RETRACTED ARTICLE: Mouse models of intestinal inflammation and cancer

Peiminine alleviate coliti-like phenotype in mice induced by lead exposure

The deleterious impact of lead (Pb) pollution on human health is evident in both domestic and occupational settings, provoking an inflammatory response across multiple tissue, limited attention has been devoted to its adverse effects on colitis and the underlying mechanisms. Peiminine (PMI) has been recognized for its anti-inflammatory properties, yet its specific anti-inflammatory effects in lead-induced colitis models remain elusive. Through the establishment of both in vivo and in vitro lead exposure models, suggests that lead exposure can induce colitis and that PMI regulates lead exposure-induced colitis by inhibiting the NF-kB signaling pathway, and alleviates the ability of lead to apoptosis and inflammation levels in intestinal epithelial cells. Consequently, these results present a promising avenue for further exploration of the molecular mechanisms underlying lead-induced colitis, evaluation of the associated risks linked to lead exposure, and the development of therapeutic interventions for colitis resulting from lead exposure.

Qingchang Wenzhong Decoction Prevents the Occurrence of Intestinal Tumors by Regulating Intestinal Microbiota and Gasdermin E

Background: Intestinal tumors are the third most common malignant tumors worldwide, accounting for approximately 10% of all new cancer cases worldwide. Cancer prevention is a promising way to limit the intestinal tumor incidence rate; however, challenges remain. Qingchang Wenzhong decoction (QCWZD) can clinically treat mild to moderate ulcerative colitis symptoms. Moreover, the mechanism by which it prevents intestinal tumors has not been clarified. In this study, we explored the mechanism by which QCWZD prevents the occurrence of intestinal tumors.

Methods: To study the preventive mechanism of QCWZD on intestinal tumors, we used two model mice with azoxymethane/dextran sodium sulfate (AOM/DSS)- and Apcmin/+-induced intestinal tumor formation. The two models exhibited colitis-associated cancer and familial adenomatous polyposis, respectively. Colon and small intestine tissues were collected and analyzed based on histopathology and immunohistochemistry analyses. Fecal samples were collected, and 16S rRNA sequencing was used to analyze the correlation between intestinal microbiota and the prevention of intestinal tumors.

Results: In the AOM/DSS mice, the QCWZD reduced the number and size of tumors, as well as tumor load. Similarly, in the Apcmin/+ mice, QCWZD can also reduce the number of tumors and the tumor load. The results of 16S rRNA sequencing confirmed that QCWZD altered the composition of intestinal microbiota in mice, a phenomenon that may prevent the occurrence of intestinal tumors by aiding the increase in the abundance of beneficial bacteria, such as Ralstonia and Butyricicoccus, and reducing that of pathogenic bacteria, such as Desulfobacterota and Bacteroides, in the intestine. Further, immunohistochemistry reveald that QCWZD can improve the expression of intestinal barrier-related proteins and inhibit pyroptosis-related proteins.

Conclusions: QCWZD has the potential to prevent the occurrence of intestinal tumors. The anti-tumor activity may be achieved by regulating the intestinal microbiota, improving the function of the intestinal barrier, and inhibiting GSDME mediated pyroptosis.

Chronic Experimental Model of TNBS-Induced Colitis to Study Inflammatory Bowel Disease

Background: Inflammatory bowel disease (IBD) is a world healthcare problem. In order to evaluate the effect of new pharmacological approaches for IBD, we aim to develop and validate chronic trinitrobenzene sulfonic acid (TNBS)-induced colitis in mice. Methods: Experimental colitis was induced by the rectal administration of multiple doses of TNBS in female CD-1 mice. The protocol was performed with six experimental groups, depending on the TNBS administration frequency, and two control groups (sham and ethanol groups). Results: The survival rate was 73.3% in the first three weeks and, from week 4 until the end of the experimental protocol, the mice’s survival remained unaltered at 70.9%. Fecal hemoglobin presented a progressive increase until week 4 (5.8 ± 0.3 µmol Hg/g feces, p < 0.0001) compared with the ethanol group, with no statistical differences to week 6. The highest level of tumor necrosis factor-α was observed on week 3; however, after week 4, a slight decrease in tumor necrosis factor-α concentration was verified, and the level was maintained until week 6 (71.3 ± 3.3 pg/mL and 72.7 ± 3.6 pg/mL, respectively). Conclusions: These findings allowed the verification of a stable pattern of clinical and inflammation signs after week 4, suggesting that the chronic model of TNBS-induced colitis develops in 4 weeks.

