Regulation of colon cancer cell proliferation and migration by MD-2 activity

Effects of human donor milk on gut barrier function and inflammation: in vitro study of the beneficial properties to the newborn

Introduction

The gastrointestinal and immune systems of premature infants are not fully developed, rendering them more vulnerable to severe complications like necrotizing enterocolitis. Human milk offers a rich array of bioactive factors that collectively contribute to reducing the incidence of gut infections and inflammatory conditions. When a mother's milk is unavailable, preterm infants are often provided with donor human milk processed in Human Milk Banks. However, it remains uncertain whether pasteurized milk confers the same level of risk reduction as unprocessed milk. This uncertainty may stem from the well-documented adverse effects of heat treatment on milk composition. Yet, our understanding of the comprehensive impact on protective mechanisms is limited.

Methods

In this study, we conducted a comparative analysis of the effects of raw versus pasteurized milk and colostrum versus mature milk on cellular functions associated with the gut epithelial barrier and responses to inflammatory stimuli. We utilized THP-1 and HT-29 cell lines, representing monocyte/macrophages and gut epithelial cells, respectively.

Results

Our observations revealed that all milk types stimulated epithelial cell proliferation. However, only raw colostrum increased cell migration and interfered with the interaction between E. coli and epithelial cells. Furthermore, the response of epithelial and macrophage cells to lipopolysaccharide (LPS) was enhanced solely by raw colostrum, with a milder effect observed with mature milk. In contrast, both raw and pasteurized milk diminished the LPS induced response in monocytes. Lastly, we examined how milk affected the differentiation of monocytes into macrophages, finding that milk reduced the subsequent inflammatory response of macrophages to LPS.

Discussion

Our study sheds light on the impact of human milk on certain mechanisms that potentially account for its protective effects against necrotizing enterocolitis, highlighting the detrimental influence of pasteurization on some of these mechanisms. Our findings emphasize the urgency of developing alternative pasteurization methods to better preserve milk properties. Moreover, identifying the key components critically affected by these protective mechanisms could enable their inclusion in donor milk or formula, thereby enhancing immunological benefits for vulnerable newborns.

MD2 Is a Potential Biomarker Associated with Immune Cell Infiltration in Gliomas

Background

Glioma is the most common primary malignant tumor in the central nervous system. Myeloid differentiation protein 2 (MD2) acts as a coreceptor of toll-like receptor 4 (TLR4) to mediate innate immune response. However, the actual roles of MD2 in the regulation of progression and immune cell infiltration in gliomas remain largely unclear. This study aims to explore whether MD2 could be an independent prognostic factor through the mediation of immune cell infiltration in gliomas.

Methods

The mRNA expression and DNA methylation differential analyses of MD2 were performed using CGGA, TCGA and Rembrandt databases and survival analyses were performed using Kaplan-Meier plotter. Univariate and multivariate Cox regression was applied to analyze the prognostic value of MD2 and nomograms were constructed to evaluate the clinical value of MD2. Then, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were utilized to analyze MD2-related signal pathways. Furthermore, correlations between MD2 and immune cell infiltration were calculated by TIMER and CIBERSOPT. The correlation between MD2 expression and the infiltrations of macrophages and neutrophils was experimentally verified by the knockdown of MD2 expression using small interfering RNA (siRNA) in glioma cells.

Results

We found that MD2 was overexpressed and associated with a poor prognosis in gliomas. Meanwhile, higher expression of MD2 could be a result of lower DNA methylation of MD2 gene in gliomas. In addition, univariate and multivariate Cox regression analysis indicated that MD2 could be an independent prognostic factor for gliomas. Further functional enrichment analysis revealed that the functions of MD2 were closely related to immune responses. Moreover, the expression level of MD2 was strongly correlated with the infiltration and polarization of pro-tumor phenotype of tumor-associated macrophages and tumor-associated neutrophils in gliomas.

