Propofol ameliorates doxorubicin-induced oxidative stress and cellular apoptosis in rat cardiomyocytes. Toxicol Appl Pharmacol. 2011;257:437-448. [PMID: 22015447 DOI: 10.1016/j.taap.2011.10.001]

Dexpanthenol ameliorates doxorubicin-induced lung injury by regulating endoplasmic reticulum stress and apoptosis

Doxorubicin (DOX), which is used as a chemotherapeutic agent in the treatment of tumors, has limited use due to its toxicity in various organs and tissues. One of the organs where DOX has a toxic effect is the lung. DOX shows this effect by increasing oxidative stress, inflammation, and apoptosis. Dexpanthenol (DEX), a homologue of pantothenic acid, has anti-inflammatory, antioxidant, and anti-apoptotic properties. Therefore, the purpose of our investigation was to explore how DEX could counteract the harmful effects of DOX on the lungs. Thirty-two rats were used in the study, and 4 groups were formed (control, DOX, DOX + DEX, and DEX). In these groups, parameters of inflammation, ER stress, apoptosis, and oxidative stress were evaluated by immunohistochemistry, RT-qPCR, and spectrophotometric methods. In addition, lung tissue was evaluated histopathologically in the groups. While CHOP/GADD153, caspase-12, caspase-9, and Bax gene expressions increased in the DOX group, Bcl-2 gene expression levels significantly decreased. In addition, changes in Bax and Bcl-2 were supported immunohistochemically. There was a significant increase in oxidative stress parameters and a significant decrease in antioxidant levels. In addition, an increase in inflammatory marker (TNF-α and IL-10) levels was determined. There was a decrease in CHOP/GADD153, caspase-12, caspase-9, and Bax gene expressions and an increase in Bcl-2 gene expression in the DEX-treated group. In addition, it was determined that there was a decrease in oxidative stress levels and inflammatory findings. The curative effect of DEX was supported by histopathological findings. As a result, it was experimentally determined that DEX has a healing effect on oxidative stress, ER stress, inflammation, and apoptosis in lung damage caused by DOX toxicity.

Regulation of the Keap1-Nrf2 Signaling Axis by Glycyrrhetinic Acid Promoted Oxidative Stress-Induced H9C2 Cell Apoptosis

Excessive reactive oxygen species (ROS) could interfere with the physiological capacities of H₉C₂ cells and cause cardiomyocyte apoptosis. Glycyrrhetinic acid (GA), one of the main medicinal component of Glycyrrhetinic Radix et Rhizoma, shows toxic and adverse side effects in the clinic setting. In particular, some studies have reported that GA exerts toxic effects on H₉C₂ cells. The purpose of this study is to assess the effect of GA-induced oxidative stress on cultured H₉C₂ cells and reveal the relevant signaling pathways. LDH assay was used to assess cell damage. Apoptosis was detected using Hoechst 33242 and a propidium iodide (PI) assay. An Annexin V-fluorescein isothiocyanate/PI double-staining assay was utilized to investigate GA-induced apoptosis in H₉C₂ cells. The expression level of specific genes/proteins was evaluated by RT-qPCR and Western blotting. Flow cytometry and DCFH-DA fluorescent testing were used to determine the ROS levels of H₉C₂ cells. The potential mechanism of GA-induced cardiomyocyte injury was also investigated. GA treatment increased ROS generation and mitochondrial membrane depolarization and triggered caspase-3/9 activation and apoptosis. GA treatment also caused the nuclear translocation of NF-E2-related factor 2 after its dissociation from Keap1. This change was accompanied by a dose-dependent decline in the expression of the downstream target gene heme oxygenase-1. The findings demonstrated that GA could regulate the Keap1-Nrf2 signaling axis and induce oxidative stress to promote the apoptosis of H₉C₂ cells.

