Pathology of rodent models of intestinal cancer: progress report and recommendations

Early administration of Wumei Wan inhibit myeloid-derived suppressor cells via PI3K/Akt pathway and amino acids metabolism to prevent colitis-associated colorectal cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Wumei Wan (WMW), a traditional Chinese medicine prescription, has been proved to be effective in treating Colitis-associated colorectal cancer (CAC), but it has not been proven to be effective in different stages of CAC.

AIM OF THE STUDY

The purpose of our study is to investigate the therapeutic effect and mechanism of WMW on the progression of CAC.

MATERIALS AND METHODS

Azioximethane (AOM) and dextran sulfate sodium (DSS) were used to treat mice for the purpose of establishing CAC models. WMW was administered in different stages of CAC. The presentative chemical components in WMW were confirmed by LC-MS/MS under the optimized conditions. The detection of inflammatory cytokines in the serum and colon of mice were estimated by qRT-PCR and ELISA. The changes of T cells and myeloid-derived suppressor cells (MDSCs) in each group were detected by flow cytometry. The metabolic components in serum of mice were detected by UPLC-MS/MS. Expression of genes and proteins were detected by eukaryotic transcriptomics and Western blot to explore the key pathway of WMW in preventing CAC.

RESULTS

WMW had significant effect on inhibiting inflammatory responses and tumors during the early development stage of CAC when compared to other times. WMW increased the length of mice's colons, reduced the level of IL-1β, IL-6, TNF-α in colon tissues, and effectively alleviated colonic inflammation, and improved the pathological damage of colon tissues. WMW could significantly reduce the infiltration of MDSCs in the spleen, increase CD4+ T cells and CD8+ T cells in the spleen of CAC mice, and effectively reform the immune microenvironment in CAC mice. Transcriptomics analysis revealed that 2204 genes had different patterns of overlap in the colon tissues of mice between control group, AOM + DSS group, and early administration of WMW group. And KEGG enrichment analysis showed that PI3K/Akt signaling pathway, ECM-receptor interaction, IL-17 signaling pathway, MAPK signaling pathway, pancreatic secretion, thermogenesis, and Rap1 signaling pathway were all involved. The serum metabolomics results of WMW showed that the metabolic compositions of the control group, AOM + DSS group and the early stage of WMW were different, and 42 differential metabolites with the opposite trends of changes were screened. The metabolic pathways mainly included pyrimidine metabolism, glycine, serine and threonine metabolism, tryptophan metabolism, and purine metabolism. And amino acids and related metabolites may play an important role in WMW prevention of CAC.

CONCLUSION

WMW can effectively prevent the occurrence and development of CAC, especially in the initial stage. WMW can reduce the immune infiltration of MDSCs in the early stage. Early intervention of WMW can improve the metabolic disorder caused by AOM + DSS, especially correct the amino acid metabolism. PI3K/Akt signaling pathway was inhabited in early administration of WMW, which can regulate the amplification and function of MDSCs.

Microcystin-LR Regulates Interaction between Tumor Cells and Macrophages via the IRE1α/XBP1 Signaling Pathway to Promote the Progression of Colorectal Cancer

Microcystin-LR (MC-LR), a cyanobacterial toxin, is a potent carcinogen implicated in colorectal cancer (CRC) progression. However, its impact on the tumor microenvironment (TME) during CRC development remains poorly understood. This study investigates the interaction between tumor cells and macrophages mediated by MC-LR within the TME and its influence on CRC progression. CRC mice exposed to MC-LR demonstrated a significant transformation from adenoma to adenocarcinoma. The infiltration of macrophages increased, and the IRE1α/XBP1 pathway was activated in CRC cells after MC-LR exposure, influencing macrophage M2 polarization under co-culture conditions. Additionally, hexokinase 2 (HK2), a downstream target of the IRE1α/XBP1 pathway, was identified, regulating glycolysis and lactate production. The MC-LR-induced IRE1α/XBP1/HK2 axis enhanced lactate production in CRC cells, promoting M2 macrophage polarization. Furthermore, co-culturing MC-LR-exposed CRC cells with macrophages, along with the IRE1α/XBP1 pathway inhibitor 4μ8C and the hexokinase inhibitor 2-DG, suppressed M2 macrophage-induced CRC cell migration, clonogenicity, and M2 macrophage polarization. This study elucidates the mechanism by which MC-LR-mediated interactions through the IRE1α/XBP1 pathway promote CRC progression, highlighting potential therapeutic targets.

A Novel CRISPR/Cas9-mediated Mouse Model of Colon Carcinogenesis

BACKGROUND & AIMS

Human sporadic colorectal cancer (CRC) results from a multistep pathway with sequential acquisition of specific genetic mutations in the colorectal epithelium. Modeling CRC in vivo is critical for understanding the tumor microenvironment. To accurately recapitulate human CRC pathogenesis, mouse models must include these multi-step genetic abnormalities. The aim of this study was to generate a sporadic CRC model that more closely mimics this multi-step process and to use this model to study the role of a novel Let7 target PLAGL2 in CRC pathogenesis.

METHODS

We generated a CRISPR/Cas9 somatic mutagenesis mouse model that is inducible and multiplexed for simultaneous inactivation of multiple genes involved in CRC pathogenesis. We used both a doxycycline-inducible transcriptional activator and a doxycycline-inactivated transcriptional repressor to achieve tight, non-leaky expression of the Cas9 nickase. This mouse has transgenic expression of multiple guide RNAs to induce sporadic inactivation in the gut epithelium of 4 tumor suppressor genes commonly mutated in CRC, Apc, Pten, Smad4, and Trp53. These were crossed to Vil-LCL-PLAGL2 mice, which have Cre-inducible overexpression of PLAGL2 in the gut epithelium.

RESULTS

These mice exhibited random somatic mutations in all 4 targeted tumor suppressor genes, resulting in multiple adenomas and adenocarcinomas in the small bowel and colon. Crosses with Vil-LCL-PLAGL2 mice demonstrated that gut-specific PLAGL2 overexpression increased colon tumor growth.

CONCLUSIONS

This conditional model represents a new CRISPR/Cas9-mediated mouse model of colorectal carcinogenesis. These mice can be used to investigate the role of novel, previously uncharacterized genes in CRC, in the context of multiple commonly mutated tumor suppressor genes and thus more closely mimic human CRC pathogenesis.

Plant-based natural products in cancer therapeutics

Various cells in our body regularly divide to replace old cells and dead cells. For a living cell to be growing, cell division and differentiation is highly essential. Cancer is characterised by uncontrollable cell division and invasion of other tissues due to dysregulation in the cell cycle. An accumulation of genetic changes or mutations develops through different physical (UV and other radiations), chemical (chewing and smoking of tobacco, chemical pollutants/mutagens), biological (viruses) and hereditary factors that can lead to cancer. Now, cancer is considered as a major death-causing factor worldwide. Due to advancements in technology, treatment like chemotherapy, radiation therapy, bone marrow transplant, immunotherapy, hormone therapy and many more in the rows. Although, it also has some side effects like fatigue, hair fall, anaemia, nausea and vomiting, constipation. Modern improved drug therapies come with severe side effects. There is need for safer, more effective, low-cost treatment with lesser side-effects. Biologically active natural products derived from plants are the emerging strategy to deal with cancer proliferation. Moreover, they possess anti-carcinogenic, anti-proliferative and anti-mutagenic properties with reduced side effects. They also detoxify and remove reactive substances formed by carcinogenic agents. In this article, we discuss different plant-based products and their mechanism of action against cancer.

Loss of primary cilia promotes inflammation and carcinogenesis

Primary cilia (PC) are important signaling hubs, and we here explored their role in colonic pathology. In the colon, PC are mostly present on fibroblasts, and exposure of mice to either chemically induced colitis-associated colon carcinogenesis (CAC) or dextran sodium sulfate (DSS)-induced acute colitis decreases PC numbers. We generated conditional knockout mice with reduced numbers of PC on colonic fibroblasts. These mice show increased susceptibility to CAC, as well as DSS-induced colitis. Secretome and immunohistochemical analyses of DSS-treated mice display an elevated production of the proinflammatory cytokine IL-6 in PC-deficient colons. An inflammatory environment diminishes PC presence in primary fibroblast cultures, which is triggered by IL-6 as identified by RNA-seq analysis together with blocking experiments. These findings suggest an activation loop between IL-6 production and PC loss. An analysis of PC presence on biopsies of patients with ulcerative colitis or colorectal cancer (CRC) reveals decreased numbers of PC on colonic fibroblasts in pathological compared with surrounding normal tissue. Taken together, we provide evidence that a decrease in colonic PC numbers promotes colitis and CRC.