Role of Mucin 2 Glycoprotein and L-Fucose in Interaction of Immunity and Microbiome within the Experimental Model of Inflammatory Bowel Disease

Many factors underlie the development of inflammatory bowel disease (IBD) in humans. In particular, imbalance of microbiota and thinning of the mucosal layer in the large intestine play a huge role. Pathogenic microorganisms also exacerbate the course of diseases. In this research the role of mucin 2 deficiency in the formation of intestinal microflora in the experimental model using the Muc2 gene knockout mice in the presence of Helicobacter spp. was investigated. Also, restorative and anti-inflammatory effect of the dietary L-fucose in the Muc2^-/- mice on microflora and immunity was evaluated. For this purpose, bacterial diversity in feces was studied in the animals before and after antibiotic therapy and role of the dietary L-fucose in their recovery was assessed. To determine the effect of bacterial imbalance and fucose on the immune system, mRNA levels of the genes encoding pro-inflammatory cytokines (Tnf, Il1a, Il1b, Il6) and transcription factors of T cells (Foxp3 - Treg, Rorc - Th17, Tbx21 - Th1) were determined in the colon tissue of the Muc2^-/- mice. Significant elimination of bacteria due to antibiotic therapy caused decrease of the fucose levels in the intestine and facilitated reduction of the regulatory T cell transcription factor (Foxp3). When the dietary L-fucose was added to antibiotics, the level of bacterial DNA of Bacteroides spp. in the feces of the Muc2^-/- mice was partially restored. T regulatory cells are involved in the regulation of inflammation in the Muc2^-/- mice. Antibiotics reduced the number of regulatory T cell but did not decrease the inflammatory response to infection. Fucose, as a component of mucin 2, helped to maintain the level of Bacteroides spp. during antibiotic therapy of the Muc2^-/- mice and restored biochemical parameters, but did not affect the inflammatory response.

Epac-2 ameliorates spontaneous colitis in Il-10-/- mice by protecting the intestinal barrier and suppressing NF-κB/MAPK signalling

Intestinal barrier dysfunction and intestinal inflammation interact in the progression of Crohn's disease (CD). A recent study indicated that Epac-2 protected the intestinal barrier and had anti-inflammatory effects. The present study examined the function of Epac-2 in CD-like colitis. Interleukin-10 gene knockout (Il-10-/- ) mice exhibit significant spontaneous enteritis and were used as the CD model. These mice were treated with Epac-2 agonists (Me-cAMP) or Epac-2 antagonists (HJC-0350) or were fed normally (control), and colitis and intestinal barrier structure and function were compared. A Caco-2 and RAW 264.7 cell co-culture system were used to analyse the effects of Epac-2 on the cross-talk between intestinal epithelial cells and inflammatory cells. Epac-2 activation significantly ameliorated colitis in mice, which was indicated by reductions in the colitis inflammation score, the expression of inflammatory factors and intestinal permeability. Epac-2 activation also decreased Caco-2 cell permeability in an LPS-induced cell co-culture system. Epac-2 activation significantly suppressed nuclear factor (NF)-κB/mitogen-activated protein kinase (MAPK) signalling in vivo and in vitro. Epac-2 may be a therapeutic target for CD based on its anti-inflammatory functions and protective effects on the intestinal barrier.

Ulcerative colitis: Gut microbiota, immunopathogenesis and application of natural products in animal models

Ulcerative colitis (UC) is an inflammatory bowel disease with increasing incidence in the world, especially in developing countries. Although knowledge of its pathogenesis has progressed over the last years, some details require clarification. Studies have highlighted the role of microbial dysbiosis and immune dysfunction as essential factors that may initiate the typical high-grade inflammatory outcome. In order to better understand the immunopathophysiological aspects of UC, experimental murine models are valuable tools. Some of the most commonly used chemicals to induce colitis are trinitrobenzene sulfonic acid, oxazolone and dextran sodium sulfate. These may also be used to investigate new ways of preventing or treating UC and therefore improving targeting in human studies. The use of functional foods or bioactive compounds from plants may constitute an innovative direction towards the future of alternative medicine. Considering the above, this review focused on updated information regarding the 1. gut microbiota and immunopathogenesis of UC; 2. the most utilized animal models of the disease and their relevance; and 3. experimental application of natural products, not yet tested in clinical trials.

A Pathology Review of the Lower Gastrointestinal Tract in Relation to Ulcerative Colitis in Rats and Cynomolgus Macaques Treated With Ammonium Perfluorooctanoate

Among many short-term, subchronic, and chronic toxicology studies with ammonium perfluorooctanoate (PFOA), the gastrointestinal tract has not been identified as a target organ for PFOA-related toxicity in laboratory animals where the corresponding serum PFOA concentrations typically approach several orders of magnitude higher than the general human population. These lack of gastrointestinal tract-related findings were in direct contrast to an epidemiological observation where a positive trend was observed for ulcerative colitis, an idiopathic chronic inflammatory condition of the gut, in a Mid-Ohio River community whose drinking water contained higher levels of PFOA. This study was conducted to perform a histological reevaluation of large intestine sections in laboratory animals from 2 long-term toxicological studies: one was with Sprague Dawley rats that received ammonium PFOA in their diet for 2 years and the other one was with cynomolgus macaques that received daily capsules of ammonium PFOA for 6 months. In both studies, there was a lack of histological evidence of treatment-related inflammatory lesions that was suggestive of the occurrence of ulcerative colitis in these laboratory animals even under the most rigorous treatment schedules. These findings do not offer support for the biological plausibility of the epidemiological associations reported.

