The antioxidant paradox: what are antioxidants and how should they be used in a therapeutic context for cancer

Laser-responsive erastin-loaded chondroitin sulfate nanomedicine targeting CD44 and system xc- in liver cancer: A non-ferroptotic approach

Erastin, a ferroptosis-inducing system xc- inhibitor, faces clinical challenges due to suboptimal physicochemical and pharmacokinetic properties, as well as relatively low potency and off-target toxicity. Addressing these, we developed ECINs, a novel laser-responsive erastin-loaded nanomedicine utilizing indocyanine green (ICG)-grafted chondroitin sulfate A (CSA) derivatives. Our aim was to improve erastin's tumor targeting via CSA-CD44 interactions and enhance its antitumor efficacy through ICG's photothermal and photodynamic effects in the laser-on state while minimizing off-target effects in the laser-off state. ECINs, with their nanoscale size of 186.7 ± 1.1 nm and high erastin encapsulation efficiency of 93.0 ± 0.8%, showed excellent colloidal stability and sustained drug release up to 120 h. In vitro, ECINs demonstrated a mechanism of cancer cell inhibition via G1-phase cell cycle arrest, indicating a non-ferroptotic action. In vivo biodistribution studies in SK-HEP-1 xenograft mice revealed that ECINs significantly enhanced tumor distribution of erastin (1.9-fold greater than free erastin) while substantially reducing off-target accumulation in the lungs and spleen by 203-fold and 19.1-fold, respectively. Combined with laser irradiation, ECINs significantly decreased tumor size (2.6-fold, compared to free erastin; 2.4-fold, compared to ECINs without laser irradiation) with minimal systemic toxicity. This study highlights ECINs as a dual-modality approach for liver cancer treatment, demonstrating significant efficacy against tumors overexpressing CD44 and system xc-.

Mechanisms of doxorubicin-induced cardiac inflammation and fibrosis; therapeutic targets and approaches

Doxorubicin plays a pivotal role in the treatment of various malignancies. Despite its efficacy, the cardiotoxicity associated with doxorubicin limits its clinical utility. The cardiotoxic nature of doxorubicin is attributed to several mechanisms, including its interference with mitochondrial function, the generation of reactive oxygen species (ROS), and the subsequent damage to cardiomyocyte DNA, proteins, and lipids. Furthermore, doxorubicin disrupts the homeostasis of cardiac-specific transcription factors and signaling pathways, exacerbating cardiac dysfunction. Oxidative stress, cell death, and other severe changes, such as mitochondrial dysfunction, activation of pro-oxidant enzymes, the renin-angiotensin system (RAS), endoplasmic reticulum (ER) stress, and infiltration of immune cells in the heart after treatment with doxorubicin, may cause inflammatory and fibrotic responses. Fibrosis and inflammation can lead to a range of disorders in the heart, resulting in potential cardiac dysfunction and disease. Various adjuvants have shown potential in preclinical studies to mitigate these challenges associated with cardiac inflammation and fibrosis. Antioxidants, plant-based products, specific inhibitors, and cardioprotective drugs may be recommended to alleviate cardiotoxicity. This review explores the complex mechanisms of doxorubicin-induced heart inflammation and fibrosis, identifies possible cellular and molecular targets, and investigates potential substances that could help reduce these harmful effects.

Lutein supplementation for early-life health and development: current knowledge, challenges, and implications

Macular carotenoids, which consist of lutein, zeaxanthin, and meso-zeaxanthin, are dietary antioxidants and macular pigments in the eyes, protecting the macula from light-induced oxidative stress. Lutein is also the main carotenoid in the infant brain and is involved in cognitive development. While a few articles reviewed the role of lutein in early health and development, the current review is the first that focuses on the outcomes of lutein supplementation, either provided to mothers or to infants. Additionally, lutein status and metabolism during pregnancy and lactation, factors that limit the potential application of lutein as a nutritional intervention, and solutions to overcome the limitation are also discussed. In brief, the lutein intake in pregnant and lactating women in the United States may not be optimal. Furthermore, preterm and formula-fed infants are known to have compromised lutein status compared to term and breast-fed infants, respectively. While lutein supplementation via both maternal and infant consumption improves lutein status in infants, the application of lutein as a nutritional intervention may be compromised by its low bioavailability. Various encapsulation techniques have been developed to enhance the delivery of lutein in adult animals or human but should be further evaluated in neonatal models.

Nanozymes: a new approach for leukemia therapy

Leukemia is a type of clonal disorder of hematopoietic stem and progenitor cells characterized by bone marrow failure, differentiation arrest, and lineage skewing. Despite leukemia being a complex disease and it being difficult to identify a single driving force, redox homeostasis, the balance between reactive oxygen species (ROS) producers and cellular antioxidant systems, is normally impaired during leukemogenesis. In this context, the modulation of ROS in leukemia cells can be harnessed for therapeutic purposes. Nanozymes are functional nanomaterials with enzyme-like characteristics, which address the intrinsic limitations of natural enzymes and exhibit great potential in synergistic antitumor therapy. Nanozymes possess catalytic activities (e.g., peroxidase-like activity, catalase-like activity, superoxide dismutase-like activity, and oxidase-like activity) to regulate ROS levels in vitro and in vivo, making them promising for leukemia therapy. On account of the rapid development of nanozymes recently, their application potentials in leukemia therapy are gradually being explored. To highlight the achievements of nanozymes in the leukemia field, this review summarizes the recent studies of nanozymes with anti-leukemia efficacy and the underlying mechanism. In addition, the challenges and prospects of nanozyme research in leukemia therapy are discussed.

Network pharmacology and experimental validation for deciphering the action mechanism of Fritillaria cirrhosa D. Don constituents in suppressing breast carcinoma

Fritillaria cirrhosa D. Don is a well-known medicinal plant of Kashmir Himalaya. Traditionally, it has been used to treat several diseases, including cancer. However, the molecular mechanism behind anticancer activity remains unclear. Therefore, in the present study, we have performed high performance-liquid chromatography-mass spectrometry (HR-LC/MS), network pharmacology, molecular docking and molecular dynamic (MD) simulation methods were used to explore the underlying molecular mechanism of F. cirrhosa for the treatment of breast cancer (BC). The targets of F. cirrhosa for treating BC were predicted using databases like SwissTargetPrediction, Gene Cards and OMIM. Protein-protein interaction analysis and network construction were performed using the Search Tool for the Retrieval of Interacting Genes/Proteins programme, and analysis of Gene Ontology term enrichment and Kyoto Encyclopedia of Genes and Genomes pathway enrichment was done using the Cytoscape programme. In addition, molecular docking was used to investigate intermolecular interactions between the compounds and the proteins using the Autodock tool. MD simulations studies were also used to explore the stability of the representative AKT1 gene peiminine and Imperialine-3-β-glucoside. In addition, experimental treatment of F. cirrhosa was also verified. HR-LC/MS detected the presence of several secondary metabolites. Afterward, molecular docking was used to verify the effective activity of the active ingredients against the prospective targets. Additionally, Peiminine and Imperialine-3-β-glucoside showed the highest binding energy score against AKT-1 (-12.99 kcal/mol and -12.08 kcal/mol). AKT1 with Peiminine and Imperialine-3-β-glucoside was further explored for MD simulations. During the MD simulation study at 100 nanoseconds, a stable complex formation of AKT1 + Peiminine and Imperialine-3-β-glucoside was observed. The binding free energy calculations using MM/GBSA showed significant binding of the ligand with protein (ΔG: -79.83 ± 3.0 kcal/mol) between AKT1 + Peiminine was observed. The principal component analysis exhibited a stable converged structure by achieving global motion. Lastly, F. cirrhosa extracts also exhibited momentous anticancer activity through in vitro studies. Therefore, present study revealed the molecular mechanism of F. cirrhosa constituents for the effective treatment of BC by deactivating various multiple gene targets, multiple pathways particularly the PI3K-Akt signaling pathway. These findings emphasized the momentous anti-BC activity of F. cirrhosa constituents.Communicated by Ramaswamy H. Sarma.

