Drug-induced oxidative stress and toxicity. J Toxicol. 2012;2012:645460. [PMID: 22919381 PMCID: PMC3420138 DOI: 10.1155/2012/645460]

Curcumin Acts as a Chemosensitizer for Leiomyosarcoma Cells In Vitro But Fails to Mediate Antioxidant Enzyme Activity in Cisplatin-Induced Experimental Nephrotoxicity in Rats

Background. Cisplatin (cis-diamminedichloroplatinum) is a widely used chemotherapeutic agent for the treatment of various cancers. Although it represents an effective regimen, its application is accompanied by side effects to normal tissues, especially to the kidneys. Cisplatin generates free radicals and impairs the function of antioxidant enzymes. Modulation of cisplatin-induced oxidative stress by specific antioxidant molecules represents an attractive approach to minimize side effects. Methods. We studied the ability of curcumin to sensitize leiomyosarcoma (LMS) cells to cisplatin. Assays for cell proliferation, mitochondrial function, induction of apoptosis, and cell cycle arrest were performed using various concentrations of cisplatin and a concentration of curcumin that caused a nonsignificant reduction in cell viability. Moreover, the effect of curcumin was examined against cisplatin-induced experimental nephrotoxicity. Renal injury was assessed by measuring serum creatinine, blood urea nitrogen (BUN), and the kidney's relative weight. Oxidative stress was measured by means of enzymatic activities of superoxide dismutase and glutathione peroxidase in the rats' blood and malondialdehyde levels in rats' urine. Results. In our study, we found that curcumin sensitizes LMS cells to cisplatin by enhancing apoptosis and impairing mitochondrial function. In an in vivo model of cisplatin-induced experimental nephrotoxicity, intraperitoneal administration of curcumin failed to preserve blood's antioxidant enzyme activity and decrease lipid peroxidation. Nevertheless, curcumin was able to protect nephrons' histology from cisplatin's toxic effect. Conclusion. Our results showed that curcumin can act as chemosensitizer, but its role as an adjunctive cisplatin-induced oxidative stress inhibitor requires further dose-finding studies to maximize the effectiveness of chemotherapy.

Neuroprotective effect of diclofenac on chlorpromazine induced catalepsy in rats

Neuroinflammation plays a key role in progressive degeneration of dopaminergic cells. Upregulation of prostaglandins and free radicals formation are involved in the mechanisms of cell death in Parkinson's disease (PD). The present study aimed to investigate the neuroprotective effect of diclofenac against chlorpromazine (CPZ) induced catalepsy and motor impairment in mice. Adult Wistar rats treated with CPZ (3 mg/kg/day, IP) were orally dosed with diclofenac and L-dopa/carbidopa for 21 days. Catalepsy was measured after 21 days of dosing by using standard bar test at 30, 60, 90, 120 and 180 min then motor performances were assessed via open field test and wire hanging test. Histopathological investigation and determination of dopamine (DA) and 3,4-Dihydroxyphenylacetic acid (DOPAC) levels of rat's brain was also carried out. We found that CPZ treated group exhibited reduced motor impairment after 21 days of treatment in open field and wire hanging test (P < 0.01) as compared to control group. The cataleptic scores of CPZ treated rats were also significantly increased (P < 0.01) after 21 days of chronic dosing, however diclofenac treated groups showed significant reduction in cataleptic scores with improved motor performances. Histopathology of CPZ treated rats showed marked degeneration with architecture distortion in the mid brain region. Dopaminergic degeneration is confirmed by neurochemical results that showed reduced amount of dopamine and DOPAC levels in mid brain. Moreover, histopathological slides of diclofenac treated rats showed improved architecture with reduced gliosis of mid brain region as well as improved dopamine and DOPAC levels were achieved after 21 days dosing of diclofenac. Taken together, the present work provide an evidence that diclofenac ameliorated behavioral performances by mediating neuroprotection against CPZ induced PD via preventing dopaminergic neuronal cell death.

Establishing a role for environmental toxicant exposure induced epigenetic remodeling in malignant transformation

Humans are exposed to a wide variety of environmental exposures throughout their lifespan. These include both naturally occurring toxins and chemical toxicants like pesticides, herbicides, and industrial chemicals, many of which have been implicated as possible contributors to human disease susceptibility [1-3]. We, and others, have hypothesized that environmental exposures may cause adaptive epigenetic changes in regenerative cell populations and developing organisms, leading to abnormal gene expression and increased disease susceptibility later in life [3]. Common epigenetic changes include changes in miRNA expression, covalent histone modifications, and methylation of DNA. Importantly, due to their heritable nature, abnormal epigenetic modifications which occur within stem cells may be particularly deleterious. Abnormal epigenetic changes in regenerative cell linages can be passed onto a large population of daughter cells and can persist for long periods of time. It is well established that an accumulation of epigenetic changes can lead to many human diseases including cancer [4-6]. Subsequently, it is imperative that we increase our understanding of how common environmental toxins and toxicants can induce epigenetic changes, particularly in stem cell populations. In this review, we will discuss how common environmental exposures in the United States and around the world may lead to epigenetic changes and discuss potential links to human disease, including cancer.

Nicorandil combats doxorubicin-induced nephrotoxicity via amendment of TLR4/P38 MAPK/NFκ-B signaling pathway

Nicorandil ameliorated doxorubicin-induced nephrotoxicity; this study aimed to show and explain the mechanism of this protection. A precise method was elucidated to study the effect of nicorandil on doxorubicin-induced nephrotoxicity in rats depending on the critical inflammation pathway TLR4/MAPK P38/NFκ-B. Adult male rats were subdivided into four groups. The 1st group was normal control, the 2nd group received nicorandil (3 mg/kg; p.o., for 4 weeks), the 3rd group received doxorubicin (2.6 mg/kg, i.p., twice per week for 4 weeks), and the fourth group was combination of doxorubicin and nicorandil for 4 weeks. Nephrotoxicity was assessed by biochemical tests through measuring Kidney function biomarkers such as [serum levels of urea, creatinine, albumin and total protein] besides renal kidney injury molecule-1 (KIM-1) and cystatin C], oxidative stress parameters such as [renal tissue malondialdehyde (MDA), reduced glutathione (GSH), SOD, catalase and nrf-2], mediators of inflammation such as [Toll like receptor 4 (TLR-4), Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB), p38 MAPK, Interleukin 1 beta (IL-1 β), and Tumor necrosis factor alpha (TNF-α)] and markers of apoptosis [BAX and Bcl-2 in renal tissue]. Finally, our data were supported by histopathology examination. Nicorandil pretreatment resulted in a significant decrease in nephrotoxicity biomarkers, oxidative stress markers, inflammatory mediators and prevented apoptosis through decreasing BAX and increasing Bcl-2 in renal tissues. Nicorandil prevented all the histological alterations caused by doxorubicin. Nicorandil is a promising antidote against doxorubicin-induced nephrotoxicity by neutralizing all toxicity mechanisms caused by doxorubicin through normalizing inflammatory cascade of TLR4/MAPK P38/NFκ-B.

