Free radical mediated oxidative stress and toxic side effects in brain induced by the anti cancer drug adriamycin: insight into chemobrain

Advances in chemically modified HSA as a multifunctional carrier for transforming cancer therapy regimens

Human serum albumin (HSA) is a versatile, biodegradable, biocompatible, non-toxic, and non-immunogenic protein nanocarrier, making it an ideal platform for developing advanced drug delivery systems. These properties have garnered significant attention in utilizing HSA nanoparticles for the safe and efficient delivery of chemotherapeutic agents. HSA-based nanoparticles can be surface-modified with various ligands to enable tumor-targeted drug delivery, enhancing therapeutic specificity and efficacy. Furthermore, the multifunctionality of HSA nanoparticles offers promising strategies to overcome challenges in cancer therapy, including poor bioavailability, off-target toxicity, and drug resistance. This review highlights the structural features of HSA, explores its diverse modifications to improve drug-binding affinity and targeting ability, and discusses its potential as a multifunctional carrier in oncology. By summarizing the latest advances in HSA modification techniques and applications, this review provides a comprehensive perspective on the future of protein-based drug delivery systems in tumor therapy.

α-Bisabolol alleviates doxorubicin-induced cognitive dysfunction in rats via enhancing the hippocampal BDNF/TrKB signaling and inhibiting neuroinflammation

Chemofog is a serious sequela commonly manifested among cancer patients receiving doxorubicin (DOX) chemotherapy. Our goal was to explore the abrogative action of α-Bisabolol (BISA), a phytochemical sesquiterpene, against DOX-induced cognitive deficit. Rats were allocated into 5 groups: Group I: control; Group II received BISA orally (100 mg/kg/day for 4 weeks); Group III received DOX (2 mg/kg/week/i.p.) for 4 weeks; Groups IV and V were administered BISA orally at 50 and 100 mg/kg, respectively plus DOX, i. p. Results: 1) BISA attenuated DOX-induced chemofog as shown in memory-related behavioral tests. 2) BISA restored the hippocampal histological structure and redox homeostasis via diminishing MDA content and upregulating Nrf2 and HO-1 genes. 3) BISA mitigated DOX-induced neuroinflammation through reducing NF-kB, TNF-α, IL-6, IL-1β, and GFAP expressions. 4) BISA repressed the hippocampal apoptosis via downregulating Bax gene and upregulating Bcl-2 gene. 5) BISA enhanced the synaptic plasticity by activating the BDNF/TrKB signaling and increasing the levels of neurotransmitters that enhance memory, i.e., ACh, 5-HT, and DA. BISA at 100 mg/kg/day exerted a better neuroprotection than BISA at 50 mg/kg/day. Thus, BISA may protect cancer patients from cognitive disorders caused by DOX.

The Biological Intersection Between Chemotherapy-Related Cognitive Impairment and Alzheimer Disease

Alzheimer disease (AD) is the most common type of dementia and one of the leading causes of death in elderly patients. The number of patients with AD in the United States is projected to double by 2060. Thus, understanding modifiable risk factors for AD is an urgent public health priority. In parallel with the number of patients with AD, the number of cancer survivors is estimated to increase significantly, and up to 80% of cancer patients treated with chemotherapy will develop cognitive deficits, termed chemotherapy-related cognitive impairment. This review discusses biologically plausible pathways underlying both disorders, with the goal of understanding why a proportion of chemotherapy patients may be at higher risk of developing AD. Highlighted are the E4 allele of the apolipoprotein E gene, neuroinflammation, oxidative stress, DNA damage, mitochondrial dysfunction, neuronal and synaptic loss, cellular senescence, brain-derived neurotrophic factor signaling, white matter damage, blood-brain barrier/vascular dysfunction, tau pathology, and transposable element reactivation.

Enhanced antichemobrain activity of amino acid assisted ferulic acid solid dispersion in adult zebrafish (Danio rerio)

Chemotherapy-induced cognitive impairment (CICI), also known as "chemobrain," is a common side effect of breast cancer therapy which causes oxidative stress and generation of reactive oxygen species (ROS). Ferulic acid (FA), a natural polyphenol, belongs to BCS class II is confirmed to have nootropic, neuroprotective and antioxidant effects. Here, we have developed FA solid dispersion (SD) in order to enhance its therapeutic potential against chemobrain. An amorphous ferulic acid loaded leucin solid dispersion (FA-Leu SD) was prepared by utilizing amino acid through spray-drying technique. The solid-state characterization was carried out via Fourier-transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM). Additionally, in-vitro release studies and antioxidant assay were also performed along with in-vivo locomotor, biochemical and histopathological analysis. The physical properties showed that FA-Leu SD so formed exhibited spherical, irregular surface hollow cavity of along with broad melting endotherm as observed from FE-SEM and DSC results. The XRD spectra demonstrated absence of sharp and intense peaks in FA-Leu SD which evidenced for complete encapsulation of drug into carrier. Moreover, in-vitro drug release studies over a period of 5 h in PBS (pH 7.4) displayed a significant enhanced release in the first hr (68. 49 ± 5.39%) and in-vitro DPPH assay displayed greater antioxidant potential of FA in FA-Leu SD. Furthermore, the in-vivo behavioral findings of FA-Leu SD (equivalent to 150 mg/kg of free FA) exhibited positive results accompanied by in-vivo biochemical and molecular TNF-α showed a significant difference (p < 0.001) vis-à-vis DOX treated group upon DOX + FA-Leu SD. Additionally, histopathological analysis revealed neuroprotective effects of FA-Leu SD together with declined oxidative stress due to antioxidant potential of FA which was induced by anticancer drug doxorubicin (DOX). Overall, the above findings concluded that spray-dried FA-Leu SD could be useful for the treatment of chemotherapy induced cognitive impairment.

Melatonin mitigates doxorubicin induced chemo brain in a rat model in a NRF2/p53-SIRT1 dependent pathway

Cancer is a critical health problem, and chemotherapy administration is mandatory for its eradication. However, chemotherapy like doxorubicin (Dox) has serious side-effects including cognitive impairment or chemo brain. Melatonin is a neuroprotective agent that has antioxidant, and anti-inflammatory effects. We aimed to explore melatonin's effect on Dox-induced chemo brain to discover new mechanisms associated with Dox-induced neurotoxicity and try to prevent its occurrence. Thirty-two male albino rats had been equally divided into four groups; control, melatonin-administrated, Dox-induced chemo brain, and melatonin + Dox treated. On the 9th day, brain had been excised after scarification and had been assessed for reactive oxygen species measurement, histopathological analysis, immunohistochemical, gene and protein expressions for the nuclear factor erythroid 2-related factor 2 (Nrf2), p53 and Silent information regulator 2 homolog 1 (SIRT1). Our results show that melatonin coadministration diminished Dox induced hippocampal and prefrontal cortex (PFC) cellular degeneration. It alleviated Nitric Oxide (NO) level and reversed the decline of antioxidant enzyme activities. It also upregulated Nrf2, SIRT1 and downregulated p53 gene expression in rats receiving Dox. Moreover, melatonin elevated the protein expression level of Nrf2, SIRT1 and reduced p53 corresponding to immunohistochemical results. The data suggested that melatonin can mitigate Dox-induced neurotoxicity by aggravating the endogenous antioxidants and inducing neurogenesis through activation of Nrf2/p53-SIRT1signaling pathway in adult rats' PFC. These effects were associated with Nrf2, SIRT1 activation and p53 inhibition. This could be guidance to add melatonin as an adjuvant supplement to Dox regimens to limit its adverse effect on the brain function.

Susceptibility to radiation adverse effects in veterans with Gulf War illness and healthy civilians

We evaluated whether veterans with Gulf War illness (VGWI) report greater ionizing radiation adverse effects (RadAEs) than controls; whether radiation-sensitivity is tied to reported chemical-sensitivity; and whether environmental exposures are apparent risk factors for reported RadAEs (rRadAEs). 81 participants (41 VGWI, 40 controls) rated exposure to, and rRadAEs from, four radiation types. The relations of RadAE-propensity (defined as the ratio of rRadAEs to summed radiation exposures) to Gulf War illness (GWI) presence and severity, and to reported chemical-sensitivity were assessed. Ordinal logistic regression evaluated exposure prediction of RadAE-propensity in the full sample, in VGWI, and stratified by age and chemical-sensitivity. RadAE-propensity was increased in VGWI (vs. controls) and related to GWI severity (p < 0.01) and chemical-sensitivity (p < 0.01). Past carbon monoxide (CO) exposure emerged as a strong, robust predictor of RadAE-propensity on univariable and multivariable analyses (p < 0.001 on multivariable assessment, without and with adjustment for VGWI case status), retaining significance in age-stratified and chemical-sensitivity-stratified replication analyses. Thus, RadAE-propensity, a newly-described GWI-feature, relates to chemical-sensitivity, and is predicted by CO exposure-both features reported for nonionizing radiation sensitivity, consistent with shared mitochondrial/oxidative toxicity across radiation frequencies. Greater RadAE vulnerability fits an emerging picture of heightened drug/chemical susceptibility in VGWI.