Conclusions

These findings have provided strong evidence that MD2 could be served as a valuable immune-related biomarker to diagnose and predict the progression of gliomas.

Evaluation of the compounds commonly known as superoxide dismutase and catalase mimics in cellular models

Oxidative stress that results from an imbalance between the concentrations of reactive species (RS) and antioxidant defenses is associated with many pathologies. Superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase are among the key enzymes that maintain the low nanomolar physiological concentrations of superoxide and hydrogen peroxide. The increase in the levels of these species and their progeny could have deleterious effects. In this context, chemists have developed SOD and CAT mimics to supplement them when cells are overwhelmed with oxidative stress. However, the beneficial activity of such molecules in cells depends not only on their intrinsic catalytic activities but also on their stability in biological context, their cell penetration and their cellular localization. We have employed cellular assays to characterize several compounds that possess SOD and CAT activities and have been frequently used in cellular and animal models. We used cellular assays that address SOD and CAT activities of the compounds. Finally, we determined the effect of compounds on the suppression of the inflammation in HT29-MD2 cells challenged by lipopolysaccharide. When the assay requires penetration inside cells, the SOD mimics Mn(III) meso-tetrakis(N-(2'-n-butoxyethyl)pyridinium-2-yl)porphyrin (MnTnBuOE-2-PyP⁵⁺) and Mn(II) dichloro[(4aR,13aR,17aR,21aR)-1,2,3,4,4a,5,6,12,13,13a,14,15,16,17,17a,18,19,20,21,21a-eicosahydro-11,7-nitrilo-7Hdibenzo[b,h] [1,4, 7,10] tetraazacycloheptadecine-κN5,κN13,κN18,κN21,κN22] (Imisopasem manganese, M40403, CG4419) were found efficacious at 10 μM, while Mn(II) chloro N-(phenolato)-N,N'-bis[2-(N-methyl-imidazolyl)methyl]-ethane-1,2-diamine (Mn1) requires an incubation at 100 μM. This study thus demonstrates that MnTnBuOE-2-PyP⁵⁺, M40403 and Mn1 were efficacious in suppressing inflammatory response in HT29-MD2 cells and such action appears to be related to their ability to enter the cells and modulate reactive oxygen species (ROS) levels.

Suppression of MD2 inhibits breast cancer in vitro and in vivo

Purpose

To explore the effects of the intervening measure targeting myeloid differentiation 2 (MD2) on breast cancer progression in vitro and in vivo.

Methods

The expression of MD2 in normal breast cells (Hs 578Bst) and three kinds of breast carcinoma cell lines (MCF-7, MDA-MB-231 s and 4T1) were detected by western blot. MTT assay was used to detect the proliferation of 4T1 cells treated by L6H21, cell migration and invasion was measured by wound healing assay and trans-well matrigel invasion assay, respectively. In addition, to further study the role of MD2 in tumor progression, we assessed the effects of inhibition of MD2 on the progression of xenograft tumors in vivo.

Results

The expression of MD2 is much higher in MDA-MB-231 s and 4T1cells than that in normal breast cells (Hs 578Bst) or MCF-7 cells (p < 0.05). In vitro, suppression of MD2 by L6H21 has a significant inhibition of proliferation, migration and invasion in 4T1 cells in dose-dependent manner. In vivo, L6H21 pretreatment significantly improved survival of 4T1-bearing mice (p < 0.05). Additionally, we also observed that none of the mice died from the toxic effect of 10 mg kg⁻¹ L6H21 in 60 days.

Conclusion

Overall, this work indicates that suppression of MD2 shows progression inhibition in vitro and significantly prolong survival in vivo. These findings provide the potential experimental evidence for using MD2 as a therapeutic target of breast carcinoma.

