Influence of myeloperoxidase on colon tumor occurrence in inflamed versus non-inflamed colons of Apc(Min/+) mice

Influence of in vitro gastrointestinal digestion and colonic fermentation on carbonyl scavenging capacity of fiber-bound polyphenols from quinoa

Whole grain insoluble dietary fiber (IDF) is a good source of bound-form polyphenols. In the present study, insoluble dietary fiber rich in bound polyphenols (BP-IDF) from quinoa, rye and wheat was prepared. The carbonyl scavenging capacities of these three BP-IDFs and the effects of in vitro gastrointestinal (GI) digestion and colonic fermentation on their scavenging activities were studied. The results indicated that the fiber-bound polyphenols from quinoa showed the highest carbonyl scavenging capacity compared to those from rye and wheat. After colonic fermentation, more than 73% of the bound polyphenols were still retained in the fermented residues of the quinoa BP-IDF. The fiber-bound polyphenols in the GI-digested residues of quinoa retained considerable carbonyl scavenging activities. During the fermentation process, the residual fiber-bound polyphenols in the fermented residues still scavenged 35.8% to 45.2% of methylglyoxal, 19.3% to 25.4% of glyoxal, 50.7% to 60.5% of acrolein and 5.2% to 9.7% of malondialdehyde, showing a critical role in the scavenging of carbonyl compounds compared to the released and metabolized polyphenols. These findings confirm the capacity of fiber-bound polyphenols from three whole grains to scavenge carbonyls during in vitro digestion and fermentation processes, suggesting that they could be used as functional ingredients to maintain continuous defenses against carbonyls along the digestive tract.

Engineering of a novel D-A type fluorophore with hydrogen bond-induced enhanced emission property for sensitively detecting endogenous HOCl in living cells and tissues

Fluorescence imaging has been widely employed for biomedical research and clinical diagnostics. With ease of synthesis and excellent photophysical properties, D-A type fluorophores are widely designed for fluorescence imaging. However, traditional D-A type fluorophores are solvatochromic which reduces the fluorescence brightness in the biological system. To solve this problem and build on our previous work, we devised a novel HIEE fluorophore MTC with typical anti-solvatochromic fluorescence. Furthermore, the activated fluorescent probe designed based on MTC showed excellent imaging performance. We believe that the strategy based on the fluorophores with typical anti-solvatohromic fluorescence can be a useful platform for designing fluorescent probes for high-brightness imaging in the biological system.

Moringa oleifera leaves alleviated inflammation through downregulation of IL-2, IL-6, and TNF-α in a colitis-associated colorectal cancer model

New chemopreventive alternatives are needed due to the rising worldwide incidence of colorectal cancer. The objective was to evaluate the chemopreventive activity of Moringa oleifera leaves (MO) in a colitis-associated colon carcinogenesis model. We hypothesized that MO contain bioactive compounds capable of modulating the expression of genes involved in the inflammatory response and carcinogenesis. Forty-eight male mice (CD-1) were divided into six groups; 1: Healthy control; 2: Positive control induced with azoxymethane (AOM, 10 mg/Kg body weight, intraperitoneal injection) and three cycles of dextran sodium sulfate (DSS, 1.5% in drinking water); groups 3, 4, and 5 were induced with AOM/DSS and supplemented with 5%, 10%, and 20% of MO, respectively; group 6: had no disease induction and supplemented with 20% of MO. Mice were treated for 12 weeks and euthanized. Significant differences (p < 0.05) were found for the moringa-administered groups in morphological and histopathological parameters compared to the AOM/DSS control. A decrease in myeloperoxidase activity (~50%) and lipid peroxidation (1.9-3.1 times) were found in groups with 10% and 20% of MO compared to the AOM/DSS control (p < 0.05). The group supplemented with 10% MO showed a significant increase (~3 times) in butyrate and propionate in fecal and cecal content. Groups supplemented with 10%, and 20% MO showed a reduction in proinflammatory cytokines in serum (MCP-1, IL-6, TNF-α) compared to the AOM/DSS control. Treatment with 10% MO induced differential expression of 65 genes in colon tissue such as IL-2, IL-6, TNF, IL-1ß, and INF-γ. MO downregulated proinflammatory mediators showing chemopreventive properties against inflammatory response and colon carcinogenesis.