Potential roles of 4HNE-adducted protein in serum extracellular vesicles as an early indicator of oxidative response against doxorubicin-induced cardiomyopathy in rats

Late-onset cardiomyopathy is becoming more common among cancer survivors, particularly those who received doxorubicin (DOXO) treatment. However, few clinically available cardiac biomarkers can predict an unfavorable cardiac outcome before cell death. Extracellular vesicles (EVs) are emerging as biomarkers for cardiovascular diseases and others. This study aimed to measure dynamic 4-hydroxynonenal (4HNE)-adducted protein levels in rats treated chronically with DOXO and examine their link with oxidative stress, antioxidant gene expression in cardiac tissues, and cardiac function. Twenty-two male Wistar rats were randomly assigned to receive intraperitoneal injection of normal saline (n = 8) or DOXO (3 mg/kg, 6 doses, n = 14). Before and after therapy, serum EVs and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels were determined. Tunable resistive pulse sensing was used to measure EV size and concentration. ELISA was used to assess 4HNE-adducted protein in EVs and cardiac tissues. Differential-display reverse transcription-PCR was used to quantitate cardiac Cat and Gpx1 gene expression. Potential correlations between 4HNE-adducted protein levels in EVs, cardiac oxidative stress, antioxidant gene expression, and cardiac function were determined. DOXO-treated rats showed more serum EV 4HNE-adducted protein than NSS-treated rats at day 9 and later endpoints, whereas NT-proBNP levels were not different between groups. Moreover, on day 9, surviving rats' EVs had higher levels of 4HNE-adducted protein, and these correlated positively with concentrations of heart tissue 4HNE adduction and copy numbers of Cat and Gpx1, while at endpoint correlated negatively with cardiac functions. Therefore, 4HNE-adducted protein in serum EVs could be an early, minimally invasive biomarker of the oxidative response and cardiac function in DOXO-induced cardiomyopathy.

A Review on the Neurotoxic Effects of Doxorubicin

Anthracyclines, a class of drugs considered as most effective anticancer drugs, used in the various regimens of cancer chemotherapy, induce long-term impairment of mitochondrial respiration, increase reactive oxygen species, and induce other mechanisms potentially leading to neurotoxicity. According to literature findings, one drug of this class - doxorubicin used to treat e.g. breast cancer, bladder cancer, lymphoma, and acute lymphocytic leukemia may induce such effects in the nervous system. Doxorubicin has poor penetration into the brain due to the lack of drug penetration through the blood-brain barrier, thus the toxicity of this agent is the result of its peripheral action. This action is manifested by cognitive impairment and anatomical changes in the brain and peripheral nervous system found in both preclinical and clinical studies in adult patients. Furthermore, more than 50% of children with cancer are treated with anthracyclines including doxorubicin, which may affect their nervous system, and lead to lifelong damage in many areas of their life. Despite ongoing research into the side effects of this drug, the mechanism of its neurotoxicity action on the central and peripheral nervous system is still not well understood. This review aims to summarize the neurotoxic effects of doxorubicin in preclinical (in vitro and in vivo) research and in clinical studies. Furthermore, it discusses the possible mechanisms of the toxic action of this agent on the nervous system.

Mitochondrial impairment but not peripheral inflammation predicts greater Gulf War illness severity

Gulf War illness (GWI) is an important exemplar of environmentally-triggered chronic multisymptom illness, and a potential model for accelerated aging. Inflammation is the main hypothesized mechanism for GWI, with mitochondrial impairment also proposed. No study has directly assessed mitochondrial respiratory chain function (MRCF) on muscle biopsy in veterans with GWI (VGWI). We recruited 42 participants, half VGWI, with biopsy material successfully secured in 36. Impaired MRCF indexed by complex I and II oxidative phosphorylation with glucose as a fuel source (CI&CIIOXPHOS) related significantly or borderline significantly in the predicted direction to 17 of 20 symptoms in the combined sample. Lower CI&CIIOXPHOS significantly predicted GWI severity in the combined sample and in VGWI separately, with or without adjustment for hsCRP. Higher-hsCRP (peripheral inflammation) related strongly to lower-MRCF (particularly fatty acid oxidation (FAO) indices) in VGWI, but not in controls. Despite this, whereas greater MRCF-impairment predicted greater GWI symptoms and severity, greater inflammation did not. Surprisingly, adjusted for MRCF, higher hsCRP significantly predicted lesser symptom severity in VGWI selectively. Findings comport with a hypothesis in which the increased inflammation observed in GWI is driven by FAO-defect-induced mitochondrial apoptosis. In conclusion, impaired mitochondrial function-but not peripheral inflammation-predicts greater GWI symptoms and severity.

Dendritic Self-assembled Structures from Therapeutic Charged Pentapeptides

CRE^NKA [Cys-Arg-(NMe)Glu-Lys-Ala, where (NMe)Glu refers to N-methyl-Glu], an anti-cancer pentapeptide that induces prostate tumor necrosis and significant reduction in tumor growth, was engineered to increase the resistance to endogenous proteases of its parent peptide, CREKA (Cys-Arg-Glu-Lys-Ala). Considering their high tendency to aggregate, the self-assembly of CRE^NKA and CREKA into well-defined and ordered structures has been examined as a function of peptide concentration and pH. Spectroscopic studies and atomistic molecular dynamics simulations reveal significant differences between the secondary structures of CREKA and CRE^NKA. Thus, the restrictions imposed by the (NMe)Glu residue reduce the conformational variability of CRE^NKA with respect to CREKA, which significantly affects the formation of well-defined and ordered self-assembly morphologies. Aggregates with poorly defined morphology are obtained from solutions with low and moderate CREKA concentrations at pH 4, whereas well-defined dendritic microstructures with fractal geometry are obtained from CRE^NKA solutions with similar peptide concentrations at pH 4 and 7. The formation of dendritic structures is proposed to follow a two-step mechanism: (1) pseudo-spherical particles are pre-nucleated through a diffusion-limited aggregation process, pre-defining the dendritic geometry, and (2) such pre-nucleated structures coalesce by incorporating conformationally restrained CRE^NKA molecules from the solution to their surfaces, forming a continuous dendritic structure. Instead, no regular assembly is obtained from solutions with high peptide concentrations, as their dynamics is dominated by strong repulsive peptide-peptide electrostatic interactions, and from solutions at pH 10, in which the total peptide charge is zero. Overall, results demonstrate that dendritic structures are only obtained when the molecular charge of CRE^NKA, which is controlled through the pH, favors kinetics over thermodynamics during the self-assembly process.

Galangin Mitigates DOX-induced Cognitive Impairment in Rats: Implication of NOX-1/Nrf-2/HMGB1/TLR4 and TNF-α/MAPKs/RIPK/MLKL/BDNF

The cognitive and behavioral decline observed in cancer survivors who underwent doxorubicin (DOX)-based treatment raises the need for therapeutic interventions to counteract these complications. Galangin (GAL) is a flavonoid-based phytochemical with pronounced protective effects in various neurological disorders. However, its impact on DOX-provoked neurotoxicity has not been clarified. Hence, the current investigation aimed to explore the ability of GAL to ameliorate DOX-provoked chemo-brain in rats. DOX (2mg/kg, once/week, i.p.) and GAL (50mg/kg, 5 times/week., via gavage) were administered for four successive weeks. The MWM and EPM tests were used to evaluate memory disruption and anxiety-like behavior, respectively. Meanwhile, targeted biochemical markers and molecular signals were examined by the aid of ELISA, Western blotting, and immune-histochemistry. In contrast to DOX-impaired rats, GAL effectively preserved hippocampal neurons, improved cognitive/behavioral functions, and enhanced the expression of the cell repair/growth index and BDNF. The antioxidant feature of GAL was confirmed by the amelioration of MDA, NO and NOX-1, along with restoring the Nrf-2/HO-1/GSH cue. In addition, GAL displayed marked anti-inflammatory properties as verified by the suppression of the HMGB1/TLR4 nexus and p-NF-κB p65 to inhibit TNF-α, IL-6, IL-1β, and iNOS. This inhibitory impact extended to entail astrocyte activation, as evidenced by the diminution of GFAP. These beneficial effects were associated with a notable reduction in p-p38^MAPK, p-JNK1/2, and p-ERK1/2, as well as the necroptosis cascade p-RIPK1/p-RIPK3/p-MLKL. Together, these pleiotropic protective impacts advocate the concurrent use of GAL as an adjuvant agent for managing DOX-driven neurodegeneration and cognitive/behavioral deficits. DATA AVAILABILITY: The authors confirm that all relevant data are included in the supplementary materials.

