Inducible Nitric Oxide Synthase in the Carcinogenesis of Gastrointestinal Cancers

Precision Oncology, Artificial Intelligence, and Novel Therapeutic Advancements in the Diagnosis, Prevention, and Treatment of Cancer: Highlights from the 59th Irish Association for Cancer Research (IACR) Annual Conference

Advancements in oncology, especially with the era of precision oncology, is resulting in a paradigm shift in cancer care. Indeed, innovative technologies, such as artificial intelligence, are paving the way towards enhanced diagnosis, prevention, and personalised treatments as well as novel drug discoveries. Despite excellent progress, the emergence of resistant cancers has curtailed both the pace and extent to which we can advance. By combining both their understanding of the fundamental biological mechanisms and technological advancements such as artificial intelligence and data science, cancer researchers are now beginning to address this. Together, this will revolutionise cancer care, by enhancing molecular interventions that may aid cancer prevention, inform clinical decision making, and accelerate the development of novel therapeutic drugs. Here, we will discuss the advances and approaches in both artificial intelligence and precision oncology, presented at the 59th Irish Association for Cancer Research annual conference.

The transcriptomic expression pattern of immune checkpoints shows heterogeneity between and within cancer types

Transcriptomic expression profiles of immune checkpoint markers are of interest in order to decipher the mechanisms of immunotherapy response and resistance. Overall, 514 patients with various solid tumors were retrospectively analyzed in this study. The RNA expression levels of tumor checkpoint markers (ADORA2A, BTLA, CD276, CTLA4, IDO1, IDO2, LAG3, NOS2, PD-1, PD-L1, PD-L2, PVR, TIGIT, TIM3, VISTA, and VTCN) were ranked from 0-100 percentile based on a reference population. The expression of each checkpoint was correlated with cancer type, microsatellite instability (MSI), tumor mutational burden (TMB), and programmed death-ligand 1 (PD-L1) by immunohistochemistry (IHC). The cohort included 30 different tumor types, with colorectal cancer being the most common (27%). When RNA percentile rank values were categorized as "Low" (0-24), "Intermediate" (25-74), and "High" (75-100), each patient had a distinctive portfolio of the categorical expression of 16 checkpoint markers. Association between some checkpoint markers and cancer types were observed; NOS2 showed significantly higher expression in colorectal and stomach cancer (P < 0.001). Principal component analysis demonstrated no clear association between combined RNA expression patterns of 16 checkpoint markers and cancer types, TMB, MSI or PD-L1 IHC. Immune checkpoint RNA expression varies from patient to patient, both within and between tumor types, though colorectal and stomach cancer showed the highest levels of NOS2, a mediator of inflammation and immunosuppression. There were no specific combined expression patterns correlated with MSI, TMB or PD-L1 IHC. Next generation immunotherapy trials may benefit from individual analysis of patient tumors as selection criteria for specific immunomodulatory approaches.

Nitric oxide inhibits ten-eleven translocation DNA demethylases to regulate 5mC and 5hmC across the genome

DNA methylation at cytosine bases of eukaryotic DNA (5-methylcytosine, 5mC) is a heritable epigenetic mark that can regulate gene expression in health and disease. Enzymes that metabolize 5mC have been well-characterized, yet the discovery of endogenously produced signaling molecules that regulate DNA methyl-modifying machinery have not been described. Herein, we report that the free radical signaling molecule nitric oxide (NO) can directly inhibit the Fe(II)/2-OG-dependent DNA demethylases ten-eleven translocation (TET) and human AlkB homolog 2 (ALKBH2). Physiologic NO concentrations reversibly inhibited TET and ALKBH2 demethylase activity by binding to the mononuclear non-heme iron atom which formed a dinitrosyliron complex (DNIC) preventing cosubstrates (2-OG and O2) from binding. In cancer cells treated with exogenous NO, or cells endogenously synthesizing NO, there was a global increase in 5mC and 5-hydroxymethylcytosine (5hmC) in DNA, the substrates for TET, that could not be attributed to increased DNA methyltransferase activity. 5mC was also elevated in NO-producing cell-line-derived mouse xenograft and patient-derived xenograft tumors. Genome-wide DNA methylome analysis of cells chronically treated with NO (10 days) demonstrated enrichment of 5mC and 5hmC at gene-regulatory loci which correlated to changes in the expression of NO-regulated tumor-associated genes. Regulation of DNA methylation is distinctly different from canonical NO signaling and represents a novel epigenetic role for NO.

Co-inhibition of TGF-β and PD-L1 pathways in a metastatic colorectal cancer mouse model triggers interferon responses, innate cells and T cells, alongside metabolic changes and tumor resistance

Colorectal cancer (CRC) is the third most prevalent cancer worldwide with a high mortality rate (20-30%), especially due to metastasis to adjacent organs. Clinical responses to chemotherapy, radiation, targeted and immunotherapies are limited to a subset of patients making metastatic CRC (mCRC) difficult to treat. To understand the therapeutic modulation of immune response in mCRC, we have used a genetically engineered mouse model (GEMM), "KPN", which resembles the human 'CMS4'-like subtype. We show here that transforming growth factor (TGF-β1), secreted by KPN organoids, increases cancer cell proliferation, and inhibits splenocyte activation in vitro. TGF-β1 also inhibits activation of naive but not pre-activated T cells, suggesting differential effects on specific immune cells. In vivo, the inhibition of TGF-β inflames the KPN tumors, causing infiltration of T cells, monocytes and monocytic intermediates, while reducing neutrophils and epithelial cells. Co-inhibition of TGF-β and PD-L1 signaling further enhances cytotoxic CD8+T cells and upregulates innate immune response and interferon gene signatures. However, simultaneous upregulation of cancer-related metabolic genes correlated with limited control of tumor burden and/or progression despite combination treatment. Our study illustrates the importance of using GEMMs to predict better immunotherapies for mCRC.

NOS2 Polymorphism in Aspect of Left and Right-Sided Colorectal Cancer

Background: The NOS2 gene polymorphism rs2297518 is associated with an increased level of NO, which could contribute to colorectal cancer (CRC) development. We hypothesized that the potential influence of the NOS2 gene polymorphism on cancer development may vary between right-sided and left-sided colon cancers, and rectal cancers. The aim of this study was to determine the rs2297518 polymorphism influence on colorectal cancer development with regard to tumor localization. Methods: This case-control study included 199 patients with CRC and 120 controls. The qPCR endpoint genotyping was conducted using the TaqMan® genotyping assay. Results: This study revealed significant differences in tumor characteristic and in the minor alelle A frequency in the NOS2 genotype between colorectal cancers with different localizations. The mucinous adenocarcinoma was diagnosed significantly more often in right-sided cancers than in left-sided (30.6% vs. 10.9%, p = 0.009) and rectal cancers (30.6% vs. 7.1%, p = 0.0003). The minor allele A of the NOS2 genotype was observed more frequently in right-sided cancers than in left-sided cancers (44.9% vs. 23.1%, p = 0.0137) and more frequently in rectal cancers than in left-sided cancers (40.0% vs. 23.1%, p = 0.0285). Conclusions: In conclusion, the results support the hypothesis that the SNP rs2297518 of the NOS2 gene influences colorectal cancer development with regard to tumor localization.

All That Glitters Is Not Gold: Assessment of Bee Pollen Supplementation Effects on Gastric Mucosa

The aim of this study was to assess the influence of bee pollen supplementation on the levels of enzymes important for gastric mucosal homeostasis, namely cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), and a biomarker-asymmetric dimethylarginine (ADMA)-in the gastric mucosa of Wistar rats. The experimental phase divided the rats into four groups: two control groups, sedentary and active, both not supplemented, and two experimental groups, sedentary and active, supplemented with bee pollen. The results indicated that bee pollen supplementation reduced the levels of COX-1 and elevated iNOS levels, while showing no significant impact on COX-2 levels. These findings do not conclusively support the gastroprotective and anti-inflammatory effects of bee pollen on gastric mucosa. However, the supplementation could have resulted in reduced ADMA levels in the physically active supplemented group. Our study does not unequivocally demonstrate the positive effects of bee pollen supplementation on the gastric mucosa, which may be attributed to the specific metabolism and bioavailability of substances within unprocessed, dried bee pollen. Further research should explore the topic of potential therapeutic applications of bee pollen in gastrointestinal health and its interactions with ADMA signaling pathways.