Bioactivity profile of dissolved organic matter and its relation to molecular composition

Dissolved organic matter (DOM) occupies a huge and uncharted molecular space. Given its properties, DOM can be presented as a promising biotechnological resource. However, research into bioactivities of DOM is still in early stages. In this study, the biotechnological potential of terrestrial and marine DOM, its molecular composition and their relationships are investigated. Samples were screened for their in vitro antibacterial, antifungal, anticancer and antioxidant activities. Antibacterial activity was detected against Staphylococcus aureus in almost all DOM samples, with freshwater DOM showing the lowest IC50 values. Most samples also inhibited Staphylococcus epidermidis, and four DOM extracts showed up to fourfold higher potency than the reference drug. Antifungal activity was limited to only porewater DOM towards human dermatophyte Trichophyton rubrum. No significant in vitro anticancer activity was observed. Low antioxidant potential was exerted. The molecular characterization by FT-ICR MS allowed a broad compositional overview. Three main distinguished groups have been identified by PCoA analyses. Antibacterial activities are related to high aromaticity content and highly-unsaturated molecular formulae (O-poor). Antifungal effect is correlated with highly-unsaturated molecular formulae (O-rich). Antioxidant activity is positively related to the presence of double bonds and polyphenols. This study evidenced for the first time antibacterial and antifungal activity in DOM with potential applications in cosmeceutical, pharmaceutical and aquaculture industry. The lack of cytotoxicity and the almost unlimited presence of this organic material may open new avenues in future marine bioprospecting efforts.

Consumption and supplementation of vitamin E in breast cancer risk, treatment, and outcomes: A systematic review with meta-analysis

BACKGROUND

Robust evidence have shown diet or dietary components in playing a direct role on cancer chemoprevention such as breast cancer (BC), and also prevention against cancer therapy side effects. In this context, vitamin E isoforms have been associated with tumor suppression pathways, mainly related to proliferation, invasion, metastasis, tumor metabolism and chemoresistance.

OBJECTIVE

Therefore, we performed a systematic review with meta-analysis to assess the effects of vitamin E consumption and/or supplementation on breast cancer risk, treatment, and outcomes.

METHODS

The studies were selected in the electronic databases PubMed, Science Direct, Scopus and Web of Science.

RESULTS

A total of 22 articles were selected, which nine manuscripts we perform the meta-analysis. The summary effect estimate did not indicate any significant association between consumption versus non-consumption of total vitamin E and breast cancer risk. After assessing the effects of vitamin E supplementation on breast cancer risk, only two had data for comparison and vitamin E supplementation presented no impact on breast cancer risk. However, the summary effect estimate from the included studies indicated that vitamin E consumption was inversely associated with breast cancer recurrence in the control group. There are no significant results regarding dietary or supplemental vitamin E intake and BC risk reduction.

CONCLUSION

Finally, regarding recurrence, survival, and mortality, the results indicated that vitamin E consumption was inversely associated with breast cancer recurrence, although no association was found for breast cancer mortality.

Chemopreventive and anti-tumor potential of vitamin E in preclinical breast cancer studies: A systematic review

BACKGROUND

Vitamin E has been investigated for its antitumor potential, including the ability to change cancer gene pathways as well as promote antioxidant and pro-oxidant activity.

OBJECTIVE

Therefore, this systematic review aimed to evaluate antitumor and chemopreventive activity of different vitamin E isoforms (tocopherols and tocotrienols) through in vitro and in vivo studies.

METHOD

The systematic review was registered in PROSPERO (No. CRD4202126207) and the search was carried out in four electronic databases (PubMed, Science Direct, Scopus and Web of Science) in June 2021 by three independent reviewers. The search equation used was: "Supplementation" AND ("Vitamin E" OR Tocopherol OR Tocotrienol) AND "breast cancer" AND (chemotherapy OR therapy OR prevention). In vitro studies and animal models of breast cancer supplemented with tocopherol or tocotrienol vitamers, alone or in combination, were included.

RESULTS

The results revealed 8546 relevant studies that were initially identified in our search. After analysis, a total of 12 studies were eligible for this systematic review. All studies included animal models, and 5 of them also performed in vitro experiments on cancer cell lines. The studies performed supplementation with tocopherols, mixtures (tocopherols and tocotrienols) and synthetic vitamin E forms. There was an significant association of estradiol, dendritic cells and pterostilbene in combined therapy with vitamin E. Vitamin E delayed tumor development, reduced tumor size, proliferation, viability, expression of anti-apoptotic and cell proliferation genes, and upregulated pro-apoptotic genes, tumor suppressor genes and increased immune response. The effects on oxidative stress markers and antioxidant activity were conflicting among studies. Only one study with synthetic vitamin E reported cardiotoxicity, but it did not show vitamin E genotoxicity.

CONCLUSION

In conclusion, vitamin E isoforms, isolated or associated, showed antitumor and chemopreventive activity. However, due to studies heterogeneity, there is a need for further analysis to establish dose, form, supplementation time and breast cancer stage.

The role of dietary antioxidants in type 2 diabetes and neurodegenerative disorders: An assessment of the benefit profile

Healthy diet is vital to cellular health. The human body succumbs to numerous diseases which afflict severe economic and psychological burdens on the patient and family. Oxidative stress is a possible crucial regulator of various pathologies, including type 2 diabetes and neurodegenerative diseases. It generates reactive oxygen species (ROS) that trigger the dysregulation of essential cellular functions, ultimately affecting cellular health and homeostasis. However, lower levels of ROS can be advantageous and are implicated in a variety of signaling pathways. Due to this dichotomy, the terms oxidative "eustress," which refers to a good oxidative event, and "distress," which can be hazardous, have developed. ROS affects multiple signaling pathways, leading to compromised insulin secretion, insulin resistance, and β-cell dysfunction in diabetes. ROS is also associated with increased mitochondrial dysfunction and neuroinflammation, aggravating neurodegenerative conditions in the body, particularly with age. Treatment includes drugs/therapies often associated with dependence, side effects including non-selectivity, and possible toxicity, particularly in the long run. It is imperative to explore alternative medicines as an adjunct therapy, utilizing natural remedies/resources to avoid all the possible harms. Antioxidants are vital components of our body that fight disease by reducing oxidative stress or nullifying the excess toxic free radicals produced under various pathological conditions. In this review, we focus on the antioxidant effects of components of dietary foods such as tea, coffee, wine, oils, and honey and the role and mechanism of action of these antioxidants in alleviating type 2 diabetes and neurodegenerative disorders. We aim to provide information about possible alternatives to drug treatments used alone or combined to reduce drug intake and encourage the consumption of natural ingredients at doses adequate to promote health and combat pathologies while reducing unwanted risks and side effects.

Network pharmacology and in vitro testing of Theobroma cacao extract's antioxidative activity and its effects on cancer cell survival

Theobroma cacao L. is a commercially important food/beverage and is used as traditional medicine worldwide against a variety of ailments. In the present study, computational biology approaches were implemented to elucidate the possible role of cocoa in cancer therapy. Bioactives of cocoa were retrieved from the PubChem database and queried for targets involved in cancer pathogenesis using BindingDB (similarity index ≥0.7). Later, the protein-protein interactions network was investigated using STRING and compound-protein via Cytoscape. In addition, intermolecular interactions were investigated via molecular docking. Also, the stability of the representative complex Hirsutrin-epidermal growth factor receptor (EGFR) complex was explored using molecular dynamics simulations. Crude extract metabolite profile was carried out by LC-MS. Further, anti-oxidant and cytotoxicity studies were performed in Chinese hamster ovary (normal) and Ehrlich ascites carcinoma (cancer) cell lines. Herein, the gene set enrichment and network analysis revealed 34 bioactives in cocoa targeting 50 proteins regulating 21 pathways involved in cancer and oxidative stress in humans. EGFR scored the highest edge count amongst 50 targets modulating 21 key pathways. Hence, it was selected as a promising anticancer target in this study. Structural refinement of EGFR was performed via all-atom molecular dynamics simulations in explicit solvent. A complex EGFR-Hirsutrin showed the least binding energy (-7.2 kcal/mol) and conserved non-bonded contacts with binding pocket residues. A stable complex formation of EGFR-Hirsutrin was observed during 100 ns MD simulation. In vitro studies corroborated antioxidant activity for cocoa extract and showed a significantly higher cytotoxic effect on cancer cells compared to normal cells. Our study virtually predicts anti-cancer activity for cocoa affected by hirsutrin inhibiting EGFR. Further wet-lab studies are needed to establish cocoa extract against cancer and oxidative stress.