A Narrative Review of Cancer-Related Fatigue (CRF) and Its Possible Pathogenesis

Many cancer patients suffer from severe fatigue when treated with chemotherapy or radiotherapy; however, the etiology and pathogenesis of this kind of fatigue remains unknown. Fatigue is associated with cancer itself, as well as adjuvant therapies and can persist for a long time. Cancer patients present a high degree of fatigue, which dramatically affects the quality of their everyday life. There are various clinical research studies and reviews that aimed to explore the mechanisms of cancer-related fatigue (CRF). However, there are certain limitations in these studies: For example, some studies have only blood biochemical texts without histopathological examination, and there has been insufficient systemic evaluation of the dynamic changes in relevant indexes. Thus, we present this narrative review to summarize previous studies on CRF and explore promising research directions. Plenty of evidence suggests a possible association between CRF and physiological dysfunction, including skeletal muscular and mitochondrial dysfunction, peripheral immune activation and inflammation dysfunction, as well as central nervous system (CNS) disorder. Mitochondrial DNA (mtDNA), mitochondrial structure, oxidative pressure, and some active factors such as ATP play significant roles that lead to the induction of CRF. Meanwhile, several pro-inflammatory and anti-inflammatory cytokines in the peripheral system, even in the CNS, significantly contribute to the occurrence of CRF. Moreover, CNS function disorders, such as neuropeptide, neurotransmitter, and hypothalamic-pituitary-adrenal (HPA) axis dysfunction, tend to amplify the sense of fatigue in cancer patients through various signaling pathways. There have been few accurate animal models established to further explore the molecular mechanisms of CRF due to different types of cancer, adjuvant therapy schedules, living environments, and physical status. It is imperative to develop appropriate animal models that can mimic human CRF and to explore additional mechanisms using histopathological and biochemical methods. Therefore, the main purpose of this review is to analyze the possible pathogenesis of CRF and recommend future research that will clarify CRF pathogenesis and facilitate the formulation of new treatment options.

Polyphenolic Nutraceuticals to Combat Oxidative Stress Through Microbiota Modulation

Due to their direct relationship with the activity of the gut microbiota, nutraceuticals are, at present, an effective alternative for the mitigation and alleviation of the dysfunctions governed by oxidative stress. The escalation in the number of the target group patients (diabetes, cardiovascular dysfunction, cancer, etc.) has spurred the quest for alternative action methods. The therapeutic value is determined through in vitro and in vivo methods, and involves the analysis of the therapeutic index. As the adverse outcomes are decreased, the pharmacological potential is assessed by the mechanisms, including biotransformation and the identification of the relevant biomarkers. Inflammatory action is among the principal effects that need to be reduced because it favors the presence of free radicals and dysbiosis. This article aimed at highlighting the action of the nutraceuticals in minimizing the oxidative stress by directly influencing the microbiota and slowing down the inflammatory progression. The pharmacological aspects as a therapeutic indicator of the use of nutraceuticals in improving the population health.

The effect of antioxidants in acute amitriptyline poisoning

Objective

To study the effect of Antioxidants supplementation in reducing oxidative stress induced in acute amitriptyline poisoning cases.

Design and methods

We compared the effect of supplementation of treatment of acute amitriptyline poisoning cases with alpha lipoic acid alone or with vitamin C, with that of those receiving only routine standard treatment (RST) as a control group.A total of 132 subjects divided into 5 groups were selected from IMCU (Intensive Medical Care Unit) and Toxicology Ward, Govt. General Hospital, Chennai, India. The study was restricted to grade 1 coma in poisoned subjects per the Edinburg scale. Each of the subjects was in the groups were supplemented with either placebo, RST, RST with vitamin C, RST with ALA, or RST with vitamin C and ALA.Acute anti-depressant poisoning (especially with amitriptyline) induced oxidative stress caused lipid peroxidation. Plasma cholinesterases (chE) play a major role in combating this effect. A determination of the level of cholinesterase (chE) acts as an indirect indicator of the level of oxidative stress and a measure of the efficacy of antioxidant supplementation. Plasma cholinesterase estimation was done by colorimetric method. The change in color of the indicator bromothymol blue caused by the liberated acetic acid from cholinesterase read by spectrophotometer at 620 nm was used to determine the levels of cholinesterase.

Result

A decrease in the level of oxidative stress was observed among those supplemented with either alpha lipoic acid alone or along with vitamin C, with a slightly more decrease in oxidative stress in the latter group. A p-value of <0.001 is considered significant statistically. The percentage of the benefit of treatment on supplementation with vitamin C and alpha lipoic acid showed a marked increase in group V (26.9%) cases after supplementation with both in combination.

Conclusion

The results provide evidence that the oxidative stress induced by acute amitriptyline poisoning is comparatively decreased by supplementation with antioxidants like alpha lipoic acid and vitamin C, than those only on routine standard treatment.

Toxicity of C60 fullerene-cisplatin nanocomplex against Lewis lung carcinoma cells

Cisplatin (Cis-Pt) is the cytotoxic agent widely used against tumors of various origin, but its therapeutic efficiency is substantially limited by a non-selective effect and high toxicity. Conjugation of Cis-Pt with nanocarriers is thought to be one option to enable drug targeting. The aim of this study was to estimate toxic effects of the nanocomplex formed by noncovalent interaction of C₆₀ fullerene with Cis-Pt against Lewis lung carcinoma (LLC) cells in comparison with free drug. Scanning tunneling microscopy showed that the minimum size of C₆₀-Cis-Pt nanoparticles in aqueous colloid solution was 1.1 nm whereas that of C₆₀ fullerene was 0.72 nm, thus confirming formation of the nanocomplex. The cytotoxic effect of C₆₀-Cis-Pt nanocomplex against LLC cells was shown to be higher with IC₅₀ values 3.3 and 4.5 times lower at 48 h and 72 h, respectively, as compared to the free drug. 12.5 µM Cis-Pt had no effect on LLC cell viability and morphology while C₆₀-Cis-Pt nanocomplex in Cis-Pt-equivalent concentration substantially decreased the cell viability, impaired their shape and adhesion, inhibited migration and induced accumulation in proapoptotic subG1 phase. Apoptosis induced by the C₆₀-Cis-Pt nanocomplex was confirmed by caspase 3/7 activation and externalization of phosphatidylserine on the outer surface of LLC cells with the double Annexin V-FITC/PI staining. We assume that C₆₀ fullerene as a component of the C₆₀-Cis-Pt nanocomplex promoted Cis-Pt entry and intracellular accumulation thus contributing to intensification of the drug's toxic effect against lung cancer cells.

Glutamine-451 Confers Sensitivity to Oxidative Inhibition and Heme-Thiolate Sulfenylation of Cytochrome P450 4B1

Human cytochrome P450 (P450) family 4 enzymes are involved in the metabolism of fatty acids and the bioactivation of carcinogenic arylamines and toxic natural products, e.g., 4-ipomeanol. These and other drug-metabolizing P450s are redox sensitive, showing a loss of activity resulting from preincubation with H2O2 and recovery with mild reducing agents [Albertolle, M. W., et al. (2017) J. Biol. Chem. 292, 11230-11242]. The inhibition is due to sulfenylation of the heme-thiolate ligand, as determined by chemopreoteomics and spectroscopy. This phenomenon may have implications for chemical toxicity and observed disease-drug interactions, in which the decreased metabolism of P450 substrates occurs in patients with inflammatory diseases (e.g., influenza and autoimmunity). Human P450 1A2 was determined to be redox insensitive. To determine the mechanism underlying the differential redox sensitivity, molecular dynamics (MD) simulations were employed using the crystal structure of rabbit P450 4B1 (Protein Data Bank entry 5T6Q ). In simulating either the thiolate (Cys-S-) or the sulfenic acid (Cys-SOH) at the heme ligation site, MD revealed Gln-451 in either an "open" or "closed" conformation, respectively, between the cytosol and heme-thiolate cysteine. Mutation to either an isosteric leucine (Q451L) or glutamate (Q451E) abrogated the redox sensitivity, suggesting that this "open" conformation allows for reduction of the sulfenic acid and religation of the thiolate to the heme iron. In summary, MD simulations suggest that Gln-451 in P450 4B1 adopts conformations that may stabilize and protect the heme-thiolate sulfenic acid; mutating this residue destabilizes the interaction, producing a redox insensitive enzyme.