Cathelicidin-mediated lipopolysaccharide signaling via intracellular TLR4 in colonic epithelial cells evokes CXCL8 production

We hypothesized that the antimicrobial peptide cathelicidin has a physiological role in regulating gut inflammatory homeostasis. We determined that cathelicidin synergizes with LPS to facilitate its internalization and signaling via endosomic TLR4 in colonic epithelium, evoking synthesis of the human neutrophil chemoattractant, CXCL8 (or murine homolog, CXCL1). Interaction of cathelicidin with LPS in the control of CXCL8/CXCL1 synthesis was assessed in human colon epithelial cells, murine colonoids and cathelicidin-null mice (Camp^-/- ). Mechanistically, human cathelicidin (LL-37), as an extracellular complex with LPS, interacted with lipid raft-associated GM1 gangliosides to internalize and activate intracellular TLR4. Two signaling pathways converged on CXCL8/CXCL1 production: (1) a p38MAPK-dependent pathway regulated by Src-EGFR kinases; and, (2) a p38MAPK-independent, NF-κB-dependent pathway, regulated by MEK1/2-MAPK. Increased cathelicidin-dependent CXCL8 secretion in the colonic mucosa activated human blood-derived neutrophils. These cathelicidin effects occurred in vitro at concentrations well below those needed for microbicidal function. The important immunomodulatory role of cathelicidins was evident in cathelicidin-null/Camp^-/- mice, which had diminished colonic CXCL1 secretion, decreased neutrophil recruitment-activation and reduced bacterial clearance when challenged with the colitis-inducing murine pathogen, Citrobacter rodentium. We conclude that in addition to its known microbicidal action, cathelicidin has a unique pathogen-sensing role, facilitating LPS-mediated intestinal responses, including the production of CXCL8/CXCL1 that would contribute to an integrated tissue response to recruit neutrophils during colitis.

Tuning the Dual Inhibition of Carbonic Anhydrase and Cyclooxygenase by Dihydrothiazole Benzensulfonamides

A novel series of of 4-[(3-phenyl-4-aryl-2,3-dihydro-1,3-thiazol-2-ylidene)amino]benzene-1-sulfonamides (EMAC10111a-g) was synthesized and assayed toward both human carbonic anhydrase isozymes I, II, IX, and XII and cyclooxygenase isoforms. The majority of these derivatives preferentially inhibit hCA isoforms II and XII and hCOX-2 isozyme, indicating that 2,3,4-trisubstituted 2,3-dihydrothiazoles are a promising scaffold for the inhibition of hCA isozymes and of hCOX-2 enzyme. The nature of the substituent at the dihydrothiazole ring position 4 influenced the activity and selectivity toward both enzyme families. EMAC10111g resulted as the best performing compound toward both enzyme families and exhibited preferential activity toward hCA XII and hCOX-2 isozymes.

hTERT promotes tumor progression by enhancing TSPAN13 expression in osteosarcoma cells

Telomerase complex maintains the length of the telome, cbre, and protects erosion of the physical ends of the eukaryotic chromosome in all actively dividing cells including cancer cells. Telomerase activation extends the lifespan of cells in culture by maintaining the length of the telomere. Compared to terminally differentiated somatic cells, telomerase activity remains high in over 90% of cancer cells. It has now become clear that the role of telomerase is much more complex than just telomere lengthening. The remaining 10% of cancers deploy ALT (alternative lengthening of telomeres) pathway to maintain telomere length. Telomerase inhibitors offer a good therapeutic option. Also, telomerase-associated molecules can be targeted provided their roles are clearly established. In any case, it is necessary to understand the major role of telomerase in cancer cells. Many studies have already been done to explore gene profiling of a telomerase positive cell by knocking down expression of hTERT (telomerase reverse transcriptase). To complement these studies, we performed global gene profiling of a telomerase negative cell by ectopically expressing hTERT and studied changes in the global gene expression patterns. Analysis of microarray data for telomerase negative cells ectopically expressing telomerase showed 76 differentially regulated genes, out of which 39 genes were upregulated, and 37 were downregulated. Three upregulated genes such as TSPAN13, HMGCS2, DLX5, and three downregulated genes like DHRS2, CRYAB, and PDLIM1 were validated by real-time PCR. Knocking down of TSAPN13 in hTERT overexpressing U2OS cells enhanced the apoptosis of the cells. TSPAN13 knockdown in these cells suppressed mesenchymal properties and enhanced epithelial character.