Curcumin and Graphene Oxide Incorporated into Alginate Hydrogels as Versatile Devices for the Local Treatment of Squamous Cell Carcinoma

With the aim of preparing hybrid hydrogels suitable for use as patches for the local treatment of squamous cell carcinoma (SCC)-affected areas, curcumin (CUR) was loaded onto graphene oxide (GO) nanosheets, which were then blended into an alginate hydrogel that was crosslinked by means of calcium ions. The homogeneous incorporation of GO within the polymer network, which was confirmed through morphological investigations, improved the stability of the hybrid system compared to blank hydrogels. The weight loss in the 100-170 °C temperature range was reduced from 30% to 20%, and the degradation of alginate chains shifted to higher temperatures. Moreover, GO enhanced the stability in water media by counteracting the de-crosslinking process of the polymer network. Cell viability assays showed that the loading of CUR (2.5% and 5% by weight) was able to reduce the intrinsic toxicity of GO towards healthy cells, while higher amounts were ineffective due to the antioxidant/prooxidant paradox. Interestingly, the CUR-loaded systems were found to possess a strong cytotoxic effect in SCC cancer cells, and the sustained CUR release (~50% after 96 h) allowed long-term anticancer efficiency to be hypothesized.

Mitochondrial Dysfunction and Oxidative Stress in Liver Transplantation and Underlying Diseases: New Insights and Therapeutics

Mitochondria are essential organelles for cellular energy and metabolism. Like with any organ, the liver highly depends on the function of these cellular powerhouses. Hepatotoxic insults often lead to an impairment of mitochondrial activity and an increase in oxidative stress, thereby compromising the metabolic and synthetic functions. Mitochondria play a critical role in ATP synthesis and the production or scavenging of free radicals. Mitochondria orchestrate many cellular signaling pathways involved in the regulation of cell death, metabolism, cell division, and progenitor cell differentiation. Mitochondrial dysfunction and oxidative stress are closely associated with ischemia-reperfusion injury during organ transplantation and with different liver diseases, including cholestasis, steatosis, viral hepatitis, and drug-induced liver injury. To develop novel mitochondria-targeting therapies or interventions, a better understanding of mitochondrial dysfunction and oxidative stress in hepatic pathogenesis is very much needed. Therapies targeting mitochondria impairment and oxidative imbalance in liver diseases have been extensively studied in preclinical and clinical research. In this review, we provide an overview of how oxidative stress and mitochondrial dysfunction affect liver diseases and liver transplantation. Furthermore, we summarize recent developments of antioxidant and mitochondria-targeted interventions.

Phenolic Thiazoles with Antioxidant and Antiradical Activity. Synthesis, In Vitro Evaluation, Toxicity, Electrochemical Behavior, Quantum Studies and Antimicrobial Screening

Oxidative stress represents the underlying cause of many chronic diseases in human; therefore, the development of potent antioxidant compounds for preventing or treating such conditions is useful. Starting from the good antioxidant and antiradical properties identified for the previously reported Dihydroxy-Phenyl-Thiazol-Hydrazinium chloride (DPTH), we synthesized a congeneric series of phenolic thiazoles. The radical scavenging activity, and the antioxidant and chelation potential were assessed in vitro, a series of quantum descriptors were calculated, and the electrochemical behavior of the synthesized compounds was studied to evaluate the impact on the antioxidant and antiradical activities. In addition, their antibacterial and antifungal properties were evaluated against seven aerobic bacterial strains and a strain of C. albicans, and their cytotoxicity was assessed in vitro. Compounds 5a-b, 7a-b and 8a-b presented remarkable antioxidant and antiradical properties, and compounds 5a-b, 7a and 8a displayed good Cu⁺² chelating activity. Compounds 7a and 8a were very active against P. aeruginosa ATCC 27853 compared to norfloxacin, and proved less cytotoxic than ascorbic acid against the human keratinocyte cell line (HaCaT cells, CLS-300493). Several phenolic compounds from the synthesized series presented excellent antioxidant activity and notable anti-Pseudomonas potential.

A Comprehensive Review of the Use of Antioxidants and Natural Products in Cancer Patients Receiving Anticancer Therapy

Cancer is the leading cause of mortality and morbidity worldwide. The side effects of cancer treatment affect the quality of life. Cancer patients search for antioxidant dietary supplements and natural products during or after conventional cancer treatment for the alleviation of side effects, improvement of the benefits of treatment, and promotion of well-being. However, the efficacy and safety of these products remain controversial; moreover, previous data do not support the standardized use of those alternative treatments in clinics. The current study reviewed the manuscripts reporting the administration of antioxidants and natural products during cancer treatment and revised preclinical and clinical studies on various types of cancer. Most of the positive results were obtained from experimental animal models; however, human clinical studies are discouraging in this regard. Therefore, further precise and distinguishable studies are required regarding antioxidant dietary supplementation. Future studies are also needed to clarify dietary supplements' mechanism of action and pharmacokinetics in a suitable cancer patient population that will benefit the therapeutic regimens. Despite the popularity of dietary supplements, clinicians and patients should always consider their potential benefits and risks. Patients should discuss with their physician before taking any dietary antioxidant supplements or natural products.

Synthesis and Biological Evaluation of Novel 2-imino-4-thiazolidinones as Potential Antitumor Agents for Glioblastoma

AIMS

The purpose of our study was to explore the molecular hybridization between 2-imino-4-thizolidione and piridinic scaffolds and its potential antitumor activity.

BACKGROUND

Glioblastoma is the most aggressive glioma tumor clinically diagnosed malignant and highly recurrent primary brain tumor type. The standard of treatment for a glioblastoma is surgery, followed by radiation and chemotherapy using temozolomide. However, the chemoresistance has become the main barrier to treatment success. 2-imino-4-thiazolidinones are an important class of heterocyclic compounds that feature anticancer activity; however the antiglioblastoma activity is yet to be explored.

OBJECTIVE

To synthesize and characterize a series of novel 2-imino-4-thiazolidinones and evaluate their antiglioblastoma activity.

METHOD

The 2-imino-4-thiazolidinone (5a-p) was synthesized according to the literature with modifications. Compounds were identified and characterized using spectroscopic analysis and X-ray diffraction. The antitumor activity was analyzed by 3-(4,5- dimethyl)-2,5-diphenyltetrazolium bromide (MTT) assay both in primary astrocyte and glioma (C6). Apoptosis and cell cycle phase were determined by flow cytometry analysis. The expression of caspase-3/7 was measured by luminescence assay. Oxidative stress parameters as: determination of reactive oxygen species (ROS), superoxide dismutase (SOD) activity, catalase (CAT) activity and total sulfhydryl content quantification were analyzed by colorimetric assays according to literature.

RESULTS

Among sixteen synthesized compounds, three displayed potent antitumor activities against tested glioblastoma cell line showed IC50 values well below the standard drug temozolomide. Therefore, compounds 5a, 5l and 5p were evaluated using cell cycle and death analysis, due to potent toxicity (2.17±1.17, 6.24±0.59, 2.93±1.12µM, respectively) in C6 cell line. The mechanism of action studies demonstrated that 5a and 5l induced apoptosis significantly increase the percentage of cells in Sub-G1 phase in the absence of necrosis. Consistent with these results, caspase-3/7 assay revealed that 5l presents pro-apoptotic activity due to the significant stimulation of caspases-3/7. Moreover, 5a, 5l and 5p increased antioxidant defense and decreased reactive oxygen species (ROS) production.

CONCLUSION

The compounds were synthesized with good yield and three of these presented (5a, 5l and 5p) good cytotoxicity against C6 cell line. Both affected cell cycle distribution via arresting more C6 cell line at Sub-G1 phase promoting apoptosis. Furthermore, 5a, 5l and 5p modulated redox status. These findings suggest that these compounds can be considered as promising lead molecules for further development of potential antitumor agents.