Propofol Protects Myocardium From Ischemia/Reperfusion Injury by Inhibiting Ferroptosis Through the AKT/p53 Signaling Pathway

The molecular mechanism underlying the protective role of propofol against myocardial ischemia/reperfusion (I/R) injury remains poorly understood. Previous studies have shown that ferroptosis is an imperative pathological process in myocardial I/R injury. We hypothesized that propofol prevents myocardial I/R injury by inhibiting ferroptosis via the AKT/p53 signaling pathway. The ferroptosis-inducing agent erastin (E) and AKT inhibitor MK2206 (MK) were used to investigate the role of propofol in myocardial I/R injury. H9C2 cells treated without any reagents, erastin for 24 h, propofol for 1 h before adding erastin were assigned as the control (C), E, and E + P group, respectively. Cell viability, reactive oxygen species (ROS), and the expression of antioxidant enzymes, including ferritin heavy chain 1 (FTH1), cysteine/glutamate transporter (XCT), and glutathione peroxidase 4 (GPX4) in H9C2 cells. Rat hearts from the I/R + P or I/R groups were treated with or without propofol for 20 min before stopping perfusion for 30 min and reperfusion for 60 min. Rat hearts from the I/R + P + MK or I/R + MK groups were treated with or without propofol for 20 min, with a 10-min treatment of MK2206 before stopping perfusion. Myocardial histopathology, mitochondrial structure, iron levels, and antioxidant enzymes expression were assessed. Our results demonstrated that erastin increased H9C2 cell mortality and reduced the expression of antioxidant enzymes. I/R, which reduced the expression of antioxidant enzymes and increased iron or p53 (p < 0.05), boosted myocardium pathological and mitochondrion damage. Propofol inhibited these changes; however, the effects of propofol on I/R injury were antagonized by MK (p < 0.05). In addition, AKT siRNA inhibited the propofol-induced expression of antioxidant enzymes (p < 0.05). Our findings confirm that propofol protects myocardium from I/R injury by inhibiting ferroptosis via the AKT/p53 signal pathway.

Propofol Inhibits Ischemia/Reperfusion-Induced Cardiotoxicity Through the Protein Kinase C/Nuclear Factor Erythroid 2-Related Factor Pathway

Both hydrogen peroxide (H₂O₂, H) and ischemia/reperfusion (I/R) can damage cardiomyocytes, which was inhibited by propofol (P). The present research was designed to examine whether propofol can reduce myocardial I/R injury by activating protein kinase C (PKC)/nuclear factor erythroid-2-related factor 2 (NRF2) pathway in H9C2 cells and rat Langendorff models. H9C2 cells were disposed of no reagents (C), H₂O₂ for 24 h (H), propofol for 1 h before H₂O₂ (H+P), and chelerythrine (CHE, PKC inhibitor) for 1 h before propofol and H₂O₂ (H+P+CHE). N = 3. The PKC gene of H9C2 was knocked down by siRNA and overexpressed by phorbol 12-myristate 13-acetate (PMA, PKC agonist). The cell viability and the expressions of PKC, NRF2, or heme oxygenase-1(HO-1) were evaluated. Propofol significantly reduced H9C2 cell mortality induced by H₂O₂, and significantly increased NRF2 nuclear location and HO-1 expression, which were restrained by siRNA knockout of PKC and promoted by PMA. Rat hearts were treated with KrebsHenseleit solution for 120 min (C), with (I/R+P) or without (I/R) propofol for 20 min before stopping perfusion for 30 min and reperfusion for 60 min, and CHE for 10 min before treated with propofol. N = 6. The levels of lactate dehydrogenase (LDH), superoxide dismutase (SOD), and creatine kinase-MB (CK-MB) in perfusion fluid and antioxidant enzymes in the myocardium were assessed. I/R, which increased LDH and CK-MB expression and reduced SOD expression, boosted the pathological damage and infarcts of the myocardium after reperfusion. However, propofol restrained all these effects, an activity that was antagonized by CHE. The results suggest that propofol pretreatment protects against I/R injury by activating of PKC/NRF2 pathway.

