hyperhomocysteinemia (HHcy), causes skeletal muscle myopathy. Among many cellular and metabolic alterations caused by HHcy, oxidative and endoplasmic reticulum (ER) stress are considered the major ones; however, the precise molecular mechanism(s) in this process is unclear. Nevertheless, there is no treatment option available to treat HHcy-mediated muscle injury. Hydrogen sulfide (H₂S) is increasingly recognized as a potent anti-oxidant, anti-apoptotic/necrotic/pyroptotic, and anti-inflammatory compound and also has been shown to improve angiogenesis during ischemic injury. Patients with CBS mutation produce less H₂S, making them vulnerable to Hcy-mediated cellular damage. Many studies have reported bidirectional regulation of ER stress in apoptosis through JNK activation and concomitant attenuation of cell proliferation and protein synthesis via PI3K/AKT axis. Whether H₂S mitigates these detrimental effects of HHcy on muscle remains unexplored. In this review, we discuss molecular mechanisms of HHcy-mediated oxidative/ER stress responses, apoptosis, angiogenesis, and atrophic changes in skeletal muscle and how H₂S can restore skeletal muscle homeostasis during HHcy condition. This review also highlights the molecular mechanisms on how H₂S could be developed as a clinically relevant therapeutic option for chronic conditions that are aggravated by HHcy.

Suppression of mitochondrial oxygen metabolism mediated by the transcription factor HIF-1 alleviates propofol-induced cell toxicity

A line of studies strongly suggest that the intravenous anesthetic, propofol, suppresses mitochondrial oxygen metabolism. It is also indicated that propofol induces the cell death in a reactive oxygen species (ROS)-dependent manner. Because hypoxia-inducible factor 1 (HIF-1) is a transcription factor which is involved in cellular metabolic reprogramming by modulating gene expressions of enzymes including glycolysis pathway and oxygen utilization of mitochondria, we examined the functional role of HIF-1 activity in propofol-induced cell death. The role of HIF-1 activity on oxygen and energy metabolisms and propofol-induced cell death and caspase activity was examined in renal cell-derived RCC4 cells: RCC4-EV cells which lack von Hippel-Lindau protein (VHL) protein expression and RCC4-VHL cells, which express exogenous VHL, and in neuronal SH-SY5Y cells. It was demonstrated that HIF-1 is involved in suppressing oxygen consumption and facilitating glycolysis in cells and that the resistance to propofol-induced cell death was established in a HIF-1 activation-dependent manner. It was also demonstrated that HIF-1 activation by treatment with HIFα-hydroxylase inhibitors such as n-propyl gallate and dimethyloxaloylglycine, alleviated the toxic effects of propofol. Thus, the resistance to propofol toxicity was conferred by HIF-1 activation by not only genetic deletion of VHL but also exposure to HIFα-hydroxylase inhibitors.

Propofol induces a metabolic switch to glycolysis and cell death in a mitochondrial electron transport chain-dependent manner

The intravenous anesthetic propofol (2,6-diisopropylphenol) has been used for the induction and maintenance of anesthesia and sedation in critical patient care. However, the rare but severe complication propofol infusion syndrome (PRIS) can occur, especially in patients receiving high doses of propofol for prolonged periods. In vivo and in vitro evidence suggests that the propofol toxicity is related to the impaired mitochondrial function. However, underlying molecular mechanisms remain unknown. Therefore, we investigated effects of propofol on cell metabolism and death using a series of established cell lines of various origins, including neurons, myocytes, and trans-mitochondrial cybrids, with defined mitochondrial DNA deficits. We demonstrated that supraclinical concentrations of propofol in not less than 50 μM disturbed the mitochondrial function and induced a metabolic switch, from oxidative phosphorylation to glycolysis, by targeting mitochondrial complexes I, II and III. This disturbance in mitochondrial electron transport caused the generation of reactive oxygen species, resulting in apoptosis. We also found that a predisposition to mitochondrial dysfunction, caused by a genetic mutation or pharmacological suppression of the electron transport chain by biguanides such as metformin and phenformin, promoted propofol-induced caspase activation and cell death induced by clinical relevant concentrations of propofol in not more than 25 μM. With further experiments with appropriate in vivo model, it is possible that the processes to constitute the molecular basis of PRIS are identified.

HIF-1-mediated suppression of mitochondria electron transport chain function confers resistance to lidocaine-induced cell death

The local anesthetic lidocaine induces cell death by altering reactive oxygen species (ROS) generation and mitochondrial electron transport chain function. Because hypoxia-inducible factor 1 (HIF-1) is involved in determining oxygen metabolism and mitochondria function, we investigated the involvement of HIF-1 activity in lidocaine-induced cell death. We investigated the role of HIF activation on lidocaine-induced caspase activation and cell death in renal cell-derived RCC4 cells lacking functional von Hippel-Lindau (VHL) protein. We demonstrate that HIF-1 suppressed oxygen consumption and facilitated glycolysis in a pyruvate dehydrogenase kinase-1-dependent manner and that activation of HIF-1 conferred resistance to lidocaine-induced cell death. We also demonstrated that exogenous HIF-1 activation, through HIFα-hydroxylase inhibition or exposure to hypoxic conditions, alleviates lidocaine toxicity by suppressing mitochondria function and generating ROS, not only in RCC4 cells, but also in the neuronal SH-SY5Y cells. In conclusion, we demonstrate that HIF-1 activation due to VHL deletion, treatment with small molecule HIFα-hydroxylase inhibitors, and exposure to hypoxic conditions suppresses mitochondrial respiratory chain function and confers resistance to lidocaine toxicity.

Dexmedetomidine Protects PC12 Cells from Lidocaine-Induced Cytotoxicity Through Downregulation of COL3A1 Mediated by miR-let-7b

Safety concerns of some local anesthetics, such as lidocaine, have been raised in recent years due to potential neurological impairment. Dexmedetomidine may protect humans from neurotoxicity, and miR-let-7b is activated by nerve injury; however, the roles of miR-let-7b and its target gene in lidocaine-induced cytotoxicity are not well known. Through bioinformatics and a luciferase reporter assay, COL3A1 was suggested as a direct target gene of miR-let-7b. Here, we confirmed by measuring mRNA and protein levels that miR-let-7b was downregulated and COL3A1 was upregulated in lidocaine-treated cells, an observation that was reversed by dexmedetomidine. Similar to miR-let-7b mimics or knockdown of COL3A1, dexmedetomidine treatment reduced the expression of COL3A1, suppressed cell apoptosis and cell migration/invasion ability, and induced cell cycle progression and cell proliferation in PC12 cells, effects that were reversed by the miR-let-7b inhibitor. Meanwhile, proteins involved in cell apoptosis, such as Bcl2 and caspase 3, were impacted as well. Taken together, dexmedetomidine may protect PC12 cells from lidocaine-induced cytotoxicity through miR-let-7b and COL3A1, while also increasing Bcl2 and inhibiting caspase 3. Therefore, miR-let-7b and COL3A1 might play critical roles in neuronal injury, and they are potential therapeutic targets.