Improvement in Redox Homeostasis after Cytoreductive Surgery in Colorectal Adenocarcinoma

Colorectal cancer (CRC) as one the most common cancer type is associated with oxidative stress. Surgery is the only curative modality for early-stage CRC. The aim of this study was to evaluate the oxidative damage biomarkers as well as enzymatic and nonenzymatic antioxidants in patients with CRC before and after tumor resection and in healthy controls. 60 patients with stage I/II colorectal adenocarcinoma and 43 healthy controls were recruited in this study. We measured plasma levels of oxidative damage biomarkers, including advanced oxidation protein products (AOPP), advanced glycation end products (AGEs), malondialdehyde (MDA), and oxidized low-density lipoprotein (ox-LDL) at baseline and after tumor removal. We also evaluated the plasma activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) as enzymatic antioxidants and the ferric reducing antioxidant power (FRAP) assay for nonenzymatic antioxidant capacity. Patients with CRC had significantly higher AGE, AOPP, MDA, and ox-LDL and also FRAP levels and higher SOD and GPx and lower CAT activity levels compared to healthy controls (p < 0.05). We did not observe any statistically significant correlation between redox biomarkers and the size and stage of the tumor. AGEs (72.49 ± 4.7 vs. 67.93 ± 8.8, p < 0.001), AOPP (137.64 ± 21.9 vs. 119.08 ± 33.1, p < 0.001), MDA (3.56 ± 0.30 vs. 3.05 ± 0.33, p < 0.001), and ox-LDL (19.78 ± 0.97 vs. 16.94 ± 1.02, p < 0.001) concentrations reduced significantly after tumor removal. The largest effect sizes were found in ox-LDL (d = -2.853, 95% CI 2.50-3.19) and MDA (d = -1.617, 95% CI 0.43-0.57). Serum FRAP levels (1097.5 ± 156.7 vs. 1239.3 ± 290, p < 0.001) and CAT (2.34 ± 0.34 vs. 2.63 ± 0.38, p < 0.001), GPx (102.37 ± 6.58 vs. 108.03 ± 6.95, p < 0.001), and SOD (5.13 ± 0.39 vs. 5.53 ± 0.31, p < 0.001) activity levels increased significantly after surgery. The largest effect sizes among antioxidants were seen in SOD (d = 1.135, 95% CI 0.46-0.34) and GPx (d = 0.836, 95% CI 0.35-0.23). This study indicated that patients with colorectal cancer had higher levels of oxidative stress and antioxidant activity compared to healthy controls. After surgical resection of tumor, we observed a substantial improvement in redox homeostasis.

Dextran-Curcumin Nanosystems Inhibit Cell Growth and Migration Regulating the Epithelial to Mesenchymal Transition in Prostate Cancer Cells

Functional nanocarriers which are able to simultaneously vectorize drugs to the site of interest and exert their own cytotoxic activity represent a significant breakthrough in the search for effective anticancer strategies with fewer side effects than conventional chemotherapeutics. Here, we propose previously developed, self-assembling dextran-curcumin nanoparticles for the treatment of prostate cancer in combination therapy with Doxorubicin (DOXO). Biological effectiveness was investigated by evaluating the cell viability in either cancer and normal cells, reactive oxygen species (ROS) production, apoptotic effect, interference with the cell cycle, and the ability to inhibit cell migration and reverse the epithelial to mesenchymal transition (EMT). The results proved a significant enhancement of curcumin efficiency upon immobilization in nanoparticles: IC50 reduced by a half, induction of apoptotic effect, and improved ROS production (from 67 to 134%) at low concentrations. Nanoparticles guaranteed a pH-dependent DOXO release, with a more efficient release in acidic environments. Finally, a synergistic effect between nanoparticles and Doxorubicin was demonstrated, with the free curcumin showing additive activity. Although in vivo studies are required to support the findings of this study, these preliminary in vitro data can be considered a proof of principle for the design of an effective therapy for prostate cancer treatment.

Chemical profile, antioxidant and anti-inflammatory properties of Miconia albicans (Sw.) Triana (Melastomataceae) fruits extract

ETHNOPHARMACOLOGICAL RELEVANCE

Miconia albicans (Sw.) Triana has been widely used in Brazilian popular medicine for the treatment of several diseases. Aerial parts are used as an infusion to treat arthrosis and arthritis, to relieve rheumatic and stomach pains, and intestinal disorders due to its anti-inflammatory, anti-mutagenic anti-nociceptive, digestive and hepatoprotective properties.

AIM OF THE STUDY

This study aimed to characterize the of M. albicans (Sw.) Triana fruits extract (MAFRE) chemical profile and to evaluate its antioxidant, anti-inflammatory and antitumor activities, as well as its toxicity.

MATERIALS AND METHODS

Maceration with methanol as liquid extractor was used to prepare MAFRE. M. albicans (Sw.) Triana fruits chemical composition was characterized by UHPLC-QTOF-MS/MS and GC-FID (fatty acid methyl esters composition from lyophilized fruits). MAFRE antioxidant potential was evaluated in vitro using a combination of assays: Folin-Ciocalteu reducing capacity, DPPH^• and ABTS radical scavenging ability and ferric reducing antioxidant power (FRAP). In vitro antiproliferative activity was investigated in four human tumor cell lines (U251, 786-0, HT29 and MDA-MB-231) while the effect on the non-tumor cell viability was assessed in the VERO cell line using the on-step MTT assay. In addition, in vivo anti-inflammatory effect was assessed by Croton oil-induced ear edema in mice followed by myeloperoxidase (MPO) activity evaluation.

RESULTS

Thirty-five compounds were identified by UHPLC-QTOF-MS/MS. Among it flavonoids derived from quercetin (8), myricetin (1), kaempferol (2), terpenoids (6) and other compounds (18). GC-FID analysis identified and quantified nine fatty acids: palmitic, stearic, arachidic, behenic, elaidic, oleic, eicosenoic, and linoleic acids. The most abundant fatty acids were polyunsaturated fatty acids (5.33 ± 0.17 mg g^-1), followed by saturated fatty acids (2.38 ± 0.07 mg g^-1) and monounsaturated fatty acids (1.74 ± 0.09 mg g^-1). The extract revealed high content of phenolic compounds (43.68 ± 0.50 mg GAE/g of extract), potent antioxidant, and ferrous chelating capacities. Morever, it proved to be non-toxic to the VERO cells, not affecting cells viability (95% of viable cells). No antiproliferative effect against human tumor cell lines were found. Furthermore, MAFRE significantly (p<0.05) reduced ear edema (≈35%) and MPO activity (84.5%) having a statistical effect similar to traditional steroidal and non-steroidal anti-inflammatory drugs.

CONCLUSIONS

Taken together, the results evidenced that M. albicans fruit extract has antioxidant properties, a higher concentration of phenolic compounds, flavonoids, fatty acids, and also topical anti-inflammatory activity with low toxicity of extract on VERO cells. Through the ethnomedicinal study, these findings supporting the popular use of M. albicans, but also highlight that not only aerial parts and leaves deserve attention, but the fruits also have anti-inflammatory proprieties and can be a source of phenolic compounds and other substances with potential health benefices.

N-Alkylation of Anthracycline Antibiotics by Natural Sesquiterpene Lactones as a Way to Obtain Antitumor Agents with Reduced Side Effects

Anthracycline antitumor antibiotics are one of the promising classes of chemotherapeutic agents for cancer treatment. The main deterrent to their use is high toxicity to a healthy environment, including cumulative cardiotoxicity. In our work, bipharmacophore molecules containing in their structure a fragment of the known anthracycline antibiotics daunorubicin and doxorubicin and natural sesquiterpene lactones were obtained for the first time. When studying the biological activity of the synthesized compounds, it was found that with equal and, in some cases, higher cytotoxicity and glycolysis inhibition by anthracycline antibiotics conjugates with sesquiterpene lactones in comparison with doxo- and daunorubicin, a reduced damaging effect on the functioning of rat heart mitochondria was observed. The results obtained allow us to confirm the assumption that the chemical modification of the anthracycline antibiotics molecules doxo- and daunorubicin by natural sesquiterpene lactones can be a promising strategy for creating potential antitumor chemotherapeutic drugs with a pronounced cytotoxic effect on tumor cells and a reduced damaging effect on healthy cells of the human organism.

Liposome-Imipramine Blue Inhibits Sonic Hedgehog Medulloblastoma In Vivo

Simple Summary

Imipramine blue (IB) is a novel NADPH oxidase inhibitor. We assessed the single agent activity of IB against a well-established model of medulloblastoma, the most common malignant brain tumor of childhood. IB slowed progression of medulloblastoma and increased survival of mice with transgenic medulloblastoma. Clinical trials of IB for medulloblastoma should be pursued.