Targeting Oncogenic Nuclear Factor Kappa B Signaling with Redox-Active Agents for Cancer Treatment

SIGNIFICANCE

Nuclear factor kappa B (NF-κB) signaling is essential under physiologically relevant conditions. However, aberrant activation of this pathway plays a pertinent role in tumorigenesis and contributes to resistance. Recent Advances: The importance of the NF-κB pathway means that its targeting must be specific to avoid side effects. For many currently used therapeutics and those under development, the ability to generate reactive oxygen species (ROS) is a promising strategy.

CRITICAL ISSUES

As cancer cells exhibit greater ROS levels than their normal counterparts, they are more sensitive to additional ROS, which may be a potential therapeutic niche. It is known that ROS are involved in (i) the activation of NF-κB signaling, when in sublethal amounts; and (ii) high levels induce cytotoxicity resulting in apoptosis. Indeed, ROS-induced cytotoxicity is valuable for its capabilities in killing cancer cells, but establishing the potency of ROS for effective inhibition of NF-κB signaling is necessary. Indeed, some cancer treatments, currently used, activate NF-κB and may stimulate oncogenesis and confer resistance.

FUTURE DIRECTIONS

Thus, combinatorial approaches using ROS-generating agents alongside conventional therapeutics may prove an effective tactic to reduce NF-κB activity to kill cancer cells. One strategy is the use of thiosemicarbazones, which form redox-active metal complexes that generate high ROS levels to deliver potent antitumor activity. These agents also upregulate the metastasis suppressor, N-myc downstream regulated gene 1 (NDRG1), which functions as an NF-κB signaling inhibitor. It is proposed that targeting NF-κB signaling may proffer a new therapeutic niche to improve the efficacy of anticancer regimens.

Notch pathway deactivation mediated by F-box/WD repeat domain-containing 7 ameliorates hydrogen peroxide-induced apoptosis in rat periodontal ligament stem cells

OBJECTIVE

To investigate the protective role of F-box/WD repeat domain-containing 7 in rat periodontal ligament stem cells under oxidative stress.

MATERIALS AND METHODS

The apoptosis of rat periodontal ligament stem cells was induced by exposure to various concentrations of hydrogen peroxide for 24 h, after which cell viability and the cleaved caspase-3 and -9 levels were determined. The levels of proteins in the Notch signaling pathway were determined by western blotting.

RESULTS

The overexpression of F-box/WD repeat domain-containing 7 increased cell viability following hydrogen peroxide administration and suppressed the activation of caspases-3 and -9. The overexpression of F-box/WD repeat domain-containing 7 inhibited Notch signaling. Furthermore, the protective effect of F-box/WD repeat domain-containing 7 could be resumed by PF-03084014, a Notch-specific inhibitor.

CONCLUSIONS

These observations suggest a protective role of F-box/WD repeat domain-containing 7 against hydrogen peroxide-induced oxidative stress in rat periodontal ligament stem cells. These findings will facilitate the in vitro culturing of periodontal ligament stem cell for clinical usage and promote stem cell-based therapy for periodontal tissue regeneration.

β-Caryophyllene, a natural bicyclic sesquiterpene attenuates doxorubicin-induced chronic cardiotoxicity via activation of myocardial cannabinoid type-2 (CB2) receptors in rats

The cannabinoid type 2 receptor (CB₂) has recently emerged as an important therapeutic target for cancer as well as cardiovascular diseases. The CB₂ receptor downregulation has been reported in solid tumors and cardiovascular diseases, therefore the CB₂ receptor activation has been considered as a viable strategy for chemotherapy as well as cardioprotection. Doxorubicin (DOX) is an important drug that continues to be the mainstay of chemotherapy in solid tumors, leukemia, and lymphoma. However, the use of DOX is often limited due to its lethal cardiotoxicity. Considering the role of CB₂ receptors in cardiovascular diseases and cancer, the activation of CB₂ receptors may protect against DOX-induced chronic cardiotoxicity in rats. In the present study, we investigated the cardioprotective effect of a selective CB₂ receptor agonist; β-Caryophyllene (BCP), a natural bicyclic sesquiterpene, against DOX-induced chronic cardiotoxicity in rats. AM630, a CB₂ receptor antagonist was administered as a pharmacological challenge prior to BCP treatment to demonstrate CB₂ receptor mediated cardioprotective mechanism of BCP. DOX (2.5 mg/kg) was injected intraperitoneally once a week for five weeks to induce chronic cardiotoxicity in rats. BCP was also injected into rats six days a week for a total duration of five weeks. DOX induced a significant decline in cardiac function and oxidative stress evidenced by the depletion of antioxidant enzymes, glutathione, and increased lipid peroxidation. DOX also triggered activation of nuclear factor kappa B (NF-κB) and increased the levels of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β) and expression of the inflammatory mediators (iNOS and COX-2) in the heart. Furthermore, DOX also upregulated the expression of pro-apoptotic markers such as Bax, p53, cleaved PARP, active caspase-3 and downregulated anti-apoptotic marker Bcl-2 in the myocardium. BCP treatment exerted significant cardioprotective effect by salvaging the heart tissues, improving cardiac function, mitigating oxidative stress, inflammation, and apoptosis. The histological and ultrastructural studies also appear in line with our findings of biochemical and molecular parameters. The CB₂ receptor-mediated cardioprotective mechanism was further confirmed by the abrogation of the beneficial effects of BCP with prior administration of the CB₂ receptor antagonist; AM630. Our study revealed the novel mechanism of BCP in cardioprotection against DOX-induced chronic cardiotoxicity by the activation of CB₂ receptors.

Assessing the effect of human pharmaceuticals (carbamazepine, diclofenac and ibuprofen) on the marine clam Ruditapes philippinarum: An integrative and multibiomarker approach

The presence of pharmaceuticals in the aquatic ecosystem has become a topic of growing interest in recent years. In this study, the marine clam Ruditapes philippinarum was exposed during 14 days to concentrations close to those found in the environment: (15 μg L^-1) of carbamazepine (CBZ), diclofenac (DCF) and ibuprofen (IBU), three pharmaceuticals widely used worldwide and commonly found within the aquatic environment. Additionally, exposure was followed by a depuration phase (7 days). A battery of biomarkers (superoxide dismutase SOD, catalase CAT, glutathione reductase GR, total glutathione peroxidase T-GPx, glutathione transferase GST, lipid peroxidation LPO, acetylcholinesterase AChE and metallothionein MT) was evaluated throughout the exposure and depuration. The Integrated Biomarker Response index was calculated with all selected biomarkers and used as a complementary tool in the evaluation of the organisms' health status. Exposure induced changes in the clams' biochemical responses that led to the hypothesis of the harmful role of the pharmaceuticals resulting in negative effects (changes in enzyme activities, LPO and MT levels, related to ROS production) particularly after short-term exposure. However, the clams showed the ability to cope with these imbalances by recovering their general oxidative status by the end of exposure.

l-Arginine Protects Ovine Intestinal Epithelial Cells from Lipopolysaccharide-Induced Apoptosis through Alleviating Oxidative Stress

