Nitrative and oxidative DNA damage in infection-related carcinogenesis in relation to cancer stem cells

Tumor-associated macrophages: A sentinel of innate immune system in tumor microenvironment gone haywire

The tumor microenvironment (TME) is a critical determinant in the initiation, progression, and treatment outcomes of various cancers. Comprising of cancer-associated fibroblasts (CAF), immune cells, blood vessels, and signaling molecules, the TME is often likened to the soil supporting the seed (tumor). Among its constituents, tumor-associated macrophages (TAMs) play a pivotal role, exhibiting a dual nature as both promoters and inhibitors of tumor growth. This review explores the intricate relationship between TAMs and the TME, emphasizing their diverse functions, from phagocytosis and tissue repair to modulating immune responses. The plasticity of TAMs is highlighted, showcasing their ability to adopt either protumorigenic or anti-tumorigenic phenotypes based on environmental cues. In the context of cancer, TAMs' pro-tumorigenic activities include promoting angiogenesis, inhibiting immune responses, and fostering metastasis. The manuscript delves into therapeutic strategies targeting TAMs, emphasizing the challenges faced in depleting or inhibiting TAMs due to their multifaceted roles. The focus shifts towards reprogramming TAMs to an anti-tumorigenic M1-like phenotype, exploring interventions such as interferons, immune checkpoint inhibitors, and small molecule modulators. Noteworthy advancements include the use of CSF1R inhibitors, CD40 agonists, and CD47 blockade, demonstrating promising results in preclinical and clinical settings. A significant section is dedicated to Chimeric Antigen Receptor (CAR) technology in macrophages (CAR-M cells). While CAR-T cells have shown success in hematological malignancies, their efficacy in solid tumors has been limited. CAR-M cells, engineered to infiltrate solid tumors, are presented as a potential breakthrough, with a focus on their development, challenges, and promising outcomes. The manuscript concludes with the exploration of third-generation CAR-M technology, offering insight into in-vivo reprogramming and nonviral vector approaches. In conclusion, understanding the complex and dynamic role of TAMs in cancer is crucial for developing effective therapeutic strategies. While early-stage TAM-targeted therapies show promise, further extensive research and larger clinical trials are warranted to optimize their targeting and improve overall cancer treatment outcomes.

The role of nitric oxide synthase/ nitric oxide in infection-related cancers: Beyond antimicrobial activity

As a free radical and endogenous effector molecule, mammalian endogenous nitric oxide (NO) is mainly derived from nitric oxide synthase (NOS) via L-arginine. NO participates in normal physiological reactions and provides immune responses to prevent the invasion of foreign bacteria. However, NO also has complex and contradictory biological effects. Abnormal NO signaling is involved in the progression of many diseases, such as cancer. In the past decades, cancer research has been closely linked with NOS/ NO, and many tumors with poor prognosis are associated with high expression of NOS. In this review, we give a overview of the biological effects of NOS/ NO. Then we focus on the oncogenic role of iNOS/ NO in HPV, HBV, EBV and H. pylori related tumors. In fact, there is growing evidence that iNOS could be used as a potential therapeutic target in cancer therapy. We emphasize that the pro-tumor effect of NOS/ NO is greater than the anti-tumor effect.

The Crucial Role of Inflammation and the Immune System in Colorectal Cancer Carcinogenesis: A Comprehensive Perspective

Chronic inflammation drives the growth of colorectal cancer through the dysregulation of molecular pathways within the immune system. Infiltration of immune cells, such as macrophages, into tumoral regions results in the release of proinflammatory cytokines (IL-6; IL-17; TNF-α), fostering tumor proliferation, survival, and invasion. Tumors employ various mechanisms to evade immune surveillance, effectively 'cloaking' themselves from detection and subsequent attack. A comprehensive understanding of these intricate molecular interactions is paramount for advancing novel strategies aimed at modulating the immune response against cancer.

Evaluation of antioxidant enzyme levels, oxidative stress markers and serum prolidase activity in testicular cancer

INTRODUCTION

Testicular cancer is a significant malignancy affecting males, and understanding the underlying biochemical changes associated with the disease is essential for improved management and treatment strategies. Prolidase enzyme, has been implicated in various disease processes. The assessment of serum prolidase activity and its relationship with testicular cancer can provide valuable insights into the pathophysiology of the disease. The objective of this study was to investigate serum prolidase activity, oxidative stress markers, and antioxidant enzyme levels in patients with testicular cancer and evaluate their potential associations, aiming to enhance our understanding of the biochemical alterations and potential implications for testicular cancer management.

METHODS

A total of 33 male patients diagnosed with testicular cancer were included, along with 35 age-matched male volunteers as the control group. Serum samples were collected and stored at -20°C until analysis. The measurement of superoxide dismutase (SOD), glutathione peroxidase (GSHPx), glutathione-S-transferase (GST), malondialdehyde (MDA), glutathione (GSH), and prolidase levels was performed.

RESULTS

The findings demonstrated significantly elevated serum prolidase activity and malondialdehyde (MDA) levels in testicular cancer patients compared to the control group (all, p < 0.05). Conversely, superoxide dismutase (SOD), glutathione peroxidase (GSHPx), and glutathione-S-transferase (GST) levels were significantly lower in testicular cancer patients (p < 0.05).

CONCLUSION

In this study, serum prolidase activity and biochemical markers associated with oxidative stress were investigated in testicular cancer patients. Oxidative stress markers and serum prolidase activity were found to be elevated in testicular cancer. Long-term prospective studies are needed to determine the effectiveness of antioxidant use in cancer treatment.

Unlocking the potential of Rosa roxburghii Tratt polyphenol: a novel approach to treating acute lung injury from a perspective of the lung-gut axis

Introduction

Acute lung injury (ALI) is a serious respiratory disease characterized by progressive respiratory failure with high morbidity and mortality. It is becoming increasingly important to develop functional foods from polyphenol-rich medicinal and dietary plants in order to prevent or alleviate ALI by regulating intestinal microflora. Rosa roxburghii Tratt polyphenol (RRTP) has significant preventive and therapeutic effects on lipopolysaccharide-induced ALI mice, but its regulatory effects on gut homeostasis in ALI mice remains unclear.

Methods

This study aims to systematically evaluate the ameliorative effects of RRTP from the perspective of "lung-gut axis" on ALI mice by intestine histopathological assessment, oxidative stress indicators detection and short-chain fatty acids (SCFAs) production, and then explore the modulatory mechanisms of RRTP on intestinal homeostasis by metabolomics and gut microbiomics of cecal contents.

Results

The results showed that RRTP can synergistically exert anti-ALI efficacy by significantly ameliorating intestinal tissue damage, inhibiting oxidative stress, increasing SCFAs in cecal contents, regulating the composition and structure of intestinal flora, increasing Akkermansia muciniphila and modulating disordered intestinal endogenous metabolites.

Discussion

This study demonstrated that RRTP has significant advantages in adjuvant therapy of ALI, and systematically clarified its comprehensive improvement mechanism from a new perspective of "lung-gut axis", which provides a breakthrough for the food and healthcare industries to develop products from botanical functional herbs and foods to prevent or alleviate ALI by regulating intestinal flora.

Evolving perspectives regarding the role of the PD-1/PD-L1 pathway in gastric cancer immunotherapy

Gastric cancer (GC) is an increasing global health problem and is one of the leading cancers worldwide. Traditional therapies, such as radiation and chemotherapy, have made limited progress in enhancing their efficacy for advanced GC. The development of immunotherapy for advanced GC has considerably improved with a deeper understanding of the tumor microenvironment. Immunotherapy using checkpoint inhibitors is a new therapeutic option that has made substantial advances in the treatment of other malignancies and is increasingly used in other clinical oncology treatments. Particularly, therapeutic antibodies targeting the programmed cell death protein-1 (PD-1)/programmed cell death ligand 1 (PD-L1) pathway have been effectively used in the clinical treatment of cancer. Monoclonal antibodies blocking the PD-1/PD-L1 pathway have been developed for cancer immunotherapy to enhance T cell function to restore the immune response and represent a breakthrough in the treatment of GC. This review provides an outline of the progress of PD-1/PD-L1 blockade therapy and its expression characteristics and clinical application in advanced GC.