sTLR4/MD-2 complex inhibits colorectal cancer in vitro and in vivo by targeting LPS

Colorectal cancer (CRC) is aggressive and associated with TLR4-MD-2 signaling. Toll-like receptor 4 (TLR4) and myeloid differentiation protein 2 (MD-2) were highly expressed in human CRC. The soluble form of extracellular TLR4 domain (sTLR4) and MD-2 may have important roles in binding lipopolysaccharide (LPS). In this study, sTLR4 and MD-2 protein and prepared sTLR4/MD-2 complex were synthesized successfully to restrain LPS-TLR4/MD-2 activation by competing with cellular membrane TLR4 for binding LPS. The sTLR4/MD-2 complex can significantly attenuate LPS induced pro-inflammatory and migration cytokine production in vitro and in vivo, and inhibit the effect of LPS on the cell cycle, migration and invasion of human CRC cells in vitro. Administration of sTLR4/MD-2 complex protected mice from tumor both in xenograft and implantation metastasis model. The sTLR4/MD-2 complex treated mice had smaller tumor, less body weight loss and lower expression of inflammatory cytokines. Here, the azoxymethane/dextran sulfate sodium salt (AOM/DSS) murine model was used as an experimental platform to simulate the physiological and pathological processes of cancers associated with chronic intestinal inflammation. AOM/DSS-induced tumors were inhibited in mice treated by sTLR4/MD-2 complex. It is demonstrated in our study that sTLR4/MD-2 complex could inhibit CRC by competing with binding LPS, raising the complex's possibility of a new prevention agent against CRC.

Eritoran Suppresses Colon Cancer by Altering a Functional Balance in Toll-like Receptors That Bind Lipopolysaccharide

Colorectal carcinogenesis is affected by overexpression of the lipopolysaccharide (LPS) receptors CD14 and TLR4, which antagonize each other by affecting epithelial cell proliferation and apoptosis. Eritoran is an investigational drug for sepsis treatment that resembles the lipid A moiety of LPS and therefore acts as a TLR4 inhibitor. In the present study, we explored the potential therapeutic uses and mechanisms of action of eritoran in reducing colon cancer progression. Eritoran administration via intracolonic, intragastric, or intravenous routes significantly reduced tumor burden in a chemically induced mouse model of colorectal carcinoma. Decreased proliferation and increased apoptosis were observed in mouse tumor cells after eritoran treatment. In vitro cultures of mouse primary tumor spheroids and human cancer cell lines displayed increased cell proliferation and cell-cycle progression following LPS challenge. This effect was inhibited by eritoran and by silencing CD14 or TLR4. In contrast, apoptosis induced by eritoran was eliminated by silencing CD14 or protein kinase Cζ (PKCζ) but not TLR4. Lastly, LPS and eritoran caused hyperphosphorylation of PKCζ in a CD14-dependent and TLR4-independent manner. Blocking PKCζ activation by a Src kinase inhibitor and a PKCζ-pseudosubstrate prevented eritoran-induced apoptosis. In summary, our work offers a preclinical proof of concept for the exploration of eritoran as a clinical treatment, with a mechanistic rationale to reposition this drug to improve the management of colorectal cancer. Cancer Res; 76(16); 4684-95. ©2016 AACR.