Comparative Study of the Role of Interepithelial Mucosal Mast Cells in the Context of Intestinal Adenoma-Carcinoma Progression

Mast cells (MCs) are crucial players in the relationship between the tumor microenvironment (TME) and cancer cells and have been shown to influence angiogenesis and progression of human colorectal cancer (CRC). However, the role of MCs in the TME is controversially discussed as either pro- or anti-tumorigenic. Genetically engineered mouse models (GEMMs) are the most frequently used in vivo models for human CRC research. In the murine intestine there are at least three different MC subtypes: interepithelial mucosal mast cells (ieMMCs), lamina proprial mucosal mast cells (lpMMCs) and connective tissue mast cells (CTMCs). Interepithelial mucosal mast cells (ieMMCs) in (pre-)neoplastic intestinal formalin-fixed paraffin-embedded (FFPE) specimens of mouse models (total lesions n = 274) and human patients (n = 104) were immunohistochemically identified and semiquantitatively scored. Scores were analyzed along the adenoma-carcinoma sequence in humans and 12 GEMMs of small and large intestinal cancer. The presence of ieMMCs was a common finding in intestinal adenomas and carcinomas in mice and humans. The number of ieMMCs decreased in the course of colonic adenoma-carcinoma sequence in both species (p < 0.001). However, this dynamic cellular state was not observed for small intestinal murine tumors. Furthermore, ieMMC scores were higher in GEMMs with altered Wnt signaling (active β-catenin) than in GEMMs with altered MAPK signaling and wildtypes (WT). In conclusion, we hypothesize that, besides stromal MCs (lpMMCs/CTMCs), particularly the ieMMC subset is important for onset and progression of intestinal neoplasia and may interact with the adjacent neoplastic epithelial cells in dependence on the molecular environment. Moreover, our study indicates the need for adequate GEMMs for the investigation of the intestinal immunologic TME.

Loss of DRO1/CCDC80 in the tumor microenvironment promotes carcinogenesis

Tumors are composed of the tumor cells and the surrounding microenvironment. Both are closely interwoven and interact by a complex and multifaceted cross-talk which plays an integral part in tumor initiation, growth, and progression. Dro1/Ccdc80 has been shown to be a potent suppressor of colorectal cancer and ubiquitous inactivation of Dro1/Ccdc80 strongly promoted colorectal carcinogenesis in Apc^Min/+ mice and in a chemically-induced colorectal cancer model.

The aim of the present study was to investigate whether Dro1/Ccdc80’s tumor suppressive function is tumor-cell-autonomous. Expression of Dro1/Ccdc80 in cancer cells had no effect on both colon tumor development in Apc^Min/+ mice and formation of xenograft tumors. In contrast, DRO1/CCDC80 loss in the microenvironment strongly increased tumor growth in xenograft models, inhibited cancer cell apoptosis, and promoted intestinal epithelial cell migration. Moreover, stromal Dro1/Ccdc80 inactivation facilitated formation of intestinal epithelial organoids. Expression analyses showed Dro1/Ccdc80 to be significantly down-regulated in murine gastric cancer associated fibroblasts, in Apc^Min/+ colon tumor primary stromal cells and in microdissected stroma from human colorectal cancer compared to normal, non-tumor stroma. Our results demonstrate epithelial derived DRO1/CCDC80 to be dispensable for intestinal tissue homeostasis and identify Dro1/Ccdc80 as tumor suppressor in the tumor microenvironment.

In Vivo and In Vitro Enhanced Tumoricidal Effects of Metformin, Active Vitamin D3, and 5-Fluorouracil Triple Therapy against Colon Cancer by Modulating the PI3K/Akt/PTEN/mTOR Network

Chemoresistance to 5-fluorouracil (5-FU) is common during colorectal cancer (CRC) treatment. This study measured the chemotherapeutic effects of 5-FU, active vitamin D3 (VD3), and/or metformin single/dual/triple regimens as complementary/alternative therapies. Ninety male mice were divided into: negative and positive (PC) controls, and 5-FU, VD3, Met, 5-FU/VD3, 5-FU/Met, VD3/Met, and 5-FU/VD3/Met groups. Treatments lasted four weeks following CRC induction by azoxymethane. Similar regimens were also applied in the SW480 and SW620 CRC cell lines. The PC mice had abundant tumours, markedly elevated proliferation markers (survivin/CCND1) and PI3K/Akt/mTOR, and reduced p21/PTEN/cytochrome C/caspase-3 and apoptosis. All therapies reduced tumour numbers, with 5-FU/VD3/Met being the most efficacious regimen. All protocols decreased cell proliferation markers, inhibited PI3K/Akt/mTOR molecules, and increased proapoptotic molecules with an apoptosis index, and 5-FU/VD3/Met revealed the strongest effects. In vitro, all therapies equally induced G1 phase arrest in SW480 cells, whereas metformin-alone showed maximal SW620 cell numbers in the G0/G1 phase. 5-FU/Met co-therapy also showed the highest apoptotic SW480 cell numbers (13%), whilst 5-FU/VD3/Met disclosed the lowest viable SW620 cell percentages (81%). Moreover, 5-FU/VD3/Met revealed maximal inhibitions of cell cycle inducers (CCND1/CCND3), cell survival (BCL2), and the PI3K/Akt/mTOR molecules alongside the highest expression of cell cycle inhibitors (p21/p27), proapoptotic markers (BAX/cytochrome C/caspase-3), and PTEN in both cell lines. In conclusion, metformin monotherapy was superior to VD3, whereas the 5-FU/Met protocol showed better anticancer effects relative to the other dual therapies. However, the 5-FU/VD3/Met approach displayed the best in vivo and in vitro tumoricidal effects related to cell cycle arrest and apoptosis, justifiably by enhanced modulations of the PI3K/PTEN/Akt/mTOR pathway.

Enhanced anti-cancer effects of oestrogen and progesterone co-therapy against colorectal cancer in males

Although ovarian sex steroids could have protective roles against colorectal cancer (CRC) in women, little is currently known about their potential anti-tumorigenic effects in men. Hence, this study measured the therapeutic effects of 17β-oestradiol (E2) and/or progesterone (P4) against azoxymethane-induced CRC in male mice that were divided into (n = 10 mice/group): negative (NC) and positive (PC) controls, E2 (580 µg/Kg/day; five times/week) and P4 (2.9 mg/Kg/day; five times/week) monotherapies, and concurrent (EP) and sequential (E/P) co-therapy groups. Both hormones were injected intraperitoneally to the designated groups for four consecutive weeks. Similar treatment protocols with E2 (10 nM) and/or P4 (20 nM) were also used in the SW480 and SW620 human male CRC cell lines. The PC group showed abundant colonic tumours alongside increased colonic tissue testosterone levels and androgen (AR) and oestrogen (ERα) receptors, whereas E2 and P4 levels with ERβ and progesterone receptor (PGR) decreased significantly compared with the NC group. E2 and P4 monotherapies equally increased ERβ/PGR with p21/Cytochrome-C/Caspase-3, reduced testosterone levels, inhibited ERα/AR and CCND1/survivin and promoted apoptosis relative to the PC group. Both co-therapy protocols also revealed better anti-cancer effects with enhanced modulation of colonic sex steroid hormones and their receptors, with E/P the most prominent protocol. In vitro, E/P regimen showed the highest increases in the numbers of SW480 (2.1-fold) and SW620 (3.5-fold) cells in Sub-G1 phase of cell cycle. The E/P co-therapy also disclosed the lowest percentages of viable SW480 cells (2.8-fold), whilst both co-therapy protocols equally showed the greatest SW620 apoptotic cell numbers (5.2-fold) relative to untreated cells. Moreover, both co-therapy regimens revealed maximal inhibitions of cell cycle inducers, cell survival markers, and AR/ERα alongside the highest expression of cell cycle suppressors, pro-apoptotic molecules, and ERβ/PGR in both cell lines. In conclusion, CRC was associated with abnormal levels of colonic sex steroid hormones alongside aberrant protein expression of their receptors. While the anti-cancer effects of E2 and P4 monotherapies were equal, their combination protocols showed boosted tumoricidal actions against CRC in males, possibly by promoting ERβ and PGR-mediated androgen deprivation together with inhibition of ERα-regulated oncogenic pathways.

TIPE2 Promotes Tumor Initiation But Inhibits Tumor Progression in Murine Colitis-Associated Colon Cancer

BACKGROUND

Colorectal cancer (CRC) is the third leading cause of cancer in the United States, and inflammatory bowel disease patients have an increased risk of developing CRC due to chronic intestinal inflammation with it being the cause of death in 10% to 15% of inflammatory bowel disease patients. TIPE2 (TNF-alpha-induced protein 8-like 2) is a phospholipid transporter that is highly expressed in immune cells and is an important regulator of immune cell function.

METHODS

The azoxymethane/dextran sulfate sodium murine model of colitis-associated colon cancer (CAC) was employed in Tipe2 -/- and wild-type mice, along with colonoid studies, to determine the role of TIPE2 in CAC.

RESULTS

Early on, loss of TIPE2 led to significantly less numbers of visible tumors, which was in line with its previously described role in myeloid-derived suppressor cells. However, as time went on, loss of TIPE2 promoted tumor progression, with larger tumors appearing in Tipe2 -/- mice. This was associated with increased interleukin-22/STAT3 phosphorylation signaling. Similar effects were also observed in primary colonoid cultures, together demonstrating that TIPE2 also directly regulated colonocytes in addition to immune cells.

CONCLUSIONS

This work demonstrates that TIPE2 has dual effects in CAC. In the colonocytes, it works as a tumor suppressor. However, in the immune system, TIPE2 may promote tumorigenesis through suppressor cells or inhibit it through IL-22 secretion. Going forward, this work suggests that targeting TIPE2 for CRC therapy requires cell- and pathway-specific approaches and serves as a cautionary tale for immunotherapy approaches in general in terms of colon cancer, as intestinal inflammation can both promote and inhibit cancer.