Oxidative Stress and Redox-Dependent Pathways in Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a primary liver tumor that accounts for 2% of all cancer-related deaths worldwide yearly. It can arise from cholangiocytes of biliary tracts, peribiliary glands, and possibly from progenitor cells or even hepatocytes. CCA is characterized by high chemoresistance, aggressiveness, and poor prognosis. Potentially curative surgical therapy is restricted to a small number of patients with early-stage disease (up to 35%). Accumulating evidence indicates that CCA is an oxidative stress-driven carcinoma resulting from chronic inflammation. Oxidative stress, due to enhanced reactive oxygen species (ROS) production and/or decreased antioxidants, has been recently suggested as a key factor in cholangiocyte oncogenesis through gene expression alterations and molecular damage. However, due to different experimental models and conditions, contradictory results regarding oxidative stress in cholangiocarcinoma have been reported. The role of ROS and antioxidants in cancer is controversial due to their context-dependent ability to stimulate tumorigenesis and support cancer cell proliferation or promote cell death. On these bases, the present narrative review is focused on illustrating the role of oxidative stress in cholangiocarcinoma and the main ROS-driven intracellular pathways. Heterogeneous data about antioxidant effects on cancer development are also discussed.

Contributions of viral oncogenes of HPV-18 and hypoxia to oxidative stress and genetic damage in human keratinocytes

Infection with high-risk human papillomaviruses like HPV-16 and HPV-18 is highly associated with the development of cervical and other cancers. Malignant transformation requires viral oncoproteins E5, E6 and E7, which promote cell proliferation and increase DNA damage. Oxidative stress and hypoxia are also key factors in cervical malignant transformation. Increased levels of reactive species of oxygen (ROS) and nitrogen (RNS) are found in the hypoxic tumor microenvironment, promoting genetic instability and invasiveness. In this work, we studied the combined effect of E5, E6 and E7 and hypoxia in increasing oxidative stress and promoting DNA damage and nuclear architecture alterations. HaCaT cells containing HPV-18 viral oncogenes (HaCaT E5/E6/E7-18) showed higher ROS levels in normoxia and higher levels of RNS in hypoxia compared to HaCaT parental cells, as well as higher genetic damage in hypoxia as measured by γH2AX and comet assays. In hypoxia, HaCaT E5/E6/E7-18 increased its nuclear dry mass and both cell types displayed marked heterogeneity in nuclear dry mass distribution and increased nuclear foci. Our results show contributions of both viral oncogenes and hypoxia to oxidative stress, DNA damage and altered nuclear architecture, exemplifying how an altered microenvironment combines with oncogenic transformation to promote tumor progression.

Reduced Lipid Peroxidation Predicts Unfavorable Prognosis in Hepatocellular Carcinoma, but Not Intrahepatic Cholangiocarcinoma

Primary liver cancer, including hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA), remains a significant contributor to cancer-related mortality worldwide. Oxidative stress and lipid peroxidation play a key role in chronic liver diseases and have been shown to be pivotal for tumor initiation and progression. 4-hydroxy-nonenal (4-HNE), one of the major mediators of oxidative stress and a well-established biomarker for lipid peroxidation, can act as a signal transducer, inducing inflammation and exerting carcinogenic effects. However, the role of 4-HNE in primary liver cancer remains poorly explored. In this study, we investigated 4-HNE levels in 797 liver carcinomas, including 561 HCC and 236 iCCA, by immunohistochemistry. We then correlated 4-HNE levels with comprehensive clinical data and survival outcomes. In HCC, lower expression levels of 4-HNE were associated with vascular invasion, a high tumor grade, a macrotrabecular-massive HCC subtype, and poor overall survival. Concerning iCCA, large duct iCCA showed significantly higher 4-HNE levels when compared to small duct iCCA. Yet, in iCCA, 4-HNE levels did not correlate with known prognostic parameters or survival outcomes. To conclude, in HCC but not in iCCA, low amounts of 4-HNE predict unfavorable survival outcomes and are associated with aggressive tumor behavior. These findings provide insights into the role of 4-HNE in liver cancer progression and may enable novel therapeutic strategies.

Spin-orbit charge transfer from guanine and 9-methylguanine radical cations to nitric oxide radicals and the induced triplet-to-singlet intersystem crossing

Nitric oxide (●NO) participates in many biological activities, including enhancing DNA radiosensitivity in ionizing radiation-based radiotherapy. To help understand the radiosensitization of ●NO, we report reaction dynamics between ●NO and the radical cations of guanine (a 9HG●+ conformer) and 9-methylguanine (9MG●+). On the basis of the formation of 9HG●+ and 9MG●+ in the gas phase and the collisions of the radical cations with ●NO in a guided-ion beam mass spectrometer, the charge transfer reactions of 9HG●+ and 9MG●+ with ●NO were examined. For both reactions, the kinetic energy-dependent product ion cross sections revealed a threshold energy that is 0.24 (or 0.37) eV above the 0 K product 9HG (or 9MG) + NO+ asymptote. To interrogate this abnormal threshold behavior, the reaction potential energy surface for [9MG + NO]+ was mapped out at closed-shell singlet, open-shell singlet, and triplet states using density functional and coupled cluster theories. The results showed that the charge transfer reaction requires the interaction of a triplet-state surface originating from a reactant-like precursor complex 3[9MG●+(↑)⋅(↑)●NO] with a closed-shell singlet-state surface evolving from a charge-transferred complex 1[9MG⋅NO+]. During the reaction, an electron is transferred from π∗(NO) to perpendicular π∗(9MG), which introduces a change in orbital angular momentum. The latter offsets the change in electron spin angular momentum and facilitates intersystem crossing. The reaction threshold in excess of the 0 K thermochemistry and the low charge-transfer efficiency are rationalized by the vibrational excitation in the product ion NO+ and the kinetic shift arising from a long-lived triplet intermediate.

Helicobacter Species and Hepato-Biliary Tract Malignancies: A Systematic Review and Meta-Analysis

Helicobacter species may cause chronic inflammation of the biliary tract, but its relationship with cancer is controversial. We performed a systematic review and meta-analysis to evaluate the association between Helicobacter species and hepatobiliary tract malignancies. Twenty-six studies (4083 patients) were included in qualitative synthesis, and 18 studies (n = 1895 qualified for meta-analysis. All studies were at high-intermediate risk of bias. Most studies combined several direct microbiological methods, mostly PCR (23 studies), culture (8 studies), and/or CLOtest (5 studies). Different specimens alone or in combination were investigated, most frequently bile (16 studies), serum (7 studies), liver/biliary tissue (8 studies), and gastric tissue (3 studies). Patients with Helicobacter species infection had an increased risk of hepatobiliary tract malignancies (OR = 3.61 [95% CI 2.18-6.00]; p < 0.0001), with high heterogeneity in the analysis (I² = 61%; p = 0.0003). This effect was consistent when Helicobacter was assessed in bile (OR = 3.57 [95% CI 1.73-7.39]; p = 0.0006), gastric tissue (OR = 42.63 [95% CI 5.25-346.24]; p = 0.0004), liver/biliary tissue (OR = 4.92 [95% CI 1.90-12.76]; p = 0.001) and serum (OR = 1.38 [95% CI 1.00-1.90]; p = 0.05). Heterogeneity was reduced in these sub-analyses (I² = 0-27%; p = ns), except for liver/biliary tissue (I² = 57%; p = 0.02). In conclusion, based on low-certainty data, Helicobacter species chronic infection is associated with a tripled risk of hepatobiliary tract malignancy. Prospective studies are required to delineate public health interventions.

Non-CpG sites preference in G:C > A:T transition of TP53 in gastric cancer of Eastern Europe (Poland, Romania and Hungary) compared to East Asian countries (China and Japan)

AIM

Mutation spectrum of TP53 in gastric cancer (GC) has been investigated world-widely, but a comparison of mutation spectrum among GCs from various regions in the world are still sparsely documented. In order to identify the difference of TP53 mutation spectrum in GCs in Eastern Europe and in East Asia, we sequenced TP53 in GCs from Eastern Europe, Lujiang (China), and Yokohama, Kanagawa (Japan) and identified the feature of TP53 mutations of GC in these regions.

SUBJECTS AND METHOD

In total, 689 tissue samples of GC were analyzed: 288 samples from East European populations (25 from Hungary, 71 from Poland and 192 from Romania), 268 from Yokohama, Kanagawa, Japan and 133 from Lujiang, Anhui province, China. DNA was extracted from FFPE tissue of Chinese, East European cases; and from frozen tissue of Japanese GCs. PCR products were direct-sequenced by Sanger method, and in ambiguous cases, PCR product was cloned and up to 8 clones were sequenced. We used No. NC_000017.11(hg38) as the reference sequence of TP53. Mutation patterns were categorized into nine groups: six base substitutions, insertion, deletion and deletion-insertion. Within G:C > A:T mutations the mutations in CpG and non-CpG sites were divided. The Cancer Genome Atlas data (TCGA, ver.R20, July, 2019) having somatic mutation list of GCs from Whites, Asians, and other ethnicities were used as a reference for our data.