LPS receptor subunits have antagonistic roles in epithelial apoptosis and colonic carcinogenesis

Colorectal carcinoma (CRC) is characterized by unlimited proliferation and suppression of apoptosis, selective advantages for tumor survival, and chemoresistance. Lipopolysaccharide (LPS) signaling is involved in both epithelial homeostasis and tumorigenesis, but the relative roles had by LPS receptor subunits CD14 and Toll-like receptor 4 (TLR4) are poorly understood. Our study showed that normal human colonocytes were CD14(+)TLR4(-), whereas cancerous tissues were CD14(+)TLR4(+), by immunofluorescent staining. Using a chemical-induced CRC model, increased epithelial apoptosis and decreased tumor multiplicity and sizes were observed in TLR4-mutant mice compared with wild-type (WT) mice with CD14(+)TLR4(+) colonocytes. WT mice intracolonically administered a TLR4 antagonist displayed tumor reduction associated with enhanced apoptosis in cancerous tissues. Mucosa-associated LPS content was elevated in response to CRC induction. Epithelial apoptosis induced by LPS hypersensitivity in TLR4-mutant mice was prevented by intracolonic administration of neutralizing anti-CD14. Moreover, LPS-induced apoptosis was observed in primary colonic organoid cultures derived from TLR4 mutant but not WT murine crypts. Gene silencing of TLR4 increased cell apoptosis in WT organoids, whereas knockdown of CD14 ablated cell death in TLR4-mutant organoids. In vitro studies showed that LPS challenge caused apoptosis in Caco-2 cells (CD14(+)TLR4(-)) in a CD14-, phosphatidylcholine-specific phospholipase C-, sphingomyelinase-, and protein kinase C-ζ-dependent manner. Conversely, expression of functional but not mutant TLR4 (Asp299Gly, Thr399Ile, and Pro714His) rescued cells from LPS/CD14-induced apoptosis. In summary, CD14-mediated lipid signaling induced epithelial apoptosis, whereas TLR4 antagonistically promoted cell survival and cancer development. Our findings indicate that dysfunction in the CD14/TLR4 antagonism may contribute to normal epithelial transition to carcinogenesis, and provide novel strategies for intervention against colorectal cancer.

Atractylenolide-I sensitizes human ovarian cancer cells to paclitaxel by blocking activation of TLR4/MyD88-dependent pathway

Paclitaxel, a known TLR4 ligand, leads to activation of TLR4/MyD88-dependent pathway that mediates chemoresistance and tumor progression in epithelial ovarian carcinoma (EOC). Atractylenolide-I (AO-I), a novel TLR4-antagonizing agent, inhibits TLR4 signaling by interfering with the binding of LPS or paclitaxel to membrane TLR4 of human leukocytes. In this study, AO-I was found to attenuate paclitaxel-induced protein expression of IL-6, VEGF and survivin, and to enhance early apoptosis and growth inhibition in MyD88⁺ EOC cells; AO-I was shown to fit into the hydrophobic pocket of human MD-2 and to partially overlap with the binding site of paclitaxel by docking simulations, suggesting that AO-I may block the MD-2-mediated TLR4/MyD88-dependent paclitaxel signaling in MyD88⁺ EOC cells. Therefore, AO-I could significantly sensitize the response of MyD88⁺ EOC cells to paclitaxel by blocking MD-2-mediated TLR4/MyD88 signaling, and that AO-I-paclitaxel combination could be a promising strategy for the treatment of EOC with a functional TLR4/MyD88/NF-κB pathway.

Should a Toll-like receptor 4 (TLR-4) agonist or antagonist be designed to treat cancer? TLR-4: its expression and effects in the ten most common cancers

Toll-like receptor 4 (TLR-4) is well known for its host innate immunity. Despite the fact that TLR-4 activation confers antitumor responses; emerging evidence suggests that TLR-4 is associated with tumor development and progression. It is now clear that overactivation of TLR-4, through various immune mediators, may cause immune response dysfunction, resulting in tumorigenesis. Different cancers could have different extents of TLR-4 involvement during tumorigenesis or tumor progression. In this review, we focus on infection- and inflammation-related TLR-4 activation in noncancer and cancer cells, as well as on the current evidence about the role of TLR-4 in ten of the most common cancers, viz, head and neck cancer, lung cancer, gastrointestinal cancer, liver cancer, pancreatic cancer, skin cancer, breast cancer, ovarian cancer, cervical cancer, and prostate cancer.