Unveiling pathogenic mutations in BRCA1 and BRCA2 genes across head and neck squamous cell carcinoma patients via next generation sequencing

Head and Neck Squamous Cell Carcinoma (HNSC) presents a formidable challenge in the field of oncology due to its aggressive nature and the limited therapeutic options available. In this study, our primary focus was on the Pakistani HNSC patient population, aiming to investigate germline oncogenic mutations within the BRCA1 and BRCA2 genes via Next Generation Sequencing (NGS) and explore their clinical implications. We sought to understand the functional consequences of these mutations via RT-qPCR and Immunohistochemistry (IHC) techniques. The key discovery of our research lies in the identification of three pathogenic mutations, including two within BRCA1 (p.Cys274Ter and p.Glu272Ter) and one within BRCA2 (p.Met1Val), among Pakistani HNSC patients. These mutations previously associated with an increased risk of various cancers. What sets our study apart is the uniqueness of these pathogenic mutations, absent in HNSC patients from other populations. This suggests a distinct genetic profile in Pakistani HNSC patients, possibly contributing to their susceptibility to this malignancy. Furthermore, our research revealed elevated expression levels of BRCA1 and BRCA2 genes in HNSC samples harboring pathogenic mutations, offering insights into mechanisms driving tumor progression in HNSC. Importantly, we identified significant enrichment of BRCA1/2 genes in pathways related to cancer development within the KEGG database. Finally, in our quest to explore therapeutic avenues, we systematically analyzed drugs targeting up-regulated and mutated BRCA1/2 genes, identifying promising candidates for tailored treatment modalities in HNSC. In conclusion, our study reveals the unique genetic profile of HNSC in Pakistani patients, featuring unique pathogenic mutations in BRCA1 and BRCA2 genes. These mutations offer promise as valuable diagnostic markers and potential therapeutic targets.

Nitric oxide inhibits FTO demethylase activity to regulate N6-methyladenosine mRNA methylation

N6-methyladenosine (m6A) is the most abundant internal modification on eukaryotic mRNAs. Demethylation of m6A on mRNA is catalyzed by the enzyme fat mass and obesity-associated protein (FTO), a member of the nonheme Fe(II) and 2-oxoglutarate (2-OG)-dependent family of dioxygenases. FTO activity and m6A-mRNA are dysregulated in multiple diseases including cancers, yet endogenous signaling molecules that modulate FTO activity have not been identified. Here we show that nitric oxide (NO) is a potent inhibitor of FTO demethylase activity by directly binding to the catalytic iron center, which causes global m6A hypermethylation of mRNA in cells and results in gene-specific enrichment of m6A on mRNA of NO-regulated transcripts. Both cell culture and tumor xenograft models demonstrated that endogenous NO synthesis can regulate m6A-mRNA levels and transcriptional changes of m6A-associated genes. These results build a direct link between NO and m6A-mRNA regulation and reveal a novel signaling mechanism of NO as an endogenous regulator of the epitranscriptome.

Pharmacological effects of mTORC1/C2 inhibitor in a preclinical model of NASH progression

Knowledge of the benefits of mTOR inhibition concerning adipogenesis and inflammation has recently encouraged the investigation of a new generation of mTOR inhibitors for non-alcoholic steatohepatitis (NASH). We investigated whether treatment with a specific mTORC1/C2 inhibitor (Ku-0063794; KU) exerted any beneficial impacts on experimentally-induced NASH in vitro and in vivo. The results indicated that KU decreases palmitic acid-induced lipotoxicity in cultivated primary hepatocytes, thus emerging as a successful candidate for testing in an in vivo NASH dietary model, which adopted the intraperitoneal KU dosing route rather than oral application due to its significantly greater bioavailability in mice. The pharmacodynamics experiments commenced with the feeding of male C57BL/6 mice with a high-fat atherogenic western-type diet (WD) for differing intervals over several weeks aimed at inducing various phases of NASH. In addition to the WD, the mice were treated with KU for 3 weeks or 4 months. Acute and chronic KU treatments were observed to be safe at the given concentrations with no toxicity indications in the mice. KU was found to alleviate NASH-related hepatotoxicity, mitochondrial and oxidative stress, and decrease the liver triglyceride content and TNF-α mRNA in at least one set of in vivo experiments. The KU modulated liver expression of selected metabolic and oxidative stress-related genes depended upon the length and severity of the disease. Although KU failed to completely reverse the histological progression of NASH in the mice, we demonstrated the complexity of mTORC1/C2 signaling regulation and suggest a stratified therapeutic management approach throughout the disease course.

CS-NO suppresses inhibits glycolysis and gastric cancer progression through regulating YAP/TAZ signaling pathway

CONTEXT

Gastric cancer (GC) is a significant contributor to global mortality and is recognized for its elevated prevalence and fatality rates. Nitric Oxide (NO) plays a role in multiple aspects of cancer metastasis and progression. CS-NO is a polysaccharide-based biomaterial with NO-releasing properties that shows promising therapeutic potential. Nonetheless, the action mechanism of CS-NO in GC is still largely unclear.

METHODS

The present study employed various experimental techniques, including CCK-8 assay, colony formation assay, EdU staining, and transwell assays, to evaluate the proliferation, migration, and invasion of GC cells. Additionally, ELISA was utilized to measure glucose uptake, lactate production, and cellular ATP levels in GC cells. In vivo investigations on nude mice were conducted to validate the in vitro results.

OBJECTIVE

The present study aimed to examine the potential anti-tumor properties of CS-NO on GC through in vitro and in vivo investigations, while also exploring the underlying mechanisms involved.

RESULTS

Our data suggested that CS-NO might prevent GC cell invasion and migration. Decreased expressions of GLUT1, HK2, and LDHA further demonstrated that CS-NO significantly suppressed aerobic glycolysis in GC cells. The administration of CS-NO resulted in a significant reduction of YAP and TAZ levels in GC cells. Our data further show that CS-NO treatment could inhibit GC cancer growth in mice, consistent with the significant decrease in Ki67, GLUT1 and YAP expression levels.

DISCUSSION AND CONCLUSION

These findings could reveal the good effects of CS-NO therapy on inhibiting GC.

IL-1β transgenic mouse model of inflammation driven esophageal and oral squamous cell carcinoma

Chronic inflammation is integral to the development of esophageal adenocarcinoma (EAC) and esophageal squamous cell carcinoma (ESCC), although the latter has not been associated with reflux esophagitis. The L2-IL-1β transgenic mice, expressing human interleukin (IL)-1β in the oral, esophageal and forestomach squamous epithelia feature chronic inflammation and a stepwise development of Barrett's esophagus-like metaplasia, dysplasia and adenocarcinoma at the squamo-columnar junction. However, the functional consequences of IL-1β-mediated chronic inflammation in the oral and esophageal squamous epithelia remain elusive. We report for the first time that in addition to the previously described Barrett's esophagus-like metaplasia, the L2-IL-1β mice also develop squamous epithelial dysplasia with progression to squamous cell carcinoma (SCC) in the esophagus and the tongue. L2-IL-1β showed age-dependent progression of squamous dysplasia to SCC with approximately 40% (n = 49) and 23.5% (n = 17) incidence rates for esophageal and tongue invasive SCC respectively, by 12-15 months of age. Interestingly, SCC development and progression in L2-IL-1β was similar in both Germ Free (GF) and Specific Pathogen Free (SPF) conditions. Immunohistochemistry revealed a T cell predominant inflammatory profile with enhanced expression of Ki67, Sox2 and the DNA double-strand break marker, γ-H2AX, in the dysplastic squamous epithelia of L2-IL-1β mice. Pro-inflammatory cytokines, immunomodulatory players, chemoattractants for inflammatory cells (T cells, neutrophils, eosinophils, and macrophages) and oxidative damage marker, iNOS, were significantly increased in the esophageal and tongue tissues of L2-IL-1β mice. Our recent findings have expanded the translational utility of the IL-1β mouse model to aid in further characterization of the key pathways of inflammation driven BE and EAC as well as ESCC and Oral SCC.

