The role of oxidative stress in chemical carcinogenesis

Enhancing the effects of curcumin on oxidative stress injury in brain vascular endothelial cells using lactoferrin peptide nano-micelles: antioxidant activity and mechanism

BACKGROUND

Curcumin is widely known for its antioxidant and anti-inflammatory properties, but its mechanism of action in mitigating oxidative stress injury in brain vascular endothelial cells remains unclear. Due to the poor bioavailability of curcumin, it is challenging to achieve effective concentrations at the target sites. Nano-micelles are known for their ability to improve the solubility, stability, and bioavailability of hydrophobic compounds like curcumin. This study investigated the effects and mechanisms of free curcumin and curcumin embedded in nano-micelles (M(Cur)) on oxidative stress-induced injury in bEnd.3 cells.

RESULTS

At a protective concentration of 10 μg mL-1, micellar curcumin was better able to recover the morphology of bEnd.3 cells under oxidative stress while increasing cell viability, restoring mitochondrial membrane electrical potential, and effectively inhibiting reactive oxygen species generation with a positive cell rate of 2.21%. These results indicate that curcumin significantly improves H2O2-induced oxidative stress damage in endothelial cells by maintaining the cellular antioxidant balance.

CONCLUSION

This study adds to knowledge regarding the role of nano-micelles in curcumin intervention for endothelial cell oxidative damage and provides insights for the development of curcumin-based dietary supplements. © 2024 Society of Chemical Industry.

Mode of action of dieldrin-induced liver tumors: application to human risk assessment

Dieldrin is an organochlorine insecticide that was widely used until 1970 when its use was banned because of its liver carcinogenicity in mice. Several long-term rodent bioassays have reported dieldrin to induce liver tumors in in several strains of mice, but not in rats. This article reviews the available information on dieldrin liver effects and performs an analysis of mode of action (MOA) and human relevance of these liver findings. Scientific evidence strongly supports a MOA based on CAR activation, leading to alterations in gene expression, which result in increased hepatocellular proliferation, clonal expansion leading to altered hepatic foci, and ultimately the formation of hepatocellular adenomas and carcinomas. Associative events include increased liver weight, centrilobular hypertrophy, increased expression of Cyp2b10 and its resulting increased enzymatic activity. Other associative events include alterations of intercellular gap junction communication and oxidative stress. Alternative MOAs are evaluated and shown not to be related to dieldrin administration. Weight of evidence shows that dieldrin is not DNA reactive, it is not mutagenic, and it is not genotoxic in general. Furthermore, activation of other pertinent nuclear receptors, including PXR, PPARα, AhR, and estrogen are not related to dieldrin-induced liver tumors nor is there liver cytotoxicity. In previous studies, rats, dogs, and non-human primates did not show increased cell proliferation or production of pre-neoplastic or neoplastic lesions following dieldrin treatment. Thus, the evidence strongly indicates that dieldrin-induced mouse liver tumors are due to CAR activation and are specific to the mouse, which are qualitatively not relevant to human hepatocarcinogenesis. Thus, there is no carcinogenic risk to humans. This conclusion is also supported by a lack of positive epidemiologic findings for evidence of liver carcinogenicity. Based on current understanding of the mode of action of dieldrin-induced liver tumors in mice, the appropriate conclusion is that dieldrin is a mouse specific liver carcinogen and it does not pose a cancer risk to humans.

The role of tryptophan derivatives as anti-kinetoplastid agents

Kinetoplastids are the causative agents for a spectrum of vector-borne diseases including Leishmaniasis, Chagas disease and Trypanosomiasis that affect millions of people worldwide. In the absence of safe and effective vaccines, chemotherapy, in conjunction with vector control, remain the most significant control approach for kinetoplastid diseases. However, commercially available treatment for these neglected tropical diseases frequently ends up with toxic side effects and increasing resistance. To meet the rising need for innovative medications, alternative chemotherapeutic agents are required. Moreover, insights into target-based mode of action of chemotherapeutic agents are required if novel drugs that may outwit resistance to commercially available drugs are to be developed. Tryptophan has been implicated in a variety of diseases and disorders due to its fundamental role as a precursor to several bioactive metabolites, as well as its importance in the improvement of health and nutrition, diagnostics, and therapeutics. The regulation of tryptophan metabolism plays a fundamental role in the growth of kinetoplastids. Moreover, the levels of tryptophan may serve as a biomarker to distinguish between the stages of kinetoplastids making it an important amino acid to explore for drug targets. The main aim of this review is thus to provide a comprehensive literature synthesis of tryptophan derivatives to explore as potential anti-kinetoplastids. Here we highlight the role of tryptophan derivatives as chemotherapeutic agents against kinetoplastids. The reviewed compounds provide insights into potential new drug interventions that may combat the increasing problem of anti-kinetoplastid resistance.

Research progress on the interaction between oxidative stress and platelets: Another avenue for cancer?

Oxidative stress (OS) is a chemical imbalance between an oxidant and an antioxidant, causing damage to redox signaling and control or causing molecular damage. Unbalanced oxidative metabolism can produce excessive reactive oxygen species (ROS). These excess ROS can cause drastic changes in platelet metabolism and further affect platelet function. It will also lead to an increase in platelet procoagulant phenotype and cell apoptosis, which will increase the risk of thrombosis. The creation of ROS and subsequent platelet activation, adhesion, and recruitment are then further encouraged in an auto-amplifying loop by ROS produced from platelets. Meanwhile, cancer cells produce a higher concentration of ROS due to their fast metabolism and high proliferation rate. However, excessive ROS can result in damage to and modification of cellular macromolecules. The formation of cancer and its progression is strongly associated with oxidative stress and the resulting oxidative damage. In addition, platelets are an important part of the tumor microenvironment, and there is a significant cross-communication between platelets and cancer cells. Cancer cells alter the activation status of platelets, their RNA spectrum, proteome, and other properties. The "cloaking" of cancer cells by platelets providing physical protection，avoiding destruction from shear stress and the attack of immune cells, promoting tumor cell invasion.We explored the vicious circle interaction between ROS, platelets, and cancer in this review, and we believe that ROS can play a stimulative role in tumor growth and metastasis through platelets.

The Multi-Faceted Consequences of NRF2 Activation throughout Carcinogenesis

The oxidative balance of a cell is maintained by the Kelch-like ECH-associated protein 1 (KEAP1)/nuclear factor erythroid 2-related factor 2 (NRF2) pathway. This cytoprotective pathway detoxifies reactive oxygen species and xenobiotics. The role of the KEAP1/NRF2 pathway as pro-tumorigenic or anti-tumorigenic throughout stages of carcinogenesis (including initiation, promotion, progression, and metastasis) is complex. This mini review focuses on key studies describing how the KEAP1/NRF2 pathway affects cancer at different phases. The data compiled suggest that the roles of KEAP1/NRF2 in cancer are highly dependent on context; specifically, the model used (carcinogen-induced vs genetic), the tumor type, and the stage of cancer. Moreover, emerging data suggests that KEAP1/NRF2 is also important for regulating the tumor microenvironment and how its effects are amplified either by epigenetics or in response to co-occurring mutations. Further elucidation of the complexity of this pathway is needed in order to develop novel pharmacological tools and drugs to improve patient outcomes.