Current smoking differentially affects blood mononuclear cells from patients with Crohn's disease and ulcerative colitis: relevance to its adverse role in the disease

BACKGROUND

Epidemiologic data suggest that smoking increases the risk and the severity of Crohn's disease (CD), although it may protect patients with ulcerative colitis (UC). To investigate this paradox, we evaluated the effect of cigarette smoke in the function of blood mononuclear cells from healthy subjects and patients with CD or UC in flare up.

METHODS

The production of mediators associated with inflammation but also with protective functions was evaluated by enzyme-linked immunosorbent assay (ELISA) and enzyme immunoassay (EIA), following either in vivo or in vitro exposure to cigarette smoke.

RESULTS

We found that mononuclear cells from smokers with CD were functionally impaired. These cells secreted lower levels of chemokines and cytokines as compared with nonsmoker counterparts, whereas healthy smokers or smokers with UC were not affected. Similar findings were noted after in vitro exposure to cigarette smoke extract. In addition, cells from patients with CD who smoke presented a defective sensitivity to antiinflammatory or antioxidant protection, and particularly synthesized lower levels of cytoprotective Hsp70. The effects observed were not due to diminished cell viability. Our experiments suggest that cigarette smoke-related responses were largely dependent on oxidative stress generated, and not on the nicotine component.

CONCLUSIONS

Overall, our data point out the presence of biological differences between blood mononuclear cells from patients with CD and UC toward cigarette smoke that might support its opposite role in both diseases.

Quantum dots hold promise for early cancer imaging and detection

Despite all major breakthroughs in recent years of research concerning the complex events that lead to cancer expression and metastasis, we are not yet able to effectively treat cancer that has spread to vital organs. The various clinical phases originating from cancer diagnosis through treatment and prognosis require a comprehensive understanding of these events, to utilise pre-symptomatic, minimally invasive and targeted cancer management techniques. Current imaging modalities such as ultrasound, computed tomography, magnetic resonance imaging and gamma scintigraphy facilitate the pre-operative study of tumours, but they have been rendered unable to visualise cancer in early stages, due to their intrinsic limitations. The semiconductor nanocrystal quantum dots (QDs) have excellent photo-physical properties, and the QDs-based probes have achieved encouraging developments in cellular (in vitro) and in vivo molecular imaging. However, the same unique physical and chemical properties which renowned QDs attractive may be associated with their potentially catastrophic effects on living cells and tissues. There are critical issues that need to be further examined to properly assess the risks associated with the manufacturing and use of QDs in cancer management. In this review, we aim to describe the current utilisation of QDs as well as their future prospective to decipher and confront cancer.

Targeted extracellular nanoparticles enable intracellular detection of activated epidermal growth factor receptor in living brain cancer cells

Mechanistic study of biological processes via Quantum Dots (QDs) remain constrained by inefficient QD delivery methods and consequent altered cell function. Here the authors present a rapid method to label activated receptor populations in live cancer cells derived from medulloblastoma and glioma tumors. The authors used QDs to bind the extracellular domain of Epidermal Growth Factor Receptor (EGF-R) proteins and then induced receptor activation to facilitate specific detection of intracellular, activated EGF-R subpopulations. Such labeling enables rapid identification of biological markers characteristic of tumor type, grade and chemotherapy resistance.

FROM THE CLINICAL EDITOR

In this paper, a rapid, quantum dot-based method is presented with the goal of labeling activated receptor populations in live cancer cells. More accurate characterization of medulloblastoma and glioma cancer cells using this biomarker detection technique may lead to a more specific targeted therapy.