Role of Oxidative Stress and Nrf2/KEAP1 Signaling in Colorectal Cancer: Mechanisms and Therapeutic Perspectives with Phytochemicals

Colorectal cancer still has a high incidence and mortality rate, according to a report from the American Cancer Society. Colorectal cancer has a high prevalence in patients with inflammatory bowel disease. Oxidative stress, including reactive oxygen species (ROS) and lipid peroxidation, has been known to cause inflammatory diseases and malignant disorders. In particular, the nuclear factor erythroid 2-related factor 2 (Nrf2)/Kelch-like ECH-related protein 1 (KEAP1) pathway is well known to protect cells from oxidative stress and inflammation. Nrf2 was first found in the homolog of the hematopoietic transcription factor p45 NF-E2, and the transcription factor Nrf2 is a member of the Cap 'N' Collar family. KEAP1 is well known as a negative regulator that rapidly degrades Nrf2 through the proteasome system. A range of evidence has shown that consumption of phytochemicals has a preventive or inhibitory effect on cancer progression or proliferation, depending on the stage of colorectal cancer. Therefore, the discovery of phytochemicals regulating the Nrf2/KEAP1 axis and verification of their efficacy have attracted scientific attention. In this review, we summarize the role of oxidative stress and the Nrf2/KEAP1 signaling pathway in colorectal cancer, and the possible utility of phytochemicals with respect to the regulation of the Nrf2/KEAP1 axis in colorectal cancer.

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.

Eosinophil peroxidase over-expression predicts the clinical outcome of patients with primary lung adenocarcinoma

Eosinophil peroxidase (EPO), a heme protein abundantly expressed in eosinophils, involves in the catalysis of cytotoxic oxidants associated with the pathogenesis of cancer, asthma, and allergic inflammatory disorders. To date, its roles in the pathogenesis of lung cancer are still not known. We determined the expression of EPO in the lung adenocarcinoma tissues and the normal adjacent lung tissues using Real-time PCR and Western blotting analysis, respectively. Also, EPO protein expression in 90 lung adenocarcinoma (AD) samples were confirmed with immunohistochemistry (IHC) using tissue microarrays. Meanwhile, we investigated the association between EPO and the clinicopathological characteristics and disease prognosis in the pulmonary adenocarcinoma patients, which demonstrated that EPO mRNA and protein were significantly higher in lung AD tissues that those of the adjacent normal lung tissues (P<0.05). EPO overexpression was significantly correlated with pathologic-tumour nodes metastasen stage (p-TNM stage, P=0.017) and lymph node metastasis (P=0.027). Patients with EPO overexpression showed shorter survival time than those with low EPO levels (P=0.017), according to the Kaplan-Meier survival curve. Furthermore, a multivariate Cox regression model was utilized to analyze the prognostic factors, which indicated that N stage (HR=0.965, 95% CI=0.328-1.359, P=0.008), p-TNM Stage (HR=3.127, 95% CI =2.463-5.015, P=0.021) and high EPO protein expression (HR=3.145, 95% CI=2.016-5.519, P=0.018) were independent factors for the prognosis of lung AD. In conclusion, increased EPO expression could be used as a biomarker for lung AD patients with poor prognosis.

Myeloperoxidase as an Active Disease Biomarker: Recent Biochemical and Pathological Perspectives

Myeloperoxidase (MPO) belongs to the family of heme-containing peroxidases, produced mostly from polymorphonuclear neutrophils. The active enzyme (150 kDa) is the product of the MPO gene located on long arm of chromosome 17. The primary gene product undergoes several modifications, such as the removal of introns and signal peptides, and leads to the formation of enzymatically inactive glycosylated apoproMPO which complexes with chaperons, producing inactive proMPO by the insertion of a heme moiety. The active enzyme is a homodimer of heavy and light chain protomers. This enzyme is released into the extracellular fluid after oxidative stress and different inflammatory responses. Myeloperoxidase is the only type of peroxidase that uses H₂O₂ to oxidize several halides and pseudohalides to form different hypohalous acids. So, the antibacterial activities of MPO involve the production of reactive oxygen and reactive nitrogen species. Controlled MPO release at the site of infection is of prime importance for its efficient activities. Any uncontrolled degranulation exaggerates the inflammation and can also lead to tissue damage even in absence of inflammation. Several types of tissue injuries and the pathogenesis of several other major chronic diseases such as rheumatoid arthritis, cardiovascular diseases, liver diseases, diabetes, and cancer have been reported to be linked with MPO-derived oxidants. Thus, the enhanced level of MPO activity is one of the best diagnostic tools of inflammatory and oxidative stress biomarkers among these commonly-occurring diseases.