The application of ApcMin/+ mouse model in colorectal tumor researches

PURPOSE

Apc^Min/+ mouse is an excellent animal model bearing multiple intestinal neoplasia, used to simulate human familial adenomatous polyposis and colorectal tumors. The key point of this model is the mutation of Apc gene, which is a significant tumor-suppressor gene in the Wnt signaling pathway. There are also some other possible mechanisms responsible for the development of colorectal tumors in the Apc^Min/+ mouse model, such as tumor-associated signaling pathways activation, the changes of tumor-related genes, and the involvement of some related proteins or molecules.

METHODS

The relevant literatures about Apc^Min/+ mouse model from PUBMED databases are reviewed in this study.

RESULTS

In recent years, increasing studies have focused on the application of Apc^Min/+ mouse model in colorectal tumor, trying to find effective therapeutic targets for further use.

CONCLUSION

This article will give a brief review on the related molecular mechanisms of the Apc^Min/+ mouse model and its application in colorectal tumor researches.

Clinicopathological and Molecular Specificities of Inflammatory Bowel Disease-Related Colorectal Neoplastic Lesions: The Role of Inflammation

Compared with the general population, patients with inflammatory bowel disease [IBD] have an increased risk of developing colorectal cancer. Molecular mechanisms underlying colorectal carcinogenesis in the setting of IBD are not well understood. However, modern molecular investigative tools have facilitated the identification of features that help distinguish IBD-related carcinoma from sporadic carcinoma. Moreover, with advances in endoscopic technology and improved understanding of the natural history, the management of colorectal neoplastic lesions in IBD patients has evolved. This review discusses the clinicopathological and molecular features of colorectal neoplastic lesions complicating IBD. Chronic inflammation is believed to promote the development of neoplasia, partly by producing reactive oxygen and nitrogen species [ROS and NOS], which may interact with genes involved in carcinogenetic pathways. Furthermore, alterations in microbiota and in the innate and adaptive immune responses might contribute to this process, particularly by initiating, regulating, and sustaining chronic inflammation. Earlier detection and better characterization of neoplastic colorectal lesions complicating IBD and a better knowledge of the molecular mechanisms underlying carcinogenesis in this setting should facilitate improvements in the risk stratification of patients with longstanding IBD and in the management of dysplastic and malignant colorectal lesions that arise in this setting.

Energy balance and gastrointestinal cancer: risk, interventions, outcomes and mechanisms

Obesity increases the risk of multiple gastrointestinal cancers and worsens disease outcomes. Conversely, strong inverse associations have emerged between physical activity and colon cancer and possibly other gastrointestinal malignancies. The effect of weight loss interventions - such as modifications of diet and/or physical activity or bariatric surgery - remains unclear in patients who are obese and have gastrointestinal cancer, although large clinical trials are underway. Human intervention studies have already shed light on potential mechanisms underlying the energy balance-cancer relationship, with preclinical models supporting emerging pathway effects. Central to interventions that reduce obesity or increase physical activity are pluripotent cancer-preventive effects (including reduced systemic and adipose tissue inflammation and angiogenesis, altered adipokine levels and improved insulin resistance) that directly interface with the hallmarks of cancer. Other mechanisms, such as DNA repair, oxidative stress and telomere length, immune function, effects on cancer stem cells and the microbiome, could also contribute to energy balance effects on gastrointestinal cancers. Although some mechanisms are well understood (for instance, systemic effects on inflammation and insulin signalling), other areas remain unclear. The current state of knowledge supports the need to better integrate mechanistic approaches with preclinical and human studies to develop effective, personalized diet and exercise interventions to reduce the burden of obesity on gastrointestinal cancer.

Body Fatness, Adipose Tissue Compartments, and Biomarkers of Inflammation and Angiogenesis in Colorectal Cancer: The ColoCare Study

BACKGROUND

Adiposity has been linked to both risk and prognosis of colorectal cancer; however, the impact of different fat areas [visceral (VFA) vs. subcutaneous fat area (SFA)] is unclear. We investigated associations between adiposity and biomarkers of inflammation and angiogenesis among patients with colorectal cancer.