Bridging the Species Gap: Morphological and Molecular Comparison of Feline and Human Intestinal Carcinomas

Simple Summary

Colorectal cancer (CRC) is the second leading cause of cancer deaths in humans (2020) but modeling late-stage human CRC, including high tumor budding and metastatic activity, experimentally in mouse models is a major challenge. In the present study, histopathological, immunohistochemical and molecular features of spontaneous intestinal carcinomas in cats were evaluated with a special focus on their potential applicability as a valuable model for human CRC. Feline intestinal tumors display aggressive growth patterns and adequately model invasive late-stage human CRC. They exhibit the same histological subtypes and display strikingly high tumor budding activity, both of which are highly significant prognostic factors in human CRC. Moreover, human and feline colorectal tumors harbor the same mutations of the CTNNB1 gene, encoding β-catenin. Our data indicate that feline intestinal carcinomas constitute a valuable and promising in vivo model for human CRC. Further comparative oncological research, and especially investigation of the molecular landscape of feline intestinal neoplasms, is imperative.

Abstract

Limited availability of in vivo experimental models for invasive colorectal cancer (CRC) including metastasis and high tumor budding activity is a major problem in colorectal cancer research. In order to compare feline and human intestinal carcinomas, tumors of 49 cats were histologically subtyped, graded and further characterized according to the human WHO classification. Subsequently, feline tumors were compared to a cohort of 1004 human CRC cases. Feline intestinal tumors closely resembled the human phenotype on a histomorphological level. In both species, adenocarcinoma not otherwise specified (ANOS) was the most common WHO subtype. In cats, the second most common subtype of the colon (36.4%), serrated adenocarcinoma (SAC), was overrepresented compared to human CRC (8.7%). Mucinous adenocarcinoma (MAC) was the second most common subtype of the small intestine (12.5%). Intriguingly, feline carcinomas, particularly small intestinal, were generally of high tumor budding (Bd) status (Bd3), which is designated an independent prognostic key factor in human CRC. We also investigated the relevance of feline CTNNB1 exon 2 alterations by Sanger sequencing. In four cases of feline colonic malignancies (3 ANOS, 1 SAC), somatic missense mutations of feline CTNNB1 (p.D32G, p.D32N, p.G34R, and p.S37F) were detected, indicating that mutational alterations of the WNT/β-catenin signaling pathway potentially play an essential role in feline intestinal tumorigenesis comparable to humans and dogs. These results indicate that spontaneous intestinal tumors of cats constitute a useful but so far underutilized model for human CRC. Our study provides a solid foundation for advanced comparative oncology studies and emphasizes the need for further (molecular) characterization of feline intestinal carcinomas.

Effects of 1,2-Dimethylhydrazine on Barrier Properties of Rat Large Intestine and IPEC-J2 Cells

Colon cancer is accompanied by a decrease of epithelial barrier properties, which are determined by tight junction (TJ) proteins between adjacent epithelial cells. The aim of the current study was to analyze the expression of TJ proteins in a rat model of 1,2-dimethylhydrazine (DMH)-induced colorectal cancer, as well as the barrier properties and TJ protein expression of IPEC-J2 cell monolayers after incubation with DMH. Transepithelial electrical resistance and paracellular permeability for sodium fluorescein of IPEC-J2 were examined by an epithelial volt/ohm meter and spectrophotometry. The expression and localization of TJ proteins were analyzed by immunoblotting and immunohistochemistry. In the colonic tumors of rats with DMH-induced carcinogenesis, the expression of claudin-3 and -4 was significantly increased compared to controls. The transepithelial electrical resistance of IPEC-J2 cells increased, while paracellular permeability for sodium fluorescein decreased, accompanied by an increased expression of claudin-4. The increase of claudin-4 in rat colon after chronic DMH exposure was consistent with the acute effect of DMH on IPEC-J2 cells, which may indicate an essential role of this protein in colorectal cancer development.

The Western Dietary Pattern Combined with Vancomycin-Mediated Changes to the Gut Microbiome Exacerbates Colitis Severity and Colon Tumorigenesis

Previous work by our group using a mouse model of inflammation-associated colorectal cancer (CAC) showed that the total Western diet (TWD) promoted colon tumor development. Others have also shown that vancomycin-mediated changes to the gut microbiome increased colorectal cancer (CRC). Therefore, the objective of this study was to determine the impact of vancomycin on colon tumorigenesis in the context of a standard mouse diet or the TWD. A 2 × 2 factorial design was used, in which C57Bl/6J mice were fed either the standard AIN93G diet or TWD and with vancomycin in the drinking water or not. While both the TWD and vancomycin treatments independently increased parameters associated with gut inflammation and tumorigenesis compared to AIN93G and plain water controls, mice fed the TWD and treated with vancomycin had significantly increased tumor multiplicity and burden relative to all other treatments. Vancomycin treatment significantly decreased alpha diversity and changed the abundance of several taxa at the phylum, family, and genus levels. Conversely, basal diet had relatively minor effects on the gut microbiome composition. These results support our previous research that the TWD promotes colon tumorigenesis and suggest that vancomycin-induced changes to the gut microbiome are associated with higher tumor rates.

Differential Effects of Trp53 Alterations in Murine Colorectal Cancer

BACKGROUND

Colorectal cancer (CRC) development is a multi-step process resulting in the accumulation of genetic alterations. Despite its high incidence, there are currently no mouse models that accurately recapitulate this process and mimic sporadic CRC. We aimed to develop and characterize a genetically engineered mouse model (GEMM) of Apc/Kras/Trp53 mutant CRC, the most frequent genetic subtype of CRC.

METHODS

Tumors were induced in mice with conditional mutations or knockouts in Apc, Kras, and Trp53 by a segmental adeno-cre viral infection, monitored via colonoscopy and characterized on multiple levels via immunohistochemistry and next-generation sequencing.

RESULTS

The model accurately recapitulates human colorectal carcinogenesis clinically, histologically and genetically. The Trp53 R172H hotspot mutation leads to significantly increased metastatic capacity. The effects of Trp53 alterations, as well as the response to treatment of this model, are similar to human CRC. Exome sequencing revealed spontaneous protein-modifying alterations in multiple CRC-related genes and oncogenic pathways, resulting in a genetic landscape resembling human CRC.

CONCLUSIONS

This model realistically mimics human CRC in many aspects, allows new insights into the role of TP53 in CRC, enables highly predictive preclinical studies and demonstrates the value of GEMMs in current translational cancer research and drug development.

Emodin Inhibits Inflammation, Carcinogenesis, and Cancer Progression in the AOM/DSS Model of Colitis-Associated Intestinal Tumorigenesis

Colorectal cancer (CRC) is one of the most common cancer worldwide. Chronic inflammation contributes to CRC development and progression. Emodin, is a natural anthraquinone derivative with anti-oxidant, anti-inflammatory, and anti-tumor activities. We used the AOM/DSS model of colitis-associated intestinal tumorigenesis to characterize the effect of Emodin on inflammation and tumorigenesis at weeks 3, 5, and 14 after initiation with AOM. At all three time points, Emodin (50 mg/kg) reduced inflammatory cell (i.e. CD11b⁺ and F4/80⁺) recruitment, cytokine (i.e. TNFα, IL1α/β, IL6, CCL2, CXCL5) and pro-inflammatory enzymes (i.e. COX-2, NOS2) expression in the tumor microenvironment, while promoting recruitment of CD3⁺ T lymphocytes at 14 weeks. Emodin decreased the incidence of premalignant lesions (adenoma) at week 3, the incidence of dysplastic lesions and carcinomas at week 5, and the incidence, size and the invasiveness of carcinomas at week 14. Emodin also reduced the acute clinical intestinal symptoms (i.e. bleeding and diarrhea) during DSS treatment. In vitro, Emodin inhibited the expression of pro-inflammatory mediators by LPS-stimulated RAW 264.7 macrophages, and reduced viability, adhesion, migration, and fibroblasts-induced invasion of SW620 and HCT116 colon cancer cells. In conclusion, this work demonstrates that Emodin suppresses carcinogenesis-associated intestinal inflammation and prevents AOM/DSS-induced intestinal tumorigenesis and progression. These results instigate further studies on Emodin as a natural agent for the prevention or treatment of colorectal cancer.

Chemopreventive effects of vitamin D3 and its analogue, paricalcitol, in combination with 5-fluorouracil against colorectal cancer: The role of calcium signalling molecules

BACKGROUND

Although vitamin D (VD) is chemoprotective and enhances 5-fluorouracil (5-FU) cytotoxicity against colorectal cancer (CRC), little is known about its potential calcium (Ca²⁺)-mediated anti-tumorigenic actions. Therefore, this study compared between VD and its non-calcaemic analogue, Paricalcitol (Pcal), ± 5-FU in relation to chemoprevention and Ca²⁺-mediated apoptosis in vivo and in vitro.