RESULTS

The most frequent base substitutions were G:C > A:T transition in all the areas investigated. The G:C > A:T transition in non-CpG sites were prominent in East European GCs, compared with Asian ones. Mutation pattern from TCGA data revealed the same trend between GCs from White (TCGA category) vs Asian countries. Chinese and Japanese GCs showed higher ratio of G:C > A:T transition in CpG sites and A:T > G:C mutation was more prevalent in Asian countries.

CONCLUSION

The divergence in mutation spectrum of GC in different areas in the world may reflect various pathogeneses and etiologies of GC, region to region. Diversified mutation spectrum in GC in Eastern Europe may suggest GC in Europe has different carcinogenic pathway of those from Asia.

Fast and biphasic 8-nitroguanine production from guanine and peroxynitrite

Guanine (Gua), among purines, is a preferred oxidation/nitration target because of its low one-electron redox potential. The reactive oxygen/nitrogen species peroxynitrite (ONOO^-), produced in vivo by the reaction between nitric oxide (^•NO) and superoxide radical (O₂^•‒), is responsible for several oxidative modifications in biomolecules, including nitration, nitrosation, oxidation, and peroxidation. In particular, the nitration of Gua, although detected, as well as its reaction kinetics have been seldom investigated. Thus, we studied the concentration- and temperature-dependent formation of 8-nitroguanine (8-NitroGua) in phosphate buffer (pH 7.40) using stopped-flow spectrophotometry. Traces showed a biexponential behavior, with best-fit rate constants: k_fast = 4.4 s^-1 and k_slow = 0.41 s^-1 (30 °C, 400 μM both Gua and ONOO^-). k_fast increased linearly with the concentration of both reactants whereas k_slow was concentration-independent. Linear regression analysis of k_fast as a function of Gua and ONOO^- concentration yielded values of 2.5-6.3 × 10³ M^-1s^-1 and 1.5-3.5 s^-1 for the second-order (slope) and first-order (ordinate) rate constants, respectively (30 °C). Since ONOO^- is a short-lived species, its decay kinetics was also taken into account for this analysis. The 8-NitroGua product was stable for at least 4 h, so no spontaneous denitration was observed. Stopped-flow assays using antioxidants and free-radical scavengers suggested a mixed direct/indirect reaction mechanism for 8-NitroGua formation. Gua nitration by ONOO^- was also observed in the presence of physiologically relevant CO₂ concentrations. The reaction product identity, its yield (∼4.2%, with 400 μM ONOO^- and 200 μM Gua), and the reaction mechanism were unequivocally determined by HPLC-MS/MS experiments. In conclusion, 8-NitroGua production at physiologic pH reached significant levels in a few hundred milliseconds, suggesting that the process might be kinetically relevant in vivo and can likely cause permanent nitrative damage to DNA bases.

The Drivers, Mechanisms, and Consequences of Genome Instability in HPV-Driven Cancers

Simple Summary

Cells infected with high-risk human papillomaviruses (HPV) can accumulate DNA damage and eventually transform into HPV-driven cancers. Genome instability, or the progressive accumulation of DNA alterations (e.g., mutations), in HPV-infected cells is directly induced by the HPV genes and indirectly promoted by HPV infection through the consequences of chronic infection maintenance, increased cell growth, and accumulation of damaging mutations in genes that themselves affect genome instability. While the HPV genome typically exists as a separate entity within cells, genome instability increases the chances of HPV integrating within the host (human) genome, which is common in HPV-induced cancers. The DNA regions surrounding HPV integrations are unstable and can undergo complex alterations that affect both human and HPV genes. This review discusses HPV-dependent and -independent drivers and mechanisms of genome instability in HPV-driven cancers, both globally and around sites of HPV integration, and describes the changes induced in the tumour genome.

Abstract

Human papillomavirus (HPV) is the causative driver of cervical cancer and a contributing risk factor of head and neck cancer and several anogenital cancers. HPV’s ability to induce genome instability contributes to its oncogenicity. HPV genes can induce genome instability in several ways, including modulating the cell cycle to favour proliferation, interacting with DNA damage repair pathways to bring high-fidelity repair pathways to viral episomes and away from the host genome, inducing DNA-damaging oxidative stress, and altering the length of telomeres. In addition, the presence of a chronic viral infection can lead to immune responses that also cause genome instability of the infected tissue. The HPV genome can become integrated into the host genome during HPV-induced tumorigenesis. Viral integration requires double-stranded breaks on the DNA; therefore, regions around the integration event are prone to structural alterations and themselves are targets of genome instability. In this review, we present the mechanisms by which HPV-dependent and -independent genome instability is initiated and maintained in HPV-driven cancers, both across the genome and at regions of HPV integration.

Visualization of DNA Damage and Protection by Atomic Force Microscopy in Liquid

DNA damage is closely related to cancer and many aging-related diseases. Peroxynitrite is a strong oxidant, thus a typical DNA damage agent, and is a major mediator of the inflammation-associated pathogenesis. For the first time, we directly visualized the process of DNA damage by peroxynitrite and DNA protection by ectoine via atomic force microscopy in liquid. We found that the persistence length of DNA decreases significantly by adding a small amount of peroxynitrite, but the observed DNA chains are still intact. Specifically, the persistence length of linear DNA in a low concentration of peroxynitrite (0 µM to 200 µM) solution decreases from about 47 nm to 4 nm. For circular plasmid DNA, we observed the enhanced superhelices of plasmid DNA due to the chain soften. When the concentration of peroxynitrite was above 300 µM, we observed the fragments of DNA. Interestingly, we also identified single-stranded DNAs during the damage process, which is also confirmed by ultraviolet spectroscopy. However, if we added 500 mM ectoine to the high concentration PN solution, almost no DNA fragments due to double strand breaks were observed because of the protection of ectoine. This protection is consistent with the similar effect for DNA damage caused by ionizing radiation and oxygenation. We ascribe DNA protection to the preferential hydration of ectoine.

o-Aminoazotoluene, 7,12-dimethylbenz[a]anthracene, and N-ethyl-N-nitrosourea, which are mutagenic but not carcinogenic in the colon, rapidly induce colonic tumors in mice with dextran sulfate sodium-induced colitis

BACKGROUND

Several rodent models with chemically induced colon cancer have been developed. Among these models, dextran sulfate sodium (DSS), a colitis inducer, combined with azoxymethane as a colon mutagenic carcinogen, is commonly used. We previously reported that although benzo [a] pyrene (BP) is mutagenic but not carcinogenic in the colon, it rapidly develops colon tumors at a high incidence/multiplicity after treatment with DSS. In the present study, we examined whether other colon-mutagenic non-carcinogens (CMNCs) induced colon tumors after treatment with DSS.

RESULTS

o-Aminoazotoluene, 7,12-dimethylbenz[a]anthracene, and N-ethyl-N-nitrosourea were selected as CMNCs. Male CD2F1 mice were orally administered CMNC for 5 consecutive days. After a 9-day dose-free period, mice were treated with 4% DSS in drinking water for 1 week. Three months after DSS treatment, colon samples were collected for histopathology and β-catenin immunohistochemistry analyses. All CMNCs in combination with DSS induced colonic adenocarcinomas at a high incidence/multiplicity in the distal and middle parts of the colon, coinciding with the location of colitis. Unlike in normal cells where β-catenin is exclusively located on the cell membrane, in adenocarcinoma cells, it was translocated to both the nucleus and cytoplasm or only to cytoplasm. The translocation of β-catenin is closely associated with colon carcinogenesis in rodents and humans. No colonic tumors or dysplastic lesions were found after exposure to either CMNC or DSS alone.

CONCLUSION

We provided further evidence clearly showing that CMNCs can rapidly induce colonic tumors in mice with DSS-induced colitis, even if they are not colonic carcinogens.