Human Amnion Membrane Proteins Prevent Doxorubicin-Induced Oxidative Stress Injury and Apoptosis in Rat H9c2 Cardiomyocytes

Doxorubicin (DOX) is widely used as an effective chemotherapy agent in cancer treatment. Cardiac toxicity in cancer treatment with DOX demand urgent attention and no effective treatment has been established for DOX-induced cardiomyopathy. It has been well documented that human amniotic membrane proteins (AMPs), extracted from amnion membrane (AM), have antioxidant, anti-apoptotic, and cytoprotective properties. Therefore, in this study, we aimed to investigate the protective effects of AMPs against cardiotoxicity induced by DOX in cultured rat cardiomyocyte cells (H9c2). DOX-induced cell injury was evaluated using multi-parametric assay including thiazolyl blue tetrazolium bromide (MTT), the release of lactic dehydrogenase (LDH), intracellular Ca2+ , reactive oxygen species (ROS) levels, cellular antioxidant status, mitochondrial membrane potential (ΔΨm), malondialdehyde (MDA), and NF-κB p65 DNA-binding activity. Moreover, expression profiling of apoptosis-related genes (P53, Bcl-2, and Bax) and Annexin V by flow cytometry were used for cell apoptosis detection. It was shown that AMPs pretreatment inhibited the cell toxicity induced by DOX. AMPs effectively attenuated the increased levels of LDH, Ca2+ , ROS, and MDA and also simultaneously elevated the ΔΨm and antioxidant status such as superoxide dismutase (SOD) and Catalase (CAT) in pretreated H9c2 cardiomyocytes. Besides, the activity of NF-kB p65 was reduced and the p53 and Bax protein levels were inhibited in these myocardial cells subjected to DOX. These findings provide the first evidence that AMPs potently suppressed DOX-induced toxicity in cardiomyocytes through inhibition of oxidative stress and apoptosis. Thus, AMPs can be a potential therapeutic agent against DOX cardiotoxicity.

Propofol inhibits migration and induces apoptosis of pancreatic cancer PANC-1 cells through miR-34a-mediated E-cadherin and LOC285194 signals

Propofol has exhibited potent antitumor activity in pancreatic cancer cells in vitro and in vivo. The study aimed to investigate the anti-tumor mechanisms of propofol on pancreatic cancer PANC-1 cells in vitro. PANC-1 cells were exposure to concentration 20 μg/ml of propofol for 72 h. Long non-coding RNA LOC285194 siRNA LOC285194 siRNA, E-cadherin siRNA and microRNA-34a (miR-34a) inhibitor were used to investigate the effect of propofol on PANC-1 cells. miR-34a and LOC285194 were analyzed by quantitative real-time PCR (qRT-PCR). Pro-apoptotic protein bax, cleaved-caspase-3 and anti-apoptotic protein bcl-2 were analyzed by Western blot. Cell viability and cell apoptosis were detected by MTT and TUNEL staining, respectively. Cell migration was detected by wound-healing assay. The results showed that propofol upregulated miR-34a expression, which, in turn, upregulated LOC285194 expression, resulting in PANC-1 cell apoptosis and growth inhibition. In addition, propofol upregulated miR-34a expression, which, in turn, upregulated E-cadherin expression, resulting in cell migration inhibition. Our research confirmed that propofol-induced cell apoptosis and inhibited cell migration in PANC-1 cells in vitro via promoting miR-34a-dependent LOC285194 and E-cadherin upregulation, respectively.

Oxidative stress under general intravenous and inhalation anaesthesia

Oxidative stress occurs when reactive oxygen species (ROS) production overwhelms cell protection by antioxidants. This review is focused on general anaesthesia-induced oxidative stress because it increases the rate of complications and delays recovery after surgery. It is important to know what effects of anaesthetics to expect in terms of oxidative stress, particularly in surgical procedures with high ROS production, because their either additive or antagonistic effect may be pivotal for the outcome of surgery. In vitro and animal studies on this topic are numerous but show large variability. There are not many human studies and what we know has been learned from different surgical procedures measuring different endpoints in blood samples taken mostly before and after surgery. In these studies most intravenous anaesthetics have antioxidative properties, while volatile anaesthetics temporarily increase oxidative stress in longer surgical procedures.