Inactivation of interleukin-30 in colon cancer stem cells via CRISPR/Cas9 genome editing inhibits their oncogenicity and improves host survival

BACKGROUND

Progression of colorectal cancer (CRC), a leading cause of cancer-related death worldwide, is driven by colorectal cancer stem cells (CR-CSCs), which are regulated by endogenous and microenvironmental signals. Interleukin (IL)-30 has proven to be crucial for CSC viability and tumor progression. Whether it is involved in CRC tumorigenesis and impacts clinical behavior is unknown.

METHODS

IL30 production and functions, in stem and non-stem CRC cells, were determined by western blot, immunoelectron microscopy, flow cytometry, cell viability and sphere formation assays. CRISPR/Cas9-mediated deletion of the IL30 gene, RNA-Seq and implantation of IL30 gene transfected or deleted CR-CSCs in NSG mice allowed to investigate IL30's role in CRC oncogenesis. Bioinformatics and immunopathology of CRC samples highlighted the clinical implications.

RESULTS

We demonstrated that both CR-CSCs and CRC cells express membrane-anchored IL30 that regulates their self-renewal, via WNT5A and RAB33A, and/or proliferation and migration, primarily by upregulating CXCR4 via STAT3, which are suppressed by IL30 gene deletion, along with WNT and RAS pathways. Deletion of IL30 gene downregulates the expression of proteases, such as MMP2 and MMP13, chemokine receptors, mostly CCR7, CCR3 and CXCR4, and growth and inflammatory mediators, including ANGPT2, CXCL10, EPO, IGF1 and EGF. These factors contribute to IL30-driven CR-CSC and CRC cell expansion, which is abrogated by their selective blockade. IL30 gene deleted CR-CSCs displayed reduced tumorigenicity and gave rise to slow-growing and low metastatic tumors in 80% of mice, which survived much longer than controls. Bioinformatics and CIBERSORTx of the 'Colorectal Adenocarcinoma TCGA Nature 2012' collection, and morphometric assessment of IL30 expression in clinical CRC samples revealed that the lack of IL30 in CRC and infiltrating leucocytes correlates with prolonged overall survival.

CONCLUSIONS

IL30 is a new CRC driver, since its inactivation, which disables oncogenic pathways and multiple autocrine loops, inhibits CR-CSC tumorigenicity and metastatic ability. The development of CRISPR/Cas9-mediated targeting of IL30 could improve the current therapeutic landscape of CRC.

Phenolic Phytochemicals for Prevention and Treatment of Colorectal Cancer: A Critical Evaluation of In Vivo Studies

Colorectal cancer (CRC) is the third most diagnosed and second leading cause of cancer-related death worldwide. Limitations with existing treatment regimens have demanded the search for better treatment options. Different phytochemicals with promising anti-CRC activities have been reported, with the molecular mechanism of actions still emerging. This review aims to summarize recent progress on the study of natural phenolic compounds in ameliorating CRC using in vivo models. This review followed the guidelines of the Preferred Reporting Items for Systematic Reporting and Meta-Analysis. Information on the relevant topic was gathered by searching the PubMed, Scopus, ScienceDirect, and Web of Science databases using keywords, such as "colorectal cancer" AND "phenolic compounds", "colorectal cancer" AND "polyphenol", "colorectal cancer" AND "phenolic acids", "colorectal cancer" AND "flavonoids", "colorectal cancer" AND "stilbene", and "colorectal cancer" AND "lignan" from the reputed peer-reviewed journals published over the last 20 years. Publications that incorporated in vivo experimental designs and produced statistically significant results were considered for this review. Many of these polyphenols demonstrate anti-CRC activities by inhibiting key cellular factors. This inhibition has been demonstrated by antiapoptotic effects, antiproliferative effects, or by upregulating factors responsible for cell cycle arrest or cell death in various in vivo CRC models. Numerous studies from independent laboratories have highlighted different plant phenolic compounds for their anti-CRC activities. While promising anti-CRC activity in many of these agents has created interest in this area, in-depth mechanistic and well-designed clinical studies are needed to support the therapeutic use of these compounds for the prevention and treatment of CRC.

Downregulation of iNOS/NO Promotes Epithelial-Mesenchymal Transition and Metastasis in Colorectal Cancer

Metastasis is the major cause of cancer-related death in patients with colorectal cancer. Although inducible nitric oxide synthase (iNOS) is a crucial regulator of cancer development and progression, its roles in epithelial-mesenchymal transition (EMT) and the pathogenesis of metastatic colorectal cancer have not been fully investigated. Primary colorectal cancer and liver metastatic tissue specimens were analyzed showing 90% of liver metastatic colorectal cancer with reduced expressions of iNOS compared with 6% of primary colorectal cancer. The Cancer Genome Atlas database analyses via cBioPortal reveal that mRNA expression of iNOS negatively correlated with selected EMT markers in colorectal cancer in a cancer type-dependent manner. The transcriptomic profiling (RNA sequencing data) indicates that iNOS knockdown in SW480 colorectal cancer cells induced an EMT program with upregulated expression of selected stem-cell markers. iNOS knockdown did not alter E-cadherin mRNA expression but re-localized it from membrane to cytoplasm through iNOS-GATA4-Crb2-E-cadherin pathway. iNOS knockdown induced a change in cell morphology, and promoted cell invasion and migration in vitro, and metastasis in vivo.

IMPLICATIONS

iNOS downregulation-induced pathway networks mediate the EMT program and metastasis. As an EMT inducer, the reduced-iNOS may serve as a potential therapeutic target for patients with colorectal cancer.

Identification and verification of ferroptosis-related genes in gastric intestinal metaplasia

Background: Gastric intestinal metaplasia (IM) is the key link of gastric precancerous lesions. Ferroptosis is a novel form of programmed cell death. However, its impact on IM is unclear. The focus of this study is to identify and verify ferroptosis-related genes (FRGs) that may be involved in IM by bioinformatics analysis. Materials and methods: Differentially expressed genes (DEGs) were obtained from microarray dataset GSE60427 and GSE78523 downloaded from Gene Expression Omnibus (GEO) database. Differentially expressed ferroptosis-related genes (DEFRGs) were obtained from overlapping genes of DEGs and FRGs got from FerrDb. DAVID database was used for functional enrichment analysis. Protein-protein interaction (PPI) analysis and Cytoscape software were used to screen hub gene. In addition, we built a receiver operating characteristic (ROC) curve and verified the relative mRNA expression by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Finally, the CIBERSORT algorithm was used to analyze the immune infiltration in IM. Results: First, a total of 17 DEFRGs were identified. Second, a gene module identified by Cytoscape software was considered as hub gene: PTGS2, HMOX1, IFNG, and NOS2. Third, ROC analysis showed that HMOX1 and NOS2 had good diagnostic characteristics. qRT-PCR experiments confirmed the differential expression of HMOX1 in IM and normal gastric tissues. Finally, immunoassay showed that the proportion of T cells regulatory (Tregs) and macrophages M0 in IM was relatively higher, while the proportion of T cells CD4 memory activated and dendritic cells activated was lower. Conclusion: We found significant associations between FRGs and IM, and HMOX1 may be diagnostic biomarkers and therapeutic targets for IM. These results may enhance our understanding of IM and may contribute to its treatment.

Inflammation-targeted nanomedicine against brain cancer: From design strategies to future developments

Brain cancer is an aggressive type of cancer with poor prognosis. While the immune system protects against cancer in the early stages, the tumor exploits the healing arm of inflammatory reactions to accelerate its growth and spread. Various immune cells penetrate the developing tumor region, establishing a pro-inflammatory tumor milieu. Additionally, tumor cells may release chemokines and cytokines to attract immune cells and promote cancer growth. Inflammation and its associated mechanisms in the progression of cancer have been extensively studied in the majority of solid tumors, especially brain tumors. However, treatment of the malignant brain cancer is hindered by several obstacles, such as the blood-brain barrier, transportation inside the brain interstitium, inflammatory mediators that promote tumor growth and invasiveness, complications in administering therapies to tumor cells specifically, the highly invasive nature of gliomas, and the resistance to drugs. To resolve these obstacles, nanomedicine could be a potential strategy that has facilitated advancements in diagnosing and treating brain cancer. Due to the numerous benefits provided by their small size and other features, nanoparticles have been a prominent focus of research in the drug-delivery field. The purpose of this article is to discuss the role of inflammatory mediators and signaling pathways in brain cancer as well as the recent advances in understanding the nano-carrier approaches for enhancing drug delivery to the brain in the treatment of brain cancer.