Cannabinoid drugs against chemotherapy-induced adverse effects: focus on nausea/vomiting, peripheral neuropathy and chemofog in animal models

Although new drugs are being developed for cancer treatment, classical chemotherapeutic agents are still front-line therapies, despite their frequent association with severe side effects that can hamper their use. Cannabinoids may prevent or palliate some of these side effects. The aim of the present study is to review the basic research which has been conducted evaluating the effects of cannabinoid drugs in the treatment of three important side effects induced by classical chemotherapeutic agents: nausea and vomiting, neuropathic pain and cognitive impairment. Several published studies have demonstrated that cannabinoids are useful in preventing and reducing the nausea, vomits and neuropathy induced by different chemotherapy regimens, though other side effects can occur, such as a reduction of gastrointestinal motility, along with psychotropic effects when using centrally-acting cannabinoids. Thus, peripherally-acting cannabinoids and new pharmacological options are being investigated, such as allosteric or biased agonists. Additionally, due to the increase in the survival of cancer patients, there are emerging data that demonstrate an important cognitive deterioration due to chemotherapy, and because the cannabinoid drugs have a neuroprotective effect, they could be useful in preventing chemotherapy-induced cognitive impairment (as demonstrated through studies in other neurological disorders), but this has not yet been tested. Thus, although cannabinoids seem a promising therapeutic approach in the treatment of different side effects induced by chemotherapeutic agents, future research will be necessary to find pharmacological options with a safer profile. Moreover, a new line of research awaits to be opened to elucidate their possible usefulness in preventing cognitive impairment.

The Role of ROS as a Double-Edged Sword in (In)Fertility: The Impact of Cancer Treatment

Simple Summary

Tumor cells are highly resistant to oxidative stress, but beyond a certain threshold, it may lead to apoptosis/necrosis. Thus, induced loss of redox balance can be a strategy used in anticancer therapies. However, the effectiveness of drugs contrasts with unknown mechanisms involved in the loss of fertility. Considering that cancer patients’ life expectancy is increasing, it raises concerns about the unknown adverse effects. Therefore, new strategies should be pursued alongside explaining to the patients their options regarding the reproduction side effects.

Abstract

Tumor cells are highly resistant to oxidative stress resulting from the imbalance between high reactive oxygen species (ROS) production and insufficient antioxidant defenses. However, when intracellular levels of ROS rise beyond a certain threshold, largely above cancer cells’ capacity to reduce it, they may ultimately lead to apoptosis or necrosis. This is, in fact, one of the molecular mechanisms of anticancer drugs, as most chemotherapeutic treatments alter redox homeostasis by further elevation of intracellular ROS levels or inhibition of antioxidant pathways. In traditional chemotherapy, it is widely accepted that most therapeutic effects are due to ROS-mediated cell damage, but in targeted therapies, ROS-mediated effects are mostly unknown and data are still emerging. The increasing effectiveness of anticancer treatments has raised new challenges, especially in the field of reproduction. With cancer patients’ life expectancy increasing, many aiming to become parents will be confronted with the adverse effects of treatments. Consequently, concerns about the impact of anticancer therapies on reproductive capacity are of particular interest. In this review, we begin with a short introduction on anticancer therapies, then address ROS physiological/pathophysiological roles in both male and female reproductive systems, and finish with ROS-mediated adverse effects of anticancer treatments in reproduction.

Crosstalk between anticancer drugs and mitochondrial functions

Chemotherapy is an important component of cancer treatment, which has side effects like vomiting, peripheral neuropathy, and numerous organ toxicity but the most significant outcomes of chemotherapy are cognitive impairment, which is mainly referred to as chemobrain or CICI (chemotherapy-induced cognitive impairment). It is characterized by difficulty with language, concentrating, processing speed, learning, and memory, as it affects the hippocampus areas of the brain. Mitochondrial dysfunction and oxidative stress are one of the major mechanisms causing chemobrain. The generation of reactive oxygen species (byproducts of oxidative phosphorylation) mainly occurs in mitochondria that play a prominent role in the induction of oxidative stress. The homeostasis of ROS in the mitochondria is maintained by mitochondrial antioxidant mechanism via enzymes like catalase, glutathione, and superoxide dismutase. Lungs and breast cancer are the two most common types of cancer, which are the most leading cancers in the world with about 4.18 million cases. In this review we exposed the current knowledge regarding chemotherapy-induced oxidative stress and mitochondrial dysfunction to cause cognitive impairment.We especially focused on the antineoplastic agent (ADRIAMYCIN, CYCLOPHOSPHAMIDE), platinum group agent CISPLATIN, antimetabolite agents (METHOTREXATE), and nitrogen mustard agent (CARMUSTINE) which increase oxidative stress and inflammatory markers in the PNS (peripheral nervous system) as well as the central nervous system. We also highlight the behavioural and functional changes in the brain.

Propagating acoustic waves on a culture substrate regulate the directional collective cell migration

Collective cell migration plays a critical role in physiological and pathological processes such as development, wound healing, and metastasis. Numerous studies have demonstrated how various types of chemical, mechanical, and electrical cues dictate the collective migratory behaviors of cells. Although an acoustic cue can be advantageous because of its noninvasiveness and biocompatibility, cell migration in response to acoustic stimulation remains poorly understood. In this study, we developed a device that is able to apply surface acoustic waves to a cell culture substrate and investigated the effect of propagating acoustic waves on collective cell migration. The migration distance estimated at various wave intensities revealed that unidirectional cell migration was enhanced at a critical wave intensity and that it was suppressed as the intensity was further increased. The increased migration might be attributable to cell orientation alignment along the direction of the propagating wave, as characterized by nucleus shape. Thicker actin bundles indicative of a high traction force were observed in cells subjected to propagating acoustic waves at the critical intensity. Our device and technique can be useful for regulating cellular functions associated with cell migration.

Improvement of the performance of anticancer peptides using a drug repositioning pipeline

The use of anticancer peptides (ACPs) as an alternative/complementary strategy to conventional chemotherapy treatments has been shown to decrease drug resistance and/or severe side effects. However, the efficacy of the positively-charged ACP is inhibited by elevated levels of negatively-charged cell-surface components which trap the peptides and prevent their contact with the cell membrane. Consequently, this decreases ACP-mediated membrane pore formation and cell lysis. Negatively-charged heparan sulphate (HS) and chondroitin sulphate (CS) have been shown to inhibit the cytotoxic effect of ACPs. In this study, we propose a strategy to promote the broad utilization of ACPs. In this context, we developed a drug repositioning pipeline to analyse transcriptomics data generated for four different cancer cell lines (A549, HEPG2, HT29, and MCF7) treated with hundreds of drugs in the LINCS L1000 project. Based on previous studies identifying genes modulating levels of the glycosaminoglycans (GAGs) HS and CS at the cell surface, our analysis aimed at identifying drugs inhibiting genes correlated with high HS and CS levels. As a result, we identified six chemicals as likely repositionable drugs with the potential to enhance the performance of ACPs. The codes in R and Python programming languages are publicly available in https://github.com/ElyasMo/ACPs_HS_HSPGs_CS. As a conclusion, these six drugs are highlighted as excellent targets for synergistic studies with ACPs aimed at lowering the costs associated with ACP-treatment.

Effects induced by a 50 Hz electromagnetic field and doxorubicin on Walker-256 carcinosarcoma growth and hepatic redox state in rats

We compare the effects of an extremely low-frequency electromagnetic field (EMF) with the chemotherapeutic agent doxorubicin (DOX) on tumor growth and the hepatic redox state in Walker-256 carcinosarcoma-bearing rats. Animals were divided into five groups with one control (no tumor) and four tumor-bearing groups: no treatment, DOX, DOX combined with EMF and EMF. While DOX and DOX + EMF provided greater inhibition of tumor growth, treatment with EMF alone resulted in some level of antitumor effect (p < .05). Superoxide dismutase, catalase activity and glutathione content were significantly decreased in the liver of tumor-bearing animals as compared with the control group (p < .05). The decreases in antioxidant defenses accompanied histological findings of suspected liver damage. However, hepatic levels of thiobarbituric acid reactive substances, an indicator of lipid peroxidation, were three times lower in EMF and DOX + EMF groups than in no treatment and DOX (p < .05). EMF and DOX + EMF showed significantly lower activity of serum ALT than DOX alone (p < .05). These results indicate that EMF treatment can inhibit tumor growth, causing less pronounced oxidative stress damage to the liver. Therefore, EMF can be used as a therapeutic strategy to influence the hepatic redox state and combat cancer with reduced side-effects.