Genotoxic effect of microplastics and COVID-19: The hidden threat

Microplastics (MPs) are ubiquitous anthropogenic contaminants, and their abundance in the entire ecosystem raises the question of how far is the impact of these MPs on the biota, humans, and the environment. Recent research has overemphasized the occurrence, characterization, and direct toxicity of MPs; however, determining and understanding their genotoxic effect is still limited. Thus, the present review addresses the genotoxic potential of these emerging contaminants in aquatic organisms and in human peripheral lymphocytes and identified the research gaps in this area. Several genotoxic endpoints were implicated, including the frequency of micronuclei (MN), nucleoplasmic bridge (NPB), nuclear buds (NBUD), DNA strand breaks, and the percentage of DNA in the tail (%Tail DNA). In addition, the mechanism of MPs-induced genotoxicity seems to be closely associated with reactive oxygen species (ROS) production, inflammatory responses, and DNA repair interference. However, the gathered information urges the need for more studies that present environmentally relevant conditions. Taken into consideration, the lifestyle changes within the COVID-19 pandemic, we discussed the impact of the pandemic on enhancing the genotoxic potential of MPs whether through increasing human exposure to MPs via inappropriate disposal and overconsumption of plastic-based products or by disrupting the defense system owing to unhealthy food and sleep deprivation as well as stress. Overall, this review provided a reference for the genotoxic effect of MPs, their mechanism of action, as well as the contribution of COVID-19 to increase the genotoxic risk of MPs.

Chemoprevention by aspirin against inflammation-related colorectal cancer in mice

Inflammation is a primary risk factor for cancer. Epidemiological studies previously demonstrated that aspirin decreased the incidence of cancer and specifically reduced the risk of colorectal cancer. However, the number of animal studies that have confirmed the efficacy of aspirin remains limited. Therefore, the purpose of the present study was to investigate the mechanisms by which aspirin prevents colorectal cancer in mice. ICR mice were treated with azoxymethane and the ulcerative colitis inducer, dextran sodium sulfate, to induce colorectal tumors. Aspirin was orally administered three times per week for 12 weeks. Aspirin significantly reduced the number and size of colorectal tumors. Aspirin also significantly decreased tumor necrosis factor alpha and reactive oxygen species (ROS) levels in the plasma. Immunohistochemical analyses and western blots showed that cyclooxygenase 2 (COX2), inducible nitric oxide synthase (iNOS), and the active form of Yes-associated protein 1 (YAP1), and cytosolic high mobility group box 1 (HMGB1) were strongly expressed at colorectal tumor sites and clearly suppressed by aspirin. An indicator of inflammation-related DNA damage, 8-nitroguanine, also accumulated in the colorectal tissues and was suppressed by aspirin. The present results suggest that the ingestion of aspirin suppressed carcinogenesis caused by inflammation through decreases in COX2 and ROS levels, resulting in reductions in DNA damage and oncogenic YAP1.

Reactive oxygen species: Role in carcinogenesis, cancer cell signaling and tumor progression

Cancer is one of the major causes of death in the world and its global burden is expected to continue increasing. In several types of cancers, reactive oxygen species (ROS) have been extensively linked to carcinogenesis and cancer progression. However, studies have reported conflicting evidence regarding the role of ROS in cancer, mostly dependent on the cancer type or the step of the tumorigenic process. We review recent studies describing diverse aspects of the interplay of ROS with cancer in the different stages of cancer progression, with a special focus on their role in carcinogenesis, their importance for cancer cell signaling and their relationship to the most prevalent cancer risk factors.

The cross talk between gastric cancer stem cells and the immune microenvironment: a tumor-promoting factor

Cross talk between cancer cells and the immune system is determinant for cancer progression. Emerging evidence demonstrates that GC characteristics such as metastasis, treatment resistance, and disease recurrence are associated with a tumor subpopulation called gastric cancer stem cells (GCSCs). However, the specific interaction between GCSCs and the immune microenvironment is still under investigation. Although immune evasion has been well described for cancer stem cells (CSCs), recent studies show that GCSCs can also regulate the immune system and even benefit from it. This review will provide an overview of bidirectional interactions between CSCs and immune cells in GC, compiling relevant data about how CSCs can induce leukocyte reprogramming, resulting in pro-tumoral immune cells that orchestrate promotion of metastasis, chemoresistance, tumorigenicity, and even increase in number of cancer cells with stem properties. Some immune cells studied are tumor-associated macrophages (TAMs), neutrophils, Th17 and T regulatory (T_reg) cells, mesenchymal stem cells (MSCs), and cancer-associated fibroblasts (CAFs), as well as the signaling pathways involved in these pro-tumoral activities. Conversely, although there are cytotoxic leukocytes that can potentially eliminate GCSCs, we describe mechanisms for immune evasion in GCSCs and their clinical implications. Furthermore, we describe current available immunotherapy targeting GCSC-related markers as possible treatment for GC, discussing how the CSC-modified immune microenvironment can mitigate or inactivate these immunotherapies, limiting their effectiveness. Finally, we summarize key concepts and relevant evidence to understand the cross talk between GCSCs and the immune microenvironment as an important process for effective design of therapies against GCSCs that improve the outcome of patients with GC.

Plasma checkpoint protein 1 (Chk1) as a potential diagnostic biomarker for opisthorchiasis and cholangiocarcinoma

BACKGROUND

Patients infected with a parasite often develop opisthorchiasis viverrini, which often progresses into cholangiocarcinoma (CCA) due to the asymptomatic nature of the infection. Currently, there are no effective diagnostic methods for opisthorchiasis or cholangiocarcinoma.

OBJECTIVE

The aim of this study was to identify the host-responsive protein that can be developed as a diagnostic biomarker of opisthorchiasis and cholangiocarcinoma.

METHODS

Plasma samples were collected from non-OVCCA, OV, and CCA subjects, and the proteomes were investigated by LC-MS/MS. Venn diagrams and protein network prediction by STITCH were used to identify the potential biomarkers. The level of candidate protein, the plasma checkpoint protein 1 (Chk1), was measured by indirect enzyme-linked immunosorbent assay (ELISA).

RESULTS

Chk1 was present in the center of the protein network analysis in both the OV and CCA groups. In addition, the plasma Chk1 levels were significantly increased in both groups (P< 0.05). The sensitivity of the opisthorchiasis viverrini and cholangiocarcinoma was 59.38% and 65.62%, respectively, while the specificity of both was 85.71%.

CONCLUSION

Chk1 was identified by differential plasma proteomes and was increased in O. viverrini-infected and cholangiocarcinoma-derived plasma samples. Higher levels of plasma Chk1 levels may serve as a potential diagnostic biomarker for opisthorchiasis and cholangiocarcinoma.

Reduced Expression Level of GPX2 in T1 Bladder Cancer and its Role in Early-phase Invasion of Bladder Cancer

BACKGROUND/AIM

The role of glutathione peroxidase 2 (GPX2) expression in urothelial carcinoma (UC) is rarely reported. The aim of this study was to assess the expression status of GPX2 in UC of the bladder.

MATERIALS AND METHODS

We collected samples from 112 patients treated with radical cystectomy for immunohistochemical study.

RESULTS

Following immunohistochemical analysis of the specimens, 86 (76.8%) had weak GPX2 expression. In cases with consistent GPX2 expression within the same lesion, the levels of GPX2 showed significant decreases from pTa to pT1 (47.1%) compared to those from pT1 to pT2 (5.9%) (p=0.017). Specimens obtained with transurethral resection before cancer progressed to muscle invasive bladder cancer showed that pT1 had a lower expression for GPX2 than that of pTa (63.3% vs. 93.3%; p=0.009).

CONCLUSION

The decrease in GPX2 expression among those with UC of the bladder may be involved in the early step of cancer invasion.

Protective effects of astaxanthin on lipopolysaccharide-induced inflammation in bovine endometrial epithelial cells†

Astaxanthin (AST), a natural antioxidant carotenoid, has been shown to exert anti-inflammatory effects. However, to our knowledge, no study has specifically addressed the potential protective effects of AST against bovine endometritis. The purpose of this study was to examine whether treatment with AST could protect endometrial epithelial cells against lipopolysaccharide (LPS)-induced inflammatory injury. Treatment of bovine endometrial (BEND) epithelial cell line with AST reduced LPS-induced production of interleukin-6 and tumor necrosis factor-alpha, increased the cellular activity of superoxide dismutase and catalase, decreased the proportion of apoptotic cells, and promoted the production of insulin-like growth factor and epithelial growth factor. The effects of AST were mediated through the downregulation of B-cell lymphoma 2 (Bcl-2) associated X, apoptosis regulator (Bax), and cleaved caspase-3 and through the upregulation of Bcl-2. Moreover, AST significantly increased the expression of the tight junction proteins (TJP) claudin, cadherin-1, and TJP1, which play an essential role in the maintenance of host endometrial defense barrier against pathogen infection. Collectively, these results demonstrated that treatment with AST protected against oxidative stress, prevented cell apoptosis, promoted BEND cells viability, and increased the production of growth factors, in addition to activating the endometrial defense barrier. Therefore, AST is a promising therapeutic agent for the prevention and treatment of endometritis. This finding is of utmost importance in the present times when the excessive use of antibiotics has resulted in the development of antibiotic-resistant bacteria.