This research aims to explore the effect of l-arginine (Arg) upon lipopolysaccharide (LPS)-induced induction of the oxidative stress as well as subsequent apoptosis within ovine intestinal epithelial cells (IOECs). Through a 16 h incubation, cells were divided into four groups and the medium was replaced with different medium as follows: (1) control (Con), Arg-free Dulbecco's modified Eagle's F12 Ham medium (DMEM); (2) Arg treatment, Arg-free DMEM supplemented with 100 μM Arg; (3) LPS treatment, Arg-free DMEM supplemented with 10 μg/mL LPS; (4) LPS with Arg treatment, Arg-free DMEM supplemented with both 10 μg/mL LPS and 100 μM Arg. After culturing for 24 h in different mediums, some characteristics of cells in the four groups were measured. Addition of Arg increased cell viability induced with LPS compared with the LPS group ( p < 0.05). Arg significantly decreased the release of dehydrogenase (LDH) and the production of malonaldehyde (MDA) ( p < 0.05) within IOECs challenged by the LPS. Compared with the LPS group, cells treated with Arg and Arg + LPS increased ( p < 0.05) mRNA as well as protein expression of glutathione peroxidase 1 (GPx1), catalase (CAT), superoxide dismutase 2 (SOD2), B-cell lymphoma 2 (Bcl2), quinone oxidoreductase 1 (NQO1), heme oxygenase (HO-1), and nuclear factor erythroid 2-related factor 2 (Nrf2). IOEC treatment with Arg reduced significantly ( p < 0.05) apoptosis induced by the LPS (12.58 ± 0.79%). The results showed that Arg promoted the protein expression of Nrf2, up-regulated expression of the phase II metabolizing enzymes (NQO1 and HO-1), as well as antioxidative enzymes (GPx1, CAT, and SOD2) for alleviating oxidative injury and protected IOECs from LPS-induced apoptosis.

Short-term exposure to carbamazepine causes oxidative stress on common carp (Cyprinus carpio)

The aim of this research was to determine the bioconcentration factor and if subacute exposure to carbamazepine (2 mg L^-1) modifies the oxidative state of liver, gills and brain of Cyprinus carpio. This was measured through the following biomarkers: hydroperoxide and protein carbonyl content, lipid peroxidation degree, as well as superoxide dismutase, catalase and glutathione peroxidase activity. Carbamazepine concentration in carp's tissue was also determined by liquid chromatography with a diode arrangement detector. An increase in lipid peroxidation degree, hydroperoxide and protein carbonyl content, and a decrease in the activity of the antioxidant enzymes (P < 0.05) with respect to control was observed. Also, there is an increase in the concentration of carbamazepina present in the organs with respect to the water in the system, which denotes bioconcentration of the drug. In conclusion, carbamazepine is bioconcentrated and produces oxidative stress on the common carp (C. carpio).

Chlorella-gold nanorods hydrogels generating photosynthesis-derived oxygen and mild heat for the treatment of hypoxic breast cancer

Hypoxic tumors are rarely cured because their low oxygen environment restricts the cytotoxicity of many chemotherapeutics by blocking the production of intracellular reactive oxygen species. Inspired by the highly efficient production of oxygen as a waste product of chlorella photosynthesis, we developed an in situ rapidly gelling BSA-PEG-based hydrogel depot system that contains chlorella and gold nanorods, namely Chlorella AuNRs BSA-Gel. The entrapped chlorella in our gel efficiently generated a high level of oxygen and oxygenated hemoglobin via photosynthesis in response to 660-nm light in vitro and in vivo, respectively. The incorporated gold nanorods showed excellent performance in precisely increasing the surrounding temperature to 41-42 °C responding to 808-nm near-infrared laser, which presumably played a supporting role in expanding the tumor vasculature and thereby facilitating the delivery of doxorubicin and oxygen to hypoxic tumors of mice. Our results showed that a combined therapy of Chlorella AuNRs BSA-Gel plus Dox followed by irradiation at 660 nm and 808 nm significantly abolished 4 T1 breast cancer cell-xenografted tumors of BALB/C mice. We believe that our oxygen-generating and mild heat-emitting hydrogel should be considered to be a valid prototype of a local depot system for treatment of hypoxic tumors.

A Review of Resveratrol as a Potent Chemoprotective and Synergistic Agent in Cancer Chemotherapy

Background: Cancer has become a major disease endangering human health around the world. Conventional chemotherapy suffers from many side effects including pain, cardiotoxicity, hepatotoxicity, and renal toxicity. This review aims to describe a natural product of resveratrol as a chemoprotective and synergistic agent in the modulation of cancer chemotherapy.

Methods: The publications were identified by comprehensive searching of SciFinder, PubMed, Web of Science, and our own reference library. Search terms included combinations of “resveratrol,” “cancer,” “natural products,” “chemotherapy,” and “side effects.” Selection of material focused on resveratrol reducing the side effects on cancer chemotherapy.

Results: Thirty one references were referred in this review to outline resveratrol as a potent chemoprotective and synergistic agent in cancer chemotherapy, including 22 papers for describing the chemoprotective effects, and 9 papers for illustrating the synergistic effects.

Conclusion: This study provides a systematic summary of resveratrol serving as a potent chemoprotective and synergistic agent to reduce the associated-side effects and enhance the therapeutic outcomes in cancer chemotherapy. Further studies in terms of resveratrol on a large amount of preclinical tests and clinical trials are highly demanded.

Increased susceptibility to oxidative stress-induced toxicological evaluation by genetically modified nrf2a-deficient zebrafish

INTRODUCTION

Oxidative stress plays an important role in drug-induced toxicity. Oxidative stress-mediated toxicities can be detected using conventional animal models but their sensitivity is insufficient, and novel models to improve susceptibility to oxidative stress have been researched. In recent years, gene targeting methods in zebrafish have been developed, making it possible to generate homozygous null mutants. In this study, we established zebrafish deficient in the nuclear factor erythroid 2-related factor 2a (nrf2a), a key antioxidant-responsive gene, and its potential to detect oxidative stress-mediated toxicity was examined.

METHODS

Nrf2a-deficient zebrafish were generated using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 technique. The loss of nrf2a function was confirmed by the tolerability to hydrogen peroxide and hydrogen peroxide-induced gene expression profiles being related to antioxidant response element (ARE)-dependent signaling. Subsequently, vulnerability of nrf2a-deficient zebrafish to acetaminophen (APAP)- or doxorubicin (DOX)-induced toxicity was investigated.

RESULTS

Nrf2a-deficient zebrafish showed higher mortality than wild type accompanied by less induction of ARE-dependent genes with hydrogen peroxide treatment. Subsequently, this model showed increased severity and incidence of APAP-induced hepatotoxicity or DOX-induced cardiotoxicity than wild type.

DISCUSSION

Our results demonstrated that anti-oxidative response might not fully function in this model, and resulted in higher sensitivity to drug-induced oxidative stress. Our data support the usefulness of nrf2a-deficient model as a tool for evaluation of oxidative stress-related toxicity in drug discovery research.

Psoralen Induces Developmental Toxicity in Zebrafish Embryos/Larvae Through Oxidative Stress, Apoptosis, and Energy Metabolism Disorder

Psoralen toxicity is an issue of wide concern. However, an assay for psoralen-induced developmental toxicity has not been reported to date. Moreover, the underlying mechanism of psoralen-induced developmental toxicity is unclear. Therefore, this study attempted to develop a psoralen-induced developmental toxicity assay in zebrafish embryos/larvae. Psoralen treatment caused a decrease in the hatching rate and body length and a significant increase in the malformation rate of zebrafish. Yolk retention, pericardial edema, swim-bladder deficiency, and curved body shape were also observed after psoralen treatment. Yolk retention might have been caused by an abnormality in lipid metabolism. Further experiments indicated that psoralen exerted toxic effects on the developing heart, liver, phagocytes, and nervous system. Increased generation of reactive oxygen species, inhibition of total superoxide dismutase activity, and increased malondialdehyde concentrations indicated inhibition of antioxidant capacity and the presence of oxidative stress. A greater number of apoptotic cells were observed after psoralen exposure, relative to the control. Furthermore, the results of gene-expression analysis showed that psoralen induced developmental toxicity by means of oxidative stress, apoptosis, and energy metabolism abnormalities. These findings will be helpful in understanding psoralen-induced toxicity.