Elevated Oxidative Stress and DNA Damage in Cortical Neurons of Chemotherapy Patients

The unintended neurologic sequelae of chemotherapy contribute to significant patient morbidity. Chemotherapy-related cognitive impairment (CRCI) is observed in up to 80% of cancer patients treated with chemotherapy and involves multiple cognitive domains including executive functioning. The pathophysiology underlying CRCI and the neurotoxicity of chemotherapy is incompletely understood, but oxidative stress and DNA damage are highly plausible mechanisms based on preclinical data. Unfortunately, validating pathways relevant to CRCI in humans is limited by an absence of relevant neuropathologic studies of patient brain tissue. In the present study, we stained sections of frontal lobe autopsy tissue from cancer patients treated with chemotherapy (n = 15), cancer patients not treated with chemotherapy (n = 10), and patients without history of cancer (n = 10) for markers of oxidative stress (nitrotyrosine, 4-hydroxynonenal) and DNA damage (pH2AX, pATM). Cancer patients treated with chemotherapy had increased staining for markers of oxidative stress and DNA damage in frontal lobe cortical neurons compared to controls. We detected no statistically significant difference in oxidative stress and DNA damage by the duration between last administration of chemotherapy and death. The study highlights the potential relevance of oxidative stress and DNA damage in the pathophysiology of CRCI and the neurotoxicity of chemotherapy.

Role of inflammatory, oxidative, and ER stress signaling in the neuroprotective effect of atorvastatin against doxorubicin-induced cognitive impairment in rats

Doxorubicin (DOX) is a potent chemotherapeutic agent widely used for the treatment of several malignancies. Despite its effectiveness, DOX has been implicated in induced neurotoxicity manifested as cognitive dysfunction with varying degrees, commonly referred to as chemobrain. DOX-induced chemobrain is presumed to be due to cytokine-induced inflammatory, oxidative, and apoptotic responses damaging the brain. Atorvastatin (ATV), 3-hydroxy 3-methylglutaryl co-enzyme A (HMG Co-A) reductase inhibitor, is a cholesterol-lowering statin possessing beneficial pleiotropic effects, including anti-inflammatory, antioxidant, and anti-apoptotic properties. Therefore, this study aims to investigate the potential neuroprotective effects of ATV against DOX-induced cognitive impairment studying the possible involvement of heme oxygenase-1 (HO-1) and endoplasmic reticulum (ER) stress biomarkers. Rats were treated with DOX (2 mg/kg/week), i.p. for 4 weeks. Oral treatment with ATV (10 mg/kg) ameliorated DOX-induced behavioral alterations, protected brain histological features, and attenuated DOX-induced inflammatory, oxidative, and apoptotic biomarkers. In addition, ATV upregulated the protective HO-1 expression levels and downregulated the DOX-induced apoptotic ER stress biomarkers. In conclusion, ATV (10 mg/kg) exhibited neuroprotective properties against DOX-induced cognitive impairment which could possibly be attributed to their anti-inflammatory, antioxidant, and anti-apoptotic effects in the brain.

Beta-Caryophyllene, a CB2R Selective Agonist, Protects Against Cognitive Impairment Caused by Neuro-inflammation and Not in Dementia Due to Ageing Induced by Mitochondrial Dysfunction

BACKGROUND

Dementia is a neurodegenerative disorder majorly evidenced by cognitive impairment. Although there are many types of dementia, the common underlying etiological factors in all the types are neuro-inflammation or aging induced apoptosis. β-caryophyllene, a cannabinoid type-2 receptor agonist, has been reported to have promising neuroprotective effects in cerebral ischemia and neuro-inflammation.

OBJECTIVE

In the present study, we evaluated the effects of β-caryophyllene against animal models of dementia whose etiology mimicked neuro-inflammation and aging.

METHODS

Two doses (50 and 100 mg/kg of body weight) of β-caryophyllene given orally were tested against AlCl₃-induced dementia in male Sprague Dawley (SD) rats using the Morris water maze test. Subsequently, the effect of the drug was assessed for episodic memory in female SD rats using novel object recognition task in doxorubicin-induced neuro-inflammation and chemobrain model. Moreover, its effects were evaluated in D-galactose-induced mitochondrial dysfunction leading to dementia.

RESULTS

β-caryophyllene, at both doses, showed significant improvement in memory when assessed using parameters like target quadrant entries, escape latency and path efficiency in the Morris water maze test for spatial memory. In the doxorubicin-induced chemobrain model, β-caryophyllene at 100 mg/kg significantly elevated acetylcholinesterase and catalase levels and lowered lipid peroxidation compared to the disease control. In the novel object recognition task, β-caryophyllene at 100 mg/kg significantly improved recognition index and discrimination index in the treated animals compared to the disease control, with a significant increase in catalase and a decrease in lipid peroxidation in both hippocampus and frontal cortex. However, in the D-galactose-induced mitochondrial dysfunction model, β-caryophyllene failed to show positive effects when spatial memory was assessed. It also failed to improve D-galactose-induced diminished mitochondrial complex I and II activities.

CONCLUSION

Hence, we conclude that β-caryophyllene at 100 mg/kg protects against dementia induced by neuro-inflammation with no effect on neuronal aging induced by mitochondrial dysfunction.

C-phycocyanin Mitigates Cognitive Impairment in Doxorubicin-Induced Chemobrain: Impact on Neuroinflammation, Oxidative Stress, and Brain Mitochondrial and Synaptic Alterations

Chemotherapy-induced cognitive impairment (CICI) is a common detrimental effect of cancer treatment, occurring in up to 75% of cancer patients. The widely utilized chemotherapeutic agent doxorubicin (DOX) has been implicated in cognitive decline, mostly via cytokine-induced neuroinflammatory and oxidative and mitochondrial damage to brain tissues. C-phycocyanin (CP) has previously been shown to have potent anti-inflammatory, antioxidant, and mitochondrial protective properties. Therefore, this present study was aimed to investigate the neuroprotective effects of CP against DOX-elicited cognitive impairment and explore the underlying mechanisms. CP treatment (50 mg/kg) significantly improved behavioral deficits in DOX-treated mice. Furthermore, CP suppressed DOX-induced neuroinflammation and oxidative stress, mitigated mitochondrial abnormalities, rescued dendritic spine loss, and increased synaptic density in the hippocampus of DOX-treated mice. Our results suggested that CP improves established DOX-induced cognitive deficits, which could be explained at least partly by inhibition of neuroinflammatory and oxidant stress and attenuation of mitochondrial and synaptic dysfunction.

N-Acetylcysteine Attenuates the Anxiety-Like Behavior and Spatial Cognition Impairment Induced by Doxorubicin and Cyclophosphamide Combination Treatment in Rats

BACKGROUND

Cancer patients can suffer from psychological and cognitive disorders after chemotherapy, which influence quality of life.

OBJECTIVE

Oxidative stress may contribute to the psychological and cognitive disorders induced in rats by chemotherapy. In the present study, we examined the effects of N-acetylcysteine, an anti-oxidant, on anxiety-like behavior and cognitive impairment in rats treated with a combination of doxorubicin and cyclophosphamide.

METHODS

Rats were intraperitoneally injected with doxorubicin and cyclophosphamide once a week for 2 weeks. The light-dark test and the novel location recognition test were used to assess anxiety-like behavior and spatial cognition, respectively. The rats' hippocampal levels of glutathione (GSH) and glutathione disulfide (GSSG) were measured using a GSSG/GSH quantification kit.

RESULTS

Combined treatment with doxorubicin and cyclophosphamide produced anxiety-like behavior and cognitive impairment in rats. N-acetylcysteine reversed the anxiety-like behavior and inhibition of novel location recognition induced by the combination treatment. Furthermore, the combination of doxorubicin and cyclophosphamide significantly reduced the rats' hippocampal GSH/GSSG ratios. N-acetylcysteine reversed the reduction in the GSH/GSSG ratio seen in the doxorubicin and cyclophosphamide-treated rats.

CONCLUSION

These results suggest that N-acetylcysteine inhibits doxorubicin and cyclophosphamide-induced anxiety-like behavior and cognitive impairment by reducing oxidative stress in the hippocampus.