Abstract

Sonic hedgehog subtype of medulloblastoma (SHH MB) with metastasis or specific clinical or molecular alteration shas a poor prognosis and current therapy results in long-term cognitive impairment in the majority of survivors. Thus, a great need exists for new targeted therapeutic approaches to more effectively treat SHH MB in children. Imipramine blue (IB), a novel molecule with anti-tumor properties, inhibits the NADPH oxidase (NOX) family of enzymes, which are critical for SHH MB survival and treatment resistance. In this study, IB was encapsulated within a liposome to form a liposomal nanoparticle, Liposome-IB (Lipo-IB). This complex has the ability to cross the blood–brain barrier and be preferentially taken up by tumor cells within the brain. We demonstrated in vitro that Lipo-IB treatment caused a dose-dependent decrease in SHH MB cell viability and migration. Short-term administration of single agent Lipo-IB treatment of SHH MB in vivo significantly inhibited tumor growth, reduced the tumor volume, including a complete tumor response, and improved survival compared to control treated mice, without any observable toxicity. We conclude that Lipo-IB is a potential novel nanoparticle-based therapeutic for the treatment of SHH MB that warrants further preclinical safety and efficacy testing for development towards clinical investigation.

Antiproliferative Activity and Apoptotic Efficiency of Syzygium cumini Bark Methanolic Extract against EAC Cells In Vivo

BACKGROUND

Syzygium cumini is one of the evidence-based traditional medicinal plant used in the treatment of various ailments.

OBJECTIVES

Herein, the antioxidant property and anticancer property of Syzygium cumini against Ehrlich Ascites Carcinoma (EAC) cells were examined to find effective chemotherapeutics.

METHODS

In vitro assays, and phytochemical and chromatographic analyses were used to determine antioxidant properties and chemical constituents of Syzygium cummini Bark Methanolic Extract (SCBME). Functional assays were used to measure the anticancer activity of SCBME. Fluorescence microscopy and RT-PCR were used to examine morphological and molecular changes of EAC cells followed by SCBME treatment.

RESULTS

Phytochemical and GC-MS analyses confirmed the presence of compounds with antioxidant and anticancer activities. Accordingly, we have noted a strong antioxidant activity of SCBME with an IC₅₀ value of ~10μg/ml. Importantly, SCBME exerted a dose-dependent anticancer activity with significant inhibition of EAC cell growth (71.08±3.53%; p<0.001), reduction of tumor burden (69.50%; p<0.01) and increase of life span (73.13%; p<0.001) of EAC-bearing mice at 75mg/kg/day. Besides, SCBME restored the blood toxicity towards normal in EAC-bearing mice (p<0.05).

DISCUSSION

SCBME treated EAC cells showed apoptotic features under a fluorescence microscope and fragmented DNA in DNA laddering assay. Moreover, up-regulation of the tumor suppressor p53 and pro-apoptotic Bax and down-regulation of NF-κB and anti-apoptotic Bcl-2 genes implied induction of apoptosis followed by SCBME treatment.

CONCLUSION

The antiproliferative activity of SCBME against EAC cells is likely due to apoptosis, mediated by regulation of p53 and NF-κB signaling. Thus, SCBME can be considered as a useful resource in cancer chemotherapy.

New Spirocyclic Hydroxamic Acids as Effective Antiproliferative Agents

AIMS

The main goal of this work is to synthesize new original spirocyclic hydroxamic acids, investigate their cytotoxicity against the panel of tumor cell lines and possible mechanism of action of these active compounds.

BACKGROUND

Hydroxamic acids are one of the promising classes of chemical compounds with proven potential anticancer properties. This is manifested in the presence of metal chelating and antioxidant activities, the ability to inhibit histone deacetylase enzymes and a chemosensitizing effect against well known cytostatics.

OBJECTIVE

Original spirocyclic hydroxamic acids were synthesized and spectra of their antiproliferative activities were investigated.

METHODS

The cytotoxic activities on different tumor lines (SH-SY5Y, HeLa and healthy cells HEK-293) were investigated and determined possible underlying mechanisms of their activity.

RESULTS

New original spirocyclic hydroxamic acids were synthesized. These compounds exhibit antiproliferative properties against various tumor cultures cells and also exhibit antioxidant activity, a depolarizing effect on the mitochondrial membrane, inhibit the activity of the histone deacetylase enzyme, and also decrease of basal glycolysis and glycolytic capacity reserve of HeLa and SH-SY5Y tumor cell lines.

CONCLUSION

The most promising are compounds 5j-l containing two chlorine atoms as substituents in the quinazoline part of the molecule and hydroxamate function. Therefore, these compounds can be considered as hit compounds for the development on their basis multi-target anticancer agents.

Antioxidants for the Treatment of Breast Cancer: Are We There Yet?

Breast cancer is the most frequent cancer and the leading cause of cancer death in women. Oxidative stress and the generation of reactive oxygen species (ROS) have been related to cancer progression. Compared to their normal counterparts, tumor cells show higher ROS levels and tight regulation of REDOX homeostasis to maintain a low degree of oxidative stress. Traditionally antioxidants have been extensively investigated to counteract breast carcinogenesis and tumor progression as chemopreventive agents; however, there is growing evidence indicating their potential as adjuvants for the treatment of breast cancer. Aimed to elucidate whether antioxidants could be a reality in the management of breast cancer patients, this review focuses on the latest investigations regarding the ambivalent role of antioxidants in the development of breast cancer, with special attention to the results derived from clinical trials, as well as their potential use as plausible agents in combination therapy and their power to ameliorate the side effects attributed to standard therapeutics. Data retrieved herein suggest that antioxidants play an important role in breast cancer prevention and the improvement of therapeutic efficacy; nevertheless, appropriate patient stratification based on "redoxidomics" or tumor subtype is mandatory in order to define the dosage for future standardized and personalized treatments of patients.

The Role of Vitamin E in Breast Cancer Treatment and Prevention: Current Perspectives

Background:

Regarding the multifactorial etiology of breast cancer, food choices, as well as dietary intake, are the main modified factors in cancer prevention. In this sense, understanding molecular pathways involved in breast cancer proliferation can help determine the mechanisms of action of organic compounds such as antioxidant vitamins that are known to protect against cancer.

Objective:

Assess the mechanism of action of vitamin E in breast cancer modulation, with emphasis on important markers of tumor development.

Methods:

It is a systematic review carried out in PubMed and Web of Science databases, from the last 5 years, in Portuguese, English and Spanish. The following terms were selected according to The Medical Subject Headings (MeSH): “breast cancer” OR “breast neoplasms”, “tocopherol” OR “tocotrienols” OR “vitamin E”, as equated terms.

Results:

A total of 595 articles were found and 25 were selected according to inclusion criteria. Vitamin E has been related to suppression/overexpression of important tumorigenic pathways, mainly associated with proliferation, energy metabolism, chemosensitivity and invasion/metastasis. Clinical studies of vitamin E supplementation are needed to assess the dose/response effect on breast cancer patients.

Conclusion:

The safety of vitamin E supplementation is still controversial due to current studies design available. However, when vitamin E is supplemented, the dose and therapeutic regimen must be carefully decided, including the route of administration and breast cancer subtypes to enhance desired effects and minimize unwanted side effects.

Targeting the signaling in Epstein-Barr virus-associated diseases: mechanism, regulation, and clinical study

Epstein–Barr virus-associated diseases are important global health concerns. As a group I carcinogen, EBV accounts for 1.5% of human malignances, including both epithelial- and lymphatic-originated tumors. Moreover, EBV plays an etiological and pathogenic role in a number of non-neoplastic diseases, and is even involved in multiple autoimmune diseases (SADs). In this review, we summarize and discuss some recent exciting discoveries in EBV research area, which including DNA methylation alterations, metabolic reprogramming, the changes of mitochondria and ubiquitin-proteasome system (UPS), oxidative stress and EBV lytic reactivation, variations in non-coding RNA (ncRNA), radiochemotherapy and immunotherapy. Understanding and learning from this advancement will further confirm the far-reaching and future value of therapeutic strategies in EBV-associated diseases.