METHODS

Seventy male mice were distributed to: negative controls, positive controls (PC), VD, Pcal, 5-FU, VD + 5-FU and Pcal+5-FU groups. All groups, except negative, received two consecutive azoxymethane (AOM)-injections (10 mg/Kg/week) for CRC induction. VD₃ (1000 IU/kg; three times/week) and Pcal (1.25 μg/kg; three times/week) injections started week-16 post-AOM and for 10 weeks. Three successive 5-FU cycles began at week-21 (50 mg/Kg/week). Similar protocols with VD₃, Pcal and/or 5-FU were applied in the HT29 colon cancer cells.

RESULTS

The PC group had abundant malignant tumours, markedly elevated proliferation markers (survivin/CCND1) and declines in cyclin-dependent kinase-inhibitor-1A, pro-apoptotic molecules (p53/BAX/cytochrome_C/caspase-3), tissue Ca²⁺ concentrations and Ca²⁺-dependent proteins (CaSR/CAM/CAMKIIA). All monotherapies equally reduced tumour numbers and proliferation markers whilst promoting the anti-tumorigenic molecules. VD and/or 5-FU, but not Pcal monotherapy, enhanced Ca²⁺ levels and Ca²⁺-related molecules (CaSR/CAM/CAMKIIA/BAX/cytochrome_C) in vivo and in vitro. However, VD + 5-FU co-therapy showed the lowest tumour numbers, the highest cell numbers in sub-G1 phase of cell cycle, alongside the most effective modulations of oncogenes, tumour suppressors and Ca²⁺-related molecules at the gene and protein levels in vivo and in vitro.

CONCLUSIONS

VD₃ was superior than Paricalcitol in potentiating 5-FU cytotoxicity, possibly by upregulating several Ca²⁺-related molecules involved in tumour suppression.

Protective effect of Matricaria chamomilla extract against 1,2-dimethylhydrazine-induced colorectal cancer in mice

Background Colorectal cancer (CRC) is a major public health problem, with almost 1.8 million newly diagnosed cases and about 881,000 deaths annually. Chamomile (Matricaria chamomilla) is a well-documented medicinal herb that possesses anti-inflammatory and anti-carcinogenic properties. This study aimed to unravel the effect of aqueous chamomile extract against 1,2-dimethylhydrazine(DMH)-induced CRC in mice. Methods Male Balb/c mice received a weekly intraperitoneal injection of DMH (20 mg/kg body weight) for 12 weeks. Chamomile extract (150 mg/kg body weight/5 days/week p.o.) was administered at the initiation and post-initiation stages of carcinogenesis. Polyps count, histopathological analysis, real-time polymerase chain reaction (RT-PCR) analysis of Wnt signaling genes, ELISA of cyclooxygenase-2 (COX-2), and enzyme assay for inducible nitric oxide synthase (iNOS) were performed. Results Chamomile extract modulated the Wnt pathway in colonic tissues, where it significantly downregulated Wnt5a, β-catenin, T cell factor (Tcf4), lymphoid enhancer factor 1 (Lef1), c-Myc and Cyclin D1 expression levels, while it upregulated adenomatous polyposis coli (APC) and glycogen synthase kinase (GSK3β) expression levels. This extract significantly reduced COX-2 levels and iNOS activities. Polyps count and histopathological analysis provided supportive evidence for the biochemical and molecular analyses. Conclusions Chamomile can act as a potent dietary chemopreventive agent against DMH-induced CRC.

YYFZBJS ameliorates colorectal cancer progression in ApcMin/+ mice by remodeling gut microbiota and inhibiting regulatory T-cell generation

BACKGROUND

Progression of Colorectal cancer (CRC) is influenced by single or compounded environmental factors. Accumulating evidence shows that microbiota can influence the outcome of cancer immunotherapy. T cell, one of the main populations of effector immune cells in antitumor immunity, has been considered as a double-edged sword during the progression of CRC. Our previous studies indicate that traditional Chinese herbs (TCM) have potential anticancer effects in improving quality of life and therapeutic effect. However, little is known about the mechanism of TCM formula in cancer prevention.

METHODS

Here, we used C57BL/6 J Apc^Min/+ mice, an animal model of human intestinal tumorigenesis, to investigate the gut bacterial diversity and their mechanisms of action in gastrointestinal adenomas, and to evaluate the effects of Yi-Yi-Fu-Zi-Bai-Jiang-San (YYFZBJS) on of colon carcinogenesis in vivo and in vitro. Through human-into-mice fecal microbiota transplantation (FMT) experiments from YYFZBJS volunteers or control donors, we were able to differentially modulate the tumor microbiome and affect tumor growth as well as tumor immune infiltration.

RESULTS

We report herein, YYFZBJS treatment blocked tumor initiation and progression in Apc^Min/+ mice with less change of body weight and increased immune function. Moreover, diversity analysis of fecal samples demonstrated that YYFZBJS regulated animal's natural gut flora, including Bacteroides fragilis, Lachnospiraceae and so on. Intestinal tumors from conventional and germ-free mice fed with stool from YYFZBJS volunteers had been decreased. Some inflammation' expression also have been regulated by the gut microbiota mediated immune cells. Intestinal lymphatic, and mesenteric lymph nodes (MLN), accumulated CD4+ CD25+ Foxp3 positive Treg cells were reduced by YYFZBJS treatment in Apc^Min/+ mice. Although YYFZBJS had no inhibition on CRC cell proliferation by itself, the altered Tregs mediated by YYFZBJS repressed CRC cancer cell growth, along with reduction of the phosphorylation of β-catenin.

CONCLUSIONS

In conclusion, we demonstrated that gut microbiota and Treg were involved in CRC development and progression, and we propose YYFZBJS as a new potential drug option for the treatment of CRC. Video abstract.

Cancer Exacerbates Chemotherapy-Induced Sensory Neuropathy

For the constellation of neurologic disorders known as chemotherapy-induced peripheral neuropathy, mechanistic understanding and treatment remain deficient. Here, we present the first evidence that chronic sensory neuropathy depends on nonlinear interactions between cancer and chemotherapy. Global transcriptional profiling of dorsal root ganglia revealed differential expression, notably in regulators of neuronal excitability, metabolism, and inflammatory responses, all of which were unpredictable from effects observed with either chemotherapy or cancer alone. Systemic interactions between cancer and chemotherapy also determined the extent of deficits in sensory encoding and ion channel protein expression by single mechanosensory neurons, with the potassium ion channel Kv3.3 emerging as one potential contributor to sensory neuron dysfunction. Validated measures of sensorimotor behavior in awake, behaving animals revealed dysfunction after chronic chemotherapy treatment was exacerbated by cancer. Notably, errors in precise forelimb placement emerged as a novel behavioral deficit unpredicted by our previous study of chemotherapy alone. These original findings identify novel contributors to peripheral neuropathy and emphasize the fundamental dependence of neuropathy on the systemic interaction between chemotherapy and cancer. SIGNIFICANCE: These findings highlight the need to account for pathobiological interactions between cancer and chemotherapy as a major contributor to neuropathy and will have significant and immediate impact on future investigations in this field.

Patient-Derived In Vitro Models for Drug Discovery in Colorectal Carcinoma

Lack of relevant preclinical models that reliably recapitulate the complexity and heterogeneity of human cancer has slowed down the development and approval of new anti-cancer therapies. Even though two-dimensional in vitro culture models remain widely used, they allow only partial cell-to-cell and cell-to-matrix interactions and therefore do not represent the complex nature of the tumor microenvironment. Therefore, better models reflecting intra-tumor heterogeneity need to be incorporated in the drug screening process to more reliably predict the efficacy of drug candidates. Classic methods of modelling colorectal carcinoma (CRC), while useful for many applications, carry numerous limitations. In this review, we address the recent advances in in vitro CRC model systems, ranging from conventional CRC patient-derived models, such as conditional reprogramming-based cell cultures, to more experimental and state-of-the-art models, such as cancer-on-chip platforms or liquid biopsy.

The role of mouse models in colorectal cancer research-The need and the importance of the orthotopic models

Colorectal cancer is a worldwide health burden, with high incidence and mortality, especially in the advanced stages of the disease. Preclinical models are very important and valuable to discover and validate early and specific biomarkers as well as new therapeutic targets. In order to accomplish that, the animal models must replicate the clinical evolution of the disease in all of its phases. In this article, we review the existent mouse models, with their strengths and weaknesses in the replication of human cancer disease progression, with major focus on orthotopic models.

Consumption of the Total Western Diet Promotes Colitis and Inflammation-Associated Colorectal Cancer in Mice

Consumption of a Western type diet is a known risk factor for colorectal cancer. Our group previously developed the total Western diet (TWD) for rodents with energy and nutrient profiles that emulate a typical Western diet. In this study, we tested the hypothesis that consumption of the TWD would enhance colitis, delay recovery from gut injury and promote colon tumorigenesis. In multiple experiments using the azoxymethane + dextran sodium sulfate or Apc^Min/+ mouse models of colitis-associated colorectal carcinogenesis (CAC), we determined that mice fed TWD experienced more severe and more prolonged colitis compared to their counterparts fed the standard AIN93G diet, ultimately leading to markedly enhanced colon tumorigenesis. Additionally, this increased tumor response was attributed to the micronutrient fraction of the TWD, and restoration of calcium and vitamin D to standard amounts ameliorated the tumor-promoting effects of TWD. Finally, exposure to the TWD elicited large scale, dynamic changes in mRNA signatures of colon mucosa associated with interferon (IFN) response, inflammation, innate immunity, adaptive immunity, and antigen processing pathways, among others. Taken together, these observations indicate that consumption of the TWD markedly enhanced colitis, delayed recovery from gut injury, and enhanced colon tumorigenesis likely via extensive changes in expression of immune-related genes in the colon mucosa.