Cancer Chemotherapy Related Cognitive Impairment and the Impact of the Alzheimer's Disease Risk Factor APOE

Cancer related cognitive impairment (CRCI) is a serious impairment to maintaining quality of life in cancer survivors. Cancer chemotherapy contributes to this condition through several potential mechanisms, including damage to the blood brain barrier, increases in oxidative stress and inflammation in the brain, and impaired neurogenesis, each of which lead to neuronal dysfunction. A genetic predisposition to CRCI is the E4 allele of the Apolipoprotein E gene (APOE), which is also the strongest genetic risk factor for Alzheimer's disease. In normal brains, APOE performs essential lipid transport functions. The APOE4 isoform has been linked to altered lipid binding, increased oxidative stress and inflammation, reduced turnover of neural progenitor cells, and impairment of the blood brain barrier. As chemotherapy also affects these processes, the influence of APOE4 on CRCI takes on great significance. This review outlines the main areas where APOE genotype could play a role in CRCI. Potential therapeutics based on APOE biology could mitigate these detrimental cognitive effects for those receiving chemotherapy, emphasizing that the APOE genotype could help in developing personalized cancer treatment regimens.

Chemotherapy-induced cognitive impairment (CICI): An overview of etiology and pathogenesis

Many cancer patients treated with chemotherapy develop chemotherapy-induced cognitive impairment (CICI), often referred to as chemo-brain, which manifest during or post-treatment with variable degrees, onset and duration thereby affecting the patients' quality of life. Several chemotherapeutic agents have been studied to determine its possible association with cognitive impairment and to fully comprehend their contribution to CICI. A vast number of studies have emerged proposing several candidate underlying mechanisms and etiologies contributing to CICI such as direct neurotoxicity, BBB disruption, decreased hippocampal neurogenesis, white matter abnormalities, secondary neuro-inflammatory response and increased oxidative stress; however, the exact underlying mechanisms are still not well defined. This review summarizes CICI associated with most commonly used chemotherapeutic agents with emphasizes the possible underlying pathogenesis in both animal and clinical studies.

Caffeic acid phenethyl ester counteracts doxorubicin-induced chemobrain in Sprague-Dawley rats: Emphasis on the modulation of oxidative stress and neuroinflammation

Chemotherapy-induced cognitive dysfunction (chemobrain) is one of the major complaints for cancer patients treated with chemotherapy such as Doxorubicin (DOX). The induction of oxidative stress and neuroinflammation were identified as major contributors to such adverse effect. Caffeic acid phenethyl ester (CAPE) is a natural polyphenolic compound, that exhibits unique context-dependent antioxidant activity. It exhibits pro-oxidant effects in cancer cells, while it is a potent antioxidant and cytoprotective in normal cells. The present study was designed to investigate the potential neuroprotective effects of CAPE against DOX-induced cognitive impairment. Chemobrain was induced in Sprague Dawley rats via systemic DOX administration once per week for 4 weeks (2 mg/kg/week, i.p.). CAPE was administered at 10 or 20 μmol/kg/day, i.p., 5 days per week for 4 weeks. Morris water maze (MWM) and passive avoidance tests were used to assess learning and memory functions. Oxidative stress was evaluated via the colorimetric determination of GSH and MDA levels in both hippocampal and prefrontal cortex brain regions. However, inflammatory markers, acetylcholine levels, and neuronal cell apoptosis were assessed in the same brain areas using immunoassays including either ELISA, western blotting or immunohistochemistry. DOX produced significant impairment in learning and memory as indicated by the data generated from MWM and step-through passive avoidance tests. Additionally DOX-triggered oxidative stress as evidenced from the reduction in GSH levels and increased lipid peroxidation. Treatment with DOX resulted in neuroinflammation as indicated by the increase in NF-kB (p65) nuclear translocation in addition to boosting the levels of pro-inflammatory mediators (COX-II/TNF-α) along with the increased levels of glial fibrillary acid protein (GFAP) in the tested tissues. Moreover, DOX reduced acetylcholine levels and augmented neuronal cell apoptosis as supported by the increased active caspase-3 levels. Co-treatment with CAPE significantly counteracted DOX-induced behavioral and molecular abnormalities in rat brain tissues. Our results provide the first preclinical evidence for CAPE promising neuroprotective activity against DOX-induced neurodegeneration and memory deficits.

Isobaric Labeling Strategy Utilizing 4-Plex N,N-Dimethyl Leucine (DiLeu) Tags Reveals Proteomic Changes Induced by Chemotherapy in Cerebrospinal Fluid of Children with B-Cell Acute Lymphoblastic Leukemia

The use of mass spectrometry for protein identification and quantification in cerebrospinal fluid (CSF) is at the forefront of research efforts to identify and explore biomarkers for the early diagnosis and prognosis of neurologic disorders. Here we implemented a 4-plex N,N-dimethyl leucine (DiLeu) isobaric labeling strategy in a longitudinal study aiming to investigate protein dynamics in children with B-cell acute lymphoblastic leukemia (B-cell ALL) undergoing chemotherapy. The temporal profile of CSF proteome during chemotherapy treatment at weeks 5, 10-14, and 24-28 highlighted many differentially expressed proteins, such as neural cell adhesion molecule, neuronal growth regulator 1, and secretogranin-3, all of which play important roles in neurodegenerative diseases. A total of 63 proteins were significantly altered across all of the time points investigated. The most over-represented biological processes from gene ontology analysis included platelet degranulation, complement activation, cell adhesion, fibrinolysis, neuron projection, regeneration, and regulation of neuron death. We expect that results from this and future studies will provide a means to monitor neurotoxicity and develop strategies to prevent central nervous system injury in response to chemotherapy in children.

Doxorubicin chemotherapy-induced "chemo-brain": Meta-analysis

Doxorubicin is a leading chemotherapeutic halting cellular replication and inducing p53-dependent apoptosis in cancerous tissue. Like many chemotherapies, doxorubicin damages healthy tissue throughout the body through cellular mechanisms independent of its chemotherapeutic action. Although cognitive impairment is commonly recorded in patients after chemotherapy, the occurrence of doxorubicin-induced "chemo-brain" is debated, as doxorubicin cannot cross the blood-brain barrier. However, the potential of indirect doxorubicin neurotoxicity remains, providing a foundation for doxorubicin-mediated chemo-brain. We present the first meta-analysis of defined cognitive performance of doxorubicin-treated patients. A search of PubMed and MedLine collected 494 studies, 14 of which met analysis criteria. Performance of 511 doxorubicin-treated women with breast cancer was compared to that of 306 healthy controls across measures of defined cognitive modalities. Treated patients experience significant impairment in global cognition compared to controls (g₌ -0.41, P < 0.001), with select impairment in executive function (g = -0.25, P < 0.0001), language (g = -0.30, P < 0.0001), memory (g = -0.12, P < 0.01) and processing speed (g = -0.28, P < 0.01). Within memory, short-term verbal memory is most significantly affected (g = -0.21, P < 0.01). Impairment in select cognitive modalities (executive function, language, memory, short-term verbal memory, processing speed) is prevalent in doxorubicin-treated patients, with some cognitive functions remaining intact (attention, motor function, visuospatial abilities). This information can guide the development of future interventions to improve quality-of-life (QOL) and doxorubicin-derived therapies that target cytotoxicity to cancerous tissue, avoiding healthy tissue damage, which is mediated by seemingly independent mechanisms.

Neurological Impairments in Mice Subjected to Irradiation and Chemotherapy

Radiotherapy, surgery and the chemotherapeutic agent temozolomide (TMZ) are frontline treatments for glioblastoma multiforme (GBM). However beneficial, GBM treatments nevertheless cause anxiety or depression in nearly 50% of patients. To further understand the basis of these neurological complications, we investigated the effects of combined radiotherapy and TMZ chemotherapy (combined treatment) on neurological impairments using a mouse model. Five weeks after combined treatment, mice displayed anxiety-like behaviors, and at 15 weeks both anxiety- and depression-like behaviors were observed. Relevant to the known roles of the serotonin axis in mood disorders, we found that 5HT1A serotonin receptor levels were decreased by ∼50% in the hippocampus at both early and late time points, and a 37% decrease in serotonin levels was observed at 15 weeks postirradiation. Furthermore, chronic treatment with the selective serotonin reuptake inhibitor fluoxetine was sufficient for reversing combined treatment-induced depression-like behaviors. Combined treatment also elicited a transient early increase in activated microglia in the hippocampus, suggesting therapy-induced neuroinflammation that subsided by 15 weeks. Together, the results of this study suggest that interventions targeting the serotonin axis may help ameliorate certain neurological side effects associated with the clinical management of GBM to improve the overall quality of life for cancer patients.