Modulation of mitochondrial functions by xenobiotic-induced microRNA: From environmental sentinel organisms to mammals

Mitochondria play a crucial role in energetic metabolism, signaling pathways, and overall cell viability. They are in the first line in facing cellular energy requirements in stress conditions, such as in response to xenobiotic exposure. Recently, a novel regulatory key role of microRNAs (miRNAs) in important signaling pathways in mitochondria has been proposed. Consequently, alteration in miRNAs expression by xenobiotics could outcome into mitochondrial dysfunction, reactive oxygen species overexpression, and liberation of apoptosis or necrosis activating proteins. The aim of this review is to show the highlights about mitochondria-associated miRNAs in cellular processes exposed to xenobiotic stress in different cell types involved in detoxification processes or sensitive to environmental hazards in marine sentinel organisms and mammals.

Discovery of Nonquinone Substrates for NAD(P)H: Quinone Oxidoreductase 1 (NQO1) as Effective Intracellular ROS Generators for the Treatment of Drug-Resistant Non-Small-Cell Lung Cancer

The elevation of oxidative stress preferentially in cancer cells by efficient NQO1 substrates, which promote ROS generation through redox cycling, has emerged as an effective strategy for cancer therapy, even for treating drug-resistant cancers. Here, we described the identification and structural optimization studies of the hit compound 1, a new chemotype of nonquinone substrate for NQO1 as an efficient ROS generator. Further structure-activity relationship studies resulted in the most active compound 20k, a tricyclic 2,3-dicyano indenopyrazinone, which selectively inhibited the proliferation of NQO1-overexpressing A549 and A549/Taxol cancer cells. Furthermore, 20k dramatically elevated the intracellular ROS levels through NQO1-catalyzed redox cycling and induced PARP-1-mediated cell apoptosis in A549/Taxol cells. In addition, 20k significantly suppressed the growth of A549/Taxol xenograft tumors in mice with no apparent toxicity observed in vivo. Together, 20k acts as an efficient NQO1 substrate and may be a new option for the treatment of NQO1-overexpresssing drug-resistant NSCLC.

Effects of gelsemine on oxidative stress and DNA damage responses of Tetrahymena thermophila

Gelsemine is an important toxic substance extracted from Gelsemium elegans, which has a lot of biological functions in cells and organisms, but its toxicity has been rarely reported in Tetrahymena thermophila. In this study, we used the protozoan T. thermophila as an experimental model to investigate the potential toxicity-induced mechanism of gelsemine in the unicellular eukaryote. Our results clearly showed gelsemine inhibited T. thermophila growth in a dose-dependent manner. This exposure also resulted in oxidative stress on T. thermophila cells and antioxidant enzyme levels were significantly altered at high gelsemine levels (p < 0.05). Gelsemine produced a slight apoptotic effect at the highest (0.8 mg/mL) gelsemine level used here (p < 0.05). Furthermore, the toxin-induced DNA damage in a dose-dependent manner. The ultrastructural analysis also revealed mitophagic vacuoles at 0.4 and 0.8 mg/mL levels of gelsemine exposure. Moreover, expressions of oxidative stress-related and MAP kinase genes were significantly changed after exposure to 0.8 mg/mL level of gelsemine (p < 0.05). Altogether, our results clearly show that gelsemine from G. elegans can inhibit the growth via inducing oxidative stress and DNA damage in T. thermophila cells.

Adverse effects of two pharmaceuticals acetaminophen and oxytetracycline on life cycle parameters, oxidative stress, and defensome system in the marine rotifer Brachionus rotundiformis

To investigate the adverse effect of two widely used pharmaceuticals, paracetamol (acetaminophen [APAP]) and oxytetracycline (OTC) on the marine rotifer Brachionus rotundiformis (B. rotundiformis), the animals were exposed to various environmentally-relevant concentrations. Up to date, acetaminophen and oxytetracycline have been considered as toxic, if used above threshold concentration, i.e. overdosed. However, this study demonstrated these two pharmaceuticals even at low concentration (i.e., μg/L scale) elicited oxidative stress through the generation of reactive oxygen species (ROS) along with the increased glutathione S-transferase activity, despite no-observed effect in in-vivo population growth. To validate the adverse effects of the two pharmaceuticals at relatively low concentrations, mRNA expression analysis was performed of the entire set of genes encoding 26 cytochrome P450s (CYPs) of phase I and 19 glutathione S-transferases (GSTs) of phase II of the rotifer B. rotundiformis. The mRNA expression analysis suggested specific genes CYP3045A2 and GSTσ1, GSTσ4, and GSTω1 take part in detoxification of APAP and OTC, resulting in no significant changes in the population growth and undetermined no observed effect concentration (NOEC) in the marine rotifer B. rotundiformis.

Neurotoxic Outcomes of Subchronic Manganese Chloride Exposure via Contaminated Water in Adult Male Rats and the Potential Benefits of Ebselen

The neurological effects of manganese (Mn) exposure on adults consuming contaminated water remain unclear. Accordingly, the current experiment was planned to explore the neurotoxic consequences of subchronic Mn exposure via contaminated water and to examine whether ebselen (Ebs) improved these outcomes. Rats exposed to oral MnCl₂ (50 mg/kg body weight) for 30 successive days exhibited reduced rearing and ambulation. Furthermore, Mn administration increased brain Mn concentrations and induced superoxide dismutase, catalase, and glutathione depletion. Mn administration also increased lipid peroxidation biomarker levels. Additionally, Mn increased interleukin1-β and prostaglandin E2 levels and altered caspase-3 and Bcl-2 expression. Mn intoxication also induced marked gliosis, numerous vacuolations, and disoriented and pyknotic Purkinje cells as well as marked vascular congestion in brain tissue. Meanwhile, intraperitoneal administration of Ebs (15 mg/kg body weight) to Mn-intoxicated rats improved the behavioral performance and oxidative damage as well as inflammatory, apoptotic, and histopathological changes. The above results indicate that Ebs alleviated Mn neurotoxicity via its antioxidant, anti-inflammatory, and anti-apoptotic activities. Therefore, Ebs could represent a promising agent in the prevention of Mn-induced neurotoxicity.

Establishment of 2D Cell Cultures Derived From 3D MCF-7 Spheroids Displaying a Doxorubicin Resistant Profile

In vitro 3D cancer spheroids generally exhibit a drug resistance profile similar to that found in solid tumors. Due to this property, these models are an appealing for anticancer compounds screening. Nevertheless, the techniques and methods aimed for drug discovery are mostly standardized for cells cultured in 2D. The development of 2D cell culture models displaying a drug resistant profile is required to mimic the in vivo tumors, while the equipment, techniques, and methodologies established for conventional 2D cell cultures can continue to be employed in compound screening. In this work, the response of 3D-derived MCF-7 cells subsequently cultured in 2D in medium supplemented with glutathione (GSH) (antioxidant agent found in high levels in breast cancer tissues and a promoter of cancer cells resistance) to Doxorubicin (DOX) is evaluated. These cells demonstrated a resistance toward DOX closer to that displayed by 3D spheroids, which is higher than that exhibited by standard 2D cell cultures. In fact, the 50% inhibitory concentration (IC₅₀ ) of DOX in 3D-derived MCF-7 cell cultures supplemented with GSH is about eight-times higher than that obtained for conventional 2D cell cultures (cultured without GSH), and is only about two-times lower than that attained for 3D MCF-7 spheroids (cultured without GSH). Further investigation revealed that this improved resistance of 3D-derived MCF-7 cells may result from their increased P-glycoprotein (P-gp) activity and reduced production of intracellular reactive oxygen species (ROS).