Can plasma antioxidants prevent DNA damage in oxidative stress condition induced by growth hormone deficiency? A pilot study

Adult growth hormone deficiency (GHD), a condition characterized by increased oxidative stress, is related to augmented cardiovascular, metabolic and oncological risk. A case-control observational study has been performed to evaluate DNA oxidative damage analysing the production of thymidine-glycol in lymphocytes and its correlation with plasma antioxidant levels, evaluated as Total Antioxidant Capacity (TAC). GHD was diagnosed using GHRH 50μg iv+arginine 0,5 g/Kg test, with peak GH response <9 μg/L when BMI was <30 kg/m2 or <4 μg/L when BMI was >30 kg/m2. Three groups were identified: total GHD (n = 16), partial GHD (n = 11), and controls (n = 12). Thymidine-glycol, TAC and IGF-1 have been determined respectively in lymphocytes, plasma and serum samples. When considering thymidine-glycol, we found a significant difference between total vs partial GHD and controls. Unexpectedly thymidine-glycol was lower in total GHD, also accompanied with a significant increase in plasmatic TAC. Our results showed that in adult GHD condition, the production of antioxidant species, in response to increased oxidative stress, could exert a protective effect on thymidine-glycol formation, and consequently on DNA intracellular damages. This pilot study could be inserted in the complex scenario of oxidative damage of GHD, a subtle, yet poorly defined condition, worthy of further insights.

Janus Kinase/Signal Converters, and the Transcriptional Activator Signaling Pathway Promotes Lung Cancer Through Increasing M2 Macrophage

Accumulating evidence highlights the salient function of JAK/STAT signaling pathway in tumorigenesis and development. But the mechanism of JAK/STAT signaling in lung cancer remains elusive. This study assessed the impact of JAK/STAT on lung tumorigenesis and its interaction with microenvironment. Mouse model of primary lung cancer was established and then treated with JAK/STAT inhibitor. Immunofluorescence was performed to analyze fluorescent labels. Transwell assay determined the cell migration ability, and Western blot, immunohistochemistry, and immunofluorescence to detect the expression of JAK/STAT key proteins. Cell proliferation was measured by Kit-8 and colony formation. JAK/STAT key proteins were upregulated in lung cancer models. Inhibition of JAK/STAT led to a decrease in proliferative, migratory and invasive capability of lung cancer cells and macrophages from bone marrow and spleen. The cell invasion ability in the bone marrow and the proliferation of macrophages in the treatment group was weakened. When co-cultured with the treated macrophages, the proliferation of LLC1 cells was inhibited. Furthermore, in vitro flow cytometry indicated that JAK/STAT affected lung cancer progression by affecting the polarization of M1/M2 macrophages. Taken altogether, JAK/STAT signal enhances M2 macrophage expression and promotes lung cancer progression.

Environmentally relevant concentration of cypermethrin or/and sulfamethoxazole induce neurotoxicity of grass carp: Involvement of blood-brain barrier, oxidative stress and apoptosis

In water environment, the interaction between environmental pollutants is very complex, among which pesticides and antibiotics are dominant. However, most studies only focus on individual toxic effects, rather combined. In this study, the sub-chronic exposure effect of cypermethrin (CMN, 0.65 μg/L), sulfamethoxazole (SMZ, 0.30 μg/L) and their mixture on grass crap (Ctenopharyngodon idellus) was investigated. The brain tight junction, oxidative stress and apoptosis-related indices were determined after 42 days of exposure. In terms of brain function, acetyl cholinesterase (AChE) activity was significantly inhibited by CMN, SMZ and their mixtures during exposure periods. Obvious histological damage from cellular and subcellular levels were also observed, which were further confirmed by a decrease in tight junction protein levels. Malondialdehyde (MDA) and 8-hydroxy-2-deoxyguanosine (8-OHdG) contents were significantly increased by individual compounds and mixtures, in which the content of glutathione (GSH) displayed the opposite trend. In mechanism, nuclear factor (erythrocyte derived 2) like 2(Nrf2) pathway was activated, which may trigger cellular protection to cope with CMN and SMZ exposure. However, apoptosis was also detected from the level of mRNA and histochemistry. In general, these two exogenous induced similar biological responses. The neurotoxicity of CMN was strengthened by SMZ with regard to these indices in most cases and vice versa. This study will reveal the potential co-ecological risks of pesticide and antibiotic in the aquatic organism, and provide basic data for their safety and risk assessment.

Glycyrrhizin Attenuates Carcinogenesis by Inhibiting the Inflammatory Response in a Murine Model of Colorectal Cancer

Glycyrrhizin (GL), an important active ingredient of licorice root, which weakens the proinflammatory effects of high-mobility group box 1 (HMGB1) by blocking HMGB1 signaling. In this study, we investigated whether GL could suppress inflammation and carcinogenesis in an azoxymethane (AOM)/dextran sodium sulfate (DSS)-induced murine model of colorectal cancer. ICR mice were divided into four groups (n = 5, each)—control group, GL group, colon cancer (CC) group, and GL-treated CC (CC + GL) group, and sacrificed after 20 weeks. Plasma levels of interleukin (IL)-6 and tumor necrosis factor (TNF)-α were measured using an enzyme-linked immunosorbent assay. The colonic tissue samples were immunohistochemically stained with DNA damage markers (8-nitroguanine and 8-oxo-7,8-dihydro-2′-deoxy-guanosine), inflammatory markers (COX-2 and HMGB1), and stem cell markers (YAP1 and SOX9). The average number of colonic tumors and the levels of IL-6 and TNF-α in the CC + GL group were significantly lower than those in the CC group. The levels of all inflammatory and cancer markers were significantly reduced in the CC + GL group. These results suggest that GL inhibits the inflammatory response by binding HMGB1, thereby inhibiting DNA damage and cancer stem cell proliferation and dedifferentiation. In conclusion, GL significantly attenuates the pathogenesis of AOM/DSS-induced colorectal cancer by inhibiting HMGB1-TLR4-NF-κB signaling.

Surface modified multifaceted nanocarriers for oral non-conventional cancer therapy; synthesis and evaluation

Inflammatory cells orchestrate tumor niche for the proliferating neoplastic cells, leading to neoangiogenesis, lymphangiogenesis, tumor growth and metastasis. Emergence of severe side effects, multiple drug resistance and associated high cost has rendered conventional chemotherapy less effectual. The aim was to develop a multipurpose, less toxic, more potent and cheaper, oral non-conventional anticancer therapeutic. Cyclooxygenase associated with tumor niche inflammation and proliferative neoplastic cells were targeted synergistically, through anti-inflammatory and anti-proliferative effects of model drug, diclofenac sodium and fluorescent silver nanoparticles (AgNPs), respectively. Drug entrapped AgNPs were surface modified with PVA (for controlling particle size, preferred cellular uptake, evading opsonization and improved dispersion). XRD, FTIR, DSC, TGA, LIBS, particle size and surface plasmon resonance analysis confirmed the efficient drug encapsulation and PVA coating with 62% loading efficiency. In-vitro, the formulation exhibited 1st order release kinetics with sustained and maximal release at slightly acidic conditions (pH 4.5) enabling the potential for passive tumor targeting. Also, nanoparticles showed efficient protein denaturation inhibition potential, hemo-compatibility (<0.8%) and potent anti-cancer activity (P < 0.05) against breast cancer cell line (MCF-7). In-vivo, developed nanoparticles improved pharmacokinetics (2.8 fold increased AUC, 6.9 h t_1/2, C_max = 1.6 ± 0.03 μg/ml, K_el = 0.1) and pharmacodynamics manifested by potent anti-inflammatory, analgesic and anti-pyretic effects (P < 0.05) at 20 fold lower doses. LD₅₀ determination revealed a wide therapeutic window. The study showed promise of synthesized nanomaterials as cheaper, less toxic, hemo-compatible, oral and more potent anti-inflammatory and non-conventional fluorescent anti-cancer agents, vanquishing tumor niche inflammation and repressing proliferation of malignant cells.