Green Synthesis of Silver Nanoparticles Using Spilanthes acmella Leaf Extract and its Antioxidant-Mediated Ameliorative Activity against Doxorubicin-Induced Toxicity in Dalton's Lymphoma Ascites (DLA)-Bearing Mice

Green synthesis of metal nanoparticles is a rapidly growing research area in the field of nanotechnology because of their biomedical applications. This study describes the synthesis of silver nanoparticles (AgNPs) using Spilanthes acmella leaf extract and its ameliorative effects against doxorubicin-induced toxicity. The formation of AgNPs was confirmed by a ultraviolet-visible (UV-vis) spectrum that revealed an absorption band at 430 nm. A shift in the absorption bands in Fourier-transform infrared spectroscopy (FT-IR) confirmed the bioactive molecules of S. acmella leaf extract that acted as a reducing and capping agent. The spherical shape of AgNPs was confirmed by scanning electron microscope (SEM) analysis, and the presence of elemental silver was indicated by energy dispersive X-ray spectroscopy (EDS) analysis. X-ray diffraction (XRD) analysis revealed that the crystalline size of the synthesized AgNPs was 6.702 nm. Treatment of Dalton's lymphoma ascites (DLA) mice with 20 mg/kg of doxorubicin (DOX) significantly increased the activities of serum toxicity markers including aspartate amino-transferase (AST), alanine amino-transferase (ALT), and lactate dehydrogenase (LDH). However, compared to DOX alone treatment, the coadministration of DOX and AgNPs reduced AST, ALT, and LDH activities. DOX alone treatment reduced glutathione (GSH) contents and decreased the activities of glutathione-s-transferase (GST) and superoxide dismutase (SOD) in DLA mice. However, the administration of AgNPs to DOX-treated DLA mice increased GSH content and the activities of GST and SOD. Consistently, biosynthesized AgNPs were found to possess significantly higher free-radical scavenging activities when compared to the S. acmella leaf extract, as measured by ABTS, DPPH, and O2 •- assays. The biosynthesized AgNPs also showed significant inhibitory activities against erythrocyte hemolysis and lipid peroxidation in the liver homogenate.

Antioxidant Properties of Hemp Proteins: From Functional Food to Phytotherapy and Beyond

As one of the oldest plants cultivated by humans, hemp used to be banned in the United States but returned as a legal crop in 2018. Since then, the United States has become the leading hemp producer in the world. Currently, hemp attracts increasing attention from consumers and scientists as hemp products provide a wide spectrum of potential functions. Particularly, bioactive peptides derived from hemp proteins have been proven to be strong antioxidants, which is an extremely hot research topic in recent years. However, some controversial disputes and unknown issues are still underway to be explored and verified in the aspects of technique, methodology, characteristic, mechanism, application, caution, etc. Therefore, this review focusing on the antioxidant properties of hemp proteins is necessary to discuss the multiple critical issues, including in vitro structure-modifying techniques and antioxidant assays, structure-activity relationships of antioxidant peptides, pre-clinical studies on hemp proteins and pathogenesis-related molecular mechanisms, usage and potential hazard, and novel advanced techniques involving bioinformatics methodology (QSAR, PPI, GO, KEGG), proteomic analysis, and genomics analysis, etc. Taken together, the antioxidant potential of hemp proteins may provide both functional food benefits and phytotherapy efficacy to human health.

The Central Nervous Mechanism of Stress-Promoting Cancer Progression

Evidence shows that stress can promote the occurrence and development of tumors. In recent years, many studies have shown that stress-related hormones or peripheral neurotransmitters can promote the proliferation, survival, and angiogenesis of tumor cells and impair the body’s immune response, causing tumor cells to escape the “surveillance” of the immune system. However, the perception of stress occurs in the central nervous system (CNS) and the role of the central nervous system in tumor progression is still unclear, as are the underlying mechanisms. This review summarizes what is known of stress-related CNS-network activation during the stress response and the influence of the CNS on tumors and discusses available adjuvant treatment methods for cancer patients with negative emotional states, such as anxiety and depression.

The Relationship between Cancer and Paraoxonase 1

Extensive research has been carried out to understand and elucidate the mechanisms of paraoxonase 1 (PON1) in the development of diseases including cancer, cardiovascular diseases, neurological diseases, and inflammatory diseases. This review focuses on the relationship between PON1 and cancer. The data suggest that PON1, oxidative stress, chronic inflammation, and cancer are closely linked. Certainly, the gene expression of PON1 will remain challenging to study. Therefore, targeting PON1, redox-sensitive pathways, and transcription factors promise prevention and therapy in the development of several diseases, including cancer.

Aldehyde Dehydrogenase 2 as a Therapeutic Target in Oxidative Stress-Related Diseases: Post-Translational Modifications Deserve More Attention

Aldehyde dehydrogenase 2 (ALDH2) has both dehydrogenase and esterase activity; its dehydrogenase activity is closely related to the metabolism of aldehydes produced under oxidative stress (OS). In this review, we recapitulate the enzyme activity of ALDH2 in combination with its protein structure, summarize and show the main mechanisms of ALDH2 participating in metabolism of aldehydes in vivo as comprehensively as possible; we also integrate the key regulatory mechanisms of ALDH2 participating in a variety of physiological and pathological processes related to OS, including tissue and organ fibrosis, apoptosis, aging, and nerve injury-related diseases. On this basis, the regulatory effects and application prospects of activators, inhibitors, and protein post-translational modifications (PTMs, such as phosphorylation, acetylation, S-nitrosylation, nitration, ubiquitination, and glycosylation) on ALDH2 are discussed and prospected. Herein, we aimed to lay a foundation for further research into the mechanism of ALDH2 in oxidative stress-related disease and provide a basis for better use of the ALDH2 function in research and the clinic.

The Role of Gut Microbiota and Metabolites in Obesity-Associated Chronic Gastrointestinal Disorders

The gut microbiota is a complex community of microorganisms that has become a new focus of attention due to its association with numerous human diseases. Research over the last few decades has shown that the gut microbiota plays a considerable role in regulating intestinal homeostasis, and disruption to the microbial community has been linked to chronic disease conditions such as inflammatory bowel disease (IBD), colorectal cancer (CRC), and obesity. Obesity has become a global pandemic, and its prevalence is increasing worldwide mostly in Western countries due to a sedentary lifestyle and consumption of high-fat/high-sugar diets. Obesity-mediated gut microbiota alterations have been associated with the development of IBD and IBD-induced CRC. This review highlights how obesity-associated dysbiosis can lead to the pathogenesis of IBD and CRC with a special focus on mechanisms of altered absorption of short-chain fatty acids (SCFAs).

PXR mediates mifepristone-induced hepatomegaly in mice

Mifepristone (Mif), an effective synthetic steroidal antiprogesterone drug, is widely used for medical abortion and pregnancy prevention. Due to its anti-glucocorticoid effect, high-dose Mif is also used to treat Cushing's syndrome. Mif was reported to active pregnane X receptor (PXR) in vitro and PXR can induce hepatomegaly via activation and interaction with yes-associated protein (YAP) pathway. High-dose Mif was reported to induce hepatomegaly in rats and mice, but the underlying mechanism remains unclear. Here, the role of PXR was studied in Mif-induced hepatomegaly in C57BL/6 mice and Pxr-knockout mice. The results demonstrated that high-dose Mif (100 mg · kg^-1 · d^-1, i.p.) treatment for 5 days significantly induced hepatomegaly with enlarged hepatocytes and promoted proliferation, but low dose of Mif (5 mg · kg^-1 · d^-1, i.p.) cannot induce hepatomegaly. The dual-luciferase reporter gene assays showed that Mif can activate human PXR in a concentration-dependent manner. In addition, Mif could promote nuclear translocation of PXR and YAP, and significantly induced the expression of PXR, YAP, and their target proteins such as CYP3A11, CYP2B10, UGT1A1, ANKRD, and CTGF. However, Mif (100 mg · kg^-1 · d^-1, i.p.) failed to induce hepatomegaly in Pxr-knockout mice, as well as hepatocyte enlargement and proliferation, further indicating that Mif-induced hepatomegaly is PXR-dependent. In summary, this study demonstrated that PXR-mediated Mif-induced hepatomegaly in mice probably via activation of YAP pathway. This study provides new insights in Mif-induced hepatomegaly, and provides novel evidence on the crucial function of PXR in liver enlargement and regeneration.