Polydatin ameliorates chemotherapy-induced cognitive impairment (chemobrain) by inhibiting oxidative stress, inflammatory response, and apoptosis in rats

Most breast cancer survivors receiving chemotherapy have severe cognitive impairment, often referred to as "chemobrain." Polydatin (PLD) is known to have many biological activities. Thus, this study aimed to determine whether symptoms of chemobrain can be prevented or relieved by PLD. The chemobrain models were established by intraperitoneal injection of doxorubicin (DOX, 2 mg/kg) in rats once a week for 4 weeks (DOX group and DOX+PLD group). In the PLD group and DOX+PLD group, PLD (50 mg/kg) was administered orally to rats every day. We found that PLD treatment significantly protected against DOX-induced learning and memory impairment, restored hippocampal histopathological architecture. Furthermore, PLD suppressed DOX-induced oxidative stress through up-regulating Nrf2, inhibited inflammatory response by activating the NF-κB pathway, and reduced hippocampal apoptosis. Therefore, the present study indicated that PLD offered neuroprotection against DOX-induced chemobrain. PLD may assist in preventing chemobrain after chemotherapy in patients with cancers.

Antioxidant Activity of Silymarin in Microcystin-LR Cardiac and Pulmonary Induced Injuries on Mice

BACKGROUND AND OBJECTIVES

Microcystin-LR has a toxic effect on several organs causing the destruction and fibrosis of these organs. This study was done to evaluate the antioxidant activity of silymarin on some oxidative stress parameters on heart and lung injuries induced by microcystin-LR in mice.

MATERIALS AND METHODS

Total 72 Balb/c male mice aged between five to seven weeks were grouped into 6; Group 1 contained twelve mice which were assigned as the healthy control group (C). Two microcystin-LR control groups assigned M6 and M12 contain 12 mice each. A fourth group contains twelve mice called the silymarin control group(S). The fifth and sixth groups contain twenty-four mice assigned as microcystin-LR silymarin groups SM6 and SM12. A blood sample was collected for estimation of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST). The homogenates of heart and lungs were extracted for estimation of protein carbonyl content (CC), lipid peroxidation products (LPO), reduced glutathione (GSH), methylglyoxal (MG) and activity of protein phosphatase I (PPI).

RESULTS

Significant statistical differences in both ALT and AST were observed between all groups (P>0.01). In cardiac homogenate, a significant statistical difference was observed in PPI, LPO and CC between all groups (P<0.05). Furthermore, methylglyoxal showed a significant statistical difference between all groups (p<0.01).

CONCLUSION

The findings suggested a potential therapeutic role of using silymarin as an antioxidant agent against cardiac and pulmonary injuries induced by MC-LR.

Magnetically Actuated Degradable Microrobots for Actively Controlled Drug Release and Hyperthermia Therapy

Microrobots facilitate targeted therapy due to their small size, minimal invasiveness, and precise wireless control. A degradable hyperthermia microrobot (DHM) with a 3D helical structure is developed, enabling actively controlled drug delivery, release, and hyperthermia therapy. The microrobot is made of poly(ethylene glycol) diacrylate (PEGDA) and pentaerythritol triacrylate (PETA) and contains magnetic Fe₃ O₄ nanoparticles (MNPs) and 5-fluorouracil (5-FU). Its locomotion is remotely and precisely controlled by a rotating magnetic field (RMF) generated by an electromagnetic actuation system. Drug-free DHMs reduce the viability of cancer cells by elevating the temperature under an alternating magnetic field (AMF), a hyperthermic effect. 5-FU is released from the proposed DHMs in normal-, high-burst-, and constant-release modes, controlled by the AMF. Finally, actively controlled drug release from the DHMs in normal- and high-burst-release mode results in a reduction in cell viability. The reduction in cell viability is of greater magnitude in high-burst- than in normal-release mode. In summary, biodegradable DHMs have potential for actively controlled drug release and hyperthermia therapy.

Trajectories of Cognitive Function and Associated Phenotypic and Genotypic Factors in Breast Cancer

OBJECTIVES

This study identified women with unique trajectories of executive function, concentration, and visual working memory before and during adjuvant therapy for breast cancer, and examined phenotypic and genotypic predictors associated with subgroups.

SAMPLE & SETTING

399 postmenopausal women, of whom 288 were women with early-stage breast cancer and 111 were women without breast cancer, matched on age and years of education to the women with breast cancer, and all at an urban cancer center.

METHODS & VARIABLES

A repeated-measures design was used; assessments occurred before adjuvant therapy and every six months post-therapy initiation. Group-based trajectory modeling determined subgroups. Multinomial logistic regression identified phenotypic and genotypic characteristics.

RESULTS

Three executive function and concentration trajectory subgroups were identified.

IMPLICATIONS FOR NURSING

Advancing age, greater pretherapy fatigue, and poorer pretherapy cognitive function are associated with the low subgroups. DNA repair and oxidative stress mechanisms may be involved in the cognitive changes that women experience.

Plausible biochemical mechanisms of chemotherapy-induced cognitive impairment ("chemobrain"), a condition that significantly impairs the quality of life of many cancer survivors

Increasing numbers of cancer patients survive and live longer than five years after therapy, but very often side effects of cancer treatment arise at same time. One of the side effects, chemotherapy-induced cognitive impairment (CICI), also called "chemobrain" or "chemofog" by patients, brings enormous challenges to cancer survivors following successful chemotherapeutic treatment. Decreased abilities of learning, memory, attention, executive function and processing speed in cancer survivors with CICI, are some of the challenges that greatly impair survivors' quality of life. The molecular mechanisms of CICI involve very complicated processes, which have been the subject of investigation over the past decades. Many mechanistic candidates have been studied including disruption of the blood-brain barrier (BBB), DNA damage, telomere shortening, oxidative stress and associated inflammatory response, gene polymorphism of neural repair, altered neurotransmission, and hormone changes. Oxidative stress is considered as a vital mechanism, since over 50% of FDA-approved anti-cancer drugs can generate reactive oxygen species (ROS) or reactive nitrogen species (RNS), which lead to neuronal death. In this review paper, we discuss these important candidate mechanisms, in particular oxidative stress and the cytokine, TNF-alpha and their potential roles in CICI.

Chemotherapy and cognition: comprehensive review on doxorubicin-induced chemobrain

Chemobrain refers to a common sequela experienced by a substantial subset of cancer patients exposed to chemotherapeutic treatment, a phenomenon that dramatically deteriorates the survivors' quality of life and prevents them from restoring their pre-cancer life. This review is intended to address the current knowledge regarding the mechanisms underlying the pathophysiology of the chemobrain phenomenon, with special focus on the antineoplastic agent ''doxorubicin'', which has been shown to be implicated in strenuous central neurotoxicity despite being-almost entirely-peripherally confined. Moreover, the assessment of the post-chemotherapy cognitive impairment in both human and animal subjects, and the potential pharmacotherapy and behavioral intervention strategies are reviewed.

The triangle of death of neurons: Oxidative damage, mitochondrial dysfunction, and loss of choline-containing biomolecules in brains of mice treated with doxorubicin. Advanced insights into mechanisms of chemotherapy induced cognitive impairment ("chemobrain") involving TNF-α

Cancer treatments are developing fast and the number of cancer survivors could arise to 20 million in United State by 2025. However, a large fraction of cancer survivors demonstrate cognitive dysfunction and associated decreased quality of life both shortly, and often long-term, after chemotherapy treatment. The etiologies of chemotherapy induced cognitive impairment (CICI) are complicated, made more so by the fact that many anti-cancer drugs cannot cross the blood-brain barrier (BBB). Multiple related factors and confounders lead to difficulties in determining the underlying mechanisms. Chemotherapy induced, oxidative stress-mediated tumor necrosis factor-alpha (TNF-α) elevation was considered as one of the main candidate mechanisms underlying CICI. Doxorubicin (Dox) is a prototypical reactive oxygen species (ROS)-generating chemotherapeutic agent used to treat solid tumors and lymphomas as part of multi-drug chemotherapeutic regimens. We previously reported that peripheral Dox-administration leads to plasma protein damage and elevation of TNF-α in plasma and brain of mice. In the present study, we used TNF-α null (TNFKO) mice to investigate the role of TNF-α in Dox-induced, oxidative stress-mediated alterations in brain. We report that Dox-induced oxidative stress in brain is ameliorated and brain mitochondrial function assessed by the Seahorse-determined oxygen consumption rate (OCR) is preserved in brains of TNFKO mice. Further, we show that Dox-decreased the level of hippocampal choline-containing compounds and brain phospholipases activity are partially protected in TNFKO group in MRS study. Our results provide strong evidence that Dox-targeted mitochondrial damage and levels of brain choline-containing metabolites, as well as phospholipases changes decreased in the CNS are associated with oxidative stress mediated by TNF-α. These results are consistent with the notion that oxidative stress and elevated TNF-α in brain underlie the damage to mitochondria and other pathological changes that lead to CICI. The results are discussed with reference to our identifying a potential therapeutic target to protect against cognitive problems after chemotherapy.