Effect of COVID-19 on Lungs: Focusing on Prospective Malignant Phenotypes

Currently, the healthcare management systems are shattered throughout the world, even in the developed nations due to the COVID-19 viral outbreak. A substantial number of patients infected with SARS-CoV2 develop acute respiratory distress syndrome (ARDS) and need advanced healthcare facilities, including invasive mechanical ventilation. Intracellular infiltration of the SARS-CoV2 virus particles into the epithelial cells in lungs are facilitated by the spike glycoprotein (S Protein) on the outer side of the virus envelope, a membrane protein ACE2 (angiotensin-converting enzyme 2) and two proteases (TMPRSS2 and Furin) in the host cell. This virus has unprecedented effects on the immune system and induces a sudden upregulation of the levels of different pro-inflammatory cytokines. This can be a cause for the onset of pulmonary fibrosis in the lungs. Existence of a high concentration of inflammatory cytokines and viral load can also lead to numerous pathophysiological conditions. Although it is well established that cancer patients are among the high-risk population due to COVID-19-associated mortality, it is still unknown whether survivors of COVID-19-infected subjects are at high-risk population for developing cancer and whether any biologic and clinical features exist in post-COVID-19 individuals that might be related to carcinogenesis.

Anticancer therapeutics: a brief account on wide refinements

The flustering rise in cancer incidence along with treatment anomalies has made cancer the second leading cause of death globally. The total annual economic impact of cancer is pronounced and is increasing. Besides the lack of proper curative therapy, treatment associated adverse effects, drug resistance, and tumor relapse are the instigations behind increased morbidity and mortality. Meanwhile, the survival rate has inclined impressively. In the last few decades, cancer treatment has undergone wide refinements aiming towards cancer prevention, complete tumor regression, subsiding treatment adverse effects, improving patient's life standard and avoiding tumor relapse. Chemotherapy has been successfully extended towards natural, cheaper and bioactive anti-inflammatory agents manifesting potent anticancer activity. Antibody-based cancer therapy has become well established as a vital and effective strategy for treating hematological malignancies as well as solid tumors. Individualized immunotherapy is becoming the forefront of cancer treatment enabling personalized, precise and patient's cancer mutanome specific adjustable regimen. The emergence of anti-neoangiogenesis and cancer stem cell targeting techniques have dropped cancer recurrence significantly. Advancements in hyperthermia and photodynamic therapies along with improvements in cancer vaccination have declined death rate and amplified survival rate convincingly.

Nitric oxide: A radical molecule with potential biotechnological applications in fruit ripening

Nitric oxide (NO) is a short-life and free radical molecule involved in a wide range of cellular, physiological and stressful processes in higher plants. In recent years it has been observed that exogenous NO application can palliate adverse damages against abiotic and biotic stresses. Conversely, there is accumulating information indicating that endogenous NO participates significantly in the mechanism of modulation of the ripening in climacteric and non-climacteric fruits. Even more, when NO is exogenously applied, it can mediate beneficial effects during ripening and postharvest storage being one of the main effects the increase of antioxidant systems. Consequently, NO could be a promising biotechnological tool to improve crops through ameliorating nutritional indexes and to alleviate damages during fruit ripening and postharvest management. Thus, this approach should be complementary to previous strategies to allow preserving the quality and healthiness of fruits with a view of enhancing their added value. The present mini-review aims to provide an overview of NO biochemistry in plants and updated information on the relevance of NO in fruit ripening and postharvest stages with a view to its biotechnological applications.

Protective effects of dried mature Citrus unshiu peel (Chenpi) and hesperidin on aspirin-induced oxidative damage

Here we investigated the inhibitory effects in rats of mature Citrus unshiu peel (Chenpi) and its component hesperidin on aspirin-induced oxidative damage. The content of hesperidin in Chenpi extract was approximately 11.4%. Wistar rats were orally administered Chenpi extract or hesperidin (20 mg/kg body weight) and then were orally administered aspirin (200 mg/kg body weight) to induce oxidative damage to the stomach, liver, and kidneys. Such damage was evaluated using the formamidopyrimidine DNA glycosylase-modified comet assay. We also measured the amount of the oxidative marker 8-oxo-7,8-dihydroguanine (8-oxodG) in the stomach. Aspirin-induced damage to the gastric mucosa was evaluated using a bleeding score. Chenpi extract and hesperidin significantly inhibited aspirin-induced oxidative DNA damage. The bleeding score of the aspirin-induced gastric mucosa was significantly reduced by treatment with Chenpi extract and hesperidin. To investigate the effects of Chenpi extract and hesperidin on the analgesic effect of aspirin on ddY mice, we employed the acetic acid-induced writhing response test. Chenpi extract and hesperidin did not significantly affect the analgesic effect of aspirin. These results suggest that Chenpi extract and hesperidin significantly inhibit aspirin-induced gastric mucosal damage.

Defense Mechanism of Phosphorothioated DNA under Peroxynitrite-Mediated Oxidative Stress

DNA phosphorothioation (PT) exists in many pathogenic bacteria; however, the mechanism of PT-DNA resistance to the immune response is unclear. In this work, we meticulously investigated the peroxynitrite (PN) tolerance using PT-bioengineered E. coli strains. The in vivo experiment confirms that the S⁺ strain survives better than the S^- strain under moderately oxidative stress. The LCMS, IC, and GCMS experiments demonstrated that phosphorothioate partially converted to phosphate, and the byproduct included sulfate and elemental sulfur. When O,O-diethyl thiophosphate ester (DETP) was used, the reaction rate k₁ was determined to be 4.3 ± 0.5 M^-1 s^-1 in the first-order for both phosphorothioate and peroxynitrite at 35 °C and pH of 8.0. The IC₅₀ values of phosphorothioate dinucleotides are dramatically increased by 400-700-fold compared to DETP. The SH/OH Yin-Yang mechanism rationalizes the in situ DNA self-defense against PN-mediated oxidative stress at the extra bioenergetic cost of DNA modification.

Role of nitric oxide in the response to photooxidative stress in prostate cancer cells

A continuous state of oxidative stress during inflammation contributes to the development of 25% of human cancers. Epithelial and inflammatory cells release reactive oxygen species (ROS) and reactive nitrogen species (RNS) that can damage DNA. ROS/RNS have biological implications in both chemoresistance and tumor recurrence. As several clinically employed anticancer drugs can generate ROS/RNS, we have addressed herein how inducible nitric oxide synthase and nitric oxide (iNOS/^•NO) affect the molecular pathways implicated in the tumor response to oxidative stress. To mimic the oxidative stress associated with chemotherapy, we used a photosensitizer (pheophorbide a) that can generate ROS/RNS in a controlled manner. We investigated how iNOS/^•NO modulates the tumor response to oxidative stress by involving the NF-κB and Nrf2 molecular pathways. We found that low levels of iNOS induce the development of a more aggressive tumor population, leading to survival, recurrence and resistance. By contrast, high levels of iNOS/^•NO sensitize tumor cells to oxidative treatment, causing cell growth arrest. Our analysis showed that NF-κB and Nrf2, which are activated in response to oxidative stress, communicate with each other through RKIP. For this critical role, RKIP could be an interesting target for anticancer drugs. Our study provides insight into the complex signaling response of cancer cells to oxidative treatments as well as new possibilities for the rational design of new therapeutic strategies.

Dietary Flavonoids in p53-Mediated Immune Dysfunctions Linking to Cancer Prevention

The p53 protein plays a central role in mediating immune functioning and determines the fate of the cells. Its role as a tumor suppressor, and in transcriptional regulation and cytokine activity under stress conditions, is well defined. The wild type (WT) p53 functions as a guardian for the genome, while the mutant p53 has oncogenic roles. One of the ways that p53 combats carcinogenesis is by reducing inflammation. WT p53 functions as an anti-inflammatory molecule via cross-talk activity with multiple immunological pathways, such as the major histocompatibility complex I (MHCI) associated pathway, toll-like receptors (TLRs), and immune checkpoints. Due to the multifarious roles of p53 in cancer, it is a potent target for cancer immunotherapy. Plant flavonoids have been gaining recognition over the last two decades to use as a potential therapeutic regimen in ameliorating diseases. Recent studies have shown the ability of flavonoids to suppress chronic inflammation, specifically by modulating p53 responses. Further, the anti-oxidant Keap1/Nrf2/ARE pathway could play a crucial role in mitigating oxidative stress, leading to a reduction of chronic inflammation linked to the prevention of cancer. This review aims to discuss the pharmacological properties of plant flavonoids in response to various oxidative stresses and immune dysfunctions and analyzes the cross-talk between flavonoid-rich dietary intake for potential disease prevention.