Molecular alterations that precede the establishment of the hallmarks of cancer: An approach on the prevention of hepatocarcinogenesis

Chronic liver injury promotes the molecular alterations that precede the establishment of cancer. Usually, several decades of chronic insults are needed to develop the most common primary liver tumor known as hepatocellular carcinoma. As other cancer types, liver cancer cells are governed by a common set of rules collectively called the hallmarks of cancer. Although those rules have provided a conceptual framework for understanding the complex pathophysiology of established tumors, therapeutic options are still ineffective in advanced stages. Thus, the molecular alterations that precede the establishment of cancer remain an attractive target for therapeutic interventions. Here, we first summarize the chemopreventive interventions targeting the early liver carcinogenesis stages. After an integrative analysis on the plethora of molecular alterations regulated by anticancer agents, we then underline and discuss that two critical processes namely oxidative stress and genetic alterations, play the role of 'dirty work laborer' in the initial cell damage and drive the transformation of preneoplastic into neoplastic cells, respectively; besides, the activation of cellular senescence works as a key mechanism in attempting to prevent the onset and establishment of liver cancer. Whereas the detrimental effects of the binomial made up of oxidative stress and genetic alterations are either eliminated or reduced, senescence activation is promoted by anticancer agents. We argue that collectively, oxidative stress, genetic alterations, and senescence are key events that influence the fate of initiated cells and the establishment of the hallmarks of cancer.

Total Antioxidant Capacity and Lipid Peroxidation Status in Cervical Cancer Patients Compared with Women Without Cervical Cancer in Bangladesh

Purpose

Over the past several decades, research has suggested reactive oxygen species act as cofactors for cervical cancer development. The aim of this study is to evaluate the antioxidant and lipid peroxidation status in cervical cancer patients in Bangladesh.

Methods

From December 2017 to 2018, a cross-sectional observational study was conducted on 50 cervical cancer patients and 50 controls. Plasma levels of lipid peroxidation and total antioxidant capacity were measured. The Student’s t test was used for statistical analysis. P values less than 0.05 were taken as a level of significance.

Results

There was a significant reduction in total antioxidant levels in patients with cervical cancer, 972.77 ± 244.22 SD µmol equivalent to ascorbic acid/L, compared to normal controls, 1720.13 ± 150.81 SD µmol equivalent to ascorbic acid/L (P < 0.001). Levels of lipid peroxidation were found to be significantly higher in cervical cancer, 7.49 ± 2.13 SD µmol/L, than in women without cervical cancer, 3.28 ± 0.58 SD µmol/L (P < 0.001). The cervical cancer patients had significantly higher levels of oxidative stress index (0.83 ± 0.31) in comparison to controls (0.19 ± 0.04) (P < 0.001).

Conclusion

There was an increased oxidative stress index due to imbalance between lipid peroxidation generation and total antioxidant capacity in cervical cancer patients. Further studies are needed to explore the role of oxidative stress as a cofactor for cervical carcinogenesis.

Acute exposure to microcystin-LR induces hepatopancreas toxicity in the Chinese mitten crab (Eriocheir sinensis)

The Chinese mitten crab is an important economic species in the Chinese aquaculture industry due to its rich nutritional value and distinct flavor. The hepatopancreas is a popular edible part of the Chinese mitten crab, and therefore, hepatopancreatic health directly determines its quality. However, a large-scale outbreak of hepatopancreatic necrosis syndrome ("Shuibiezi" disease in Chinese), which is caused by abiotic agents correlated with cyanobacteria bloom outbreaks, adversely affects the Chinese mitten crab breeding industry. Cyanobacterial blooms that occur in high-density farming ponds can produce microcystin-LR (MC-LR), which is hepatotoxic in fish and mammals. Hepatopancreas toxicity of MC-LR (0, 25, 50 and 75 μg/kg) was investigated after 48 h of exposure. The MC-LR can cause hepatopancreatic injury by inducing hepatopancreatic structural damage, subcellular structural changes, and cell apoptosis, followed by enhanced lipid peroxidase, reactive oxygen species, and apoptosis-related enzyme (Caspase 3, 8, and 9) activities. These in turn promote gene and protein expression of apoptosis-associated proteases (Caspase 3, 7, and 8, Bcl-2, and Bax), and alter antioxidant system responses (superoxide dismutase, glutathione S-transferase, glutathione peroxidase, glutathione reductase activities, and glutathione content). The present study is the first report on MC-LR hepatotoxicity in the Chinese mitten crab and confirms hepatopancreas toxicity, providing a theoretical basis for enhancing MCs resistance and developing preventive and curative measures against hepatopancreatic disease in the Chinese mitten crab breeding industry.

Formaldehyde exposure and leukemia risk: a comprehensive review and network-based toxicogenomic approach

Formaldehyde is a widely used but highly reactive and toxic chemical. The International Agency for Research on Cancer classifies formaldehyde as a Group 1 carcinogen, based on nasopharyngeal cancer and leukemia studies. However, the correlation between formaldehyde exposure and leukemia incidence is a controversial issue. To understand the association between formaldehyde exposure and leukemia, we explored biological networks based on formaldehyde-related genes retrieved from public and commercial databases. Through the literature-based network approach, we summarized qualitative associations between formaldehyde exposure and leukemia. Our results indicate that oxidative stress-mediated genetic changes induced by formaldehyde could disturb the hematopoietic system, possibly leading to leukemia. Furthermore, we suggested major genes that are thought to be affected by formaldehyde exposure and associated with leukemia development. Our suggestions can be used to complement experimental data for understanding and identifying the leukemogenic mechanism of formaldehyde.

Genotoxicity, oxidative stress, and inflammatory response induced by crack-cocaine: relevance to carcinogenesis

Crack-cocaine is a cocaine by-product widely consumed by general population in developing countries. The drug is low cost and is associated with more intense effects when compared to other illicit drugs. Genotoxicity, oxidative stress, and inflammatory response are considered crucial events in carcinogenesis, since they actively participate in the multistep process. The purpose of this paper was to provide a mini review regarding the relationship between carcinogenesis and genotoxicity, oxidative stress, and inflammation induced by crack-cocaine. The present study was conducted on search of the scientific literature from the published studies available in PubMed, MEDLINE, Scopus, and Google Scholar for all kind of articles (all publications to November 2020) using the following key words: crack-cocaine, DNA damage, genotoxicity, cellular death, cytotoxicity, mutation, oxidative stress, inflammation, and mutagenicity. The results showed that published papers available were almost all in vivo test system being conducted in humans or rodents. Crack-cocaine was able to induce genotoxicity and oxidative stress in mammalian cells. However, the role of inflammatory response after exposure to crack-cocaine was not conclusive so far. In summary, this study is consistent with the notion that crack-cocaine is a chemical carcinogen as a result of genotoxicity and oxidative stress induced in mammalian and non-mammalian cells.

G protein-coupled receptor kinase 2 modifies the cellular reaction to cisplatin through interactions with NADPH oxidase 4

G protein-coupled receptor kinases (GRKs), in addition to their role in modulating signal transduction mechanisms associated with activated G protein-coupled receptors (GPCRs), can also interact with many non-GPCR proteins to mediate cellular responses to chemotherapeutics. The rationale for this study is based on the presumption that GRK2 modulates the responses of cancer cells to the chemotherapeutic cisplatin. In this report, we show that GRK2 modulates the responses of cancer cells to cisplatin. Cervical cancer HeLa cells stably transfected with GRK2 shRNA, to decrease GRK2 protein expression, show increased sensitivity to cisplatin. Of interest, these cells also show increased accumulation of NADPH, associating with decreased NADP buildup, at low concentrations of cisplatin tested. These changes in NADPH and NADP levels are also observed in the breast cancer MDA MB 231 cells, which has lower endogenous GRK2 protein expression levels, but not BT549, a breast cancer cell line with higher GRK2 protein expression. This effect of NADPH accumulation may be associated with a decrease in NADPH oxidase 4 (NOX4) protein expression, which is found to correlate with GRK2 protein expression in cancer cells-a relationship which mimics that observed in cardiomyocytes. Furthermore, like in cardiomyocytes, GRK2 and NOX4 interact to form complexes in cancer cells. Collectively, these results suggest that GRK2 interacts with NOX4 to modify cisplatin sensitivity in cancer cells and may also factor into the success of cisplatin-based regimens.