Protective Effects of Zerumbone on Colonic Tumorigenesis in Enterotoxigenic Bacteroides fragilis (ETBF)-Colonized AOM/DSS BALB/c Mice

Chronic inflammation has been linked to colitis-associated colorectal cancer in humans. The human symbiont enterotoxigenic Bacteroides fragilis (ETBF), a pro-carcinogenic bacterium, has the potential to initiate and/or promote colorectal cancer. Antibiotic treatment of ETBF has shown promise in decreasing colonic polyp formation in murine models of colon cancer. However, there are no reported natural products that have shown efficacy in decreasing polyp burden. In this study, we investigated the chemopreventive effects of oral administration of zerumbone in ETBF-colonized mice with azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced tumorigenesis. Zerumbone significantly reduced the severity of disease activity index (DAI) scores as well as several parameters of colonic inflammation (i.e., colon weight, colon length, cecum weight and spleen weight). In addition, inflammation of the colon and cecum as well as hyperplasia was reduced. Zerumbone treatment significantly inhibited colonic polyp numbers and prevented macroadenoma progression. Taken together, these findings suggest that oral treatment with zerumbone inhibited ETBF-promoted colon carcinogenesis in mice indicating that zerumbone could be employed as a promising protective agent against ETBF-mediated colorectal cancer.

Biodegradable fluorescent nanoparticles for endoscopic detection of colorectal carcinogenesis

Early and comprehensive endoscopic detection of colonic dysplasia - the most clinically significant precursor lesion to colorectal adenocarcinoma - provides an opportunity for timely, minimally-invasive intervention to prevent malignant transformation. Here, the development and evaluation of biodegradable near-infrared fluorescent silica nanoparticles (FSN) is described that have the potential to improve adenoma detection during fluorescence-assisted white-light colonoscopic surveillance in rodent and human-scale models of colorectal carcinogenesis. FSNs are biodegradable (t_1/2 of 2.7 weeks), well-tolerated, and enable detection and delineation of adenomas as small as 0.5 mm² with high tumor-to-background ratios. Furthermore, in the human-scale, APC ^1311/+ porcine model, the clinical feasibility and benefit of using FSN-guided detection of colorectal adenomas using video-rate fluorescence-assisted white-light endoscopy is demonstrated. Since nanoparticles of similar size (e.g., 100-150-nm) or composition (i.e., silica, silica/gold hybrid) have already been successfully translated to the clinic, and, clinical fluorescent/white light endoscopy systems are becoming more readily available, there is a viable path towards clinical translation of the proposed strategy for early colorectal cancer detection and prevention in high-risk patients.

Preparation of curcumin-poly (allyl amine) hydrochloride based nanocapsules: Piperine in nanocapsules accelerates encapsulation and release of curcumin and effectiveness against colon cancer cells

Curcumin (CUR) is a natural polyphenol present in the rhizomes of Curcuma longa and possesses diverse pharmacological effects, especially anti-carcinogenic effects against several types of cancers. Unfortunately, this novel compound has poor aqueous solubility and bioavailability that limit its pharmaceutical effects. The use of polymeric nanocapsules has been applied in order to overcome such problems. Thus, our present study aimed at developing two novel polymeric nanoparticles (NPs) systems that encapsulate either curcumin alone (CURN) or with piperine (CURPN), which acts as a glucuronidation inhibitor and increases the bioavailability of CUR. The NPs were successfully designed by self-assembled nanoprecipitation method and their characteristics were identified by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS), and Zeta potential analysis. The drug release profiles of NPs were monitored under different pH, and their cytotoxic effects were assessed in vitro against Caco-2 cells and in vivo against dimethylhydrazine-induced colon cancer in mice. The FTIR and XRD analyses and SEM images showed amorphous and spherical shaped CURN and CURPN of 80-100 nm sized diameter. In vitro drug release study showed that pH triggered the maximum release of CUR in basic medium compared to acidic and neutral media, and following Higuchi model. CUR nanoencapsulation enhanced its physiochemical properties and drug loading and release. In vitro and in vivo studies showed that CUR NPs exerted selective and potential cytotoxic effects against colon cancer cells. The addition of piperine facilitated the encapsulation and drug loading of CUR. Thus, CUR nanoencapsulation enhanced the solubility and bioavailability of curcumin rendering it more effective against colon cancer.

A Review of Current Standards and the Evolution of Histopathology Nomenclature for Laboratory Animals

The need for international collaboration in rodent pathology has evolved since the 1970s and was initially driven by the new field of toxicologic pathology. First initiated by the World Health Organization's International Agency for Research on Cancer for rodents, it has evolved to include pathology of the major species (rats, mice, guinea pigs, nonhuman primates, pigs, dogs, fish, rabbits) used in medical research, safety assessment, and mouse pathology. The collaborative effort today is driven by the needs of the regulatory agencies in multiple countries, and by needs of research involving genetically engineered animals, for "basic" research and for more translational preclinical models of human disease. These efforts led to the establishment of an international rodent pathology nomenclature program. Since that time, multiple collaborations for standardization of laboratory animal pathology nomenclature and diagnostic criteria have been developed, and just a few are described herein. Recently, approaches to a nomenclature that is amenable to sophisticated computation have been made available and implemented for large-scale programs in functional genomics and aging. Most terminologies continue to evolve as the science of human and veterinary pathology continues to develop, but standardization and successful implementation remain critical for scientific communication now as ever in the history of veterinary nosology.

Pathology Principles and Practices for Analysis of Animal Models

Over 60% of NIH extramural funding involves animal models, and approximately 80% to 90% of these are mouse models of human disease. It is critical to translational research that animal models are accurately characterized and validated as models of human disease. Pathology analysis, including histopathology, is essential to animal model studies by providing morphologic context to in vivo, molecular, and biochemical data; however, there are many considerations when incorporating pathology endpoints into an animal study. Mice, and in particular genetically modified models, present unique considerations because these modifications are affected by background strain genetics, husbandry, and experimental conditions. Comparative pathologists recognize normal pathobiology and unique phenotypes that animals, including genetically modified models, may present. Beyond pathology, comparative pathologists with research experience offer expertise in animal model development, experimental design, optimal specimen collection and handling, data interpretation, and reporting. Critical pathology considerations in the design and use of translational studies involving animals are discussed, with an emphasis on mouse models.

Supplementation with phytoestrogens and insoluble fibers reduces intestinal carcinogenesis and restores ER-β expression in Apc-driven colorectal carcinogenesis

Supplementation with phytoestrogens and insoluble fibers has been reported to reduce duodenal polyps in colectomized familial adenomatous polyposis patients, with a mechanism involving, at least in part, upregulation of estrogen receptor-β subtype, whose expression is lowered during intestinal tumorigenesis. These data suggest a protective effect also in the colon, the main target organ for tumorigenesis in familial adenomatous polyposis and a major cancer type in non-familial (sporadic) cancers. Therefore, we tested whether a similar preparation might reduce tumorigenesis in the colon of Pirc rats (F344/NTac-Apc) mutated in the Apc gene and thus, like familial adenomatous polyposis patients, spontaneously developing multiple tumors in the colon. We first demonstrate that estrogen receptor-β expression in Pirc rat colon is significantly down-regulated compared to age-matched wt rats. Then, Pirc rats aged 1 month were treated for 3 months with Adipol (Adi), a patented preparation containing phytoestrogens and insoluble fibers. Colon tumorigenesis was significantly reduced by Adi treatment (colon tumors/rat were 5.3 ± 0.8 and 2.9 ± 0.3, Mucin Depleted Foci/rat 127 ± 6.6 and 97.1 ± 8.6 in Controls and Adi-treated rats, respectively, means ± SE, P < 0.01). The treatment also normalized colon proliferation pattern along the crypt and significantly increased apoptosis in colon tumors. Estrogen receptor-β expression was increased by Adi treatment, especially in the tumors. These positive effects suggest that Adipol may be exploited as a chemopreventive agent to reduce cancer risk in familial adenomatous polyposis patients and to postpone prophylactic colectomy. Moreover, given the similarities between familial adenomatous polyposis and sporadic colorectal cancer, it might also be used as chemopreventive agent in colorectal cancer patients at risk.

Posttranscriptional regulation of colonic epithelial repair by RNA binding protein IMP1/IGF2BP1

RNA binding proteins, including IMP1/IGF2BP1, are essential regulators of intestinal development and cancer. Imp1 hypomorphic mice exhibit gastrointestinal growth defects, yet the specific role for IMP1 in colon epithelial repair is unclear. Our prior work revealed that intestinal epithelial cell-specific Imp1 deletion (Imp1 ^{Δ IEC} ) was associated with better regeneration in mice after irradiation. Here, we report increased IMP1 expression in patients with Crohn's disease and ulcerative colitis. We demonstrate that Imp1 ^{Δ IEC} mice exhibit enhanced recovery following dextran sodium sulfate (DSS)-mediated colonic injury. Imp1 ^{Δ IEC} mice exhibit Paneth cell granule changes, increased autophagy flux, and upregulation of Atg5. In silico and biochemical analyses revealed direct binding of IMP1 to MAP1LC3B, ATG3, and ATG5 transcripts. Genetic deletion of essential autophagy gene Atg7 in Imp1 ^{Δ IEC} mice revealed increased sensitivity of double-mutant mice to colonic injury compared to control or Atg7 single mutant mice, suggesting a compensatory relationship between Imp1 and the autophagy pathway. The present study defines a novel interplay between IMP1 and autophagy, where IMP1 may be transiently induced during damage to modulate colonic epithelial cell responses to damage.