The Effect of Boric Acid and Borax on Oxidative Stress, Inflammation, ER Stress and Apoptosis in Cisplatin Toxication and Nephrotoxicity Developing as a Result of Toxication

The development of treatment protocols that can reduce side effects in chemotherapy applications is extremely important in terms of cancer treatment. In this context, it was aimed to investigate the effects of boric acid and borax on cisplatin toxicity (nephrotoxicity) in rats. In the experimental phase, eight groups were formed from rats. Boric acid and borax were given to the treatment groups with three different doses using gavage. On the fifth day of the study, cisplatin (10 mg/kg) was administered to all rats except the control group. At the end of the study, oxidative stress-related (GSH, MDA, PCO, GPx, 8-OHdG), inflammation-related (TNF-α, IL-1β, IL-18, MCP-1, ICAM, TGF-β), apoptosis-related (p53, caspase 1, 3, 8, 12, bcl-2, bcl-xL, NFkB), and ER stress-related (GRP78, ATF-6, PERK) basic parameters were analyzed in serum, erythrocyte, and kidney tissues. Kidney tissues were also examined by histopathological and immunohistochemical methods. Borax and boric acid at different doses decreased inflammation and oxidative stress caused by cisplatin toxicity and increased ER stress. As a result of the treatments applied to experimental animals, it was determined that boric acid and borax reduced apoptotic damage in kidney tissue, but the decrease was statistically significant only in 200 mg/kg boric acid-administered group. In the study, low anti-apoptotic effects of borate doses with the anti-inflammatory and antioxidant effect may be due to increased ER stress at the relevant doses. Further studies on the effects of boron compounds on ER stress and apoptotic mechanisms may clarify this issue. Thus, possible side effects or if there are new usage areas of borone compounds which have many usage areas in clinics can be detected.

Bone Marrow Derived Mesenchymal Stem Cells in Addiction Related Hippocampal Damages

The brain is an important organ that controls all sensory and motor actions, memory, and emotions. Each anatomical and physiological modulation in various brain centers, results in psychological, behavioral, and sensory-motor changes. Alcohol and addictive drugs such as opioids and amphetamines have been shown to exert a great impact on brain, specifically on the hippocampus. Emerging evidence has indicated that altered hippocampal neurogenesis is associated with the pathophysiology of neuropsychological disorders including addiction. The addictive drugs impair neurogenesis and undermine the function of neural stem/progenitor cells in hippocampus. This feature was claimed to be one of the underlying mechanisms of behavioral changes in patients with addiction. As the impairment of stem cells’ function has been proven to be the underlying cause of pathologic neuroadaptations in the brain, the administration of stem cell populations has shown promising results for re-modulating of neuronal status in the brain and especially in the hippocampus. Among the different types of stem cells, bone marrow derived mesenchymal stem cells are the most proper candidates for stem cell therapies. In this review article, the recent studies on the effects of addictive drugs on brain neurogenesis, and also the promising potential effects of stem cells in curing addiction related hippocampal damages are discussed.

MAFG is a potential therapeutic target to restore chemosensitivity in cisplatin-resistant cancer cells by increasing reactive oxygen species

Adjuvant chemotherapy for solid tumors based on platinum-derived compounds such as cisplatin is the treatment of choice in most cases. Cisplatin triggers signaling pathways that lead to cell death, but it also induces changes in tumor cells that modify the therapeutic response, thereby leading to cisplatin resistance. We have recently reported that microRNA-7 is silenced by DNA methylation and is involved in the resistance to platinum in cancer cells through the action of the musculoaponeurotic fibrosarcoma oncogene family, protein G (MAFG). In the present study, we first confirm the miR-7 epigenetic regulation of MAFG in 44 normal- and/or tumor-paired samples in non-small-cell lung cancer (NSCLC). We also provide translational evidence of the role of MAFG and the clinical outcome in NSCLC by the interrogation of two extensive in silico databases of 2019 patients. Moreover, we propose that MAFG-mediated resistance could be conferred due to lower reactive oxygen species production after cisplatin exposure. We developed specifically selected aptamers against MAFG, with high sensitivity to detect the protein at a nuclear level probed by aptacytochemistry and histochemistry analyses. The inhibition of MAFG activity through the action of the specific aptamer apMAFG6F increased the levels of reactive oxygen species production and the sensitivity to cisplatin. We report first the specific nuclear identification of MAFG as a novel detection method for diagnosis in NSCLC, and then we report that MAFG modulates the redox response and confers cell protection against free radicals generated after platinum administration, thus also being a promising therapeutic target.

Oxidative DNA damage induced by ROS-modulating agents with the ability to target DNA: A comparison of the biological characteristics of citrus pectin and apple pectin

DNA targeting anticancer agents have been very successful in clinic, especially, when used in combinatorial therapy. But unfortunately, they often exhibit high levels of toxicity towards normal cells. Hence, much effort has been put into finding agents with more selectivity, and less toxicity. Pectins are natural polysaccharides, and beneficial nutritional fibers that have attracted attentions due to their antitumor properties. However, their molecular targets, and mechanism of action are widely unknown. Here, we have reported that citrus pectin (CP) and apple pectin (AP) selectively suppress viability in MDA-MB-231, MCF-7 and T47D human Breast cancer cells, while non-toxic to L929 normal cells. Upon CP, and AP treatments, cancer cells’ ROS content increased rapidly, and led to the collapse of the mitochondrial transmembrane potential which functions upstream of the caspase-dependent apoptosis. CP and AP treated cancer cells were also arrested at the S and G1 or G2/M phases of the cell cycle, respectively. Furthermore, mRNA expression of Galectin-3 (a multi-functional lectin involved in cell adhesion, cell cycle, and apoptosis) reduced in both CP and AP treated cells. Growth inhibition of MDA-MB-231 cells by CP, and AP was concomitant with DNA damage (oxidation, and strand breaks). In this context, in an effort to clarify the mechanism of action, we showed that CP, and AP are able to interact with DNA. The strength and mode of DNA binding were established by spectroscopy techniques. We demonstrated that CP, and AP bind to dsDNA by intercalation, and groove binding/partial intercalation, respectively. In conclusion, our findings suggest that CP, and AP induce apoptosis in MDA-MB-231 cells by increasing the release of ROS, which may be related to the mitochondrial apoptosis pathway, and direct interactions with DNA. Our data indicate that these compounds may be potentially useful in cancer treatment.

Curcumin-mediated effects on anti-diabetic drug-induced cardiotoxicity

The present study was designed to compare the cardiotoxicity of two very commonly used anti-diabetic drugs namely pioglitazone (Pio) and metformin (Met); and to study the effects of curcumin (Curc) against these drug-induced cardiotoxicity. Curc, being an anti-oxidant molecule and having cardio-protective potential, can have promising synergistic effects in reducing the cardiac stress induced by anti-diabetic therapies. Various dose and time-dependent cell viability and oxidative stress assays were conducted to study cardiotoxic side-effects and Curc-mediated effects in cardiomyoblasts. Effects of Curc were also studied in hyperglycaemia induced cardiac stress in the presence of drugs. Quantitative assays for cell growth, reactive oxygen species (ROS) generation, lipid peroxidation and mitochondrial permeability followed by anti-oxidant enzymes and caspases activity assays were done to study the mechanism of action of the induced cardiotoxicity. Significant dose and time mediated deleterious effects of Pio and Met were witnessed. Oxidative stress studies showed a remarkable increase in ROS with increasing dose of anti-diabetic drugs. Increased caspase activity and altered mitochondrial integrity were also witnessed in presence of Met and Pio in cardiomyoblasts. These alterations were found to be significantly reduced when treated with Curc simultaneously. The study confirms that Met and Pio exert toxic effects on cardiac cells by generating oxidative stress. Curc, being an anti-oxidative molecule, can suppress this effect and, therefore, can be used as a supplement with anti-diabetic drugs to suppress the induced cardiac stress.