Hepatitis B-related hepatocellular carcinoma and stress: untangling the host immune response from clinical outcomes

Chronic hepatitis B virus (HBV) infection is a major public health challenge on the global scale. Affecting hundreds of millions worldwide, HBV is a leading risk factor for hepatocellular carcinoma (HCC). Clinical outcomes from chronic HBV infection are varied and appear to be influenced by a complex and dysregulated host immune response. In turn, much attention has been given to the immunologic response to HBV in an effort to identify host factors that lead to the development of HCC. However, the role of nonimmunologic host factors, such as chronic stress, in HBV-related HCC is poorly defined. Indeed, a growing appreciation for the effects of stress on chronic liver diseases raises the question of its role in chronic HBV infection. In this light, the present review will untangle the roles of key host factors in HBV-related HCC with an emphasis on chronic stress as a viable contributor. First discussed is the interplay of stress, inflammation and chronic liver disease. The host immune response's role as a driver of HBV-related HCC is then reviewed, allowing for a close exploration of the effects of stress on immune function in chronic hepatitis B and as a potential risk factor for HBV-related HCC.

Targeting Epstein-Barr virus oncoprotein LMP1-mediated high oxidative stress suppresses EBV lytic reactivation and sensitizes tumors to radiation therapy

Generating oxidative stress is a critical mechanism by which host cells defend against infection by pathogenic microorganisms. Radiation resistance is a critical problem in radiotherapy against cancer. Epstein-Barr virus (EBV) is a cancer-causing virus and its reactivation plays an important role in the development of EBV-related tumors. This study aimed to explore the inner relationship and regulatory mechanism among oxidative stress, EBV reactivation, and radioresistance and to identify new molecular subtyping models and treatment strategies to improve the therapeutic effects of radiotherapy.

Methods: ROS, NADP⁺/NADPH, and GSSG/GSH were detected to evaluate the oxidative stress of cells. 8-OHdG is a reliable oxidative stress marker to evaluate the oxidative stress in patients. Its concentration in serum was detected using an ELISA method and in biopsies was detected using IHC. qPCR array was performed to evaluate the expression of essential oxidative stress genes. qPCR, Western blot, and IHC were used to measure the level of EBV reactivation in vitro and in vivo. A Rta-IgG ELISA kit and EBV DNA detection kit were used to analyze the reactivation of EBV in serum from NPC patients. NPC tumor tissue microarrays was used to investigate the prognostic role of oxidative stress and EBV reactivation. Radiation resistance was evaluated by a colony formation assay. Xenografts were treated with NAC, radiation, or a combination of NAC and radiation. EBV DNA load of tumor tissue was evaluated using an EBV DNA detection kit. Oxidative stress, EBV reactivation, and the apoptosis rate in tumor tissues were detected by using 8-OHdG, EAD, and TUNEL assays, respectively.

Results: We found that EBV can induce high oxidative stress, which promotes its reactivation and thus leads to radioresistance. Basically, EBV caused NPC cells to undergo a process of 'Redox Resetting' to acquire a new redox status with higher levels of ROS accumulation and stronger antioxidant systems by increasing the expression of the ROS-producing enzyme, NOX2, and the cellular master antioxidant regulator, Nrf2. Also, EBV encoded driving protein LMP1 promotes EBV reactivation through production of ROS. Furthermore, high oxidative stress and EBV reactivation were positively associated with poor overall survival of patients following radiation therapy and were significant related to NPC patients' recurrence and clinical stage. By decreasing oxidative stress using an FDA approved antioxidant drug, NAC, sensitivity of tumors to radiation was increased. Additionally, 8-OHdG and EBV DNA could be dual prognostic markers for NPC patients.

Conclusions: Oxidative stress mediates EBV reactivation and leads to radioresistance. Targeting oxidative stress can provide therapeutic benefits to cancer patients with radiation resistance. Clinically, we, for the first time, generated a molecular subtyping model for NPC relying on 8-OHdG and EBV DNA level. These dual markers could identify patients who are at a high risk of poor outcomes but who might benefit from the sequential therapy of reactive oxygen blockade followed by radiation therapy, which provides novel perspectives for the precise treatment of NPC.

A new integrated HPTLC - ATR/FTIR approach in marine algae bioprofiling

The aim of this study was to evaluate marine algae extracts in terms of their anti-inflammatory activity using a combination of chromatographic separation and chemical detection with subsequent infrared vibrational spectroscopy identification. Extraction parameters, chemical fingerprint, and the activity levels were considered for the method optimization. High-performance thin-layer chromatography (HPTLC) combined with microchemical derivatization, was used to separate and detect bioactive compounds with antioxidant activity and anti-inflammatory activities, and to detect different classes of terpenoids. Infrared attenuated total reflectance (ATR) spectral analysis of the bands with bioactive compounds, identified sulfated polysaccharides to be responsible for the anti-inflammatory activity in extracts of brown algae Carpoglossum confluens and Phyllospora comosa. Steroids as unique antioxidants with significant free radical scavenging activities were observed in extracts of brown algae Cystophora platylobium, Cystophora retorta, Carpoglossum confluens and Phyllospora comosa. HPTLC combined with biochemical assays and FTIR-ATR spectrometry was demonstrated to be a straightforward strategy for bioprofiling marine algae extracts.

[Mechanisms of cytotoxic action of a series of directionally synthesized heterocyclic hydroxamic acids]

Cyclic hydroxamic acids based on quinazoline-4(3H)-one and dihydroquinazoline-4(1H)-one have been synthesized. The antioxidant and iron-chelating properties of these compounds, their effect on the activity of the histone deacetylase enzyme, and their cytotoxic effect on cells of various tumor lines have been investigated. We have identified two compounds-hits, which exhibit the multipharmacological type of the antineoplastic activity. Their cytotoxic effect on cells of human lung carcinoma A549 and breast adenocarcinoma MCF-7 is obviously associated with their ability to modulate the level of reactive oxygen species and to chelate Fe(II) ions, as well as to inhibit the metalloenzymes, histone deacetylases, involved in the epigenetic regulation of tumor genesis. Thus, the synthesized hydroxamic acids may be considered as a promising basis for creating potential oncolytics.

Synthesis and Cytotoxic Activity of Azine Derivatives of 6-Hydroxyxanthanodiene

BACKGROUND

The conjugates of the sesquiterpene lactone of the eremophilane series of 6- hydroxyxanthanodiene with hydrogenated azines (piperidines and piperazines) have been synthesized and identified by NMR spectrometer.

OBJECTIVE

A lactone with an unusual skeleton "6-hydroxyxanthanodiene" was extracted from the plant Elecampane (Inula helenium L) and identified various species with NMR spectrometer.

METHODS

The cytotoxic, mitochondrial, and antioxidant activities on different tumor lines such as A549, HCT116, RD and Jurkat were investigated and determined possible mechanisms.

RESULTS

The results showed that the most potent compound was IIIi exhibiting highest cytotoxicity against RD cells (IC50 25.23 ± 0.04 μM), depolarized the mitochondrial membrane and was an effective antioxidant (IC50 inhibition of LP 10.68 ± 3.21 μM) without any toxic side effect on healthy cells.

CONCLUSION

The conjugates of sesquiterpene lactone 6-hydroxyxanthanodiene III and hydrogenated azines may help to design potential promising anticancer drugs.

Pro- and antitumor effects of mitochondrial reactive oxygen species

In cancer, mitochondrial functions are commonly altered. Directly involved in metabolic reprogramming, mitochondrial plasticity confers to cancer cells a high degree of adaptability to a wide range of stresses and to the harsh tumor microenvironment. Lack of nutrients or oxygen caused by altered perfusion, metabolic needs of proliferating cells, co-option of the microenvironment, control of the immune system, cell migration and metastasis, and evasion of exogenous stress (e.g., chemotherapy) are all, at least in part, influenced by mitochondria. Mitochondria are undoubtedly one of the key contributors to cancer development and progression. Understanding their protumoral (dys)functions may pave the way to therapeutic strategies capable of turning them into innocent entities. Here, we will focus on the production and detoxification of mitochondrial reactive oxygen species (mtROS), on their impact on tumorigenesis (genetic, prosurvival, and microenvironmental effects and their involvement in autophagy), and on tumor metastasis. We will also summarize the latest therapeutic approaches involving mtROS.