Hybrid Compounds & Oxidative Stress Induced Apoptosis in Cancer Therapy

Elevated Reactive Oxygen Species (ROS) generated by the conventional cancer therapies and the endogenous production of ROS have been observed in various types of cancers. In contrast to the harmful effects of oxidative stress in different pathologies other than cancer, ROS can speed anti-tumorigenic signaling and cause apoptosis of tumor cells via oxidative stress as demonstrated in several studies. The primary actions of antioxidants in cells are to provide a redox balance between reduction-oxidation reactions. Antioxidants in tumor cells can scavenge excess ROS, causing resistance to ROS induced apoptosis. Various chemotherapeutic drugs, in their clinical use, have evoked drug resistance and serious side effects. Consequently, drugs having single-targets are not able to provide an effective cancer therapy. Recently, developed hybrid anticancer drugs promise great therapeutic advantages due to their capacity to overcome the limitations encountered with conventional chemotherapeutic agents. Hybrid compounds have advantages in comparison to the single cancer drugs which have usually low solubility, adverse side effects, and drug resistance. This review addresses two important treatments strategies in cancer therapy: oxidative stress induced apoptosis and hybrid anticancer drugs.

Biopesticide emamectin benzoate in the liver of male mice: evaluation of oxidative toxicity with stress protein, DNA oxidation, and apoptosis biomarkers

Emamectin benzoate (EMB), which is used as a pesticide in agriculture, household, and veterinary medicine, can cause tissue damage with oxidative toxicity and can be considered as inducing apoptosis. In the present study, male mice were conducted by oral administration in EMB doses 25, 50, and 100 (mg/kg/day) for 14 days. Glutathione (GSH) and thiobarbituric acid reactive substance (TBARS) levels using spectrophotometric methods were measured. 8-hydroxy-2'-deoxyguanosine (8-OHdG) which is DNA oxidation biomarker and, stress protein (HSP70) levels, caspase 3 enzyme activities were measured by ELISA techniques. This study shows that in vivo administration of EMB caused a marked induction of oxidative damage in liver tissue as demonstrated by an increased level of TBARS and reduced GSH level. The increase in HSP70 level did not prevent the apoptosis caused by the increase of caspase 3 enzyme activity. Toxicity caused by EMB also showed the formation of genotoxicity with an increase in DNA oxidation biomarker 8-OHdG levels. As a result of the study, the effects of toxicity caused by EMB on lipid; protein; and DNA, structural macromolecules in cells, and the importance of enzymatic and non-enzymatic bonds of the cell's protective systems were determined. Consequently, under experimental conditions, EMB exposure caused toxicity in the liver of male mice, and significant adverse effects were determined with biomarkers.

Replication Stress, DNA Damage, Inflammatory Cytokines and Innate Immune Response

Complete and accurate DNA replication is essential to genome stability maintenance during cellular division. However, cells are routinely challenged by endogenous as well as exogenous agents that threaten DNA stability. DNA breaks and the activation of the DNA damage response (DDR) arising from endogenous replication stress have been observed at pre- or early stages of oncogenesis and senescence. Proper detection and signalling of DNA damage are essential for the autonomous cellular response in which the DDR regulates cell cycle progression and controls the repair machinery. In addition to this autonomous cellular response, replicative stress changes the cellular microenvironment, activating the innate immune response that enables the organism to protect itself against the proliferation of damaged cells. Thereby, the recent descriptions of the mechanisms of the pro-inflammatory response activation after replication stress, DNA damage and DDR defects constitute important conceptual novelties. Here, we review the links of replication, DNA damage and DDR defects to innate immunity activation by pro-inflammatory paracrine effects, highlighting the implications for human syndromes and immunotherapies.

Foretinib Inhibits Cancer Stemness and Gastric Cancer Cell Proliferation by Decreasing CD44 and c-MET Signaling

Purpose

CD44 isoforms are highly expressed in cancer stem cells, initiating tumor growth and sustaining tumor self-renewal. Among these isoforms, CD44 variant 9 (CD44v9) is overexpressed in chronic inflammation-induced cancer. CD44 and the mesenchymal-to-epithelial transition (MET) receptor tyrosine kinase are coactivated in some gastric cancers (GCs). In this study, we characterized MET and CD44 expression and signaling in human GC cell lines and analyzed differences in the susceptibility of these lines to foretinib.

Patients and Methods

We analyzed cell viability and the rate of apoptotic cells using MTS assays and flow cytometry, respectively. Gene and protein expression were assessed by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and immunoblotting, respectively.

Results

Foretinib treatment resulted in dose-dependent inhibition of growth in c-MET-amplified MKN45 and SNU620 cells with concomitant induction of apoptosis, but not in c-MET-reduced MKN28 and AGS cells. Foretinib treatment also significantly reduced phosphor-c-MET, phosphor-AKT, beta-catenin, and COX-2 protein expression in MKN45 and SNU620 cells. Interestingly, foretinib significantly reduced CD44, CD44v9, COX-2, OCT3/4, CCND1, c-MYC, VEGFA, and HIF-1a gene expression in CD44 and MET coactivated MKN45 cells and increased CD44s gene expression; in contrast, these drugs were only slightly active against SNU620 cells.

Conclusion

The results of this study indicate that foretinib could be a therapeutic agent for the prevention or treatment of GCs positive for CD44v9 and c-MET.

Activation of the IL-4/STAT6 Signaling Pathway Promotes Lung Cancer Progression by Increasing M2 Myeloid Cells

Emerging evidence shows that signal transducer and activator of transcription 6 (STAT6) plays critical roles in tumor development. We previously found high-level expression of STAT6 in human lung adenocarcinoma and squamous cell carcinoma, specifically in infiltrated immune cells located in the lung interstitium. Nevertheless, the role of STAT6 signaling in lung carcinogenesis and lung cancer proliferation and its underlying mechanisms remain unclear. This study aimed to investigate the role of STAT6 and the interaction between STAT6 and the tumor microenvironment in pulmonary tumorigenesis. We established a murine model of primary lung carcinogenesis in STAT6-deficient (STAT6^−/−) and STAT6 wild-type (WT) BALB/c mice using the carcinogen urethane. Two-month-old male mice were intraperitoneally injected with urethane (1 g/kg) dissolved in phosphate buffered saline (PBS). Primary tumors were monitored in vivo by positron emission tomography scanning. At 4, 6, and 9 months after urethane injection, lung tumors were harvested from the STAT6^−/− and WT mice for analysis. Small interfering RNA was used to downregulate the expression of STAT6 in tumor cells. Fluorescence activated cell sorting analysis was used to analyze fluorescence-conjugated cell markers. Transwell assays were used in coculturing experiments. STAT6 protein expression was detected by Western blotting, immunohistochemistry, and immunofluorescence. STAT6 mRNA expression was detected by quantitative real time-polymerase chain reaction. Cell Counting Kit-8 and colony formation assays were performed to evaluate cell proliferation. We detected high expression of STAT6 in CD11b⁺ cells of lung carcinoma. Our results indicate that STAT6 deficiency inhibits carcinogen-induced tumor growth and improves prognosis. STAT6 deficiency also decreased the mobilization and differentiation of CD11b⁺ cells. STAT6 deficiency in CD11b⁺ cells but not tumor cells decreased interleukin (IL)-4 secretion and the differentiation of CD11b⁺ cells into M2 macrophage cells. In conclusion, our findings indicate that IL-4/STAT6 signaling in CD11b⁺ cells promotes lung cancer progression by triggering an IL-4 positive feedback loop and increasing M2 myeloid cells. STAT6 may be a new therapeutic target for the prevention and treatment of lung cancer.