Conserved serum protein biomarkers associated with growing early colorectal adenomas

A major challenge for the reduction of colon cancer is to detect patients carrying high-risk premalignant adenomas with minimally invasive testing. As one step, we have addressed the feasibility of detecting protein signals in the serum of patients carrying an adenoma as small as 6-9 mm in maximum linear dimension. Serum protein biomarkers, discovered in two animal models of early colonic adenomagenesis, were studied in patients using quantitative mass-spectrometric assays. One cohort included patients bearing adenomas known to be growing on the basis of longitudinal computed tomographic colonography. The other cohort, screened by optical colonoscopy, included both patients free of adenomas and patients bearing adenomas whose risk status was judged by histopathology. The markers F5, ITIH4, LRG1, and VTN were each elevated both in this patient study and in the studies of the Pirc rat model. The quantitative study in the Pirc rat model had demonstrated that the elevated level of each of these markers is correlated with the number of colonic adenomas. However, the levels of these markers in patients were not significantly correlated with the total adenoma volume. Postpolypectomy blood samples demonstrated that the elevated levels of these four conserved markers persisted after polypectomy. Two additional serum markers rapidly renormalized after polypectomy: growth-associated CRP levels were enhanced only with high-risk adenomas, while PI16 levels, not associated with growth, were reduced regardless of risk status. We discuss biological hypotheses to account for these observations, and ways for these signals to contribute to the prevention of colon cancer.

Dro1/Ccdc80 inactivation promotes AOM/DSS-induced colorectal carcinogenesis and aggravates colitis by DSS in mice

Colorectal carcinogenesis is a progressive multistep process involving the sequential accumulation of genetic alterations in tumor suppressor genes and oncogenes. Downregulated by oncogenes 1 (Dro1/Ccdc80) has been shown to be a potent tumor suppressor of colorectal carcinogenesis in the genetic ApcMin/+ mouse model. In ApcMin/+ mice, loss of DRO1 strongly increases colonic tumor multiplicity and leads to the regular formation of adenocarcinoma in the colon. To investigate DRO1's role in chemically induced as well as inflammation-associated colorectal carcinogenesis, the effect of Dro1 inactivation was studied in mice subjected to the carcinogen azoxymethane (AOM) and upon combined treatment with AOM and the proinflammatory agent dextran sodium sulfate (DSS), respectively. Loss of DRO1 increases multiplicity of preneoplastic aberrant crypt foci and colonic tumors upon administration of AOM. Combined treatment with AOM and DSS leads to increased colonic tumor number and promotes formation of adenocarcinoma in the colon. Moreover, Dro1 inactivation aggravates histological signs of acute and chronic DSS-induced colitis, strongly enlarges the size of ulcerative lesions in the intestinal lining, and exacerbates clinical signs and morbidity by DSS. Our results demonstrate DRO1 to be a strong tumor suppressor in the chemically induced colon carcinogenic mouse model. Additionally, we demonstrate DRO1 to inhibit colitis-associated colon cancer formation and uncover a novel putative role for DRO1 in inflammatory bowel disease.

A multifaceted approach for analyzing complex phenotypic data in rodent models of autism

Autism (MIM 209850) is a multifactorial disorder with a broad clinical presentation. A number of high-confidence ASD risk genes are known; however, the contribution of non-genetic environmental factors towards ASD remains largely uncertain. Here, we present a bioinformatics resource of genetic and induced models of ASD developed using a shared annotation platform. Using this data, we depict the intricate trends in the research approaches to analyze rodent models of ASD. We identify the top 30 most frequently studied phenotypes extracted from rodent models of ASD based on 787 publications. As expected, many of these include animal model equivalents of the “core” phenotypes associated with ASD, such as impairments in social behavior and repetitive behavior, as well as several comorbid features of ASD including anxiety, seizures, and motor-control deficits. These phenotypes have also been studied in models based on a broad range of environmental inducers present in the database, of which gestational exposure to valproic acid (VPA) and maternal immune activation models comprising lipopolysaccharide (LPS) and poly I:C are the most studied. In our unique dataset of rescue models, we identify 24 pharmaceutical agents tested on established models derived from various ASD genes and CNV loci for their efficacy in mitigating symptoms relevant for ASD. As a case study, we analyze a large collection of Shank3 mouse models providing a high-resolution view of the in vivo role of this high-confidence ASD gene, which is the gateway towards understanding and dissecting the heterogeneous phenotypes seen in single-gene models of ASD. The trends described in this study could be useful for researchers to compare ASD models and to establish a complete profile for all relevant animal models in ASD research.

FXR Regulates Intestinal Cancer Stem Cell Proliferation

Increased levels of intestinal bile acids (BAs) are a risk factor for colorectal cancer (CRC). Here, we show that the convergence of dietary factors (high-fat diet) and dysregulated WNT signaling (APC mutation) alters BA profiles to drive malignant transformations in Lgr5-expressing (Lgr5+) cancer stem cells and promote an adenoma-to-adenocarcinoma progression. Mechanistically, we show that BAs that antagonize intestinal farnesoid X receptor (FXR) function, including tauro-β-muricholic acid (T-βMCA) and deoxycholic acid (DCA), induce proliferation and DNA damage in Lgr5+ cells. Conversely, selective activation of intestinal FXR can restrict abnormal Lgr5+ cell growth and curtail CRC progression. This unexpected role for FXR in coordinating intestinal self-renewal with BA levels implicates FXR as a potential therapeutic target for CRC.

Mlh1 deficiency in normal mouse colon mucosa associates with chromosomally unstable colon cancer

Colorectal cancer (CRC) genome is unstable and different types of instabilities, such as chromosomal instability (CIN) and microsatellite instability (MSI) are thought to reflect distinct cancer initiating mechanisms. Although 85% of sporadic CRC reveal CIN, 15% reveal mismatch repair (MMR) malfunction and MSI, the hallmarks of Lynch syndrome with inherited heterozygous germline mutations in MMR genes. Our study was designed to comprehensively follow genome-wide expression changes and their implications during colon tumorigenesis. We conducted a long-term feeding experiment in the mouse to address expression changes arising in histologically normal colonic mucosa as putative cancer preceding events, and the effect of inherited predisposition (Mlh1^+/−) and Western-style diet (WD) on those. During the 21-month experiment, carcinomas developed mainly in WD-fed mice and were evenly distributed between genotypes. Unexpectedly, the heterozygote (B6.129-Mlh1^tm1Rak) mice did not show MSI in their CRCs. Instead, both wildtype and heterozygote CRC mice showed a distinct mRNA expression profile and shortage of several chromosomal segregation gene-specific transcripts (Mlh1, Bub1, Mis18a, Tpx2, Rad9a, Pms2, Cenpe, Ncapd3, Odf2 and Dclre1b) in their colon mucosa, as well as an increased mitotic activity and abundant numbers of unbalanced/atypical mitoses in tumours. Our genome-wide expression profiling experiment demonstrates that cancer preceding changes are already seen in histologically normal colon mucosa and that decreased expressions of Mlh1 and other chromosomal segregation genes may form a field-defect in mucosa, which trigger MMR-proficient, chromosomally unstable CRC.

Glucocorticoids promote the development of azoxymethane and dextran sulfate sodium-induced colorectal carcinoma in mice

BACKGROUND

Stress has been suggested as a promoter of tumor growth and development. Glucocorticoids (GCs) are the main stress hormones and widely prescribed as drugs. However, the effect of GCs on the development and progression of colorectal carcinoma (CRC) is unclear.

METHODS

We evaluated the effect of corticosterone (CORT) on azoxymethane and dextran sulfate sodium (AOM/DSS)-induced carcinogenesis in the colorectum of C57BL/6 strain mice. Plasma level of CORT was detected by radioimmunoassay. The expression of proliferation markers (Ki-67 and PCNA), nuclear factor (NF)-κB p65 and phosphoto-p65 (P-p65), as well as cyclooxygenase (COX)-2 were determined by immunohistochemistry. Inflammation in colorectum was evaluated by histopathology.

RESULTS

CORT feeding in drinking water of mice not only significantly elevated plasma CORT concentration, but also significantly increased the incidence and neoplasms burden (number and size of neoplasms) in colorectum. CORT also significant enhanced the expression of cell proliferation marker (Ki-67 and PCNA), NF-κB p65 and P-p65 as well as COX-2 in colorectal neoplasm of AOM/DSS-treated mice.

CONCLUSION

In this study, we have found for the first time that CORT at stress level potentially promotes the growth and development of AOM/DSS-induced colorectal adenoma and carcinoma in mice. Up-regulation of NF-κB and COX-2 may be involved in the promoting effect of CORT.