Inhibition of Xanthine Oxidoreductase Enhances the Potential of Tyrosine Kinase Inhibitors against Chronic Myeloid Leukemia

Chronic myeloid leukemia (CML) is characterized by the expression of the oncogenic kinase BCR-ABL. Although tyrosine kinase inhibitors (TKIs) against BCR-ABL represent the standard therapeutic option for CML, resistances to TKIs can be a serious problem. Thus, the search for novel therapeutic approaches is still needed. CML cells show an increased ROS production, which is required for maintaining the BCR-ABL signaling cascade active. In line with that, reducing ROS levels could be an interesting therapeutic strategy for the clinical management of resistant CML. To analyze the therapeutic potential of xanthine oxidoreductase (XOR) in CML, we tested the effect of XOR inhibitor allopurinol. Here, we show for the first time the therapeutic potential of allopurinol against BCR-ABL-positive CML cells. Allopurinol reduces the proliferation and clonogenic ability of the CML model cell lines K562 and KCL22. More importantly, the combination of allopurinol with imatinib or nilotinib reduced cell proliferation in a synergistic manner. Moreover, the co-treatment arms hampered cell clonogenic capacity and induced cell death more strongly than each single-agent arm. The reduction of intracellular ROS levels and the attenuation of the BCR-ABL signaling cascade may explain these effects. Finally, the self-renewal potential of primary bone marrow cells from CML patients was also severely reduced especially by the combination of allopurinol with TKIs. In summary, here we show that XOR inhibition is an interesting therapeutic option for CML, which can enhance the effectiveness of the TKIs currently used in clinics.

The Role of Antioxidants in Cancer, Friends or Foes?

Consumption of dietary supplements by millions of people is increasing [1]. Between 64 to 81% of cancer patients and survivors use multivitamin supplements after the cancer diagnosis [2]. The use of antioxidants during cancer therapy has been a hot topic in medical science for the last 20 years without clear answers and recommendations. It seems that antioxidants are able to I) decrease the cancer formation risk by quenching ROS that are involved in cancer initiation and progression and II) assist in survival of cancer/precancer cells once the malignant transformation already occurred. Antioxidants were shown to assist cancer initiation, interfere with cancer treatment by reducing its efficacy and patient survival, and vice versa, there are reports of beneficial antioxidant effect during the cancer treatment.

Antioxidant, Anticancer Activity and Phytochemical Analysis of Green Algae, Chaetomorpha Collected from the Arabian Gulf

Seaweeds are a group of marine multicellular algae; the presence of antioxidant phytochemical constituents in Seaweed Chaetomorpha sp. extracts has received attention for their role in the prevention of human diseases. This study explores the phytochemical constituents, antioxidant, and anticancer properties of the Cladophoraceae, Chaetomorpha sp. Energy dispersive x-ray spectroscopy (EDX), and Gas chromatography-mass spectrometry (GC/MS) were performed to study the chemical structure and chemical formula. Different concentrations of ethanol and aqueous extracts of Chaetomorpha were used to estimate antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and total flavonoid, phenolic, and tannins content assays. Anti-tumor activity against breast cancer cell lines (MCF-7 and MDA-MB-231) was assessed by 3-(4,5-Dimethylthiazol-2-cyl)-2,5-Diphenyltetrazolium Bromide (MTT) assay. The EDX analysis indicated the presence of oxygen, silicon, and calcium as dominant elements. Antioxidant assays indicated that the ethanol extracts of Chaetomorpha consisted of a total of 189.14 ± 0.99 mg QE/g flavonoid content, 21.92 ± 0.43 mg GAE/g phenolic content and 21.81 ± 0.04 mg GAE/g tannins content. The DPPH radical scavenging assay exhibited higher antioxidant activity IC₅₀ (9.41 ± 0.54 mg/mL) in the ethanol extract. Moreover, it showed high anticancer activity by growth inhibition in the MDA-MB-231 breast cancer cell line and low IC₅₀ (225.18 ± 0.61 µg/mL). GC/MS analysis revealed the presence of Dichloracetic acid (DCA) as the active antitumor constituent of Chaetomorpha sp.; other anticancer compounds identified were Oximes and L-α-Terpinol. The results revealed that the type of Chaetomorpha sp. studied here possesses very unique and novel constituents and active potent antitumor chemical constituents and it can act as a promising antioxidant and anticancer agent for future applications in pharmaceutical industries.

Interplay Between Mitochondrial Peroxiredoxins and ROS in Cancer Development and Progression

Mitochondria are multifunctional cellular organelles that are major producers of reactive oxygen species (ROS) in eukaryotes; to maintain the redox balance, they are supplemented with different ROS scavengers, including mitochondrial peroxiredoxins (Prdxs). Mitochondrial Prdxs have physiological and pathological significance and are associated with the initiation and progression of various cancer types. In this review, we have focused on signaling involving ROS and mitochondrial Prdxs that is associated with cancer development and progression. An upregulated expression of Prdx3 and Prdx5 has been reported in different cancer types, such as breast, ovarian, endometrial, and lung cancers, as well as in Hodgkin's lymphoma and hepatocellular carcinoma. The expression of Prdx3 and Prdx5 in different types of malignancies involves their association with different factors, such as transcription factors, micro RNAs, tumor suppressors, response elements, and oncogenic genes. The microenvironment of mitochondrial Prdxs plays an important role in cancer development, as cancerous cells are equipped with a high level of antioxidants to overcome excessive ROS production. However, an increased production of Prdx3 and Prdx5 is associated with the development of chemoresistance in certain types of cancers and it leads to further complications in cancer treatment. Understanding the interplay between mitochondrial Prdxs and ROS in carcinogenesis can be useful in the development of anticancer drugs with better proficiency and decreased resistance. However, more targeted studies are required for exploring the tumor microenvironment in association with mitochondrial Prdxs to improve the existing cancer therapies and drug development.

Total Antioxidant Status (TAS), Superoxide Dismutase (SOD), and Glutathione Peroxidase (GPx) in Oropharyngeal Cancer Associated with EBV Infection

A growing number of studies reveal that oxidative stress is associated with viral infections or cancer development. However, there are few reports assessing the relationships between oxidative stress, viral infection, and carcinogenesis. The present study analyzed the level of total antioxidant status (TAS) as well as the activities of glutathione peroxidase (GPx) and superoxide dismutase (SOD) in patients with oropharyngeal cancer both Epstein-Barr virus (EBV)-positive and EBV-negative in comparison with the control group. The correlations between these parameters and EBV type (wild-type LMP1 (wt-LMP1) or LMP1 with deletion (del-LMP1)), level of antibodies against EBV, the degree of tumor differentiation, and TNM classification were also investigated. Fresh frozen tumor tissue samples collected from 66 patients with oropharyngeal squamous cell carcinoma were tested using nested PCR assay for EBV DNA detection. Spectrophotometric methods were used to measure TAS values as well as SOD and GPx activities in homogenates of tissue, using diagnostic kits produced by Randox Laboratories. Sera from all individuals were investigated using ELISA method to detect the presence of Epstein-Barr virus capsid antigen (EBVCA) IgM and IgG, Epstein-Barr virus nuclear antigen (EBNA) IgG, and early antigen (EA) IgG antibodies. The level of TAS and activities of antioxidant enzymes (GPx and SOD) were significantly decreased in tissues with oropharyngeal cancer, particularly in EBV-positive cases. In 82.3% of patients, wt-LMP1 was detected. Significantly lower TAS, GPx, and SOD values were stated in patients infected with wild-type EBV. The presence of antibodies against early antigen (anti-EA) was detected in over 80% of patients, which suggests reactivation of EBV infection. The correlation between the degree of tumor differentiation and TN classification, especially in EBV-positive patients, was also observed. Determination of these parameters may be useful in evaluating tumor burden in patients with various stages of oropharyngeal cancer and could be an important prognostic factor. Future studies are needed to understand the role of EBV lytic reactivation induced by oxidative stress.

Antioxidants: Positive or Negative Actors?

The term “antioxidant” is one of the most confusing definitions in biological/medical sciences. In chemistry, “antioxidant” is simply conceived “a compound that removes reactive species, mainly those oxygen-derived”, while in a cell context, the conceptual definition of an antioxidant is poorly understood. Indeed, non-clinically recommended antioxidants are often consumed in large amounts by the global population, based on the belief that cancer, inflammation and degenerative diseases are triggered by high oxygen levels (or reactive oxygen species) and that through blocking reactive species production, organic unbalances/disorders can be prevented and/or even treated. The popularity of these chemicals arises in part from the widespread public mistrust of allopathic medicine. In fact, reactive oxygen species play a dual role in dealing with different disorders, since they may contribute to disease onset and/or progression but may also play a key role in disease prevention. Further, the ability of the most commonly used supplements, such as vitamins C, E, selenium, and herbal supplements to decrease pathologic reactive oxygen species is not clearly established. Hence, the present review aims to provide a nuanced understanding of where current knowledge is and where it should go.