Evidence for cardiotoxicity associated with sertraline in rats

Sertraline is an antidepressant that is frequently prescribed to treat depression, obsessive-compulsive disorder, panic disorder, and anxiety. This drug had a safe cardiotoxicity profile, until the reporting of cases of sertraline-associated cardiotoxicities in the early 2000s. Since then, there have been conflicting results on the cardiotoxicity of this drug. In the study reported here we aimed to identify the cardiotoxic effects of sertraline by evaluating serum cardiac biomarkers, such as serum aspartate aminotransferase (AST), creatinine phosphokinase-myoglobin band (CK-MB), lactate dehydrogenase (LDH), and cardiac troponin T (cTn-T) levels as well as electrocardiographic parameters, DNA damage in cardiomyocytes, and histological findings of heart tissue in rats that were administered oral doses of 5, 10, or 20 mg kg-1 of sertraline for 28 days. Additionally, to investigate the possible mechanisms underlying cardiotoxicity, glutathione and malondialdehyde levels in cardiac tissue were determined to evaluate oxidative stress. According to our results, AST, LDH, and cTn-T levels were significantly increased in the 10 and 20 mg kg-1 sertraline groups when compared to the control group. Heart rates were increased, PR intervals prolonged, a short QTc value was observed, and T-wave amplitudes were decreased significantly in the 20 mg kg-1 sertraline group when compared to the control group. Significant DNA damage was observed in the high-dose groups. Histopathological investigations also revealed some degenerative changes in the 10 and 20 mg kg-1 sertraline groups. Glutathione levels were significantly decreased in the 10 and 20 mg kg-1 sertraline groups when compared with the control group. In conclusion, our findings support the cardiotoxic potential of sertraline and also suggest that oxidative stress may play a role in the toxicity of sertraline.

IL-8 analogue CXCL8 (3-72) K11R/G31P, modulates LPS-induced inflammation via AKT1-NF-kβ and ERK1/2-AP-1 pathways in THP-1 monocytes

IL-8 is elevated during inflammation, and it initiates cascade of down-stream reactions. Its antagonist, CXCL8 (3-72) K11R/G31P (G31P), represses inflammatory reactions via competitive binding to CXC chemokine family, preferentially G protein-couple receptors (GPCRs) CXCR1/2. This study reports the effect of G31P on the transcription profile of lipopolysaccharide (LPS) induced inflammation in THP-1 monocytes ex-vivo. LPS (1 µg/ml) induced elevation of IL-8 was significantly reduced by G31P (20 µg/ml and 30 µg/ml), with relatively increased inhibition of CXCR2 than CXCR1. Transcription of IL-1β, IL-6, and TNF-α were significantly inhibited, while IL-10 remained relatively unchanged. G31P treatment also had repressing effect on the inflammatory associated enzymes COX-2, MMP-2, and MMP-9. Significant restriction of c-Fos, and NF-kβ mRNA expression was observed, while that of c-Jun was marginally elevated. Conversely, SP-1 mRNA expression was seen to increase appreciably by G31P treatment. While the translation of pAKT, pERK1/2, and p65- NF-kβ were down-regulated by the G31P following THP-1 cells stimulation with LPS, reactive oxygen species (ROS) expression was on the positive trajectory. Collectively, the IL-8 analogue, G31P, modulates the inflammatory profile of LPS induced inflammation in THP-1 monocytes via AKT1-NF-kβ and ERK1/2-AP-1 pathways.

Sesquiterpene lactone from Artemisia argyi induces gastric carcinoma cell apoptosis via activating NADPH oxidase/reactive oxygen species/mitochondrial pathway

Apoptosis is an essential type of programmed cell death. Previous studies have demonstrated that a wide range of natural-derived anticancer agents induce apoptosis by trigging oxidative stress. Artemisia argyi is a traditional Chinese herb for treating diverse diseases including dyspepsia, arthroncus, and anaphylactic disease. In this study, sesquiterpene lactone 3 (SL3), a bioactive ingredient isolated from Artemisia argyi was found to show obvious inhibitory effect on two gastric carcinoma cells. Mechanism study revealed that SL3 promoted the membrane translocation of p47, activated nicotinamide adenine dinucleotide (NADPH) oxidase, and evaluated intracellular reactive oxygen species production, leading to the activation of mitochondria-dependent caspase apoptosis pathway. Collectively, these findings show that SL3 is a promising anticancer candidate against gastric carcinoma by activating NADPH oxidase/reactive oxygen species/mitochondrial pathway.

Copper Acyl Salicylate Has Potential as an Anti-Cryptococcus Antifungal Agent

The in vitro antifungal activity of aspirin against cryptococcal cells has been reported. However, the unwanted effects of aspirin may limit its clinical application. Conceivably, a derivative of aspirin could overcome this challenge. Toward this end, this study considered the usage of an aspirinate-metal complex, namely, copper acyl salicylate (CAS), as an anti-Cryptococcus antifungal agent. Additionally, the study examined the effects of this compound on macrophage function. The in vitro susceptibility results revealed that cryptococcal cells were vulnerable (in a dose-dependent manner) to CAS, which might have effected growth inhibition by damaging cryptococcal cell membranes. Interestingly, when CAS was used in combination with fluconazole or amphotericin B, synergism was observed. Furthermore, CAS did not negatively affect the growth or metabolic activity of macrophages; rather, it sensitized those immune cells to produce interferon gamma and interleukin 6, which, in turn, might have aided in the phagocytosis of cryptococcal cells. Compared to our aspirin data, CAS was noted to be more effective in killing cryptococcal cells (based on susceptibility results) and less toxic toward macrophages (based on growth inhibition results). Taking these findings together, it is reasonable to conclude that CAS may be a better anti-Cryptococcus drug that could deliver better therapeutic outcomes, compared to aspirin.

Oxidative Stress and First-Line Antituberculosis Drug-Induced Hepatotoxicity

Hepatotoxicity induced by antituberculosis drugs is a serious adverse reaction with significant morbidity and even, rarely, mortality. This form of toxicity potentially impacts the treatment outcome of tuberculosis in some patients. Covering only first-line antituberculosis drugs, this review addresses whether and how oxidative stress and, more broadly, disturbance in redox homeostasis alongside mitochondrial dysfunction may contribute to the hepatotoxicity induced by them. Risk factors for such toxicity that have been identified, in addition to genetic factors, principally include old age, malnutrition, alcoholism, chronic hepatitis C and chronic hepatitis B infection, HIV infection, and preexisting liver disease. Importantly, these comorbid conditions are associated with oxidative stress. Thus, the shared pathogenetic mechanism(s) for liver injury might be in operation due to disease-drug interaction. Our current ability to predict, prevent, or treat hepatotoxicity (other than removing potentially hepatotoxic drugs) remains limited. More translational research to unravel the pathogenesis, inclusive of the underlying molecular basis, regarding antituberculosis drug-induced hepatotoxicity is needed, and so is clinical research pertaining to the advances in therapy with antioxidants and drugs related to antioxidants, especially those for management of mitochondrial dysfunction. The role of pharmacogenetics in the clinical management of drug-induced hepatotoxicity also likely merits further evaluation.