Morin-dependent inhibition of low molecular weight protein tyrosine phosphatase (LMW-PTP) restores sensitivity to apoptosis during colon carcinogenesis: Studies in vitro and in vivo, in an Apc-driven model of colon cancer

LMW-PTP has been associated with the development of colorectal cancer (CRC) and with the resistance to chemotherapy in cancer cells. To clarify its role in vivo, we studied LMW-PTP expression in Pirc rats (F344/NTac-Apc ^am1137 ), genetically prone to CRC and resistant to apoptosis. In the morphologically normal mucosa (NM) of Pirc rats, a dramatic over-expression of LMW-PTP was found compared to wt rats (about 60 times higher). Moreover, LMW-PTP levels further increase in spontaneously developed Pirc colon tumors. To understand if and how LMW-PTP affects resistance to apoptosis, we studied CRC cell lines, sensitive (HT29 and HCT-116), or resistant (HT29R, HCT116R) to 5-Fluorouracil (5-FU): resistant cells over-express LMW-PTP. When resistant cells were challenged with morin, a polyphenol inhibiting LMW-PTP, a fast and dose-related down-regulation of LMW-PTP was observed. 5-FU and morin co-treatment dramatically decreased cell viability, increased apoptosis, and significantly impaired self-renewal ability of all the cancer cell lines we have studied. Similarly, we observed that, in Pirc rats, one-week morin administration (50 mg/kg) down-regulated LMW-PTP and restored the apoptotic response to 5-FU in the NM. Finally, administration of morin for a longer period led to a significant reduction in colon precancerous lesions, together with a down-regulation of LMW-PTP. Taken together, these results document the involvement of LMW-PTP in the process of CRC in vitro and in vivo. Morin treatment may be envisaged as a system to increase the sensitivity to chemotherapy and to prevent carcinogenesis.

Knockout of ClC-2 reveals critical functions of adherens junctions in colonic homeostasis and tumorigenicity

Adherens junctions (AJs), together with tight junctions (TJs), form an apical junctional complex that regulates intestinal epithelial cell-to-cell adherence and barrier homeostasis. Within the AJ, membrane-bound E-cadherin binds β-catenin, which functions as an essential intracellular signaling molecule. We have previously identified a novel protein in the region of the apical junction complex, chloride channel protein-2 (ClC-2), that we have used to study TJ regulation. In this study, we investigated the possible effects of ClC-2 on the regulation of AJs in intestinal mucosal epithelial homeostasis and tumorigenicity. Mucosal homeostasis and junctional proteins were examined in wild-type (WT) and ClC-2 knockout (KO) mice as well as associated colonoids. Tumorigenicity and AJ-associated signaling were evaluated in a murine colitis-associated tumor model and in a colorectal cancer cell line (HT-29). Colonic tissues from ClC-2 KO mice had altered ultrastructural morphology of intercellular junctions with reduced colonocyte differentiation, whereas jejunal tissues had minimal changes. Colonic crypts from ClC-2 KO mice had significantly higher numbers of less-differentiated forms of colonoids compared with WT. Furthermore, the absence of ClC-2 resulted in redistribution of AJ proteins and increased β-catenin activity. Downregulation of ClC-2 in colorectal cells resulted in significant increases in proliferation associated with disruption of AJs. Colitis-associated tumors in ClC-2 KO mice were significantly increased, associated with β-catenin transcription factor activation. The absence of ClC-2 results in less differentiated colonic crypts and increased tumorigenicity associated with colitis via dysregulation of AJ proteins and activation of β-catenin-associated signaling. NEW & NOTEWORTHY Disruption of adherens junctions in the absence of chloride channel protein-2 revealed critical functions of these junctional structures, including maintenance of colonic homeostasis and differentiation as well as driving tumorigenicity by regulating β-catenin signaling.

Keeping Score: Semiquantitative and Quantitative Scoring Approaches to Genetically Engineered and Xenograft Mouse Models of Cancer

There is a growing need to quantitate or "score" lesions in mouse models of human disease, for correlation with human disease and to establish their clinical relevance. Several standard semiquantitative scoring schemes have been adapted for nonneoplastic lesions; similarly, the pathologist must carefully select an approach to score mouse models of cancer. Genetically engineered mouse models with a continuum of precancerous and cancerous lesions and xenogeneic models of various derivations present unique challenges for the pathologist. Important considerations include experimental design, understanding of the human disease being modeled, standardized classification of lesions, and approaches for semiquantitative and/or quantitative scoring in the model being evaluated. Quantification should be considered for measuring the extent of neoplasia and expression of tumor biomarkers. Semiquantitative scoring schemes have been devised that include severity, frequency, and distribution of lesions. Although labor-intensive, scoring mouse models of cancer provides numerical data that enable statistical analysis and greater translational impact.

Replication Study: Intestinal inflammation targets cancer-inducing activity of the microbiota

As part of the Reproducibility Project: Cancer Biology we published a Registered Report (Eaton et al., 2015) that described how we intended to replicate selected experiments from the paper "Intestinal Inflammation Targets Cancer-Inducing Activity of the Microbiota" (Arthur et al., 2012). Here we report the results. We observed no impact on bacterial growth or colonization capacity when the polyketide synthase (pks) genotoxic island was deleted from E. coli NC101, similar to the original study (Supplementary Figure 7; Arthur et al., 2012). However, for the experiment that compared inflammation, invasion, and neoplasia in azoxymethane (AOM)-treated interleukin-10-deficient mice mono-associated with NC101 or NC101[Formula: see text] pks the experimental timing of the replication attempt was longer than that of the original study. This difference was because in the original study the methodology was not clearly stated and likely led to the increased mortality and severity of inflammation observed in this replication attempt. Additionally, early death occurred during AOM treatment with higher mortality observed in NC101[Formula: see text] pks mono-associated mice compared to NC101, which was in the same direction, but more severe than the original study (Suppleme1ntal Figure 10; Arthur et al., 2012). A meta-analysis suggests that mice mono-associated with NC101[Formula: see text] pks have higher mortality compared to NC101. While these data were unable to address whether, under the conditions of the original study, NC101 and NC101[Formula: see text] pks differ in inflammation, invasion, and neoplasia this replication attempt demonstrates that clear description of experimental methods is essential to ensure accurate reproduction of experimental studies.

The conserved protective cyclic AMP-phosphodiesterase function PDE4B is expressed in the adenoma and adjacent normal colonic epithelium of mammals and silenced in colorectal cancer

Conservation over three mammalian genera-the mouse, rat, and human-has been found for a subset of the transcripts whose level differs between the adenoma and normal epithelium of the colon. Pde4b is one of the triply conserved transcripts whose level is enhanced both in the colonic adenoma and in the normal colonic epithelium, especially adjacent to adenomas. It encodes the phosphodiesterase PDE4B, specific for cAMP. Loss of PDE4B function in the ApcMin/+ mouse leads to a significant increase in the number of colonic adenomas. Similarly, Pde4b-deficient ApcMin/+ mice are hypersensitive to treatment by the inflammatory agent DSS, becoming moribund soon after treatment. These observations imply that the PDE4B function protects against ApcMin-induced adenomagenesis and inflammatory lethality. The paradoxical enhancement of the Pde4b transcript in the adenoma versus this inferred protective function of PDE4B can be rationalized by a feedback model in which PDE4B is first activated by early oncogenic stress involving cAMP and then, as reported for frank human colon cancer, inactivated by epigenetic silencing.

Vitamin D deficiency in the ApcPirc/+ rat does not exacerbate colonic tumorigenesis, while low dietary calcium might be protective

Human studies have shown that individuals with colon cancer tend to have lower serum 25-hydroxy-vitamin D₃ [25(OH)D₃] levels compared with healthy controls, but whether this link is causative, a result of the disease or an indicator of another factor altogether has yet to be demonstrated. In humans, vitamin D, calcium and UV exposure are inextricably linked; therefore, understanding the individual and combined roles of each of these will require animal models specifically designed to address these questions. To begin to untangle this network, our group has employed the Apc^Pirc/+ rat, which contains a truncating mutation in the Apc gene, leading to the development of colonic tumors. Our group previously utilized this model to demonstrate that vitamin D supplementation above normal does not reduce colonic tumor burden and, in fact, increased tumor multiplicity in a dose-dependent manner. In the current study, we tested whether vitamin D deficiency plays a causative role in tumor development using two strains which differ in their susceptibility to intestinal tumorigenesis. In the colon, vitamin D deficiency did not increase the development of tumors in either strain, and was actually protective in one strain. Unexpectedly, low dietary calcium combined with vitamin D deficiency significantly suppressed tumor development in the small intestine and colon of both strains. The vast majority of tumors in the human intestine occur in the colon, and we find no evidence to support a direct role of vitamin D deficiency in increasing colonic tumorigenesis, and low calcium might protect against tumor development.This article has an associated First Person interview with the first author of the paper.

Increased paracellular permeability of tumor-adjacent areas in 1,2-dimethylhydrazine-induced colon carcinogenesis in rats

Objective:

The morphology and functions of the proximal and distal large intestine are not the same. The incidence of colorectal cancer in these regions is also different, as tumors more often appear in the descending colon than in the ascending colon. Inflammatory bowel disease and colorectal cancer can increase transepithelial permeability, which is a sign of reduced intestinal barrier function. However, there is not enough evidence to establish a connection between the difference in colorectal cancer incidence in the proximal and distal colon and intestinal permeability or the effects of carcinogenesis on the barrier properties in various areas of the colon. The aim of the study was to assess the permeability of different segments of the large intestine according to a developed mapping methodology in healthy rats and rats with 1,2-dimethylhydrazine (DMH)-induced colon adenocarcinoma.