Anticancer Therapy-Induced Atrial Fibrillation: Electrophysiology and Related Mechanisms

Some well-established immunotherapy, radiotherapy, postoperation, anticancer drugs such as anthracyclines, antimetabolites, human epidermal growth factor receptor 2 blockers, tyrosine kinase inhibitors, alkylating agents, checkpoint inhibitors, and angiogenesis inhibitors, are significantly linked to cardiotoxicity. Cardiotoxicity is a common complication of several cancer treatments. Some studies observed complications of cardiac arrhythmia associated with the treatment of cancer, including atrial fibrillation (AF), supraventricular arrhythmias, and cardiac repolarization abnormalities. AF increases the risk of cardiovascular morbidity and mortality; it is associated with an almost doubled risk of mortality and a nearly 5-fold increase in the risk of stroke. The occurrence of AF is also usually researched in patients with advanced cancer and those undergoing active cancer treatments. During cancer treatments, the incidence rate of AF affects the prognosis of tumor treatment and challenges the treatment strategy. The present article is mainly focused on the cardiotoxicity of cancer treatments. In our review, we discuss these anticancer therapies and how they induce AF and consequently provide information on the precaution of AF during cancer treatment.

Propofol Protects Rat Cardiomyocytes from Anthracycline-Induced Apoptosis by Regulating MicroRNA-181a In Vitro and In Vivo

We aimed to evaluate the cardioprotective effect and mechanism of propofol in anthracycline-induced cardiomyocyte apoptosis. We selected the rat myocardial cell line, H9c2, and primary cardiomyocytes for in vitro study. The cardiomyocytes were treated with vehicle, Adriamycin® (ADM), propofol, or a combination of ADM and propofol. The proportion of apoptotic cells and the expression of miR-181a were detected by flow cytometry and real-time PCR, respectively. Luciferase assays were performed to explore the direct target gene of miR-181a. In vivo assay, rats were randomly divided into different treatment groups. The apoptosis index was determined by TUNEL staining, and the expression of miR-181a and STAT3 in heart tissue was detected. The antiproliferative effect of ADM alone was significantly greater than that of ADM plus propofol. A significantly greater decrease in the proportion of apoptotic cells and in miR-181a expression was observed in the combination treatment group compared with that in the ADM groups in vitro and in vivo. The loss-of-function of miR-181a in H9c2 of ADM treatment resulted in increased Bcl-2 and decreased Bax. MiR-181a suppressed Bcl-2 expression through direct targeting of the Bcl-2 transcript. Propofol reduced anthracycline-induced apoptosis in cardiomyocytes via targeting miR-181a/Bcl-2, and a negative correlation between miR-181a and Bcl-2 was observed.

Berberine-induced cardioprotection and Sirt3 modulation in doxorubicin-treated H9c2 cardiomyoblasts

Doxorubicin (DOX) is one of the most widely used anti-neoplastic agents. However, treatment with DOX is associated with cumulative cardiotoxicity inducing progressive cardiomyocyte death. Sirtuin 3 (Sirt3), a mitochondrial deacetylase, regulates the activity of proteins involved in apoptosis, autophagy and metabolism. Our hypothesis is that pharmacological modulation by berberine (BER) pre-conditioning of Sirt3 protein levels decreases DOX-induced cardiotoxicity. Our results showed that DOX induces cell death in all experimental groups. Increase in Sirt3 content by transfection-mediated overexpression decreased DOX cytotoxicity, mostly by maintaining mitochondrial network integrity and reducing oxidative stress. p53 was upregulated by DOX, and appeared to be a direct target of Sirt3, suggesting that Sirt3-mediated protection against cell death could be related to this protein. BER pre-treatment increased Sirt3 and Sirt1 protein levels in the presence of DOX and inhibited DOX-induced caspase 9 and 3-like activation. Moreover, BER modulated autophagy in DOX-treated H9c2 cardiomyoblasts. Interestingly, mitochondrial biogenesis markers were upregulated in in BER/DOX-treated cells. Sirt3 over-expression contributes to decrease DOX cytotoxicity on H9c2 cardiomyoblasts, while BER can be used as a modulator of Sirtuin function and cell quality control pathways to decrease DOX toxicity.

Dalbergioidin Ameliorates Doxorubicin-Induced Renal Fibrosis by Suppressing the TGF-β Signal Pathway

We investigated the effect of Dalbergioidin (DAL), a well-known natural product extracted from Uraria crinita, on doxorubicin- (DXR-) induced renal fibrosis in mice. The mice were pretreated for 7 days with DAL followed by a single injection of DXR (10 mg/kg) via the tail vein. Renal function was analyzed 5 weeks after DXR treatment. DXR caused nephrotoxicity. The symptoms of nephrotic syndrome were greatly improved after DAL treatment. The indices of renal fibrosis, the phosphorylation of Smad3, and the expression of alpha-smooth muscle actin (α-SMA), fibronectin, collagen III (Col III), E-cadherin, TGF-β, and Smad7 in response to DXR were all similarly modified by DAL. The present findings suggest that DAL improved the markers for kidney damage investigated in this model of DXR-induced experimental nephrotoxicity.