Nanoparticles for active combination radio mitigating agents of zinc coumarate and zinc caffeinate in a rat model

Zinc coumarate and zinc caffeinate nanoparticles (ZnCoNPs, ZnCaNPs) affect different biological processes. This study aimed to evaluate the mitigating action of ZnCoNPs in combination with ZnCaNPs against liver damage induced by gamma rays (γ-rays). Rats were exposed to 7 Gy of γ-rays and then injected intraperitoneally (i.p) with ZnCoNPs [2U/rat/day (5 mg/kg)] and ZnCaNPs [2U/rat/day (15 mg/kg)] for 7 consecutive days. The results showed that irradiated rats treated with ZnCoNPs (5 mg/kg/body weight) in combination with ZnCaNPs (15 mg/kg/body weight) for 7 days had a significant increases in body weight, antioxidant levels, T helper cell 4 (cluster of differentiation 4 (CD4)), and T cytotoxic cell 8 (cluster of differentiation 8 (CD8)), associated with a marked decrease in lipid peroxidation (LP), nitric oxide(NOx), total free radicals concentrate (TFRC), and DNA fragmentation. There were positive alterations in the morphological state, hematological parameters and the cell cycle phases. Additionally, the histopathological study demonstrated an improvement in the liver tissue of irradiated rats after treatment. Thus, ZnCoNPs and ZnCaNPs could be used as natural mitigating agents to reduce the hazards of ionizing radiation.

Prognostic and Predictive Models for Left- and Right- Colorectal Cancer Patients: A Bioinformatics Analysis Based on Ferroptosis-Related Genes

Background

Left- and right-sided colorectal cancer (LCRC, RCRC) are significantly different in epidemiology and clinical manifestations and have altered outcomes. However, as a hot tumor prognostic marker, the role of ferroptosis-related genes (FRGs) in LCRC and RCRC is unknown.

Methods

From The Cancer Genome Atlas (TCGA) database, we downloaded the expression profiles of CRC patients. A "DESeq2" package was performed to compare the differentially expressed genes (DEGs) of LCRC and RCRC. FRGs were identified using the FerrDb. The prognostic value of differentially expressed FRG (DE-FRG) in left- and right-CRC was assessed separately by Cox regression analysis. Subsequently, functional enrichment analysis, ESTIMATE, and single sample Gene Set Enrichment Analysis (ssGSEA) were performed based on LCRC and RCRC samples to reveal the potential function of FRGs-related risk signatures. The differential expression of FRGs in tumor tissues and adjacent normal tissues were verified by Western blot. The differential expression and prognosis in LCC and RCC were verified by immunohistochemistry.

Results

Based on the identified 14 DE-FRGs, the LCRC prognostic model consisted of NOS2 and IFNG; NOS2 and ALOXE established the prognostic signature that could distinguish RCRC outcomes. In the functional analysis, the DEGs (high risk vs. low risk) of the LCRC and RCRC were significantly enriched in the immune- and lipid-related terms and pathways. ESTIMATE and ssGSEA suggested that these FRGs-related risk signatures were affiliated with the infiltration of immune cell subtypes. Western blotting results showed that NOS2 and ALOXE3 were significantly highly expressed in cancer, and the difference was statistically significant (P < 0.05). Immunohistochemical results showed that ALOXE3 was highly expressed in RCC, and those with high expression had a worse prognosis, while NOS2 gene had an effect on the prognosis of both LCC and RCC.

Conclusion

This study constructed a potential prognostic model of LCRC and RCRC, respectively. We also identified the crucial pathways that contribute to elucidating the pathogenesis of CRC.

Profile of Myracrodruon urundeuva Volatile Compounds Ease of Extraction and Biodegradability and In Silico Evaluation of Their Interactions with COX-1 and iNOS

Myracrodruon urundeuva Fr. Allem. (Anacardiaceae) is a tree popularly known as the "aroeira-do-sertão", native to the caatinga and cerrado biomes, with a natural dispersion ranging from the Northeast, Midwest, to Southeast Brazil. Its wood is highly valued and overexploited, due to its characteristics such as durability and resistance to decaying. The diversity of chemical constituents in aroeira seed has shown biological properties against microorganisms and helminths. As such, this work aimed to identify the profile of volatile compounds present in aroeira seeds. Headspace solid phase microextraction was employed (HS-SPME) using semi-polar polydimethylsiloxane-divinylbenzene fiber (PDMS/DVB) for the extraction of VOCs. 22 volatile organic compounds were identified: nine monoterpenes and eight sesquiterpenes, in addition to six compounds belonging to different chemical classes such as fatty acids, terpenoids, salicylates and others. Those that stood out were p-mentha-1,4, 4(8)-diene, 3-carene (found in all samples), caryophyllene and cis-geranylacetone. A virtual docking analysis suggested that around 65% of the VOCs molar content from the aroeiras seeds present moderate a strong ability to bind to cyclooxygenase I (COX-I) active site, oxide nitric synthase (iNOS) active site (iNOSas) or to iNOS cofactor site (iNOScs), corroborating an anti-inflamatory potential. A pharmacophoric descriptor analysis allowed to infer the more determinant characteristics of these compounds' conferring affinity to each site. Taken together, our results illustrate the high applicability for the integrated use of SPME, in silico virtual screening and chemoinformatics tools at the profiling of the biotechnological and pharmaceutical potential of natural sources.

Macrophage Reprogramming and Cancer Therapeutics: Role of iNOS-Derived NO

Nitric oxide and its production by iNOS is an established mechanism critical to tumor promotion or suppression. Macrophages have important roles in immunity, development, and progression of cancer and have a controversial role in pro- and antitumoral effects. The tumor microenvironment consists of tumor-associated macrophages (TAM), among other cell types that influence the fate of the growing tumor. Depending on the microenvironment and various cues, macrophages polarize into a continuum represented by the M1-like pro-inflammatory phenotype or the anti-inflammatory M2-like phenotype; these two are predominant, while there are subsets and intermediates. Manipulating their plasticity through programming or reprogramming of M2-like to M1-like phenotypes presents the opportunity to maximize tumoricidal defenses. The dual role of iNOS-derived NO also influences TAM activity by repolarization to tumoricidal M1-type phenotype. Regulatory pathways and immunomodulation achieve this through miRNA that may inhibit the immunosuppressive tumor microenvironment. This review summarizes the classical physiology of macrophages and polarization, iNOS activities, and evidence towards TAM reprogramming with current information in glioblastoma and melanoma models, and the immunomodulatory and therapeutic options using iNOS or NO-dependent strategies.

Knockdown of the inducible nitric oxide synthase (NOS2) splicing variant S3 promotes autophagic cell death from nitrosative stress in SW480 human colon cancer cells

Low levels of nitric oxide (NO) produced by constitutively expressed inducible NO synthase (NOS2) in tumor cells may be an important factor in their development. NOS2 expression is associated with high mortality rates for various cancers. Alternative splicing of NOS2 down-regulates its enzymatic activity, resulting in decreased intracellular NO concentrations. Specific probes to detect alternative splicing of NOS2 were used in two isogenic human colon cancer cell lines derived either from the primary tumor (SW480) or from a lymph node metastasis (SW620). Splicing variant of NOS2 S3, lacking exons 9, 10, and 11, was overexpressed in SW480 cells. NOS2 S3 was silenced in SW480 cells. Flow-cytometry analysis was used to estimate the intracellular NO levels and to analyze the cell cycle of the studied cell lines. Western blot analysis and quantitative real-time polymerase chain reaction (qRT-PCR) were used to determine apoptosis and autophagy markers. SW480 and SW620 cells expressed NOS2 S3. Overexpression of the NOS2 S3 in SW480 cells downregulated intracellular NO levels. SW480 cells with knocked down NOS2 S3 (referred to as S3C9 cells) had higher intracellular levels of NO compared to the wild-type SW480 cells under serum restriction. Higher NO levels resulted in the loss of viability of S3C9 cells, which was associated with autophagy. Induction of autophagy by elevated intracellular NO levels in S3C9 cells under serum restriction, suggests that autophagy operates as a cytotoxic response to nitrosative stress. The expression of NOS2 S3 plays an important role in regulating intracellular NO production and maintaining viability in SW480 cells under serum restriction. These findings may prove significant in the design of NOS2/NO-based therapies for colon cancer.