Low Sucrose, Omega-3 Enriched Diet Has Region-Specific Effects on Neuroinflammation and Synaptic Function Markers in a Mouse Model of Doxorubicin-Based Chemotherapy

Chemotherapeutic agents such as doxorubicin may negatively affect long-term brain functioning in cancer survivors; neuroinflammation may play a causal role. Dietary approaches that reduce inflammation, such as lowering sucrose and increasing eicosapentaenoic acid plus docosahexaenoic acid (EPA + DHA), may attenuate chemotherapy-induced neuroinflammation and synaptic damage, thereby improving quality of life. Ovariectomized, C57BL/6 mice were assigned to a chemotherapy (9 mg/kg doxorubicin + 90 mg/kg cyclophosphamide) or vehicle two-injection regimen, with injections two and four weeks after starting diets. In Study 1, mice received low sucrose diets with EPA + DHA or No EPA + DHA for four to six weeks; tissues were collected four, seven, or 14 days after the second injection. Compared to vehicle, chemotherapy increased pro-inflammatory cytokine IL-1β at day seven in the cortex and hippocampus, and reduced gene expression of synaptic marker Shank 3 at all timepoints in cortex, while EPA + DHA increased expression of Shank 3. In Study 2, high or low sucrose/EPA + DHA or No EPA + DHA diets were fed for five weeks; tissues were collected ten days after the second injection. Among chemotherapy-treated mice, brain DHA was higher with low sucrose feeding. Furthermore, low sucrose increased gene expression of Shank 1, while EPA + DHA increased expression of Shank 3 and reduced protein concentrations of pro-inflammatory markers IL-5, IL-6 and KC/GRO in the cortex, but not the hippocampus. Low sucrose, EPA + DHA diets may attenuate neuroinflammation and synaptic damage induced by doxorubicin-based chemotherapy in specific brain regions.

Brain Development and Heart Function after Systemic Single-Agent Chemotherapy in a Mouse Model of Childhood Leukemia Treatment

PURPOSE

Chemotherapy for childhood acute lymphoblastic leukemia (ALL) can cause late-appearing side effects in survivors that affect multiple organs, including the heart and brain. However, the complex ALL treatment regimen makes it difficult to isolate the causes of these side effects and impossible to separate the contributions of individual chemotherapy agents by clinical observation. Using a mouse model, we therefore assessed each of eight representative, systemically-administered ALL chemotherapy agents for their impact on postnatal brain development and heart function.

EXPERIMENTAL DESIGN

Mice were treated systemically with a single chemotherapy agent at an infant equivalent age, then allowed to age to early adulthood (9 weeks). Cardiac structure and function were assessed using in vivo high-frequency ultrasound, and brain anatomy was assessed using high-resolution volumetric ex vivo MRI. In addition, longitudinal in vivo MRI was used to determine the time course of developmental change after vincristine treatment.

RESULTS

Vincristine, doxorubicin, and methotrexate were observed to produce the greatest deficiencies in brain development as determined by volumes measured on MRI, whereas doxorubicin, methotrexate, and l-asparaginase altered heart structure or function. Longitudinal studies of vincristine revealed widespread volume loss immediately following treatment and impaired growth over time in several brain regions.

CONCLUSIONS

Multiple ALL chemotherapy agents can affect postnatal brain development or heart function. This study provides a ranking of agents based on potential toxicity, and thus highlights a subset likely to cause side effects in early adulthood for further study.

Chemotherapy and the pediatric brain

Survival rates of children with cancer are steadily increasing. This urges our attention to neurocognitive and psychiatric outcomes, as these can markedly influence the quality of life of these children. Neurobehavioral morbidity in childhood cancer survivors affects diverse aspects of cognitive function, which can include attention, memory, processing speed, intellect, academic achievement, and emotional health. Reasons for neurobehavioral morbidity are multiple with one major contributor being chemotherapy-induced central nervous system (CNS) toxicity. Clinical studies investigating the effects of chemotherapy on the CNS in children with cancer have reported causative associations with the development of leukoencephalopathies as well as smaller regional grey and white matter volumes, which have been found to correlate with neurocognitive deficits.Preclinical work has provided compelling evidence that chemotherapy drugs are potent neuro- and gliotoxins in vitro and in vivo and can cause brain injury via excitotoxic and apoptotic mechanisms. Furthermore, chemotherapy triggers DNA (deoxyribonucleic acid) damage directly or through increased oxidative stress. It can shorten telomeres and accelerate cell aging, cause cytokine deregulation, inhibit hippocampal neurogenesis, and reduce brain vascularization and blood flow. These mechanisms, when allowed to operate on the developing brain of a child, have high potential to not only cause brain injury, but also alter crucial developmental events, such as myelination, synaptogenesis, neurogenesis, cortical thinning, and formation of neuronal networks.This short review summarizes key publications describing neurotoxicity of chemotherapy in pediatric cancers and potential underlying pathomechanisms.

Physical exercise prevents cognitive impairment by enhancing hippocampal neuroplasticity and mitochondrial function in doxorubicin-induced chemobrain

Although chemotherapy increases the survival rate of patients with various cancers, such treatment can induce acute or long-term cognitive dysfunction a phenomenon known as post-chemotherapy cognitive impairment (PCCI) or "chemobrain." Exercise is known to positively affect brain function. Thus, the present study aimed to determine whether symptoms of chemobrain and disruptions in the neuroplasticity and functioning of hippocampal mitochondria can be prevented or relieved by exercise. Wistar rats were separated into the following groups: control, control plus exercise, chemobrain, and chemobrain plus exercise. For chemobrain induction, 2 mg/kg of doxorubicin (DOX) a widely utilized chemotherapeutic agent among patients with breast cancer was dissolved in saline and directly injected to the abdomen once every 4 weeks. The exercise groups were subjected to low-intensity treadmill, 6 days per week for 4 weeks. The Morris water maze and step-down avoidance tests were conducted to evaluate cognitive function, while neuroplasticity and mitochondrial function were assessed in the hippocampus and dentate gyrus. Decreased cognitive function were observed in the chemobrain group, along with decreases in levels of neurogenesis, brain derived neurotrophic factor (BDNF), tropomyosin-related kinase B (TrkB), Ca²⁺ retention in hippocampus. Rats of the chemobrain group also exhibited an increase in apoptosis, H₂O₂ emission and permeability transition pore by hippocampal mitochondria. However, exercise attenuated impairments in cognitive function, neuroplasticity, and mitochondrial function induced by DOX treatment. Therefore, the findings of the present study indicate that low-intensity exercise may assist in preventing cognitive dysfunction during or after chemotherapy in patients with various cancers, including breast cancer.

Chronic Treatment with Combined Chemotherapeutic Agents Affects Hippocampal Micromorphometry and Function in Mice, Independently of Neuroinflammation

Chemotherapeutic agents induce long-term side effects, including cognitive impairment and mood disorders, particularly in breast cancer survivors who have undergone chemotherapy. However, the precise mechanisms underpinning chemotherapy-induced hippocampal dysfunction remain unknown. In this study, we investigated the detrimental effects of chronic treatment with a combination of adriamycin and cyclophosphamide (AC) on the neuronal architecture and functions of the hippocampi of female C57BL/6 mice. After chronic AC administration, mice showed memory impairment (measured using a novel object recognition memory task) and depression-like behavior (measured using the tail suspension test and forced swim test). According to Golgi staining, chronic AC treatment significantly reduced the total dendritic length, ramification, and complexity as well as spine density and maturation in hippocampal neurons in a sub-region-specific manner. Additionally, the AC combination significantly reduced adult neurogenesis, the extent of the vascular network, and the levels of hippocampal angiogenesis-related factors. However, chronic AC treatment did not increase the levels of inflammation-related signals (microglial or astrocytic distribution, or the levels of pro-inflammatory cytokines or M1/M2 macrophage markers). Thus, chronic AC treatment changed the neuronal architecture of the adult hippocampus, possibly by reducing neurogenesis and the extent of the vasculature, independently of neuroinflammation. Such detrimental changes in micromorphometric parameters may explain the hippocampal dysfunction observed after cancer chemotherapy.