Salvianolic acid B protects against doxorubicin induced cardiac dysfunction via inhibition of ER stress mediated cardiomyocyte apoptosis

Salvia miltiorrhiza Bunge is a well-known medicinal plant in China. Salvianolic acid B (Sal B) is the most abundant bioactive compound extracted from the root of S. miltiorrhiza. The present study investigates the effect of Sal B on cardiac function and cardiomyocyte apoptosis in doxorubicin (DOX)-treated mice. After pretreatment with Sal B (2 mg kg-1 iv) for 7 d, male BALB/c mice were injected with a single dose of DOX (20 mg kg-1 ip). The cardioprotective effect of Sal B was observed on the 7th day after DOX treatment. DOX caused retarded body growth, apoptotic damage, and Bcl-2 expression disturbance. In contrast, Sal B pretreatment (2 mg kg-1 iv before DOX administration) attenuated the DOX induced apoptotic damage in heart tissues. Further study indicated that Sal B protected against DOX induced cardiotoxicity, at least, partially, by inhibiting endoplasmic reticulum stress, and by being involved in the PI3K/Akt pathway. These findings clarified the potential of Sal B as a promising reagent for treating DOX induced cardiotoxicity.

Pathophysiology of cancer therapy-provoked atrial fibrillation

Atrial fibrillation (AF) occurs with increased frequency in cancer patients, especially in patients who undergo surgery or chemotherapy. AF disturbs the prognosis of cancer patients and challenges therapeutic outcomes of cancer treatment. Elucidating the mechanisms of cancer-induced AF would help identify specific strategies for preventing AF occurrence. In addition to concurrent risk factors of cancer and AF, cancer surgery, side effects of anticancer agents, and cancer-associated immune responses play critical roles in the genesis of AF. In this review, we provide succinct potential mechanisms of AF genesis in cancer patients.

ROS-Induced Nuclear Translocation of Calpain-2 Facilitates Cardiomyocyte Apoptosis in Tail-Suspended Rats

Isoproterenol (ISO) induced nuclear translocation of calpain-2 which further increased susceptibility of cardiomyocyte apoptosis in tail-suspended rats. The underlying mechanisms remain elusive. In the present study, the results showed that ISO (10 nM) significantly elevated NADPH oxidases (NOXs) activity and NOXs-derived ROS productions which induced nuclear translocation of calpain-2 in cardiomyocytes of tail-suspended rats. In contrast, the inhibition of NADPH oxidase or cleavage of ROS not only reduced ROS productions, but also resisted nuclear translocation of calpain-2 and decreased ISO-induced apoptosis of cardiomyocyte in tail-suspended rats. ISO also increased the constitutive binding between calpain-2 and Ca(2+)/calmodulin-dependent protein kinase II δB (CaMK II δB) in nuclei, concomitant with the promotion of CaMK II δB degradation and subsequent down-regulation of Bcl-2 mRNA expression and the ratio of Bcl-2 to Bax protein in tail-suspended rat cardiomyocytes. These effects of ISO on cardiomyocytes were abolished by a calpain inhibitor PD150606. Inhibition of calpain significantly reduced ISO-induced loss of the mitochondrial membrane potential, cytochrome c release into the cytoplasm, as well as the activation of caspase-3 and caspase-9 in mitochondrial apoptotic pathway. In summary, the above results suggest that ISO increased NOXs-derived ROS which activated nuclear translocation of calpain-2, subsequently nuclear calpain-2 degraded CaMK II δB which reduced the ratio of Bcl-2 to Bax, and finally the mitochondria apoptosis pathway was triggered in tail-suspended rat cardiomyocytes. Therefore, calpain-2 may represent a potentially therapeutic target for prevention of oxidative stress-associated cardiomyocyte apoptosis.