Albumin-encapsulated Nanoparticles of Naproxen Platinum(IV) Complexes with Inflammation Inhibitory Competence Displaying Effective Antitumor Activities in vitro and in vivo

BACKGROUND

Platinum(IV) complexes with inflammation inhibitory properties are much favored in improving antitumor activities. Nanodrug-delivery system as a preferable measure for antitumor therapy are widely explored in platinum(IV) drug delivery.

PURPOSE

The aim for this study was to develop novel bovine serum albumin (BSA) nanoparticles (NPs) based on naproxen platinum(IV) complexes to display a synergistic antitumor mechanism targeting cyclooxygenase-2 (COX-2), metalloproteinase-9 (MMP-9) and inducible nitric oxide synthase (iNOS).

METHODS

Herein, we reported the preparation of two BSA NPs of naproxen platinum(IV) complexes, and their antitumor activities were investigated in vitro and in vivo.

RESULTS

Both NPs possessed relatively uniform size and good stability for 30 days in aqueous solution. They exhibited prominent antitumor activities in vitro, and showed great potential in reversing drug resistance. Furthermore, these two NPs played superior tumor growth suppression in vivo in contrast to the free compounds, which were comparable to that of cisplatin and oxaliplatin, but induced lower toxic influences than platinum(II) drugs especially to spleen and liver. Moreover, the naproxen platinum(IV) NPs could decrease tumor inflammation targeting COX-2, MMP-9 and iNOs, and decreasing NO production, which would be in favor of enhancing the antitumor competence, and reducing toxicity.

CONCLUSION

Taken together, BSA NPs of naproxen platinum(IV) complexes demonstrated a powerful antitumor efficacy in vitro and in vivo. The platinum(IV) NPs with inflammation inhibitory competence targeting multiple enzymes reported in this work afford a new strategy for the development of antitumor therapy to overcome drawbacks of clinical platinum(II) drugs.

Sitagliptin Modulates Oxidative, Nitrative and Halogenative Stress and Inflammatory Response in Rat Model of Hepatic Ischemia-Reperfusion

A possibility of repurposing sitagliptin, a well-established antidiabetic drug, for alleviating injury caused by ischemia-reperfusion (IR) is being researched. The aim of this study was to shed some light on the molecular background of the protective activity of sitagliptin during hepatic IR. The expression and/or concentration of inflammation and oxidative stress-involved factors have been determined in rat liver homogenates using quantitative RT-PCR and Luminex^® xMAP^® technology and markers of nitrative and halogenative stress were quantified using targeted metabolomics (LC-MS/MS). Animals (n = 36) divided into four groups were treated with sitagliptin (5 mg/kg) (S and SIR) or saline solution (C and IR), and the livers from IR and SIR were subjected to ischemia (60 min) and reperfusion (24 h). The midkine expression (by 2.2-fold) and the free 3-nitrotyrosine (by 2.5-fold) and IL-10 (by 2-fold) concentration were significantly higher and the Nox4 expression was lower (by 9.4-fold) in the IR than the C animals. As compared to IR, the SIR animals had a lower expression of interleukin-6 (by 4.2-fold) and midkine (by 2-fold), a lower concentration of 3-nitrotyrosine (by 2.5-fold) and a higher Nox4 (by 2.9-fold) and 3-bromotyrosine (by 1.4-fold). In conclusion, IR disturbs the oxidative, nitrative and halogenative balance and aggravates the inflammatory response in the liver, which can be attenuated by low doses of sitagliptin.

Current Advances of Nitric Oxide in Cancer and Anticancer Therapeutics

Nitric oxide (NO) is a short-lived, ubiquitous signaling molecule that affects numerous critical functions in the body. There are markedly conflicting findings in the literature regarding the bimodal effects of NO in carcinogenesis and tumor progression, which has important consequences for treatment. Several preclinical and clinical studies have suggested that both pro- and antitumorigenic effects of NO depend on multiple aspects, including, but not limited to, tissue of generation, the level of production, the oxidative/reductive (redox) environment in which this radical is generated, the presence or absence of NO transduction elements, and the tumor microenvironment. Generally, there are four major categories of NO-based anticancer therapies: NO donors, phosphodiesterase inhibitors (PDE-i), soluble guanylyl cyclase (sGC) activators, and immunomodulators. Of these, NO donors are well studied, well characterized, and also the most promising. In this study, we review the current knowledge in this area, with an emphasis placed on the role of NO as an anticancer therapy and dysregulated molecular interactions during the evolution of cancer, highlighting the strategies that may aid in the targeting of cancer.

Sleep loss mediates the effect of stress on nitrergic signaling in female mice

Nitric oxide (NO) has been implicated as an important neurotransmitter in stress responses and sleep regulatory processes. However, the role of NO in the relationship between stress and sleep remains unclear. The medial septum (MS) and vertical diagonal band (VDB), regions of the basal forebrain involved in sleep regulation, contain nitric oxide synthase (NOS) producing neurons. Additionally, NOS neurons in the dorsal raphe nucleus (DRN) encode information about stress duration. The role of nitrergic neurons in these regions in subserving sex-specific responses to stress and sleep loss has yet to be elucidated. In this study, NADPH-d, an index of NOS activity, was used to examine the effects of acute restraint stress and sleep loss on NOS activity in the MS, VDB, and DRN. We show that NOS activity in response to restraint stress, total sleep deprivation (TSD), and partial sleep restriction (PSR) differs based on sex and region. Initial analysis showed no effect of restraint stress or TSD on NOS activity in the basal forebrain. However, investigation of each sex separately revealed that restraint stress and TSD significantly decrease NOS activity in the MS of females, but not males. Interestingly, the difference in NOS activity between restraint stress and TSD in females was not significant. Furthermore, PSR was not sufficient to affect NOS activity in males or females. These data suggest that restraint stress and sleep loss regulate NOS activation in a sex-dependent manner, and that the NOS stress response in females may be mediated by sleep loss.

Simultaneous LC-MS/MS-Based Quantification of Free 3-Nitro-l-tyrosine, 3-Chloro-l-tyrosine, and 3-Bromo-l-tyrosine in Plasma of Colorectal Cancer Patients during Early Postoperative Period

Quantification with satisfactory specificity and sensitivity of free 3-Nitro-l-tyrosine (3-NT), 3-Chloro-l-tyrosine (3-CT), and 3-Bromo-l-tyrosine (3-BT) in biological samples as potential inflammation, oxidative stress, and cancer biomarkers is analytically challenging. We aimed at developing a liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based method for their simultaneous analysis without an extract purification step by solid-phase extraction. Validation of the developed method yielded the following limits of detection (LOD) and quantification (LOQ) for 3-NT, 3-BT, and 3-CT: 0.030, 0.026, 0.030 ng/mL (LODs) and 0.100, 0.096, 0.098 ng/mL (LOQs). Coefficients of variation for all metabolites and tested concentrations were <10% and accuracy was within 95-105%. Method applicability was tested on colorectal cancer patients during the perioperative period. All metabolites were significantly higher in cancer patients than healthy controls. The 3-NT was significantly lower in advanced cancer and 3-BT showed a similar tendency. Dynamics of 3-BT in the early postoperative period were affected by type of surgery and presence of surgical site infections. In conclusion, a sensitive and specific LC-MS/MS method for simultaneous quantification of free 3-NT, 3-BT, and 3-CT in human plasma has been developed.