Subcortical brain iron deposition and cognitive performance in older women with breast cancer receiving adjuvant chemotherapy: A pilot MRI study

As the number of older adults in the U.S. increases, so too will the incidence of cancer and cancer-related cognitive impairment (CRCI). However, the exact underlying biological mechanism for CRCI is not yet well understood. We utilized susceptibility-weighted imaging with quantitative susceptibility mapping, a non-invasive MRI-based technique, to assess longitudinal iron deposition in subcortical gray matter structures and evaluate its association with cognitive performance in women age 60+ with breast cancer receiving adjuvant chemotherapy and age-matched women without breast cancer as controls. Brain MRI scans and neurocognitive scores from the NIH Toolbox for Cognition were obtained before chemotherapy (time point 1) and within one month after the last infusion of chemotherapy for the patients and at matched intervals for the controls (time point 2). There were 14 patients age 60+ with breast cancer (mean age 66.3 ± 5.3 years) and 13 controls (mean age 68.2 ± 6.1 years) included in this study. Brain iron increased as age increased. There were no significant between- or within- group differences in neurocognitive scores or iron deposition at time point 1 or between time points 1 and 2 (p > 0.01). However, there was a negative correlation between iron in the globus pallidus and the fluid cognition composite scores in the control group at time point 1 (r = -0.71; p < 0.01), but not in the chemotherapy group. Baseline iron in the putamen was negatively associated with changes in the oral reading recognition scores in the control group (r = 0.74, p < 0.01), but not in the chemotherapy group. Brain iron assessment did not indicate cancer or chemotherapy related short-term differences, yet some associations with cognition were observed. Studies with larger samples and longer follow-up intervals are warranted.

Doxorubicin-induced elevated oxidative stress and neurochemical alterations in brain and cognitive decline: protection by MESNA and insights into mechanisms of chemotherapy-induced cognitive impairment ("chemobrain")

Chemotherapy-induced cognitive impairment (CICI) is now widely recognized as a real and too common complication of cancer chemotherapy experienced by an ever-growing number of cancer survivors. Previously, we reported that doxorubicin (Dox), a prototypical reactive oxygen species (ROS)-producing anti-cancer drug, results in oxidation of plasma proteins, including apolipoprotein A-I (ApoA-I) leading to tumor necrosis factor-alpha (TNF-α)-mediated oxidative stress in plasma and brain. We also reported that co-administration of the antioxidant drug, 2-mercaptoethane sulfonate sodium (MESNA), prevents Dox-induced protein oxidation and subsequent TNF-α elevation in plasma. In this study, we measured oxidative stress in both brain and plasma of Dox-treated mice both with and without MESNA. MESNA ameliorated Dox-induced oxidative protein damage in plasma, confirming our prior studies, and in a new finding led to decreased oxidative stress in brain. This study also provides further functional and biochemical evidence of the mechanisms of CICI. Using novel object recognition (NOR), we demonstrated the Dox administration resulted in memory deficits, an effect that was rescued by MESNA. Using hydrogen magnetic resonance imaging spectroscopy (H1-MRS) techniques, we demonstrated that Dox administration led to a dramatic decrease in choline-containing compounds assessed by (Cho)/creatine ratios in the hippocampus in mice. To better elucidate a potential mechanism for this MRS observation, we tested the activities of the phospholipase enzymes known to act on phosphatidylcholine (PtdCho), a key component of phospholipid membranes and a source of choline for the neurotransmitter, acetylcholine (ACh). The activities of both phosphatidylcholine-specific phospholipase C (PC-PLC) and phospholipase D were severely diminished following Dox administration. The activity of PC-PLC was preserved when MESNA was co-administered with Dox; however, PLD activity was not protected. This study is the first to demonstrate the protective effects of MESNA on Dox-related protein oxidation, cognitive decline, phosphocholine (PCho) levels, and PC-PLC activity in brain and suggests novel potential therapeutic targets and strategies to mitigate CICI.

Chemo brain or tumor brain - that is the question: the presence of extracranial tumors profoundly affects molecular processes in the prefrontal cortex of TumorGraft mice

Cancer chemotherapy causes numerous persistent central nervous system complications. This condition is known as chemo brain. Cognitive impairments occur even before treatment, and hence are referred to as cancer associated cognitive changes, or tumor brain. There is much yet to be learned about the mechanisms of both chemo brain and tumor brain. The frequency and timing of chemo brain and tumor brain occurrence and persistence strongly suggest they may be epigenetic in nature and associated with altered gene expression. Here we used TumorGraft^TM models wherein part of a patient's tumor is removed and grafted into immune-deficient mice and conducted global gene expression and DNA methylation analysis. We show that malignant non-central nervous system tumor growth causes profound molecular alterations in the brain. Mice harbouring triple negative or progesterone positive breast cancer TumorGrafts exhibited altered gene expression, decreased levels of DNA methylation, increased levels of DNA hydroxymethylation, and oxidative stress in the prefrontal cortex. Interestingly, chemotherapy did not have any additional synergistic effects on the analyzed processes. The molecular changes observed in this study are known signs of neurodegeneration and brain aging. This study provides an important roadmap for future large-scale analysis of the molecular and cellular mechanisms of tumor brain.

Protective effects of curcumin against doxorubicin-induced toxicity and resistance: A review

Doxorubicin (DOX)-induced toxicity and resistance are major obstacles in chemotherapeutic approaches. Despite effective in the treatment of numerous malignancies, some clinicians have voiced concern that DOX has the potential to cause debilitating consequences in organ tissues, especially the heart. The mechanisms of toxicity and resistance are respectively related to induction of reactive oxygen species (ROS) and up-regulation of ATP-binding cassette (ABC) transporter. Curcumin (CUR) with several biological and pharmacological properties is expected to restore DOX-mediated impairments to tissues. This review is intended to address the current knowledge on DOX adverse effects and CUR protective actions in the heart, kidneys, liver, brain, and reproductive organs. Coadministration of CUR and DOX is capable of ameliorating DOX toxicity pertained to antioxidant, apoptosis, autophagy, and mitochondrial permeability.

Prophylactic effects of ellagic acid and rosmarinic acid on doxorubicin-induced neurotoxicity in rats

Doxorubicin (DOX) is a chemotherapeutic agent widely used in human malignancies. Its long-term use cause neurobiological side effects. The aim of the present study was to investigate the prophylactic effect exerted by daily administration of ellagic acid (EA) and rosmarinic acid (RA) on DOX-induced neurotoxicity in rats. Our data showed that DOX-induced significant elevation of brain malondialdehyde, tumor necrosis factor-alpha (TNF-α), inducible nitric oxide synthase (iNOS), caspase-3, and cholinesterase associated with significant reduction in reduced glutathione, monoamines namely serotonin, dopamine, as well as norepinephrine. Concomitant administration of EA (10 mg/kg/day, p.o. for 14 days) and/or RA (75 mg/kg/day, p.o. for 14 days) with DOX significantly mitigated the neural changes induced by DOX. Meanwhile, treatment ameliorated pro-inflammatory cytokines as TNF-α, iNOS, and attenuated oxidative stress biomarkers as well as brain monoamines. In conclusion, EA and RA can effectively protect against DOX-induced neurotoxicity, and the mechanisms underlying the neuroprotective effect are potentially associated with its antioxidant, anti-inflammatory, and antiapoptotic properties.

Sex-specific effects of cytotoxic chemotherapy agents cyclophosphamide and mitomycin C on gene expression, oxidative DNA damage, and epigenetic alterations in the prefrontal cortex and hippocampus - an aging connection

Recent research shows that chemotherapy agents can be more toxic to healthy brain cells than to the target cancer cells. They cause a range of side effects, including memory loss and cognitive dysfunction that can persist long after the completion of treatment. This condition is known as chemo brain. The molecular and cellular mechanisms of chemo brain remain obscure. Here, we analyzed the effects of two cytotoxic chemotherapy drugs—cyclophosphamide (CPP) and mitomycin C (MMC) - on transcriptomic and epigenetic changes in the murine prefrontal cortex (PFC) and hippocampal regions. We for the first time showed that CPP and MMC treatments led to profound sex- and brain region-specific alterations in gene expression profiles. Gene expression changes were most prominent in the PFC tissues of female mice 3 weeks after MMC treatment, and the gene expression response was much greater for MCC than CPP exposure. MMC exposure resulted in oxidative DNA damage, evidenced by accumulation of 8-oxo-2′-deoxyguanosine (8-oxodG) and a decrease in the level of 8-oxodG repair protein OGG1 in the PFC of female animals 3 weeks after treatment. MMC treatment decreased global DNA methylation and increased DNA hydroxymethylation in the PFC tissues of female mice. The majority of the changes induced by chemotherapy in the PFC tissues of female mice resembled those that occur during the brain's aging processes. Therefore, our study suggests a link between chemotherapy-induced chemo brain and brain aging, and provides an important roadmap for future analysis.