2,5-hexanedione induced apoptosis of rat bone marrow mesenchymal stem cells by reactive oxygen species

Objectives:

n-Hexane, a common industrial organic solvent, causes multiple organ damage, especially neurotoxicity, which is proved to be caused by its metabolite 2,5-hexanedione (2,5-HD). We previously showed that 2,5-HD induced apoptosis of rat bone marrow mesenchymal stem cells (BMSCs). In the current study, we explored the mechanism of 2,5-HD-induced apoptosis, especially the role played by reactive oxygen species (ROS).

Methods:

Intracellular ROS levels after 2,5-HD treatment were measured by the dichloro-dihydro-fluorescein diacetate (DCFH-DA) method, and the antioxidant N-acetyl cysteine (NAC) was used to scavenge ROS. Apoptosis, mitochondrial membrane potential (MMP), and caspase-3 activity were measured after 2,5-HD exposure with or without NAC pretreatment.

Results:

In rat BMSCs, 20 mM 2,5-HD significantly increased ROS levels and apoptosis. In addition, MMP activity was decreased and caspase-3 activity was increased. With NAC pretreatment, ROS increases were prevented, cells were rescued from apoptosis, and both MMP and caspase-3 activity returned to normal levels. Western blotting analysis of malondialdehyde-modified proteins and superoxide dismutase (SOD) 1 showed that after 2,5-HD exposure, BMSCs had oxidative damage and abnormal SOD1 expression. These returned to normal when cells were pretreated with NAC in addition to 20 mM 2,5-HD. Furthermore, the expressions of NF-κB p65/RelA and phospho-NF-κB p65/RelA (Ser536) were suppressed after 2,5-HD exposure and restored by NAC pretreatment.

Conclusions:

2,5-HD-induced apoptosis in rat BMSCs is potentially mediated by excessive ROS production.

Shikonin Induces Apoptosis, Necrosis, and Premature Senescence of Human A549 Lung Cancer Cells through Upregulation of p53 Expression

Shikonin, a natural naphthoquinone pigment isolated from Lithospermum erythrorhizon, has been reported to suppress growth of various cancer cells. This study was aimed to investigate whether this chemical could also inhibit cell growth of lung cancer cells and, if so, works via what molecular mechanism. To fulfill this, A549 lung cancer cells were treated with shikonin and then subjected to microscopic, biochemical, flow cytometric, and molecular analyses. Compared with the controls, shikonin significantly induced cell apoptosis and reduced proliferation in a dose-dependent manner. Specially, lower concentrations of shikonin (1-2.5 μg/mL) cause viability reduction; apoptosis and cellular senescence induction is associated with upregulated expressions of cell cycle- and apoptotic signaling-regulatory proteins, while higher concentrations (5-10 μg/mL) precipitate both apoptosis and necrosis. Treatment of cells with pifithrin-α, a specific inhibitor of p53, suppressed shikonin-induced apoptosis and premature senescence, suggesting the role of p53 in mediating the actions of shikonin on regulation of lung cancer cell proliferation. These results indicate the potential and dose-related cytotoxic actions of shikonin on A549 lung cancer cells via p53-mediated cell fate pathways and raise shikonin a promising adjuvant chemotherapeutic agent for treatment of lung cancer in clinical practice.

Attenuation of cisplathin-induced toxic oxidative stress by propofol

Background:

Antioxidant effects of propofol (2, 6-diisopropylphenol) were evaluated against cisplatin-i‎nduced oxidative stress in rat.

Objectives:

In this experimental study, 20 male rats were equally divided into 4 groups (5 rats each), and were treated by propofol (10 mg/kg/day, IP), or cisplatin (7 mg /kg/day, IP), or both.

Materials and Methods:

G‎roup one was control, while group 2 was given cisplatin (7 mg /kg/day, IP). Animals of the third group received only propofol (10 mg/kg/day, IP). Group 4 was given propofol with cisplatin once per day for 7 days. After treatment, blood urea nitrogen, creatinine levels, and oxidative stress m‎arkers such as total thiol groups (TTG), lipid peroxidation (LPO), and total antioxidant ‎capacity (TAC) were measured.

Results:

Oxidative stress induced by cisplatin, was evident by a significant increase in LPO and decrease in TTG and TAC. Propofol recovered ‎cisplatin -induced changes in TAC, TTG and LPO in blood.