My career development with Ames test: A personal recollection

I first became acquainted with the Ames test at the very beginning of my career in 1978, when my task at the National Institute of Health Sciences (Tokyo) was to screen for mutagenicity of food additives used in Japan, using the Ames test. I also used this test to research the metabolic activation mechanisms of chemical carcinogens, in particular, the analgesic drug, phenacetin. This chemical was not mutagenic in Salmonella typhimurium TA100 with standard 9000 × g supernatant of liver homogenates (S9) from rat but was mutagenic with hamster S9. It was revealed that hamster S9 had much higher deacetylation activities than rat S9, which accounts for the species difference. Then, my work was focused on molecular biology. We cloned the genes encoding nitroreductase and acetyltransferase in Salmonella typhimurium TA1538. Plasmids carrying these genes made strain TA98 more sensitive to mutagenic nitroarenes and aromatic amines. Because of their high sensitivity, the resulting strains such as YG1021 and YG1024 are widely used to monitor mutagenic nitroarenes and aromatic amines in complex mixtures. Later, we disrupted the genes encoding DNA polymerases in TA1538 and classified chemical mutagens into four classes depending on their use of different DNA polymerases. I was also involved in the generation of gpt delta transgenic rodent gene mutation assays, which examine the results of the Ames test in vivo. I have unintentionally developed my career under the influence of Dr. Ames and I would like to acknowledge his remarkable achievements in the field of environmental mutagenesis and carcinogenesis.

Mechanisms for Radioprotection by Melatonin; Can it be Used as a Radiation Countermeasure?

BACKGROUND

Melatonin is a natural body product that has shown potent antioxidant property against various toxic agents. For more than two decades, the abilities of melatonin as a potent radioprotector against toxic effects of ionizing radiation (IR) have been proved. However, in the recent years, several studies have been conducted to illustrate how melatonin protects normal cells against IR. Studies proposed that melatonin is able to directly neutralize free radicals produced by IR, leading to the production of some low toxic products.

DISCUSSION

Moreover, melatonin affects several signaling pathways, such as inflammatory responses, antioxidant defense, DNA repair response enzymes, pro-oxidant enzymes etc. Animal studies have confirmed that melatonin is able to alleviate radiation-induced cell death via inhibiting pro-apoptosis and upregulation of anti-apoptosis genes. These properties are very interesting for clinical radiotherapy applications, as well as mitigation of radiation injury in a possible radiation disaster. An interesting property of melatonin is mitochondrial ROS targeting that has been proposed as a strategy for mitigating effects in radiosensitive organs, such as bone marrow, gastrointestinal system and lungs. However, there is a need to prove the mitigatory effects of melatonin in experimental studies.

CONCLUSION

In this review, we aim to clarify the molecular mechanisms of radioprotective effects of melatonin, as well as possible applications as a radiation countermeasure in accidental exposure or nuclear/radiological disasters.

Mutagenicity of Helicobacter hepaticus infection in the lower bowel mucosa of 129/SvEv Rag2-/- Il10-/- gpt delta mice is influenced by sex

Inflammatory bowel disease and colonic tumors induced by Helicobacter hepaticus (Hh) infection in susceptible mouse strains are utilized to dissect the mechanisms underlying similar human diseases. In our study, infection with genotoxic cytolethal distending toxin-producing Hh in 129/SvEv Rag2^-/- Il10^-/- gpt delta (RagIl10gpt) mice of both sexes for 21 weeks induced significantly more severe cecal and colonic pathology compared to uninfected controls. The mutation frequencies in the infected RagIl10gpt males were 2.1-fold higher for the cecum and 1.7-fold higher for the colon than male RagIl10gpt controls. In addition, there was a 12.5-fold increase of G:C-to-T:A transversions in the colon of Hh-infected males compared to controls. In contrast, there was no statistical significance in mutation frequencies between infected female Rag2Il10gpt mice and controls. Moreover, Hh infection in RagIl10gpt males significantly up-regulated transcription of Tnfα and iNos, and decreased mRNA levels of cecal Atm compared to the infected females; there was no significant difference in mRNA levels of Il-22, Il-17A, Ifnγ and Atr between the infected males and females. Significantly higher levels of cecal and colonic iNos expression and γH2AX-positive epithelial cells (a biomarker for double-strand DNA breaks [DSB]) in Hh-infected Rag2Il10gpt males vs. Hh-infected females were noted. Finally, Hh infection and associated inflammation increased levels of intestinal mucosa-associated genotoxic colibactin-producing pks+ Escherichia coli. Elevated Tnfα and iNos responses and bacterial genotoxins, in concert with suppression of the DSB repair responses, may have promoted mutagenesis in the lower bowel mucosa of Hh-infected male RagIl10gpt mice.

Protective effects of the suppressed NF-κB/TLR4 signaling pathway on oxidative stress of lung tissue in rat with acute lung injury

The pathogenesis of acute lung injury (ALI) is characterized by lung inflammation and lung oxidative stress. The study was conducted in order to investigate the effect toll-like receptor 4 (TLR4) and nuclear factor-kappa B (NF-κB) exhibited on oxidative stress in ALI. After the rats had been assigned into different groups, arterial blood, white blood cell (WBC), lung permeability index (LPI), wet/dry (W/D) ratio, TLR4 and NF-κB expression and superoxide dismutase (SOD), myeloperoxidase (MPO), malondialdehyde (MDA), glutathione (GSH), and reactive oxygen species (ROS) were examined. Afterward, the correlation between the levels of TLR4 and NF-κB was determined. Decreased levels of PaO₂ , SOD, MPO, and GSH accompanied by increased levels of PaCO₂ , WBC number, LPI and W/D ratio, MDA and ROS, as well as TLR4 and NF-κB expressions in the ALI, ALI + NF-κB inhibitor, and ALI + phosphate buffer saline groups were found. Inhibition of NF-κB resulted in increased PaO₂ and decreased PaCO₂ levels, WBC number, and LPI and W/D ratio. Decreased expression of NF-κB increased SOD, GSH, and MPO, but decreased MDA and ROS. We also found that NF-κB inhibition resulted in the improvement of ALI in rats. TLR4 and NF-κB expressions were negatively correlated with levels of SOD, MPO, and GSH, and positively correlated with MDA and ROS levels. In summary, our findings provided evidence that inhibition of the TLR4/NF-κB signaling pathway decreases oxidative stress, thereby improving ALI. As a result, NF-κB signaling pathway has shown potential as a therapeutic target in ALI therapy.

Up-regulation of tumor necrosis factor-α pathway survival genes and of the receptor TNFR2 in gastric cancer

BACKGROUND

Gastric carcinogenesis can be induced by chronic inflammation triggered by Helicobacter pylori (H. pylori) infection. Tumor necrosis factor (TNF)-α and its receptors (TNFR1 and TNFR2) regulate important cellular processes, such as apoptosis and cell survival, and the disruption of which can lead to cancer. This signaling pathway is also modulated by microRNAs (miRNAs), altering gene expression.

AIM

To evaluate the mRNA and miRNAs expression involved in the TNF-α signaling pathway in gastric cancer (GC) tissues and its relationship.

METHODS

Quantitative polymerase chain reaction (qPCR) by TaqMan^® assay was used to quantify the RNA transcript levels of TNF-α signaling pathway (TNF, TNFR1, TNFR2, TRADD, TRAF2, CFLIP, NFKB1, NFKB2, CASP8, CASP3) and miRNAs that targets genes from this pathway (miR-19a, miR-34a, miR-103a, miR-130a, miR-181c) in 30 GC fresh tissue samples. Molecular diagnosis of H. pylori was performed by nested PCR for gene HSP60. A miRNA:mRNA interaction network was construct using Cytoscape v3.1.1 from the in silico analysis performed using public databases.

RESULTS

Up-regulation of cellular survival genes as TNF, TNFR2, TRADD, TRAF2, CFLIP, and NFKB2, besides CASP8 and miR-34a was observed in GC tissues, whereas mediators of apoptosis such as TNFR1 and CASP3 were down-regulated. When the samples were stratified by histological type, the expression of miR-103a and miR-130a was significantly increased in the diffuse-type of GC compared to the intestinal-type. However, no influence of H. pylori infection was observed on the expression levels of mRNA and miRNAs analyzed. Moreover, the miRNA:mRNA interaction network showed several interrelations between the miRNAs and their target genes, highlighting miR-19a and miR-103a, which has as predicted or validated target a large number of genes in the TNF-α pathway, including TNF, TNFR1, TNFR2, CFLIP, TRADD, CASP3 and CASP8.

CONCLUSION

Our findings show that cell survival genes mediated by TNF/TNFR2 binding is up-regulated in GC favoring its pro-tumoral effect, while pro-apoptotic genes as CASP3 and TNFR1 are down-regulated, indicating disbalance between apoptosis and cell proliferation processes in this neoplasm. This process can also be influenced by an intricate regulatory network of miRNA:mRNA.