Reactive oxygen species in haematopoiesis: leukaemic cells take a walk on the wild side

Oxidative stress is related to ageing and degenerative diseases, including cancer. However, a moderate amount of reactive oxygen species (ROS) is required for the regulation of cellular signalling and gene expression. A low level of ROS is important for maintaining quiescence and the differentiation potential of haematopoietic stem cells (HSCs), whereas the level of ROS increases during haematopoietic differentiation; thus, suggesting the importance of redox signalling in haematopoiesis. Here, we will analyse the importance of ROS for haematopoiesis and include evidence showing that cells from leukaemia patients live under oxidative stress. The potential sources of ROS will be described. Finally, the level of oxidative stress in leukaemic cells can also be harnessed for therapeutic purposes. In this regard, the reliance of front-line anti-leukaemia chemotherapeutics on increased levels of ROS for their mechanism of action, as well as the active search for novel compounds that modulate the redox state of leukaemic cells, will be analysed.

Redox control of cancer cell destruction

Redox regulation has been proposed to control various aspects of carcinogenesis, cancer cell growth, metabolism, migration, invasion, metastasis and cancer vascularization. As cancer has many faces, the role of redox control in different cancers and in the numerous cancer-related processes often point in different directions. In this review, we focus on the redox control mechanisms of tumor cell destruction. The review covers the tumor-intrinsic role of oxidants derived from the reduction of oxygen and nitrogen in the control of tumor cell proliferation as well as the roles of oxidants and antioxidant systems in cancer cell death caused by traditional anticancer weapons (chemotherapeutic agents, radiotherapy, photodynamic therapy). Emphasis is also put on the role of oxidants and redox status in the outcome following interactions between cancer cells, cytotoxic lymphocytes and tumor infiltrating macrophages.

(+)-Catechin in a 1:2 Complex with Lysine Inhibits Cancer Cell Migration and Metastatic Take in Mice

Metastasis is of dismal prognosis for cancer patients, but recent evidence in mouse models of cancer shows that metastasis prevention is a reachable clinical objective. These experiments indicate that altered mitochondrial activities are associated with the metastatic phenotype. Mitochondrial transfer from metastatic to non-metastatic cells can indeed transfer the metastatic phenotype, and metastatic progenitor cells differ from other cancer cells by a higher sublethal production of mitochondrial reactive oxygen species (ROS). Moreover, mitochondria-targeted antioxidants can prevent metastatic dissemination in mouse models of cancer. Comparatively, general antioxidants have unpredictable effects on cancer metastasis, most probably because they affect several cell types, several subcellular ROS production sites and, often, several endogenous oxidant species. Thus, targeting antioxidants to mitochondria could improve their antimetastatic activities, as previously exemplified with mitochondria-targeted mitoTEMPO and mitoQ that can prevent metastatic dissemination in cancer-bearing mice. Our objective in this study was to identify whether catechins, which are known to be potent antioxidants, can inhibit cancer cell migration in vitro and metastatic take in vivo. Comparative analysis of the response to epigallocatechin-3-gallate, (+)-catechin and (+)-catechin:lysine complexes revealed that, whereas all compounds had similar general antioxidant properties, (+)-catechin:lysine 1:2, but not epigallocatechin-3-gallate, can prevent metastatic take of melanoma cells to the lungs of mice. (+)-Catechin:lysine 1:2 possesses two net positive charges provided by lysines at physiological pH, which could provide high affinity for the negatively charged mitochondrial matrix. While this study reveals that (+)-catechin:lysine 1:2 has interesting antimetastatic effects, future experiments are needed to formally demonstrate the stability of the complex, its effective tropism for mitochondria and whether or not its activity can be globally attributed to its antioxidant activity at this precise subcellular location.

Overcoming Resistance to Cetuximab with Honokiol, A Small-Molecule Polyphenol

Overexpression and activation of the EGFR have been linked to poor prognosis in several human cancers. Cetuximab is a mAb against EGFR that is used for the treatment in head and neck squamous cell carcinoma (HNSCC) and metastatic colorectal cancer. Unfortunately, most tumors have intrinsic or will acquire resistance to cetuximab during the course of therapy. Honokiol is a natural compound found in the bark and leaves of the Chinese Magnolia tree and is established to have several anticancer properties without appreciable toxicity. In this study, we hypothesized that combining cetuximab and honokiol treatments could overcome acquired resistance to cetuximab. We previously developed a model of acquired resistance to cetuximab in non-small cell lung cancer H226 cell line. Treatment of cetuximab-resistant clones with honokiol and cetuximab resulted in a robust antiproliferative response. Immunoblot analysis revealed the HER family and their signaling pathways were downregulated after combination treatment, most notably the proliferation (MAPK) and survival (AKT) pathways. In addition, we found a decrease in phosphorylation of DRP1 and reactive oxygen species after combination treatment in cetuximab-resistant clones, which may signify a change in mitochondrial function. Furthermore, we utilized cetuximab-resistant HNSCC patient-derived xenografts (PDX) to test the benefit of combinatorial treatment in vivo There was significant growth delay in PDX tumors after combination treatment with a subsequent downregulation of active MAPK, AKT, and DRP1 signaling as seen in vitro Collectively, these data suggest that honokiol is a promising natural compound in overcoming acquired resistance to cetuximab. Mol Cancer Ther; 17(1); 204-14. ©2017 AACR.

Anticancer potential of Trigonella foenum graecum: Cellular and molecular targets

A growing body of evidence supported by numerous studies on tumorigenesis confirms that it is possible to target various hallmarks of cancer. Recent studies have shown that plant-derived molecules may be used in targeting different signaling pathways for cancer drug discovery. The present paper gives an insight into the anticancer potential of fenugreek and lists the existing studies that have been carried out to demonstrate the advantages of the use of fenugreek in cancer treatment and prevention. It also aims at opening up new perspectives in the development of new drugs of natural origins in the future clinical trials. This review article will discuss; (1) the chemical constituents and bioactive compounds of fenugreek; (2) effects on oxidative stress and inflammation; (3) effects on proliferation, apoptosis, and invasion; (4) toxicity of fenugreek; and 5) future directions in cancer drug development. All of the experimental studies discussed in this paper suggest that multiple signaling pathways (hallmarks) are involved in the anticancer activities of fenugreek, but their efficacy is still unclear, which requires further investigation.

Therapeutic Applications of Rose Hips from Different Rosa Species

Rosa species, rose hips, are widespread wild plants that have been traditionally used as medicinal compounds for the treatment of a wide variety of diseases. The therapeutic potential of these plants is based on its antioxidant effects caused by or associated with its phytochemical composition, which includes ascorbic acid, phenolic compounds and healthy fatty acids among others. Over the last few years, medicinal interest in rose hips has increased as a consequence of recent research that has studied its potential application as a treatment for several diseases including skin disorders, hepatotoxicity, renal disturbances, diarrhoea, inflammatory disorders, arthritis, diabetes, hyperlipidaemia, obesity and cancer. In this review, the role of different species of Rosa in the prevention of treatment of various disorders related to oxidative stress, is examined, focusing on new therapeutic approaches from a molecular point of view.

Insights into the Role and Interdependence of Oxidative Stress and Inflammation in Liver Diseases

The crucial roles of oxidative stress and inflammation in the development of hepatic diseases have been unraveled and emphasized for decades. From steatosis to fibrosis, cirrhosis and liver cancer, hepatic oxidative stress, and inflammation are sustained and participated in this pathological progressive process. Notably, increasing evidences showed that oxidative stress and inflammation are tightly related, which are regarded as essential partners that present simultaneously and interact with each other in various pathological conditions, creating a vicious cycle to aggravate the hepatic diseases. Clarifying the interaction of oxidative stress and inflammation is of great importance to provide new directions and targets for developing therapeutic intervention. Herein, this review is concerned with the regulation and interdependence of oxidative stress and inflammation in a variety of liver diseases. In addition to classical mediators and signaling, particular emphasis is placed upon immune suppression, a potential linkage of oxidative stress and inflammation, to provide new inspiration for the treatment of liver diseases. Furthermore, since antioxidation and anti-inflammation have been extensively attempted as the strategies for treatment of liver diseases, the application of herbal medicines and their derived compounds that protect liver from injury via regulating oxidative stress and inflammation collectively were reviewed and discussed.