Prognostic Value of the Expression of DNA Repair-Related Biomarkers Mediated by Alcohol in Gastric Cancer Patients

Alcohol consumption likely induces gastric carcinogenesis through deregulation of RNA polymerase (Pol) III genes and oxidative damage. Transcription factor IIB-related factor 1 (BRF1) overexpression alleviates RNA Pol III transcription inhibition through breast cancer susceptibility gene 1 (BRCA1). Myeloperoxidase (MPO) involvement in cancer is induced by alcohol-mediated oxidative damage. BRCA1/2 and MPO play key roles in DNA repair. BRCA1 and BRCA2 exert different roles in homologous recombination repair. By using human gastric cancer (GC) biopsies, we investigated the prognostic value of these proteins upon alcohol induction. In total, high expression of BRF1 (P = 0.010) and positive cell infiltration of MPO (P = 0.004) in tumor tissues as well as positive expression of BRCA1 (P < 0.001) in para-tumor tissues were more frequent in GC patients with hazardous or harmful alcohol consumption habits. BRF1 (P = 0.021), BRCA2 (P < 0.001), and MPO (P = 0.039) were independent prognostic factors for disease-free survival. BRCA1 (P = 0.005) and BRCA2 (P < 0.001) also were identified as independent prognostic factors for overall survival. Furthermore, BRCA2 was an independent unfavorable prognostic factor for disease-free survival and overall survival (P < 0.001) in GC patients who underwent platinum-based adjuvant chemotherapy. BRF1, BRCA1/2, and MPO are DNA repair-related biomarkers, induced by alcohol with prognostic value in GC patients.

Role of the Vanins-Myeloperoxidase Axis in Colorectal Carcinogenesis

The presence of chronic inflammation in the colonic mucosa leads to an increased risk of cancer. Among proteins involved in the regulation of mucosal inflammation and that may contribute both to structural damage of the intestinal mucosa and to intestinal carcinogenesis, there are myeloperoxidase (MPO) and vanins. The infiltration of colonic mucosa by neutrophils may promote carcinogenesis through MPO, a key enzyme contained in the lysosomes of neutrophils that regulates local inflammation and the generation of reactive oxygen species (ROS) and mutagenic species. The human vanin gene family consists of three genes: vanin-1, vanin-2 and vanin-3. All vanin molecules are pantetheinases, that hydrolyze pantetheine into pantothenic acid (vitamin B5), and cysteamine, a sulfhydryl compound. Vanin-1 loss confers an increased resistance to stress and acute intestinal inflammation, while vanin-2 regulates adhesion and transmigration of activated neutrophils. The metabolic product of these enzymes has a prominent role in the inflammation processes by affecting glutathione levels, inducing ulcers through a reduction in mucosal blood flow and oxygenation, decreasing local defense mechanisms, and in carcinogenesis by damaging DNA and regulating pathways involved in cell apoptosis, metabolism and growth, as Nrf2 and HIF-1α.

Myeloperoxidase expression in human colonic mucosa is related to systemic oxidative balance in healthy subjects

OBJECTIVES

To improve understanding of the preclinical stage of colonic inflammation by exploring the existence of a link between early inflammatory changes in the colonic mucosa and the systemic redox balance.

METHODS

Clinical characteristics, a fasting blood draw, and mucosal biopsies from the right, left, and sigmoid-rectum colonic tracts collected from 28 healthy individuals (14/14 males/females) who underwent colonoscopy. Myeloperoxidase (MPO) positive cells infiltrating colonic mucosa specimens were assessed by immunohistochemistry, and patients divided into high or low MPO expressing cells/optical field groups (MPO^high or MPO^low, respectively).The systemic oxidative balance has been studied through derived-Reactive Oxygen Metabolites (d-ROMs), Biological Antioxidant Potential (BAP), and Lipoperoxide-cholesterol Oxidizing (LP-CHOLOX) tests on serum.

RESULTS

MPO^high patients demonstrated an increased systemic oxidative stress compared to MPO^low individuals (P = 0.035), especially when MPO is referred to the left-sided colonic mucosa (P = 0.007). MPO^low subjects in the sigmoid-rectum showed a significant higher antioxidant capacity in the serum (P < 0.02). Sex-specific differences in MPO expression (male and female: 4.6 ± 3.2 and 2.6 ± 1.5 MPO-positive cells/optical field, respectively, P = 0.044), and a decreasing gradient in MPO expression moving from the cecum to the rectum (ascendant, descendant, and sigmoid-rectum: 3.7 ± 2.8, 3.1 ± 1.7, and 1.4 ± 0.5, respectively, P = 0.012) were also found and discussed.

DISCUSSION

The study is the first demonstrating a connection between systemic redox balance and MPO expression in the colonic mucosa, according to the colonic tract and patient gender. Further research evaluating the MPO expression in the human colon and its relationship with pathological conditions could benefit from these results.