Methods:

The short circuit current, the transepithelial electrical resistance and the paracellular permeability to fluorescein of large intestine wall of male Wistar rats were examined in the Ussing chambers. The optical density of the solution from the serosa side to assess the concentration of the diffused fluorescein from mucosa to serosa was analyzed by spectrophotometry. The morphometric and histological studies were performed by optical microscopy.

Results:

Rats with DMH-induced colon adenocarcinomas showed elevated transepithelial electrical resistance in the areas of neoplasm development. In contrast, there was no change in the electrophysiological properties of tumor adjacent areas, however, the paracellular permeability of these areas to fluorescein was increased compared to the control rats and was characterized by sharply reduced barrier function.

Conclusions:

The barrier properties of the colon vary depending on tumor location. The tumors were less permeable than the intact intestinal wall and probably have a negative influence on tumor-adjacent tissues by disrupting their barrier function.

The Role of Resveratrol in Cancer Therapy

Natural product compounds have recently attracted significant attention from the scientific community for their potent effects against inflammation-driven diseases, including cancer. A significant amount of research, including preclinical, clinical, and epidemiological studies, has indicated that dietary consumption of polyphenols, found at high levels in cereals, pulses, vegetables, and fruits, may prevent the evolution of an array of diseases, including cancer. Cancer development is a carefully orchestrated progression where normal cells acquires mutations in their genetic makeup, which cause the cells to continuously grow, colonize, and metastasize to other organs such as the liver, lungs, colon, and brain. Compounds that modulate these oncogenic processes can be considered as potential anti-cancer agents that may ultimately make it to clinical application. Resveratrol, a natural stilbene and a non-flavonoid polyphenol, is a phytoestrogen that possesses anti-oxidant, anti-inflammatory, cardioprotective, and anti-cancer properties. It has been reported that resveratrol can reverse multidrug resistance in cancer cells, and, when used in combination with clinically used drugs, it can sensitize cancer cells to standard chemotherapeutic agents. Several novel analogs of resveratrol have been developed with improved anti-cancer activity, bioavailability, and pharmacokinetic profile. The current focus of this review is resveratrol’s in vivo and in vitro effects in a variety of cancers, and intracellular molecular targets modulated by this polyphenol. This is also accompanied by a comprehensive update of the various clinical trials that have demonstrated it to be a promising therapeutic and chemopreventive agent.

A genetically inducible porcine model of intestinal cancer

Transgenic porcine cancer models bring novel possibilities for research. Their physical similarities with humans enable the use of surgical procedures and treatment approaches used for patients, which facilitates clinical translation. Here, we aimed to develop an inducible oncopig model of intestinal cancer. Transgenic (TG) minipigs were generated using somatic cell nuclear transfer by handmade cloning. The pigs encode two TG cassettes: (a) an Flp recombinase‐inducible oncogene cassette containing KRAS‐G12D, cMYC, SV40LT – which inhibits p53 – and pRB and (b) a 4‐hydroxytamoxifen (4‐OHT)‐inducible Flp recombinase activator cassette controlled by the intestinal epithelium‐specific villin promoter. Thirteen viable transgenic minipigs were born. The ability of 4‐OHT to activate the oncogene cassette was confirmed in vitro in TG colonic organoids and ex vivo in tissue biopsies obtained by colonoscopy. In order to provide proof of principle that the oncogene cassette could also successfully be activated in vivo, three pigs were perorally treated with 400 mg tamoxifen for 2 × 5 days. After two months, one pig developed a duodenal neuroendocrine carcinoma with a lymph node metastasis. Molecular analysis of the carcinoma and metastasis confirmed activation of the oncogene cassette. No tumor formation was observed in untreated TG pigs or in the remaining two treated pigs. The latter indicates that tamoxifen delivery can probably be improved. In summary, we have generated a novel inducible oncopig model of intestinal cancer, which has the ability to form metastatic disease already two months after induction. The model may be helpful in bridging the gap between basic research and clinical usage. It opens new venues for longitudinal studies of tumor development and evolution, for preclinical assessment of new anticancer regimens, for pharmacology and toxicology assessments, as well as for studies into biological mechanisms of tumor formation and metastasis.

Papilloma-pseudovirus eradicates intestinal tumours and triples the lifespan of ApcMin/+ mice

Inducing tumour-specific adaptive immunity, such as cytotoxic T lymphocyte (CTL) response, can result in promising antitumour effect against several human malignancies, especially in combination with immune checkpoint blockade strategies. However, little is known whether activation of innate immunity can lead to direct tumoricidal effect. Here, we develop a papilloma pseudovirus-based oral immunotherapeutic approach that shows strong tumoricidal effects in the gut, resulting in an almost tripled lifespan of Apc^Min/+ mice (an animal model of human intestinal tumorigenesis). Mechanistically, these pseudoviruses activate the NLRP3 and AIM2 inflammasomes, leading to caspase-1-mediated tumour regression that is dependent on neither cytotoxic T lymphocytes nor humoral immune response. Blocking caspase-1 activation abrogated the therapeutic effects of the pseudoviruses. Thus, targeting innate immune sensors in tumours by the pseudoviruses might represent a strategy to treat intestinal tumours.

Prevention of tumorigenesis in mice by exercise is dependent on strain background and timing relative to carcinogen exposure

Among cancer diagnoses, colorectal cancer (CRC) is prevalent, with a lifetime risk of developing CRC being approximately 5%. Population variation surrounding the mean risk of developing CRCs has been associated with both inter-individual differences in genomic architecture and environmental exposures. Decreased risk of CRC has been associated with physical activity, but protective responses are variable. Here, we utilized a series of experiments to examine the effects of genetic background (strain), voluntary exercise (wheel running), and their interaction on azoxymethane (AOM)-induced intestinal tumor number and size in mice. Additionally, we investigated how the timing of exercise relative to AOM exposure, and amount of exercise, affected tumor number and size. Our results indicated that voluntary exercise significantly reduced tumor number in a strain dependent manner. Additionally, among strains where exercise reduced tumor number (A/J, CC0001/Unc) the timing of voluntary exercise relative to AOM exposure was crucial. Voluntary exercise prior to or during AOM treatment resulted in a significant reduction in tumor number, but exercise following AOM exposure had no effect. The results indicate that voluntary exercise should be used as a preventative measure to reduce risk for environmentally induced CRC with the realization that the extent of protection may depend on genetic background.

Thymoquinone potentiates chemoprotective effect of Vitamin D3 against colon cancer: a pre-clinical finding

Prevention of colon cancer among high-risk group has been long lasting research goal. Emerging data have evidenced the anticancer activities of Vitamin D3 (Vit.D) and Thymoquinone (TQ). The aim of the current study was to evaluate the synergistic potential of Thymoquinone and Vitamin D3 in the control of colon cancer progression using azoxymethane-induced rat model. Vit.D and TQ were given individually or in combination 4 week prior to induction and continued for a total of 20 week. At the end of the study, all animals were euthanized and their resected colons were examined macroscopically and microscopically for tumor growth. Colonic tissue preparations were used for measuring gene expression and/or protein levels of selected pro and anti-tumor biomarkers using quantitative RT-PCR, ELISA and immunohistochemistry. Compared with their individual supplementation, combined Vit.D/TQ showed prominent anti-tumor effect manifested by significant reduction (P < 0.05) of the numbers of grown tumors and large aberrant crypts foci. Mechanistically, gene expression and/or protein quantification studies revealed that combined Vit.D/TQ supplementation induced significant reduction (P < 0.01 and P < 0.05) of pro-cancerous molecules (Wnt, β-catenin, NF-κB, COX-2, iNOS, VEGF and HSP-90) as well as significant increase (P < 0.01 and P < 0.05, respectively) of anti-tumorigenesis biomarkers (DKK-1, CDNK-1A, TGF-β1, TGF-β/RII and smad4) as compared to un-supplemented or individually supplemented groups, respectively. In conclusion, TQ augmented the chemopreventive effect of Vit.D during the initiation phase of colon cancer in rat model, with the potential to suppress progression of pre-neoplastic lesions in colon carcinogenesis.

Murine Models of Gastric Corpus Preneoplasia

Intestinal-type gastric adenocarcinoma evolves in a field of pre-existing metaplasia. Over the past 20 years, a number of murine models have been developed to address aspects of the physiology and pathophysiology of metaplasia induction. Although none of these models has achieved true recapitulation of the induction of adenocarcinoma, they have led to important insights into the factors that influence the induction and progression of metaplasia. Here, we review the pathologic definitions relevant to alterations in gastric corpus lineages and classification of metaplasia by specific lineage markers. In addition, we review present murine models of the induction and progression of spasmolytic polypeptide (TFF2)-expressing metaplasia, the predominant metaplastic lineage observed in murine models. These models provide a basis for the development of a broader understanding of the physiological and pathophysiological roles of metaplasia in the stomach.