[A Review of High-altitude Hypoxia Adaptation and Hypoxic Solid Tumor]

Historically, the Cambrian explosion was a major life evolution event caused by changes of natural environmental oxygen concentration. The use of oxygen was part of the basic survival instinct of higher life, which evolved a complex regulation system in response to variant levels of oxygen concentration. Hypoxia is one of the typical environmental characteristics in plateau areas. After long-term natural selection in hypoxic conditions, numerous species living in plateau areas have evolved unique mechanisms adapted to hypoxia. Recent studies have found that there are some similarities in adaptation to hypoxia between the animals in highland and different types of human solid tumor cells. Herein, we will summarize recent findings about the hypoxia adaptation evolution in high-altitude animals and the characteristics of hypoxic solid tumors, especially the reactive oxygen species responses in hypoxic solid tumors. We believe that deciphering the underlying molecular mechanisms involved in hypoxia adaptation in highland will facilitate the identification of new genes or biomarkers critical for research on hypoxic solid tumors in the future.

Melatonin Inhibits the Progression of Oral Squamous Cell Carcinoma via Inducing miR-25-5p Expression by Directly Targeting NEDD9

Melatonin exerts anti-cancer roles in various types of cancers. However, to the best of our knowledge, its role in oral squamous cell carcinoma (OSCC) is unknown. The present study aimed to investigate the role of melatonin and its underlying mechanism in OSCC. MTT, colony formation, wound healing, and transwell invasion assays proved that melatonin played anti-tumor effects in OSCC cells by inhibiting cell viability, proliferation, migration, and invasion in a concentration-dependent manner. The RT-qPCR analysis showed that miR-25-5p was significantly upregulated after melatonin treatment. Further, miR-25-5p might be involved in melatonin-induced inhibitory effects on the biological behavior of OSCC. The expression of miR-25-5p was decreased in tumor tissues and OSCC cells detected by RT-qPCR. MTT assay, colony formation assay, and TUNEL staining indicated miR-25-5p overexpression inhibited OSCC cell viability, proliferation, and induced OSCC cell apoptosis. Furthermore, wound healing, transwell invasion assay, and animal experiments suggested that miR-25-5p might exert suppressive effects on the migration, invasion, and tumor formation of OSCC cells, while miR-25-5p knockdown exhibited the opposite effects in OSCC cells. Bioinformatics analysis, western blot analysis, and luciferase reporter assay suggested that neural precursor cell expressed developmentally downregulated protein 9 (NEDD9) was proved to be a putative target for miR-25-5p. The role of NEDD9 in inhibiting OSCC cell proliferation, invasion, and migration was verified with NEDD9 siRNA transfection. Thus, melatonin exerted anti-proliferative, anti-invasive, and anti-migrative effects on OSCC via miR-25-5p/NEDD9 pathway. Melatonin could be applied as a potential novel drug on treating OSCC.

Chrysin Suppresses HT-29 Cell Death Induced by Diclofenac through Apoptosis and Oxidative Damage

BACKGROUND

Diclofenac (Dic) was shown to increase in reactive oxygen species (ROS) levels thereby resulting oxidative stress and apoptotic cell death in colon cancer. The antioxidants can prevent and repair oxidative damage caused by ROS. The aim of this study was to assess the effect of chrysin (Chr) on Dic-induced toxicity in HT-29 and molecular mechanisms underlying its effect.

METHODS

Cell proliferation and cytotoxicity assays were carried out by WST-1 and LDH leakage assay, apoptotic index was calculated by TUNEL Assay, antioxidant parameters were studied by measurement of ROS, LPO and TAS levels and catalase activity, expression of caspase-3 protein levels were analyzed by immunohistochemical staining, mRNA levels of apoptotic and anti-apoptotic genes were studied by qRT-PCR.

RESULTS

The cellular processes of Dic-triggered cell death was associated with increase in ROS, malondialdehyde levels and lactate dehydrogenase release, decrease in total antioxidant and catalase activity while pretreatment with Chr reversed these effects. The expression level of p53, cas-3, cas-8, Bax and cytochrome c increased in Dic-exposed group while they were reduced by Chr.

CONCLUSION

The use of antioxidant nutritional supplements, and in particular of Chr, may reduce the efficacy of Dic in inducing apoptosis of colon cancer cells.

Gene Expression Network Analysis of Precursor Lesions in Familial Pancreatic Cancer

Purpose: High-grade pancreatic intraepithelial neoplasia (PanIN) are aggressive premalignant lesions, associated with risk of progression to pancreatic ductal adenocarcinoma (PDAC). A depiction of co-dysregulated gene activity in high-grade familial pancreatic cancer (FPC)-related PanIN lesions may characterize the molecular events during the progression from familial PanIN to PDAC. Materials and Methods: We performed weighted gene coexpression network analysis (WGCNA) to identify clusters of coexpressed genes associated with FPC-related PanIN lesions in 13 samples with PanIN-2/3 from FPC predisposed individuals, 6 samples with PDAC from sporadic pancreatic cancer (SPC) patients, and 4 samples of normal donor pancreatic tissue. Results: WGCNA identified seven differentially expressed gene (DEG) modules and two commonly expressed gene (CEG) modules with significant enrichment for Gene Ontology (GO) terms in FPC and SPC, including three upregulated (p < 5e-05) and four downregulated (p < 6e-04) gene modules in FPC compared to SPC. Among the DEG modules, the upregulated modules include 14 significant genes (p < 1e-06): ALOX12-AS1, BCL2L11, EHD4, C4B, BTN3A3, NDUFA11, RBM4B, MYOC, ZBTB47, TTTY15, NAPRT, LOC102606465, LOC100505711, and PTK2. The downregulated modules include 170 genes (p < 1e-06), among them 13 highly significant genes (p < 1e-10): COL10A1, SAMD9, PLPP4, COMP, POSTN, IGHV4-31, THBS2, MMP9, FNDC1, HOPX, TMEM200A, INHBA, and SULF1. The DEG modules are enriched for GO terms related to mitochondrial structure and adenosine triphosphate metabolic processes, extracellular structure and binding properties, humoral and complement mediated immune response, ligand-gated ion channel activity, and transmembrane receptor activity. Among the CEG modules, IL22RA1, DPEP1, and BCAT1 were found as highly connective hub genes associated with both FPC and SPC. Conclusion: FPC-related PanIN lesions exhibit a common molecular basis with SPC as shown by gene network activities and commonly expressed high-connectivity hub genes. The differential molecular pathology of FPC and SPC involves multiple coexpressed gene clusters enriched for GO terms including extracellular activities and mitochondrion function.

Constitutive androstane receptor (CAR) mediates dieldrin-induced liver tumorigenesis in mouse

Dieldrin has been shown to induce liver tumors selectively in mice. Although the exact mechanism is not fully understood, previous studies from our laboratory and others have shown that dieldrin induced liver tumors in mice through a non-genotoxic mechanism acting on tumor promotion stage. Two studies were performed to examine the role of nuclear receptor activation as a possible mode of action (MOA) for dieldrin-induced mouse liver tumors. In the initial study, male C57BL/6 mice (6- to 8-week old) were treated with dieldrin in diet (10 ppm) for 7, 14, and 28 days. Phenobarbital (PB), beta-naphthoflavone (BNF) and Di (2-ethylhexyl) phthalate (DEHP) were included as positive controls in this study for evaluating the involvement of CAR (constitutive androstane receptor), AhR (aryl hydrocarbon receptor) or PPARα (peroxisome proliferator activated receptor alpha) in the MOA of dieldrin hepatocarcinogenesis. A significant increase in hepatocyte DNA synthesis (BrdU incorporation) was seen in treated mice compared with the untreated controls. Analysis of the expression of the nuclear receptor responsive genes revealed that dieldrin induced a significant increase in the expression of genes specific to CAR activation (Cyp2b10, up to 400- to 2700-fold) and PXR activation (Cyp3a11, up to 5- to 11-fold) over untreated controls. The AhR target genes Cyp1a1 and Cyp1a2 were also slightly induced (2.0- to 3.7-fold and 1.7- to 2.8-fold, respectively). PPARα activation was not seen in the liver following dieldrin treatment. In addition, consistent with previous studies in our lab, treatment with dieldrin produced significant elevation in the hepatic oxidative stress. In a subsequent study using CAR, PXR, and CAR/PXR knockout mice, we confirmed that the dieldrin-induced liver effects in mouse were only mediated by the activation of CAR receptor. Based on these findings, we propose that dieldrin induced liver tumors in mice through a nuclear receptor CAR-mediated mode of action. The previously observed oxidative stress/damage may be an associated or modifying factor in the process of dieldrin-induced liver tumor formation subsequent to the CAR activation.