METHODS

Preoperative serum samples and computed tomography scans were obtained from 188 patients diagnosed with primary invasive stage I-IV colorectal cancer enrolled in the ColoCare Study. Adiposity was assessed by area-based quantification of VFA, SFA, and VFA:SFA ratio on spinal levels L3/L4 and L4/L5. Circulating levels of inflammation (CRP, SAA, sICAM-1, and sVCAM-1) and angiogenesis (VEGF-A and VEGF-D) were assessed from patient sera on the Meso Scale Discovery platform. Partial correlations and regression analyses, adjusted for age, sex, and tumor stage, were performed.

RESULTS

VFA was moderately correlated with CRP and SAA (CRP: L3/L4 and L4/L5:r = 0.21, P = 0.01; SAA: L3/L4:r = 0.17, P = 0.04). The correlation between SFA and the measured biomarkers were weak (r ≤ 0.13, not significant). The ratio of VFA:SFA at L3/L4 was moderately correlated with VEGF-A (r = 0.28, P = 0.0008) and SAA (r = 0.24, P = 0.006), and less so with CRP (r = 0.18, P = 0.04) and sICAM-1 (r = 0.18, P = 0.04). Similar correlations were found for the VFA:SFA ratio at L4/L5.

CONCLUSIONS

We observed an association between visceral adiposity and biomarkers of inflammation and angiogenesis in colorectal cancer. In particular, the VFA:SFA ratio was correlated with circulating levels of the proangiogenic biomarker VEGF-A.

IMPACT

Our findings support a direct association of visceral adipose tissue with inflammatory and angiogenic processes, which play fundamental roles in the development and progression of colorectal cancer.

Retraction Note to: Mouse models of intestinal inflammation and cancer

The original article can be found online.

Zoledronate Triggers Vδ2 T Cells to Destroy and Kill Spheroids of Colon Carcinoma: Quantitative Image Analysis of Three-Dimensional Cultures

New successful anti-cancer strategies are based on the stimulation of immune reaction against tumors: however, preclinical testing of such treatments is still a challenge. To improve the screening of anti-cancer drugs, three-dimensional (3D) culture systems, including spheroids, have been validated as preclinical models. We propose the spheroid 3D system to test anti-tumor drug-induced immune responses. We show that colorectal carcinoma (CRC) spheroids, generated with the epithelial growth factor (EGF), can be co-cultured with Vδ2 T cells to evaluate the anti-tumor activity of these effector lymphocytes. By computerized image analysis, the precise and unbiased measure of perimeters and areas of tumor spheroids is achievable, beside the calculation of their volume. CRC spheroid size is related to ATP content and cell number, as parameters for cell metabolism and proliferation; in turn, crystal violet staining can check the viability of cells inside the spheroids to detect tumor killing by Vδ2 T cells. In this 3D cultures, we tested (a) zoledronate that is known to activate Vδ2 T cells and (b) the therapeutic anti-EGF receptor humanized antibody cetuximab that can elicit the antibody-dependent cytotoxicity of tumor cells by effector lymphocytes. Zoledronate triggers Vδ2 T cells to kill and degrade CRC spheroids; we detected the T-cell receptor dependency of zoledronate effect, conceivably due to the recognition of phosphoantigens produced as a drug effect on target cell metabolism. In addition, cetuximab triggered Vδ2 T lymphocytes to exert the antibody-dependent cellular cytotoxicity of CRC spheroids. Finally, the system reveals differences in the sensitivity of CRC cell lines to the action of Vδ2 T lymphocytes and in the efficiency of anti-tumor effectors from distinct donors. A limitation of this model is the absence of cells, including fibroblasts, that compose tumor microenvironment and influence drug response. Nevertheless, the system can be improved by setting mixed spheroids, made of stromal and cancer cells. We conclude that this type of spheroid 3D culture is a feasible and reliable system to evaluate and measure anti-tumor drug-induced immune responses beside direct anti-cancer drug effect.

HNE and cholesterol oxidation products in colorectal inflammation and carcinogenesis

Consistent experimental data suggest the importance of inflammation-associated oxidative stress in colorectal cancer (CRC) pathogenesis. Inflammatory bowel disease with chronic intestinal inflammation is now considered a precancerous condition. Oxidative stress is an essential feature of inflammation. Activation of redox-sensitive pro-inflammatory cell signals and inflammatory mediators concur to establish a pro-tumoral environment. In this frame, lipid oxidation products, namely 4-hydroxynonenal and oxysterols, can be produced in big quantity so as to be able to exert their function as inducers of cell signaling pathways of proliferation and survival. Notably, an important source of these two compounds is represented by a high fat diet, which is undoubtedly a risk factor for inflammation and CRC development. Current evidence for the emerging implication of these two oxidized lipids in inflammation and CRC development is discussed in this review.