Chemopreventive Effect of Dietary Anthocyanins against Gastrointestinal Cancers: A Review of Recent Advances and Perspectives

Anthocyanins are a group of dietary polyphenols, abundant mainly in fruits and their products. Dietary interventions of anthocyanins are being studied extensively related to the prevention of gastrointestinal (GI) cancer, among many other chronic disorders. This review summarizes the hereditary and non-hereditary characteristics of GI cancers, chemistry, and bioavailability of anthocyanins, and the most recent findings of anthocyanin in GI cancer prevention through modulating cellular signaling pathways. GI cancer-preventive attributes of anthocyanins are primarily due to their antioxidative, anti-inflammatory, and anti-proliferative properties, and their ability to regulate gene expression and metabolic pathways, as well as induce the apoptosis of cancer cells.

Health-Promoting Effects of Thymus Phenolic-Rich Extracts: Antioxidant, Anti-Inflammatory and Antitumoral Properties

Thymus genus comprises numerous species that are particularly abundant in the West Mediterranean region. A growing body of evidence suggests that many of these species are a rich source of bioactive compounds, including phenolic compounds such as rosmarinic acid, salvianolic acids and luteolin glycosides, able to render them potential applications in a range of industrial fields. This review collects the most relevant studies focused on the antioxidant, anti-inflammatory and anti-cancer of phenolic-rich extracts from Thymus plants, highlighting correlations made by the authors with respect to the main phenolic players in such activities.

The Mechanism of Bacteroides fragilis Toxin Contributes to Colon Cancer Formation

The Bacteroides fragilis (B. fragilis) produce biofilm for colonisation in the intestinal tract can cause a series of inflammatory reactions due to B. fragilis toxin (BFT) which can lead to chronic intestinal inflammation and tissue injury and play a crucial role leading to colorectal cancer (CRC). The enterotoxigenic B. fragilis (ETBF) forms biofilm and produce toxin and play a role in CRC, whereas the non-toxigenic B. fragilis (NTBF) does not produce toxin. The ETBF triggers the expression of cyclooxygenase (COX)-2 that releases PGE2 for inducing inflammation and control cell proliferation. From chronic intestinal inflammation to cancer development, it involves signal transducers and activators of transcription (STAT)3 activation. STAT3 activates by the interaction between epithelial cells and BFT. Thus, regulatory T-cell (Tregs) will activates and reduce interleukin (IL)-2 amount. As the level of IL-2 drops, T-helper (T_h17) cells are generated leading to increase in IL-17 levels. IL-17 is implicated in early intestinal inflammation and promotes cancer cell survival and proliferation and consequently triggers IL-6 production that activate STAT3 pathway. Additionally, BFT degrades E-cadherin, hence alteration of signalling pathways can upregulate spermine oxidase leading to cell morphology and promote carcinogenesis and irreversible DNA damage. Patient with familial adenomatous polyposis (FAP) disease displays a high level of tumour load in the colon. This disease is caused by germline mutation of the adenomatous polyposis coli (APC) gene that increases bacterial adherence to the mucosa layer. Mutated-APC gene genotype with ETBF increases the chances of CRC development. Therefore, the colonisation of the ETBF in the intestinal tract depicts tumour aetiology can result in risk of hostility and effect on human health.

Nitric Oxide (NO) and NO Synthases (NOS)-Based Targeted Therapy for Colon Cancer

Colorectal cancer (CRC) is one of the most lethal malignancies worldwide and CRC therapy remains unsatisfactory. In recent decades, nitric oxide (NO)-a free-radical gas-plus its endogenous producer NO synthases (NOS), have attracted considerable attention. NO exerts dual effects (pro- and anti-tumor) in cancers. Endogenous levels of NO promote colon neoplasms, whereas exogenously sustained doses lead to cytotoxic functions. Importantly, NO has been implicated as an essential mediator in many signaling pathways in CRC, such as the Wnt/β-catenin and extracellular-signal-regulated kinase (ERK) pathways, which are closely associated with cancer initiation, metastasis, inflammation, and chemo-/radio-resistance. Therefore, NO/NOS have been proposed as promising targets in the regulation of CRC carcinogenesis. Clinically relevant NO-donating agents have been developed for CRC therapy to deliver a high level of NO to tumor sites. Notably, inducible NOS (iNOS) is ubiquitously over-expressed in inflammatory-associated colon cancer. The development of iNOS inhibitors contributes to targeted therapies for CRC with clinical benefits. In this review, we summarize the multifaceted mechanisms of NO-mediated networks in several hallmarks of CRC. We review the clinical manifestation and limitations of NO donors and NOS inhibitors in clinical trials. We also discuss the possible directions of NO/NOS therapies in the immediate future.

Molecular Mechanisms Contributing Bacterial Infections to the Incidence of Various Types of Cancer

Cancer causes a major health concern worldwide due to high incidence and mortality rates. To accomplish this purpose, the Scopus, PubMed, and Web of Science databases were searched using the keywords bacteria and cancer. Most of published research addressed several different factors that induced cancer, such as toxins, medications, smoking, and obesity. Nonetheless, few studies are dealing with cancer induction via bacterial infection. In addition, mechanisms of cancer induction via bacterial infections are not well understood. Therefore, in this review, we will shed light on different bacteria that induced cancer via different molecular mechanisms. Among the bacterial infection that induced cancer, Helicobacter pylori was the first recognized bacteria which caused gastric cancer and might be also linked to extragastric cancer in humans. H. pylori has been associated with adenocarcinoma in the distal stomach by its ability to cause severe inflammations. It has been found that inflammations induced cancer via different mechanisms including induction of cell proliferation and production of high levels of free radicals. Recently, free radicals were found to induce and cause various types of cancer. Salmonella typhi has been found to be associated with gallbladder carcinoma (GBC). Also, intercellular infection of lungs with Chlamydia pneumoniae was found to contribute as one of the ethological factors of lung cancer. Moreover, infection of the urinary tract with Staphylococcus aureus, Klebsiella spp., and Proteus mirabilis has been found to cause bladder cancer. These microorganisms produce a high level of N-nitrosamines which are metabolically activated leading to the generation of alkylating agents that damage DNA and other macromolecules. It is concluded that a certain bacterium is linked with induction of a specific type of cancer via different molecular and biochemical mechanisms as discussed in the text in details. This infection could potentially affect human health in different ways. In addition, it is important to know the possible factors involved in cancer induction for better treatment of cancer patients.

Known Antimicrobials Versus Nortriptyline in Candida albicans: Repositioning an Old Drug for New Targets

Candida albicans has the capacity to develop resistance to commonly used antimicrobials, and to solve this problem, drug repositioning and new drug combinations are being studied. Nortriptyline, a tricyclic antidepressant, was shown to have the capacity to inhibit biofilm and hyphae formation, along with the ability to efficiently kill cells in a mature biofilm. To use nortriptyline as a new antimicrobial, or in combination with known drugs to increase their actions, it is important to characterize in more detail the effects of this drug on the target species. In this study, the Candida albicans GRACE™ collection and a Haplo insufficiency profiling were employed to identify the potential targets of nortriptyline, and to classify, in a parallel screening with amphotericin B, caspofungin, and fluconazole, general multi-drug resistance genes. The results identified mutants that, during biofilm formation and upon treatment of a mature biofilm, are sensitive or tolerant to nortriptyline, or to general drug treatments. Gene ontology analysis recognized the categories of ribosome biogenesis and spliceosome as enriched upon treatment with the tricyclic antidepressant, while mutants in oxidative stress response and general stress response were commonly retrieved upon treatment with any other drug. The data presented suggest that nortriptyline can be considered a “new” antimicrobial drug with large potential for application to in vivo infection models.

Network modeling of patients' biomolecular profiles for clinical phenotype/outcome prediction

Methods for phenotype and outcome prediction are largely based on inductive supervised models that use selected biomarkers to make predictions, without explicitly considering the functional relationships between individuals. We introduce a novel network-based approach named Patient-Net (P-Net) in which biomolecular profiles of patients are modeled in a graph-structured space that represents gene expression relationships between patients. Then a kernel-based semi-supervised transductive algorithm is applied to the graph to explore the overall topology of the graph and to predict the phenotype/clinical outcome of patients. Experimental tests involving several publicly available datasets of patients afflicted with pancreatic, breast, colon and colorectal cancer show that our proposed method is competitive with state-of-the-art supervised and semi-supervised predictive systems. Importantly, P-Net also provides interpretable models that can be easily visualized to gain clues about the relationships between patients, and to formulate hypotheses about their stratification.