Polymorphisms in DNA mismatch repair pathway genes predict toxicity and response to cisplatin chemoradiation in head and neck squamous cell carcinoma patients

Head and neck squamous cell carcinoma (HNSCC) is treated with cisplatin (CDDP) and radiotherapy (RT), and distinct results are observed among patients with similar clinicopathological aspects. This prospective study aimed to investigate whether MLH1 c.-93G>A (rs1800734), MSH2 c.211+9C>G (rs2303426), MSH3 c.3133G>A (rs26279), EXO1 c.1765G>A (rs1047840), and EXO1 c.2270C>T (rs9350) single nucleotide polymorphisms (SNPs) of the mismatch repair (MMR) pathway change side effects and response rate of 90 HNSCC patients treated with CDDP and RT. DNA from peripheral blood was analyzed by PCR-based methods to obtain genotypes. It was observed 4.27-fold and 4.69-fold increased risks of presenting pronounced nephrotoxicity with treatment in patients with MSH3 GG and EXO1 rs9350 CC genotypes compared with patients with GA or AA and CT or TT genotypes, respectively. MSH3 GG or GA and GT haplotype of EXO1 rs1047840 and rs9350 SNPs conferred to patients 10.29 and 4.00 more chances of presenting pronounced ototoxicity after treatment than MSH3 AA genotype and other EXO1 haplotypes, respectively. Patients with EXO1 rs1047840 GA or AA genotype and AC haplotype of EXO1 rs1047840 and rs9350 SNPs had both 9.55-fold increased risks of achieving partial response or stable disease instead of complete remission after treatment than patients with EXO1 GG genotype and other EXO1 haplotypes, respectively. For the first time, our data show preliminary indication that inherited alterations of DNA MMR pathway, related to MSH3 rs26279, EXO1 rs1047840 and EXO1 rs9350 SNPs, modify toxicity and response to chemoradiation in HNSCC, and may contribute to future personalized treatment of patients.

Guazuma ulmifolia Lam. Decreases Oxidative Stress in Blood Cells and Prevents Doxorubicin-Induced Cardiotoxicity

Doxorubicin (DOX) is an efficient chemotherapeutic agent, but its clinical application is limited by its cardiotoxicity associated with increased oxidative stress. Thus, the combination of DOX and antioxidants has been encouraged. In this study, we evaluated (I) the chemical composition and antioxidant capacity of aqueous extracts from Guazuma ulmifolia stem bark (GUEsb) and leaves (GUEl) in 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging, 2,2′-azobis(2-amidinopropane) dihydrochloride- (AAPH-) or DOX-induced lipid peroxidation inhibition in human blood cells, and intracellular reactive oxygen species (ROS) quantification using the fluorescent probe dichloro-dihydro-fluorescein diacetate (DCFH-DA) in K562 erythroleukemia cells incubated with GUEsb and stimulated with hydrogen peroxide; (II) the viability of K562 cells and human leukocytes treated with GUEsb in the absence or presence of DOX using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay; (III) the acute toxicity of GUEsb; and (IV) the cardioprotective effect of GUEsb in C57Bl/6 mice treated with DOX. The chemical composition indicated the presence of flavan-3-ol derivatives and condensed tannins in GUEsb and glycosylated flavonoids in GUEl. GUEsb and GUEl showed free-radical scavenging antioxidant activity, antihemolytic activity, and AAPH- as well as DOX-induced malondialdehyde content reduction in human erythrocytes. Based on its higher antioxidant potential, GUEsb was selected and subsequently showed intracellular ROS reduction without impairing the chemotherapeutic activity of DOX in K562 cells or inducing leukocyte cell death, but protected them against DOX-induced cell death. Yet, GUEsb did not show in vivo acute toxicity, and it prevented MDA generation in the cardiac tissue of DOX-treated mice, thus demonstrating its cardioprotective effect. Taken together, the results show that GUEsb and GUEl are natural alternatives to treat diseases associated with oxidative stress and that, in particular, GUEsb may play an adjuvant role in DOX chemotherapy.

Mutations of p53 decrease sensitivity to the anthracycline treatments in bladder cancer cells

Due to doxorubicin (Dox) cardiotoxicity, the next generation of novel non-cardiotoxic anthracyclines, including AD 312 and AD 198, were synthesized and validated. In this study, we assessed the efficacy and mechanisms of anthracyclines-induced apoptosis and inhibition of cell viability in human bladder cancer cells expressing wild-type (wt) p53 (RT4 and SW780) and mutated (mt) p53 (UM-UC-3, 5637, T-24, J82, and TCCSUP) protein. Anthracyclines inhibited cell viability in tested TCC cells, but were less effective in mt-p53 TCC cells, especially in the drug-resistant J82 and TCCSUP cells. Anthracyclines upregulated the expression of wt p53 protein in RT4 and SW780 cells, but had no effect on expression of mt p53 protein in UM-UC-3, 5637, T-24, J82, and TCCSUP cells. The anthracyclines activated caspase 3/7 and cleavage of PARP in wt-p53 RT4 and SW780 cells, and mt-p53 5637, UM-UC-3, and T-24, but not in mt-p53 J82 and TCCSUP cells. The anthracyclines-induced cleavage of PARP was blocked by p53 siRNA in wt-p53 RT4 cells. Co-treatment of AD 198 with PRIMA-1 significantly inhibited cell viability of mt-p53 J82 cells, but had no effect in wt-p53 RT4 cells. AD 198 blocked c-myc expression in mt-p53 UM-UC-3, 5637, T-24, and J82 cells, however no expression of c-myc was detected in wt-p53 RT4 and SW780 cells. In conclusion, our results demonstrated that the anthracycline-induced resistance in bladder cancer cells positively correlated with TP53 mutations in the tetramerization domain in J82 and TCCSUP cells. Further, AD 312 and AD 198 are promising chemotherapeutic drugs for bladder cancer, especially in combination with PRIMA-1.

Elevated oxidative DNA damage in patients with coronary artery disease and its association with oxidative stress biomarkers

OBJECTIVE

The objective of the present study was to evaluate oxidative DNA damage in peripheral blood leukocytes (PBLs) of patients with coronary artery disease (CAD) and to explore the relationship of oxidised purine and pyrimidine with oxidative stress.

METHODS

The study participants (n = 100) included 50 patients and unrelated 50 age-, sex- and population-subgroup (Jat Sikhs)-matched healthy controls. Oxidative DNA damage using the modified enzymatic comet in PBLs, and malondialdehyde (MDA) levels, total oxidant status (TOS) and total antioxidant status (TAS) in blood serum samples using spectrophotometric methods was determined.

RESULTS

The basal DNA damage of percent tail DNA (T-DNA%) was increased as were tail moment (TM) and olive tail moment (OTM). Oxidative DNA damage in terms of oxidised purines and oxidised pyrimidines was also significantly (p < .001) elevated in patients. Rather the advanced stages of CAD, unstable angina and acute myocardial infarction had significantly more basal and oxidative DNA damage (p < .05) compared to stable angina. MDA levels (p < .01) and TOS (p < .001) were increased significantly in patients with significant (p < .001) decrease in TAS. There was positive correlation of oxidised purines (T-DNA% r = 0.399, p = .004; TM r = 0.623, p = .001; OTM r = 0.456, p= .001) and of total oxidative damage (TM r = 0.515, p = .001; OTM r = 0.463, p = .001) with disease severity, and, with TOS (r = 0.279, p = .050) and negative with TAS (r = -0.341, p = .015). Multiple linear regression analysis revealed TOS and disease severity as independent predictors of oxidative DNA damage.

CONCLUSIONS

There was significant increase in oxidative DNA damage and oxidative stress in CAD patients compared to levels in healthy controls.