Conclusions:

It is concluded that oxidative ‎damage is the mechanism of cisplatin toxicity, which can be recovered by propofol.‎

Endothelin-1 induces a glycolytic switch in pulmonary arterial endothelial cells via the mitochondrial translocation of endothelial nitric oxide synthase

Recent studies have indicated that, during the development of pulmonary hypertension (PH), there is a switch from oxidative phosphorylation to glycolysis in the pulmonary endothelium. However, the mechanisms underlying this phenomenon have not been elucidated. Endothelin (ET)-1, an endothelial-derived vasoconstrictor peptide, is increased in PH, and has been shown to play an important role in the oxidative stress associated with PH. Thus, in this study, we investigated whether there was a potential link between increases in ET-1 and mitochondrial remodeling. Our data indicate that ET-1 induces the redistribution of endothelial nitric oxide synthase (eNOS) from the plasma membrane to the mitochondria in pulmonary arterial endothelial cells, and that this was dependent on eNOS uncoupling. We also found that ET-1 disturbed carnitine metabolism, resulting in the attenuation of mitochondrial bioenergetics. However, ATP levels were unchanged due to a compensatory increase in glycolysis. Further mechanistic investigations demonstrated that ET-1 mediated the redistribution of eNOS via the phosphorylation of eNOS at Thr495 by protein kinase C δ. In addition, the glycolytic switch appeared to be dependent on mitochondrial-derived reactive oxygen species that led to the activation of hypoxia-inducible factor signaling. Finally, the cell culture data were confirmed in vivo using the monocrotaline rat model of PH. Thus, we conclude that ET-1 induces a glycolytic switch in pulmonary arterial endothelial cells via the redistribution of uncoupled eNOS to the mitochondria, and that preventing this event may be an approach for the treatment of PH.

Glutathione Depletion by L-Buthionine-S,R-Sulfoximine Induces Apoptosis of Cardiomyocytes through Activation of PKC-δ

In the present study, we investigated the effect of intracellular glutathione (GSH) depletion in heart-derived H9c2 cells and its mechanism. L-buthionine-S,R-sulfoximine (BSO) induced the depletion of cellular GSH, and BSO-induced reactive oxygen species (ROS) production was inhibited by glutathione monoethyl ester (GME). Additionally, GME inhibited BSO-induced caspase-3 activation, annexin V-positive cells, and annexin V-negative/propidium iodide (PI)-positive cells. Treatment with rottlerin completely blocked BSO-induced cell death and ROS generation. BSO-induced GSH depletion caused a translocation of PKC-δ from the cytosol to the membrane fraction, which was inhibited by treatment with GME. From these results, it is suggested that BSO-induced depletion of cellular GSH causes an activation of PKC-δ and, subsequently, generation of ROS, thereby inducing H9c2 cell death.

Activation of PI3K-Akt through taurine is critical for propofol to protect rat cardiomyocytes from doxorubicin-induced toxicity

Myocardial toxicity is one of the major side effects of many chemotherapeutics. It has been shown that propofol can ameliorate the cardiotoxicity of chemotherapeutic agents. In this study, we intend to investigate the role of the PI3K-Akt-Bad signaling pathway in propofol relief of doxorubicin-induced oxidative stress and apoptosis in rat cardiomyocytes. Cultured neonatal rat cardiomyocytes were treated with vehicle, doxorubicin, propofol, or propofol plus doxorubicin in the presence or absence of the PI3K inhibitor LY294002. Cells were harvested 20 h post-exposure to doxorubicin followed by analysis of their cellular taurine content, oxidative/nitrative stresses, and cellular apoptosis. The activation of the PI3K-Akt pathway was analyzed by immunoblotting. FACS, TUNEL, and LDH assays showed that the viability of cardiomyocytes was markedly reduced by doxorubicin, but was improved by propofol. Doxorubicin treatment significantly elevated cellular reactive oxygen and nitrogen contents while lowering the levels of taurine, Akt, and phosphorylated Akt and Bad. The abovementioned doxorubicin-induced changes were reversed by propofol. The protective effects of propofol were abrogated by simultaneous treatment with LY294002. In conclusion, the PI3K-Akt-Bad pathway plays a critical role in conferring the protective effects of propofol against myocardial toxicity from doxorubicin.