Comparative Evaluation of Mitochondrial Antioxidants in Oral Potentially Malignant Disorders

Various endogenous mitochondria-associated antioxidants protect mitochondria from oxidative stresses such as Superoxide Dismutase 2 (SOD2), Catalase, Glutaredoxin 2 (GLRX2), educed Glutathione (GSH), Glutathione Peroxidase (GPx), and Thioredoxin 2 (TXN2). They protect mitochondria from Reactive Oxygen Species (ROS). Excess ROS causes mitochondrial DNA damage and respiratory chain dysfunction leading to carcinogenesis. In an earlier study we found complex alterations of mitochondrial antioxidants in different stages of oral squamous cell carcinoma. Here, we profiled mitochondrial antioxidants in different oral potentially malignant disorders such as oral leukoplakia (OL), oral lichen planus (OLP), and oral submucous fibrosis (OSMF). Mitochondria was prepared from oral tissues from OL, OLP, and OSMF patients. Biochemical assays and immunoblotting were performed to investigate expression of various mitochondrial antioxidants. Catalase was expressed as Control> OL > OSMF > OLP. GLRX 2 was expressed as OLP> OL >Control >OSMF. GPX1 and GPX4 were expressed as Control >OSMF> OLP > OL. GSH increased in OL and OSMP, but decreased in OLP. SOD2 was expressed as Control >OSMF> OLP > OL. PRX3 was expressed as OL > OLP > OSMF > Control. TXN2 expression was nearly the same in all groups except OL, which showed elevated expression. We conclude that endogenous mitochondria-associated antioxidants show different levels of expressions in various oral potentially malignant disorders.

The Appearance of 4-Hydroxy-2-Nonenal (HNE) in Squamous Cell Carcinoma of the Oropharynx

Tumor growth is associated with oxidative stress, which causes lipid peroxidation. The most intensively studied product of lipid peroxidation is 4-hydroxy-2-nonenal (HNE), which is considered as a “second messenger of free radicals” that binds to proteins and acts as a growth-regulating signaling factor. The incidence of squamous cell carcinoma of the oropharynx is associated with smoking, alcohol and infection of human papilloma virus (HPV), with increasing incidence world-wide. The aim of this retrospective study involving 102 patients was to determine the immunohistochemical appearance of HNE-protein adducts as a potential biomarker of lipid peroxidation in squamous cell carcinoma of the oropharynx. The HNE-protein adducts were detected in almost all tumor samples and in the surrounding non-tumorous tissue, while we found that HNE is differentially distributed in squamous cell carcinomas in dependence of clinical stage and histological grading of these tumors. Namely, the level of HNE-immunopositivity was increased in comparison to the normal oropharyngeal epithelium in well- and in moderately-differentiated squamous cell carcinoma, while it was decreasing in poorly differentiated carcinomas and in advanced stages of cancer. However, more malignant and advanced cancer was associated with the increase of HNE in surrounding, normal tissue. This study confirmed the onset of lipid peroxidation, generating HNE-protein adducts that can be used as a valuable bioactive marker of carcinogenesis in squamous cell carcinoma of the oropharynx, as well as indicating involvement of HNE in pathophysiological changes of the non-malignant tissue in the vicinity of cancer.

NLRX1 Is a Multifaceted and Enigmatic Regulator of Immune System Function

Over the last decade, significant progress has been achieved in defining mechanisms underlying NLR regulation of immune system function. However, several NLR family members continue to defy our best attempts at characterization and routinely exhibit confounding data. This is particularly true for NLR family members that regulate signaling associated with the activation of other pattern recognition receptors. NLRX1 is a member of this NLR sub-group and acts as an enigmatic regulator of immune system function. NLRX1 has been shown to negatively regulate type-I interferon, attenuate pro-inflammatory NF-κB signaling, promote reactive oxygen species production, and modulate autophagy, cell death, and proliferation. However, the mechanism/s associated with NLRX1 modulation of these pathways is not fully understood and there are inconsistencies within the field. Likewise, it is highly likely that the full repertoire of biological functions impacted by NLRX1 are yet to be defined. Recent mouse studies have shown that NLRX1 significantly impacts a multitude of diseases, including cancer, virus infection, osteoarthritis, traumatic brain injury, and inflammatory bowel disease. Thus, it is essential that the underlying mechanism associated with NLRX1 function in each of these diseases be robustly defined. Here, we summarize the current progress in understanding mechanisms associated with NLRX1 function. We also offer insight into both unique and overlapping mechanisms regulated by NLRX1 that likely contribute to disease pathobiology. Ultimately, we believe that an improved understanding of NLRX1 will result in better defined mechanisms associated with immune system attenuation and the resolution of inflammation in a myriad of diseases.

Sestrins as a Therapeutic Bridge between ROS and Autophagy in Cancer

The regulation of Reactive Oxygen Species (ROS) levels and the contribution therein from networks regulating cell metabolism, such as autophagy and the mTOR-dependent nutrient-sensing pathway, constitute major targets for selective therapeutic intervention against several types of tumors, due to their extensive rewiring in cancer cells as compared to healthy cells. Here, we discuss the sestrin family of proteins—homeostatic transducers of oxidative stress, and drivers of antioxidant and metabolic adaptation—as emerging targets for pharmacological intervention. These adaptive regulators lie at the intersection of those two priority nodes of interest in antitumor intervention—ROS control and the regulation of cell metabolism and autophagy—therefore, they hold the potential not only for the development of completely novel compounds, but also for leveraging on synergistic strategies with current options for tumor therapy and classification/stadiation to achieve personalized medicine.

NEIL1 stimulates neurogenesis and suppresses neuroinflammation after stress

Cellular exposure to ionizing radiation leads to oxidatively generated DNA damage, which has been implicated in neurodegenerative diseases. DNA damage is repaired by the evolutionarily conserved base excision repair (BER) system. Exposure of mice to ionizing radiation affects neurogenesis and neuroinflammation. However, the consequences of deficient DNA repair on adult neurogenesis and neuroinflammation are poorly understood despite their potential relevance for homeostasis. We previously reported that loss of NEIL1, an important DNA glycosylase involved in BER, is associated with deficiencies in spatial memory, olfaction, and protection against ischemic stroke in mice. Here, we show that Neil1^-/- mice display an anxiety-mediated behavior in the open field test, a deficient recognitive memory in novel object recognition and increased neuroinflammatory response under basal conditions. Further, mice lacking NEIL1 have decreased neurogenesis and deficient resolution of neuroinflammation following gamma irradiation (IR)-induced stress compared to WT mice. Neil1^-/- IR-exposed mice also exhibit increased DNA damage and apoptosis in the hippocampus. Interestingly, behavioral tests two weeks after IR showed impaired stress response in the Neil1^-/- mice. Our data indicate that NEIL1 plays an important role in adult neurogenesis and in the resolution of neuroinflammation.

Paclitaxel-loaded biodegradable ROS-sensitive nanoparticles for cancer therapy

Background

Reactive oxygen species (ROS), such as hydrogen peroxide and superoxide, trigger biodegradation of polymer-based nanoparticles (NPs) bearing pinacol-type boronic ester groups. These NPs may selectively release their cargo, in this case paclitaxel (PTX), at the high levels of ROS present in the intracellular environment of inflamed tissues and most tumors.

Purpose

The main objective was to determine anti-tumor efficacy of PTX-loaded ROS-sensitive NPs and to examine whether macrophage infiltration had any impact on treatment efficacy.

Methods

NPs were synthesized and their characteristics in the presence of H₂O₂ were demonstrated. Both confocal microscopy as well as flow cytometry approaches were used to determine degradation of ROS-sensitive NPs. HeLa cells were cultured in vitro and used to establish tumor xenografts in nude mice. In vivo experiments were performed to understand toxicity, biodistribution and anti-tumor efficacy of the NPs. Moreover, we performed immunohistochemistry on tumor sections to study infiltration of M1 and M2 subsets of macrophages.