Small molecule inhibitors and stimulators of inducible nitric oxide synthase in cancer cells from natural origin (phytochemicals, marine compounds, antibiotics)

Nitric oxide synthases (NOS) are a family of isoforms, which generate nitric oxide (NO). NO is one of the smallest molecules in nature and acts mainly as a potent vasodilator. It participates in various biological processes ranging from physiological to pathological conditions. Inducible NOS (iNOS, NOS2) is a calcium-independent and inducible isoform. Despite high iNOS expression in many tumors, the role of iNOS is still unclear and complex with both enhancing and prohibiting actions in tumorigenesis. Nature presents a broad variety of natural stimulators and inhibitors, which may either promote or inhibit iNOS response. In the present review, we give an overview of iNOS-modulating agents with a special focus on both natural and synthetic molecules and their effects in related biological processes. The role of iNOS in physiological and pathological conditions is also discussed.

Search for Potential Inducible Nitric Oxide Synthase Inhibitors with Favorable ADMET Profiles for the Therapy of Helicobacter pylori Infections

Background:

Helicobacter pylori is a gram-negative bacterium related to chronic gastritis, peptic ulcer and gastric carcinoma. During its infection process, promotes excessive inflammatory response, increasing the release of reactive species and inducing the production of pro-inflammatory mediators. Inducible Nitric Oxide Synthase (iNOS) plays a crucial role in the gastric carcinogenesis process and a key mediator of inflammation and host defense systems, which is expressed in macrophages induced by inflammatory stimuli. In chronic diseases such as Helicobacter pylori infections, the overproduction of NO due to the prolonged induction of iNOS is of major concern.

Objective:

In this sense, the search for potential iNOS inhibitors is a valuable strategy in the overall process of Helicobacter pylori pathogeny.

Method:

In silico techniques were applied in the search of interesting compounds against Inducible Nitric Oxide Synthase enzyme in a chemical space of natural products and derivatives from the Analyticon Discovery databases.

Results:

The five compounds with the best iNOS inhibition profile were selected for activity and toxicity predictions. Compound 9 (CAS 88198-99-6) displayed significant potential for iNOS inhibition, forming hydrogen bonds with residues from the active site and an ionic interaction with heme. This compound also displayed good bioavailability and absence of toxicity/or from its probable metabolites.

Conclusion:

The top-ranked compounds from the virtual screening workflow show promising results regarding the iNOS inhibition profile. The results evidenced the importance of the ionic bonding during docking selection, playing a crucial role in binding and positioning during ligand-target selection for iNOS.

S-nitrosothiols and H2S donors: Potential chemo-therapeutic agents in cancer

Nitric Oxide (NO) and Hydrogen Sulfide (H2S) are components of an "interactome", which is defined as a redox system involving the interactions of RSS, RNS and ROS. Chemical interaction by these species is common and is characterized by one and two electron oxidation, nitrosylation, nitration and sulfuration/polysulfidation reactions. NO and H2S are gases that penetrate cell membranes, are synthesized by specific enzymes, are ubiquitous, regulate protein activities through post-translational modifications and participate in cell signaling. The two molecules at high concentrations compared to physiological concentrations may result in cellular damage particularly through their interaction with other reactive species. NO and H2S can interact with each other and form a variety of molecular species which may have constructive or destructive behavior depending on the cell type, the cellular environment (ex. oxygen tension, pH, redox state), where the products are produced and in what concentrations. Cross talk exists between NO and H2S, whereby they can influence the generation and signaling behavior of each other. Given the above mentioned properties of NO and H2S and studies in cancer cells and animal models employing NO and H2S donors that generate higher than physiological concentrations of NO and H2S and are effective in killing cancer cells but not normal cells, lend credence to the possibility of the utility of these donors in an approach to the treatment of cancer.

Correlation of adenosine deaminase operating under nitro-oxidative stress with tumor and vascularization in patients with advanced gallbladder carcinoma

This study investigates serum redox status and adenosine catabolism markers in relation to tumor and angiogenesis, in patients with gallbladder carcinoma (GBC). The level of adenosine deaminase (ADA) and xanthine oxidase (XO) activities, nitrites (NO2^-), glutathione (GSH) and malondialdehyde (MDA) were measured in sera of 40 GBC patients and 40 healthy donors. In parallel, 15 tumors at TNM stage IV were scored for CD34 expression and microvessel density (MVD). The results showed that XO and ADA activities, nitrites and MDA levels enhanced by 1.26 (p < 0.01), 2.69, 2.0, and 3.2-fold (p < 0.001), respectively, while those of GSH decreased by 44.6% (p < 0.001). According to receiver operating characteristic (ROC) curve, the optimal cut-off for XO, ADA, MDA, GSH and nitrites were 5.41U/l, 17.02 U/l, 3.72 μM, 36.91 μM and 21.21 μM, respectively. Spearman correlation revealed that ADA activity correlated to nitrites levels (r = 0.3419, p < 0.05) and XO activity (r = 0.5487, p < 0.001). Multivariate binary logistic regression analysis revealed that MDA (OR = 5.78, p < 0.05), ADA (OR = 1.28, p < 0.001) and XO (OR = 2.81, p < 0.05) correlated positively to GBC. CD34 was up expressed in 73.3% of tumors at intermediate to high levels. Multiple regression analysis showed that ADA affected MVD (r = 0.604, p < 0.01). The results suggest that high MDA/GSH ratio is a potential biomarker of GBC. In addition, the oxidative adenosine catabolism indicated that active purine salvage pathway could support tumor progression by sustaining angiogenesis.

Phenomenon of atypical vascular effects of epinephrine and an increase of photodynamic response by nitroglycerin in rats with colon adenocarcinoma: adrenergic and nitrergic mechanisms and novel applied aspects

Using an original model of stress-induced colon adenocarcinoma, we uncover atypical vasorelaxation effects of a mucosa injection of epinephrine assessed by laser speckle contrast imaging and a significant increase of fluorescent intensity of 5-ALA/PpIX from malignant colon tissues by a mucosa injection of nitroglycerine. We clearly demonstrate a high activity of adrenergic and nitrergic mechanisms underlying this phenomenon and discuss their application in improving of optical approaches for effective diagnosis of gastrointestinal cancer.

Gene expression patterns of COX-1, COX-2 and iNOS in H. Pylori infected histopathological conditions

BACKGROUND

Research indicates that Helicobacter pylori can inflict severe histological damage through the modulation of host-related genes. The current study investigated the effect of H. pylori genotypes in the outcome of disease, and the expression of anti-apoptotic related genes, COX-1, COX-2, and iNOS genes in benign, pre-malignant, and malignant lesions of gastric carcinogenesis.

MATERIALS AND METHODS

Tissue samples from H. pylori positive patients were graded based on the genotype of the infected H. pylori strain. Expression of COX-1, COX-2 and iNOS was assessed using a combination of real-time PCR and immunohistochemistry.

RESULTS

Gene expression studies confirmed that COX-2 and iNOS expression was highly and selectively induced in epithelium with premalignant changes such as atrophic conditions, metaplasia and dysplasia, suggesting an important role of these genes in the sequence to gastric carcinoma of the intestinal type. Furthermore, the expression of COX-2 and iNOS was also dependent on the genotype of H. pylori and subjects with genotype-1 exhibited significantly higher expressions of COX-2 and iNOS compared to other genotypes. Comparison of the expression levels among infected and uninfected individuals demonstrated significant difference in the expression pattern of COX-2 gene whereas iNOS expression was found only in subjects infected H. pylori (p < 0.001). Immunohistochemical staining showed 1.5619 folds higher propensity of COX-2 and 3.2941 folds higher intensity of iNOS expression in subjects infected with H. pylori genotype 1.

CONCLUSION

The up-regulation of COX-2 and iNOS was associated with the genotype of the H. pylori strain and the presence of certain genotype may greatly affect early events during carcinogenesis.