α-Linolenic acid attenuates doxorubicin-induced cardiotoxicity in rats through suppression of oxidative stress and apoptosis

Doxorubicin (DOX), a widely used anti-tumor drug, can give rise to severe cardiotoxicity by oxidative stress and cell apoptosis, which restricts its clinical application. α-Linolenic acid (ALA) has been shown to serve as a potent cardioprotective agent. The aim of this study was to explore the protective effects of ALA on DOX-induced cardiotoxicity and the underlying molecular mechanisms for this cardioprotection in rats. Rats were randomly divided into four groups and administrated with normal saline, ALA (500 µg/kg), DOX (2.5 mg/kg), or ALA (500 µg/kg) plus DOX (2.5 mg/kg) for 17 days. The results showed that DOX treatment significantly increased the heart weight/body weight, liver wet weight (WW)/dry weight (DW), lung WW/DW, serum levels of brain natriuretic peptide, creatine kinase-MB, lactate dehydrogenase, and cardiac troponin I, myocardial necrosis and myocardial malondialdehyde content, and induced the mRNA expression of Nrf2 in the nucleus, cleaved caspase-3, Bax, and superoxide dismutase (SOD). In addition, DOX led to a significant decrease in left ventricular end-diastolic volume, stroke volume, ejection fraction, SOD, glutathione-peroxidase, catalase, as well as the expression of Kelch-like ECH-associated protein 1 (Keap1) in the cytoplasm, phospho-AKT, phospho-ERK, and Bcl-2. Co-treatment with ALA significantly eliminated these changes induced by DOX except further reduction of Keap1 and elevation of Nrf2 and SOD mRNA. These results showed the cardioprotective effects of ALA on DOX-induced cardiotoxicity in rats. The mechanisms might be associated with the enhancement of antioxidant defense system through activating Keap1/Nrf2 pathway and anti-apoptosis through activating protein kinase B/extracellular signal regulated kinase pathway. Our results suggested a promising future of ALA-based preventions and therapies for myocardial damage after administration of DOX.

Propofol induces apoptosis and increases gemcitabine sensitivity in pancreatic cancer cells in vitro by inhibition of nuclear factor-κB activity

AIM: To investigate the effect of propofol on human pancreatic cells and the molecular mechanism of propofol action.

METHODS: We used the human pancreatic cancer cell line MIAPaCa-2 for in vitro studies measuring growth inhibition and degree of apoptotic cell death induced by propofol alone, gemcitabine alone, or propofol followed by gemcitabine. All experiments were conducted in triplicate and carried out on three or more separate occasions. Data were means of the three or more independent experiments ± SE. Statistically significant differences were determined by two-tailed unpaired Student’s t test and defined as P < 0.05.

RESULTS: Pretreatment of cells with propofol for 24 h followed by gemcitabine resulted in 24%-75% growth inhibition compared with 6%-18% when gemcitabine was used alone. Overall growth inhibition was directly correlated with apoptotic cell death. We also showed that propofol potentiated gemcitabine-induced killing by downregulation of nuclear factor-κB (NF-κB). In contrast, NF-κB was upregulated when pancreatic cancer cells were exposed to gemcitabine alone, suggesting a potential mechanism of acquired chemoresistance.

CONCLUSION: Inactivation of the NF-κB signaling pathway by propofol might abrogate gemcitabine-induced activation of NF-κB, resulting in chemosensitization of pancreatic tumors to gemcitabine.

Drug-induced oxidative stress and toxicity

Reactive oxygen species (ROS) are a byproduct of normal metabolism and have roles in cell signaling and homeostasis. Species include oxygen radicals and reactive nonradicals. Mechanisms exist that regulate cellular levels of ROS, as their reactive nature may otherwise cause damage to key cellular components including DNA, protein, and lipid. When the cellular antioxidant capacity is exceeded, oxidative stress can result. Pleiotropic deleterious effects of oxidative stress are observed in numerous disease states and are also implicated in a variety of drug-induced toxicities. In this paper, we examine the nature of ROS-induced damage on key cellular targets of oxidative stress. We also review evidence implicating ROS in clinically relevant, drug-related side effects including doxorubicin-induced cardiac damage, azidothymidine-induced myopathy, and cisplatin-induced ototoxicity.