Results

We demonstrated that PTX delivered in NPs containing a ROS-sensitive polymer exhibits a better anti-tumor efficacy than PTX in NPs containing ROS-non-sensitive polymer, free PTX or Abraxane^® (nab-PTX). The biodistribution revealed that ROS-sensitive NPs exhibit retention in liver, spleen and lungs, suggesting a potential to target cancer metastasizing to these organs. Finally, we demonstrated a correlation between infiltrated macrophage subsets and treatment efficacy, possibly contributing to the efficient anti-tumor effects.

Conclusion

Treatment with ROS-sensitive NPs containing PTX gave an improved therapeutic effect in HeLa xenografts than their counterpart, free PTX or nab-PTX. Our data revealed a correlation between macrophage infiltration and efficiency of the different antitumor treatments, as the most effective NPs resulted in the highest infiltration of the anti-tumorigenic M1 macrophages.

Impact of ROS Generated by Chemical, Physical, and Plasma Techniques on Cancer Attenuation

For the last few decades, while significant improvements have been achieved in cancer therapy, this family of diseases is still considered one of the deadliest threats to human health. Thus, there is an urgent need to find novel strategies in order to tackle this vital medical issue. One of the most pivotal causes of cancer initiation is the presence of reactive oxygen species (ROS) inside the body. Interestingly, on the other hand, high doses of ROS possess the capability to damage malignant cells. Moreover, several important intracellular mechanisms occur during the production of ROS. For these reasons, inducing ROS inside the biological system by utilizing external physical or chemical methods is a promising approach to inhibit the growth of cancer cells. Beside conventional technologies, cold atmospheric plasmas are now receiving much attention as an emerging therapeutic tool for cancer treatment due to their unique biophysical behavior, including the ability to generate considerable amounts of ROS. This review summarizes the important mechanisms of ROS generated by chemical, physical, and plasma approaches. We also emphasize the biological effects and cancer inhibition capabilities of ROS.

Mechanism and intervention measures of iron side effects on the intestine

Excess oral iron in the intestinal tract usually produces reactive oxygen species via Fenton and Haber-Weiss reaction, so oxidative stress is triggered. Lipid peroxidation procedurally appears, ferroptosis, apoptosis and necrosis are often induced, subsequently, mitochondrial damage, endoplasmic reticulum dysfunction and even cell death occur. As a result, the intestinal epithelial cells are destroyed, leading to the incompleteness of intestinal mechanical barrier. Simultaneously, iron supplement can change the compositions and metabolic processes of intestinal microbes, and the intestinal inflammatory may be worsened. In principle, the easier dissociation of Fe²⁺ from oral iron supplements is, the more serious intestinal inflammation will occur. Fortunately, some interventions have been developed to alleviate these side effects. For instance, some antioxidants e.g. VE and ferulic acid have been used to prevent the formation of free radicals or to neutralize the formed free radicals. Furthermore, some new iron supplements with the ability of slow-releasing Fe²⁺, e.g. ferrous citrate liposome and EDTA iron sodium, have been successfully prepared. In order to recover the intestinal micro-ecological balance, probiotics and prebiotics, bacterial consortium transplantation, and fecal microbiota transplantation have been developed. This study is meaningful for us to develop safer oral iron supplements and to maintain intestinal micro-ecological health.

The potential utility of melatonin in the treatment of childhood cancer

Childhood cancer management has improved considerably, with the overall objective of preventing early-life cancers completely. However, cancer remains a major cause of death in children, with the survivors developing anticancer treatment-specific health problems. Therefore, the anticancer treatment needs further improvement. Melatonin is a effective antioxidant and circadian pacemaker. Through multiple mechanisms, melatonin has significant positive effects on multitude adult cancers by increasing survival and treatment response rates, and slowing disease progression. In addition, melatonin appears to be safe for children. As an appealing therapeutic agent, we herein address several key concerns regarding melatonin's potential for treating children with cancer.

Impaired non-homologous end joining in human primary alveolar type II cells in emphysema

Emphysema is characterized by alveolar wall destruction induced mainly by cigarette smoke. Oxidative damage of DNA may contribute to the pathophysiology of this disease. We studied the impairment of the non-homologous end joining (NHEJ) repair pathway and DNA damage in alveolar type II (ATII) cells and emphysema development. We isolated primary ATII cells from control smokers, nonsmokers, and patients with emphysema to determine DNA damage and repair. We found higher reactive oxygen species generation and DNA damage in ATII cells obtained from individuals with this disease  in comparison with controls. We also observed low phosphorylation of H2AX, which activates DSBs repair signaling, in emphysema. Our results indicate the impairement  of NHEJ, as detected by low XLF expression. We also analyzed the role of DJ-1, which has a cytoprotective activity. We detected DJ-1 and  XLF interaction in ATII cells in emphysema, which suggests the impairment of their function. Moreover, we found that DJ-1 KO mice are more susceptible to DNA damage induced by cigarette smoke. Our results suggest that oxidative DNA damage and ineffective the DSBs repair via the impaired NHEJ may contribute to ATII cell death in emphysema.

The prognostic values of the peroxiredoxins family in ovarian cancer

Purpose: Peroxiredoxins (PRDXs) are a family of antioxidant enzymes with six identified mammalian isoforms (PRDX1-6). PRDX expression is up-regulated in various types of solid tumors; however, individual PRDX expression, and its impact on prognostic value in ovarian cancer patients, remains unclear.Methods: PRDXs family protein expression profiles in normal ovarian tissues and ovarian cancer tissues were examined using the Human Protein Atlas database. Then, the prognostic roles of PRDX family members in several sets of clinical data (histology, pathological grades, clinical stages, and applied chemotherapy) in ovarian cancer patients were investigated using the Kaplan-Meier plotter.Results: PRDXs family protein expression in ovarian cancer tissues was elevated compared with normal ovarian tissues. Meanwhile, elevated expression of PRDX3, PRDX5, and PRDX6 mRNAs showed poorer overall survival (OS); PRDX5 and PRDX6 also predicted poor progression-free survival (PFS) for ovarian cancer patients. Furthermore, PRDX3 played significant prognostic roles, particularly in poor differentiation and late-stage serous ovarian cancer patients. Additionally, PRDX5 predicted a lower PFS in all ovarian cancer patients treated with Platin, Taxol, and Taxol+Platin chemotherapy. PRDX3 and PRDX6 also showed poor PFS in patients treated with Platin chemotherapy. Furthermore, PRDX3 and PRDX5 indicated lower OS in patients treated with these three chemotherapeutic agents. PRDX6 predicted a poorer OS in patients treated with Taxol and Taxol+Platin chemotherapy.Conclusion: These results suggest that there are distinct prognostic values of PRDX family members in patients with ovarian cancer, and that the expression of PRDX3, PRDX5, and PRDX6 mRNAs are a useful prognostic indicator in the effect of chemotherapy in ovarian cancer patients.

DPEP1 Balance GSH Involve in Cadmium Stress Response in Blood Clam Tegillarca granosa

The blood clam, Tegillarca granosa, is a benthic filter feeder with a strong capacity to accumulate and tolerate cadmium (Cd). In our previous study, DPEP1 was shown to be significantly up-regulated under Cd stress based on proteomic analysis. To investigate whether DPEP1 is involved in Cd-induced response, the function of DPEP1 in T. granosa was investigated by integrated molecular and protein approaches. Rapid amplification cDNA end (RACE) assay was established to achieve the complete cDNA sequence of DPEP1 from T. granosa. The full-length cDNA of DPEP1 was 1811 bp, and it contained a 1359-bp open reading frame (ORF), including a 22-amino acid signal peptide. qRT-PCR analysis revealed that DPEP1 was expressed in all examined tissues with the highest expression in gills. At the same time, we investigated DPEP1 gene expression changes after Cd stress at different time points over 96 h. We found that the expression of DPEP1 increased upon initial Cd stress, then it was inhibited, and finally, it was maintained at a low level. Moreover, recombinant DPEP1 showed that higher glutathione (GSH) hydrolysis activity in the temperature range of 30–40°C, and its maximum activity was at pH = 6. Additionally, the results of immunohistochemistry also confirmed that DPEP1 protein was expressed in all test tissues with the highest expression in gills. In addition, there was a positive correlation between QRT-PCR and immunohistochemistry. These results suggested that DPEP1 is probably involved in Cd-induced response by balancing GSH.