ADIPOSE TISSUE AND ITS ROLE IN MICROENVIRONMENT OF THE COLORECTAL ADENOCARCINOMA CANCER CELL

Introduction. The mechanisms of adipose-tissue’s influence on tumor progression has been studied a lot, but the way of interaction of adipocytes with tumor cells have not been well defined until now. Objective. The aim of this study was to evaluate the mechanisms of adipocytes and tumor cells interaction under the influence of radiation and chemo-radiation therapy in locally advanced rectal cancer (LARC) patients. Material and methods. A prospective randomized single-center study was conducted. It involved 110 patients with LARC and pre-obesity. The patients were randomized into a main group A (radiation therapy and oxaliplatin-based chemotherapy) and a comparison group B (radiation therapy and fluoropyrimidine-based mono-chemotherapy). Superoxide free radicals and NO levels generated by mitochondria of adipocytes were evaluated In both groups’. Also, there was estimated the indices of MMP-2, MMP-9, 8-oxoG, and free fatty acids (FFA) level. Results and discussion. Level of superoxide radicals in tumor-adjacent adipose tissue was 0.58±0.15 (main group) and 0.70±0.12 nmol/g·min (comparison group) (p<0.001). Blood levels of FFA increased in group A up to 2.05±0.15, and in group B up to 2.48±0.20 mmol/l (while in it was 0.57±0.11 mmol/L). 8-oxoG levels in tumor-adjacent adipose tissue had no statistically significant differences. Conclusions. The tumor-adjacent adipose tissue is an energy depot that can act as a promoter of tumor progression supplying the locally advanced rectal cancer with an energy substrate FFA.  It has been established that the level MMP-2 activity significantly reduces the degree of intercellular matrix remodeling by the XELOX chemotherapy.

Serum prolidase activity, total oxidant/antioxidant, and nitric oxide levels in patients with esophageal squamous cell carcinoma

Background

This study aims to assess the prolidase activity, nitric oxide levels, and oxidative status in patients with esophageal squamous cell carcinoma.

Methods

The study included 30 patients with esophageal squamous cell carcinoma (11 males, 19 females; mean age 61±3 years; range, 28 to 77 years) and 30 healthy controls (10 males, 20 females; mean age 58±5 years; range, 31 to 73 years). Serum prolidase activity, total antioxidant capacity, total oxidant status, and nitric oxide levels were measured. In addition, the oxidative stress index was calculated.

Results

Prominently elevated serum prolidase activity, oxidative stress index values, total oxidant status, and nitric oxide levels were detected in the patient group (p<0.05). Lower total antioxidant capacity levels were observed in the patient group (p<0.05).

Conclusion

Increased oxidant status with increased nitric oxide levels and prolidase activity were found in esophageal squamous cell carcinoma patients. Impairment of antioxidant mechanism with increased prolidase activity and nitric oxide levels may have a crucial role in the etiopathogenesis of esophageal squamous cell carcinoma.

Expression of human inducible nitric oxide synthase in response to cytokines is regulated by hypoxia-inducible factor-1

The production of nitric oxide (NO) by inducible NO synthase (iNOS) and the regulation of gene expression by hypoxia-inducible factors (HIFs) are important for many aspects of human cell biology. However, little is known about whether iNOS expression is controlled by HIFs in human cells. Stimulation of A549 human lung epithelial cells with cytokines (TNF, IL-1 and IFNγ) increased the nuclear accumulation of HIF-1 in normoxic conditions. Activation of HIF-1 by hypoxia or CoCl₂ was not sufficient to induce iNOS expression. However, pharmacological inhibition of HIF-1 reduced the induction of iNOS expression in A549 cells and primary human astrocytes. Moreover, elimination of HIF-1α expression and activity by CRISPR/Cas9 gene editing significantly reduced the induction of human iNOS gene promoter, mRNA and protein expression by cytokine stimulation. Three putative hypoxia response elements (HRE) are present within the human iNOS gene promoter and elimination of an HRE at -4981 bp reduced the induction of human iNOS promoter activity in response to cytokine stimulation. These findings establish an important role for HIF-1α in the induction of human iNOS gene expression in response to cytokine stimulation.

Regulation of Cell Survival, Apoptosis, and Epithelial-to-Mesenchymal Transition by Nitric Oxide-Dependent Post-Translational Modifications

SIGNIFICANCE

Nitric oxide (NO) is a physiopathological messenger generating different reactive nitrogen species (RNS) according to hypoxic, acidic and redox conditions. Recent Advances: RNS and reactive oxygen species (ROS) promote relevant post-translational modifications, such as nitrosation, nitration, and oxidation, in critical components of cell proliferation and death, epithelial-to-mesenchymal transition, and metastasis.

CRITICAL ISSUES

The pro- or antitumoral properties of NO are dependent on local concentration, redox state, cellular status, duration of exposure, and compartmentalization of NO generation. The increased expression of NO synthase has been associated with cancer progression. However, the experimental strategies leading to high intratumoral NO generation have been shown to exert antitumoral properties. The effect of NO and ROS on cell signaling is critically altered by factors modulating tumor progression such as oxygen content, metabolism, and inflammatory response. The review describes the alteration of key components involved in cell survival and death, metabolism, and metastasis induced by RNS- and ROS-related post-translational modifications.

FUTURE DIRECTIONS

The identification of the molecular targets affected by nitrosation, nitration, and oxidation, as well as their interactions with other post-translational modifications, will improve the understanding on the complex signaling and cell fate decision in cancer. The therapeutic NO-based strategies have to address the complex crosstalk among NO and ROS with regard to critical components affecting tumor cell survival, metabolism, and metastasis in the progression of cancer, as well as close interaction with ionizing radiation and chemotherapy.

Acetylcholine induces stem cell properties of gastric cancer cells of diffuse type

Gastric cancer is the third leading cause of cancer-related death worldwide, but the mechanisms of gastric carcinogenesis are not completely understood. Recently, the role of cholinergic neuronal pathways in promoting this process has been demonstrated. Our aim was to extend these studies and to evaluate, using an in vitro model of tumorspheres, the effect of acetylcholine on human gastric cancer cells, and the role of acetylcholine receptors and of the nitric oxide pathway, in this effect. The gastric cancer cell line MKN-45 of the diffuse type of gastric cancer was cultured in the presence of acetylcholine, or different agonists or inhibitors of muscarinic and nicotinic acetylcholine receptors, or nitric oxide donor or inhibitor of the nitric oxide pathway, and the number and size of tumorspheres were assessed. The expression of cancer stem cell markers (CD44 and aldehyde dehydrogenase) was also evaluated by immunofluorescence and quantitative reverse transcription polymerase chain reaction. We showed that acetylcholine increased both the number and size of tumorspheres and that this effect was reproduced with both muscarinic and nicotinic acetylcholine receptors agonists and was inhibited by both receptor antagonists. The nitric oxide donor stimulated the tumorsphere formation, while the nitric oxide synthesis inhibitor inhibited the stimulatory effect of acetylcholine. Moreover, acetylcholine increased the expression of stem cell markers on gastric cancer cells. These results indicate that acetylcholine induces the stem cell properties of gastric cancer cells and both muscarinic and nicotinic receptors and a nitrergic pathway might be involved in this effect.

Src kinase activation by nitric oxide promotes resistance to anoikis in tumour cell lines

Tumour progression involves the establishment of tumour metastases at distant sites. Resistance to anoikis, a form of cell death that occurs when cells lose contact with the extracellular matrix and with neighbouring cells, is essential for metastases. NO has been associated with anoikis. NO treated HeLa cells and murine melanoma cells in suspension triggered a nitric oxide (NO)-Src kinase signalling circuitry that enabled resistance to anoikis. Two NO donors, sodium nitroprusside (SNP) (500 µM) and DETANO (125 µM), protected against cell death derived from detachment of a growth permissive surface (experimental anoikis). Under conditions of NO-mediated Src activation the following were observed: (a) down-regulation of the pro-apoptotic proteins Bim and cleaved caspase-3 and the cell surface protein, E-cadherin, (b) up-regulation of caveolin-1, and (c) the dissociation of cell aggregates formed when cells are detached from a growth permissive surface. Efficiency of reattachment of tumour cells in suspension and treated with different concentrations of an NO donor, was dependent on the NO concentration. These findings indicate that NO-activated Src kinase triggers a signalling circuitry that provides resistance to anoikis, and allows for metastases.