Mechanisms of oxidative stress-induced in vivo mutagenicity by potassium bromate and nitrofurantoin

Oxidative stress is well known as a key factor of chemical carcinogenesis. However, the actual role of oxidative stress in carcinogenesis, such as oxidative stress-related in vivo mutagenicity, remains unclear. It has been reported that 8-hydroxydeoxyguanosine (8-OHdG), an oxidized DNA lesion, might contribute to chemical carcinogenesis. Potassium bromate (KBrO3) and nitrofurantoin (NFT) are known as renal carcinogens in rats. Our previous studies showed an increase in mutant frequencies accompanied by an increased level of 8-OHdG in the kidneys of rodents following KBrO3 or NFT exposure. Furthermore, KBrO3 and NFT induced different types of gene mutations. Thus, in the present study, we performed reporter gene mutation assays and 8-OHdG measurements following KBrO3 or NFT exposure using Nrf2-proficient and Nrf2-deficient mice to clarify the relationship between KBrO3- or NFT-induced oxidative stress and subsequent genotoxicity. Administration of 1,500 ppm of KBrO3 in drinking water resulted in an increase in deletion mutations accompanied by an increase in 8-OHdG level, and administration of 2,500 ppm of NFT in diet induced an increase in guanine base substitution mutations without elevation of the 8-OHdG level in Nrf2-deficient mice. These results demonstrated that the formation of 8-OHdG, which resulted from the oxidizing potential of KBrO3, was directly involved in the increase in deletion mutations, although factors related to oxidative stress other than 8-OHdG might be crucial for NFT-induced guanine base substitution mutations. The present study provides new insight into oxidative stress-related in vivo mutagenicity.

Anti-inflammatory and antitumor action of hydrogen via reactive oxygen species

Hydrogen (H₂) has advantages that lead it to be used as a novel antioxidant in preventive and therapeutic applications. H₂ can permeate into biomembranes, cytosol, mitochondria and nuclei, and can be dissolved in water or saline to produce H₂ water or H₂-rich saline. H₂ selectively reduces oxidants of the detrimental reactive oxygen species (ROS), including hydroxyl radicals (·OH) and peroxynitrite (ONOO^-), which serve a causative role in the promotion of tumor cell proliferation, invasion and metastasis, but do not disturb metabolic oxidation-reduction reactions in cell signaling. Compared with traditional antioxidants, H₂ is a small molecule that can easily dissipate throughout the body and cells; thus, it may be a safe and effective antioxidant for inflammatory diseases and cancer, since ROS usually initiates tumor progression. Treatment with H₂ may involve correction of the oxidative/anti-oxidative imbalance and suppression of inflammatory mediators. Therefore the present review will discuss the anti-inflammatory and anti-tumorigenic action of H₂ via ROS.

Therapeutic efficacy of hydrogen‑rich saline alone and in combination with PI3K inhibitor in non‑small cell lung cancer

The aim of the present study was to investigate the effects of combination therapy of LY294002, a specific inhibitor of phosphatidylinositol 3-kinase (PI3K), with hydrogen-rich saline on the proliferation and apoptosis of the non-small cell lung cancer (NSCLC) A549 cell line and the mechanisms underpinning this. Excessive production of reactive oxygen species (ROS) may induce DNA mutations, DNA damage, genomic instability and cell proliferation, and ROS are involved in several types of cancer, particularly lung cancer. In a previous study, hydrogen was recognized as an antioxidant in preventive and therapeutic applications. The PI3K/protein kinase B (Akt) pathway is an important signaling pathway that may activate downstream of a series of extracellular signals and impact on cellular processes including cell proliferation, apoptosis and survival. To date, the PI3K/Akt signaling pathway has been indicated as a feasible target for novel antineoplastic drugs. Different strategies combining the two treatment modalities have been used in cancer therapy in order to achieve an improved therapeutic response and longer control of tumor modalities control. The present study investigated the effect of hydrogen-rich saline alone and in combination with the PI3K inhibitor, LY294002, on the proliferation, oxidative stress and apoptosis of NSCLC A549 cells. This combination therapy may be more effective than separate drug treatment; it decreased the malondialdehyde level and increased the superoxide dismutase activity. The combination therapy also enhanced the efficacy of anti-proliferation and apoptosis. Similarly, the results of the present study demonstrated that administration of the two agents in combination may inhibit phospho-Akt activity, and reduce expression of heme oxygenase-1 and nuclear factor-κB p65. The results further suggested that the combination therapy may reduce cell proliferation and promote cell apoptosis by downregulating Akt phosphorylation and inhibiting the PI3K pathway in NSCLC cell lines. Therefore, the present study provided evidence that combined therapy may be a novel therapeutic option for patients with NSCLC.

MCUR1-Mediated Mitochondrial Calcium Signaling Facilitates Cell Survival of Hepatocellular Carcinoma via Reactive Oxygen Species-Dependent P53 Degradation

AIMS

Levels of the mitochondrial calcium uniporter regulator 1 (MCUR1) increases during development of hepatocellular carcinoma (HCC). However, mechanisms of how mitochondrial Ca²⁺ homeostasis is modulated and its function remain limited in cancers.

RESULTS

MCUR1 was frequently upregulated in HCC cells to enhance the Ca²⁺ uptake into mitochondria in an MCU-dependent manner, which significantly facilitated cell survival by inhibiting mitochondria-dependent intrinsic apoptosis and promoting proliferation of HCC cells, and thus led to poor prognosis. In vivo assay confirmed these results, indicating that overexpressed MCUR1 notably decreased the fraction of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells and increased the positive Ki67 staining in xenograft tumors, while reduced MCUR1 expression was associated with impaired growth capacity of HCC cells in nude mice. The survival advantage conferred by MCUR1-mediated mitochondrial Ca²⁺ uptake was majorly caused by elevated production of mitochondrial reactive oxygen species and subsequent AKT/MDM2- induced P53 degradation, which regulated the expression level of apoptosis-related molecules and cell cycle-related molecules. Treatment of mitochondrial Ca²⁺-buffering protein parvalbumin remarkably inhibited the growth of HCC cells. Conclusions and Innovation: Our study provides evidence supporting a possible tumor-promoting role for MCUR1-mediated mitochondrial Ca²⁺ uptake and uncovers a mechanistic understanding that links change of mitochondrial Ca²⁺ homeostasis to cancer cell survival, which suggests a potential novel therapeutic target for HCC. Antioxid. Redox Signal. 28, 1120-1136.

Role of ginsenosides in reactive oxygen species-mediated anticancer therapy

Cancer is still a global public health problem, which is the leading cause of death in most countries. Ginseng has been used for centuries all over the world as a panacea that promotes longevity. As the king of herb plants, ginseng holds great promise as a new treatment option which is used either by itself or in combination with other medicinal ingredients that is widely accepted as complementary and alternative medicine in cancer therapy. Ginsenosides, the major pharmacologically active ingredients of ginseng, have been shown to have multiple medicinal effects including prominent anticancer activity. The purpose of this review is to give our perspective about the roles of ginsenosides in reactive oxygen species (ROS)-mediated anticancer therapy. Additionally, to provide new sheds light for further improvement and carry out pre-clinical and clinical trials to develop it successfully into a potential anticancer agent. Panax herbs and their derivate/metabolites ginsenosides exert beneficial effects for treating various types of cancers. The mechanism of ROS-mediated anticancer activities of ginsenosides varies depending on the specific type of cancer cells involved. Ginsenosides may suppress cancer cell proliferation through anti-oxidation on tumor initiation and induce apoptosis, paraptosis or autophagy via generation of ROS on tumor progression, promotion, angiogenesis, invasion and metastasis by various signaling pathways e.g., activation of AMPK, MEK, ASK-1/JNK, ESR2-NCF1-ROS, ER-dependent PI3K/Akt/Nrf2, P53-CHOP, ROS-JNK-autophagy, and/or inhibition of PI3K/Akt signaling pathways. These multiple effects rather than a single may play a crucial role in emerging ginsenosides as a successful anticancer drug.

Cytotoxicity Study of Cyclopentapeptide Analogues of Marine Natural Product Galaxamide towards Human Breast Cancer Cells

Herein, we report the cytotoxicity of cyclopentapeptide analogues of marine natural product galaxamide towards breast carcinoma cells and the underlying mechanisms. We examined the effect of the novel galaxamide analogues on cancer cell proliferation by MTT assay and also further examined the most active compound for morphological changes using Hoechst33342 staining technique, induction of apoptosis, cell cycle phases, mitochondrial membrane potential (MMP), and reactive oxygen species (ROS) generation using flow cytometry in human breast cancer MCF-7 cells in vitro. Galaxamide and its analogues effectively induced toxicity in human hepatocellular carcinoma HepG2, human breast carcinoma MCF-7, human epitheloid cervix carcinoma HeLa, and human breast carcinoma MB-MDA-231 cell lines. Amongst them, compound 3 exhibited excellent toxicity towards MCF-7 cells. This galaxamide analogue significantly induced apoptosis in a dose-dependent manner in MCF-7 cells involves cell cycle arrest in the G1 phase, a reduction of MMP, and a marked increase in generation of ROS. Particularly, compound 3 of galaxamide analogues might be a potential candidate for the treatment of breast cancer.

The Role of Redox-Regulating Enzymes in Inoperable Breast Cancers Treated with Neoadjuvant Chemotherapy

Although validated predictive factors for breast cancer chemoresistance are scarce, there is emerging evidence that the induction of certain redox-regulating enzymes may contribute to a poor chemotherapy effect. We investigated the possible association between chemoresistance and cellular redox state regulation in patients undergoing neoadjuvant chemotherapy (NACT) for breast cancer. In total, 53 women with primarily inoperable or inflammatory breast cancer who were treated with NACT were included in the study. Pre-NACT core needle biopsies and postoperative tumor samples were immunohistochemically stained for nuclear factor erythroid 2-related factor 2 (Nrf2), Kelch-like ECH-associated protein 1 (Keap1), thioredoxin (Trx), and peroxiredoxin I (Prx I). The expression of all studied markers increased during NACT. Higher pre-NACT nuclear Prx I expression predicted smaller size of a resected tumor (p = 0.00052; r = −0.550), and higher pre-NACT cytoplasmic Prx I expression predicted a lower amount of evacuated nodal metastasis (p = 0.0024; r = −0.472). Pre-NACT nuclear Trx expression and pre-NACT nuclear Keap1 expression had only a minor prognostic significance as separate factors, but when they were combined, low expression for both antibodies before NACT predicted dismal disease-free survival (log-rank p = 0.0030). Our results suggest that redox-regulating enzymes may serve as potential prognostic factors in primarily inoperable breast cancer patients.

Spectrum of spontaneous photon emission as a promising biophysical indicator for breast cancer research

In this study, we investigated the spectral characteristics of Spontaneous Photon Emission (SPE) from the body surface of a human breast cancer-bearing nude mice model during the overall growth process of breast cancers. By comparing and analyzing the data, we found that there was a striking difference between tumor mice and healthy controls in the spectral distribution of SPE from the body surface of lesion site, even when the morphological changes at the lesion site were not obvious. The spectral distribution of SPE from the healthy site of the tumor mice also differed from that of the healthy controls as the breast cancer developed to a certain stage. In addition, the difference in spectrum was related with different growth states of tumors. Interestingly, there was a positive correlation between the spectral ratio (610-630/395-455 nm) and the logarithm of the tumor volume for both the lesion site (R² = 0.947; p < 0.001) and the normal site (R² = 0.892; p < 0.001) of the tumor mice. The results suggested that the spectrum of SPE was sensitive to changes in the tumor status.

Control of DNA integrity in skeletal muscle under physiological and pathological conditions

Skeletal muscle is a highly oxygen-consuming tissue that ensures body support and movement, as well as nutrient and temperature regulation. DNA damage induced by reactive oxygen species is present in muscles and tends to accumulate with age. Here, we present a summary of data obtained on DNA damage and its implication in muscle homeostasis, myogenic differentiation and neuromuscular disorders. Controlled and transient DNA damage appears to be essential for muscular homeostasis and differentiation while uncontrolled and chronic DNA damage negatively affects muscle health.

Preoperative transcatheter arterial chemotherapy may suppress oxidative stress in hepatocellular carcinoma cells and reduce the risk of short-term relapse

In this study, we aim to investigate oxidative stress in hepatocellular carcinoma (HCC) tissues in patients receiving preoperative transcatheter arterial chemotherapy (TAC) and its association with prognosis. A total of 89 HCC patients enrolled in this study, 39 received preoperative TAC 1 week before surgery (pTAC group) and 50 did not (non-pTAC group). All patients underwent hepatectomy and postoperative TAC and were followed up to 400 weeks. Samples of liver tissue without HCC and hepatitis (n = 15) served as normal controls. Cellular levels of 8-hydroxy-2′-deoxyguanosine (8-OHdG), TP53, and p21^waf1/cip1 were measured in both cancer and surrounding tissues using an immunohistochemistry assay. Taken together, our data suggested that preoperative TAC might postpone postoperative HCC relapse within 1 year via suppression of tumor cells by induction of high levels of oxidative stress.

The prognostic value of NRF2 in solid tumor patients: a meta-analysis

Nuclear factor E2-related factor 2 (NRF2), a transcription factor, is known as a potential therapeutic target of solid tumor for that it is a master regulator of the injury and inflammation response, including controlling antioxidant cell progress. Recent studies showed that NRF2 played significant roles in tumorigenesis and tumor progression, however no association and relationship between NRF2 expression and different clinical manifestation of solid tumor had been accurately evaluated. The present meta-analysis picked up 17 suitable articles from EMBASE, PubMed, and ISI Web of Science databases, including 2238 patients. Combined with results of hazard ratios (HRs) and 95% confidence intervals (CIs), we concluded that a higher expression of NRF2 would have worse impact on overall survival (HR = 2.29, 95% CI 1.80–2.91, P < 0.05) and disease-free survival (HR = 2.34, 95% CI 1.36–4.00, P < 0.05) by a random-effect model. Moreover, further results were positively correlated to the clinical diagnosis, curative effect observation and prognosis, including tumor differentiation, lymph node metastasis, distant metastasis and clinical stage. Consequently, our data shown that NRF2 is a potential poor prognostic factor in a variety of solid tumors.

Progression of Hepatic Adenoma to Carcinoma in Ogg1 Mutant Mice Induced by Phenobarbital

The carcinogenic potential of phenobarbital (PB) was assessed in a mouse line carrying a mutant Mmh allele of the Mmh/Ogg1 gene encoding the enzyme oxoguanine DNA glycosylase (Ogg1) responsible for the repair of 8-hydroxy-2′-deoxyguanosine (8-OHdG). Mmh homozygous mutant (Ogg1^−/−) and wild-type (Ogg1^+/+) male and female, 10-week-old, mice were treated with 500 ppm PB in diet for 78 weeks. Hepatocellular carcinomas (HCCs) were found in PB-treated Ogg1^−/− mice, while Ogg1^+/+ animals developed only hepatocellular adenomas (HCAs) at the same rate. This was coordinated with PB-induced significant elevation of 8-OHdG formation in DNA and cell proliferation in adjacent liver of Ogg1^−/− mice. Proteome analysis predicted activation of transcriptional factor Nrf2 in the livers and HCAs of PB-administered Ogg1^+/+ mice; however, its activation was insufficient or absent in the livers and HCCs of Ogg1^−/− mice, respectively. Significant elevation of phase I and II metabolizing enzymes was demonstrated in both Ogg1^−/− and Ogg1^+/+ animals. Treatment of Ogg1^−/− mice with PB resulted in significant elevation of cell proliferation in the liver. These results indicate that PB induced progression from HCA to HCC in Ogg1^−/− mice, due to persistent accumulation of DNA oxidative base modifications and suppression of Nrf2-mediated oxidative stress response, resulting in significant elevation of cell proliferation.