Colorectal Tumorigenesis In Mice Research Articles

Expression of FIBCD1 by intestinal epithelial cells alleviates inflammation-driven tumorigenesis in a mouse model of colorectal cancer

BackgroundColorectal cancer (CRC) ranks as the third most prevalent cancer globally, highlighting the pressing need to address its development. Inflammation plays a crucial role in augmenting the risk of CRC and actively contributes to all stages of tumorigenesis. Consequently, targeting early inflammatory responses in the intestinal tract to restore homeostasis holds significant potential for preventing and treating CRC. Fibrinogen C domain-containing 1 (FIBCD1), a chitin-binding transmembrane protein predominantly found on human intestinal epithelial cells (IECs), has garnered attention in previous research for its ability to effectively suppress inflammatory responses and promote tissue homeostasis at mucosal barriers.MethodsIn this study, we investigated the role of FIBCD1 in CRC development using transgenic mice that mimic human expression of FIBCD1 at the intestinal mucosal barrier. To model aspects of CRC, we employed the azoxymethane/dextran sodium sulfate (AOM/DSS) mouse model. Additionally, we examined the expression pattern of FIBCD1 in surgical specimens obtained from human CRC patients by immunohistochemical methods. By accessing public data repositories, we further evaluated FIBCD1 expression in colon adenocarcinoma and explored survival outcomes associated with FIBCD1 expression.ResultsHere, we demonstrate that FIBCD1 substantially impacts CRC development by significantly reducing intestinal inflammation and suppressing colorectal tumorigenesis in mice. Furthermore, we identify a soluble variant of FIBCD1 that is significantly increased in feces during acute inflammation. Finally, we demonstrate increased expression of FIBCD1 by immunohistochemistry in human CRC specimens at more developed tumor stages. These results are further supported by bioinformatic analyses of publicly available repositories, indicating increased FIBCD1 expression in tumor tissues, where higher expression is associated with unfavorable prognosis.ConclusionCollectively, these findings suggest that FIBCD1 influences early inflammatory responses in the AOM/DSS model, leading to a reduction in tumor size and burden. The increased expression of FIBCD1 in human CRC samples raises intriguing questions regarding its role in CRC, positioning it as a compelling candidate and novel molecular target for future research.

Yogurt Prevents Colitis-Associated Colorectal Cancer in Mice.

Epidemiological studies indicate an inverse correlation between yogurt consumption and colorectal cancer (CRC), but whether there is a cause-and-effect relationship has not yet been validated. This study aims to investigate the effects and possible mechanisms of yogurt on colitis-associated colorectal cancer (CAC) in mice. Experimental CAC is induced by azoxymethane (AOM, 10mgkg-1 , ip) followed by three cycles of dextran sulfate sodium (DSS, 3%) treatment. Colitis is induced by adding DSS (3%) in drinking water for 5 days. Primary mouse macrophages are isolated for mechanistic studies. Data clearly show that yogurt (15gkg-1 body weight) significantly reduces the multiplicity of colonic neoplasms by 38.83% in mice. Yogurt protects mice from colitis dependent on lactate receptor GPR81. The deficiency of Gpr81 exacerbates colitis and CAC in mice. Further investigation reveals that GPR81 may be dispensable for gut barrier function but essential for colonic mucosal repair. d-lactate in yogurt can activate GPR81 to suppress proinflammatory macrophage polarization, thereby facilitating inflammatory resolution after colonic injury and consequently suppressing CAC progression. Yogurt effectively protects against colitis-associated colorectal tumorigenesis in mice, and this study provides a rationale for introducing yogurt supplementation to patients with chronic inflammatory bowel diseases.

Sulforaphane Attenuates AOM/DSS-Induced Colorectal Tumorigenesis in Mice via Inhibition of Intestinal Inflammation

Sulforaphane (SFN) is a compound derived from cruciferous plants. It has received considerable attention in recent years due to its effectiveness in cancer prevention and anti-inflammatory properties. The purpose of this study was to evaluate the antitumor potential of sulforaphane on colitis-associated carcinogenesis (CAC) through the establishment of a mouse model with AOM/DSS. First, AOM/DSS and DSS-induced model were established and administered SFN for 10 wk, and then the severity of colitis-associated colon cancer was examined macroscopically and histologically. Subsequently, immune cells and cytokines in the tumor microenvironment (TME) were quantified. Finally, the influence of sulforaphane was also investigated using different colon cell lines. We found that sulforaphane treatment decreased tumor volume, myeloid-derived suppressor cells (MDSC) expansion, the expression of the proinflammatory cytokine IL-1β, and the level of IL-10 in serum. Also, it enhanced the antitumor activities of CD8+ T cells and significantly reduced tumorigenesis as induced by AOM/DSS. SFN also attenuated intestinal inflammation in DSS-induced chronic colitis by reshaping the inflammatory microenvironment. This work demonstrates that sulforaphane suppresses carcinogenesis-associated intestinal inflammation and prevents AOM/DSS-induced intestinal tumorigenesis and progression.

High Soluble Fiber Promotes Colorectal Tumorigenesis Through Modulating Gut Microbiota and Metabolites in Mice

Dietary fibers are mainly fermented by the gut microbiota, but their roles in colorectal cancer (CRC) are largely unclear. Here, we investigated the associations of different fibers with colorectal tumorigenesis in mice. Apcmin/+ mice and C57BL/6 mice with azoxymethane (AOM) injection were used as CRC mouse models. Mice were fed with mixed high-fiber diet (20% soluble fiber and 20% insoluble fiber), high-inulin diet, high-guar gum diet, high-cellulose diet, or diets with different inulin dose. Germ-free mice were used for validation. Fecal microbiota and metabolites were profiled by shotgun metagenomic sequencing and liquid chromatography-mass spectrometry, respectively. Mixed high-fiber diet promoted colorectal tumorigenesis with increased tumor number and tumor load in AOM-treated and Apcmin/+ mice. Antibiotics use abolished the pro-tumorigenic effect of mixed high-fiber diet, while transplanting stools from mice fed with mixed high-fiber diet accelerated tumor growth in AOM-treated germ-free mice. We therefore characterized the contribution of soluble and insoluble fiber in CRC separately. Our results revealed that soluble fiber inulin or guar gum, but not insoluble fiber cellulose, promoted colorectal tumorigenesis in AOM-treated and Apcmin/+ mice. Soluble fiber induced gut dysbiosis with Bacteroides uniformis enrichment and Bifidobacterium pseudolongum depletion, accompanied by increased fecal butyrate and serum bile acids and decreased inosine. We also identified a positive correlation between inulin dosage and colorectal tumorigenesis. Moreover, transplanting stools from mice fed with high-inulin diet increased colonic cell proliferation and oncogene expressions in germ-free mice. High-dose soluble but not insoluble fiber potentiates colorectal tumorigenesis in a dose-dependent manner by dysregulating gut microbiota and metabolites in mice.

Abstract 2573: A novel regulation of the Wnt/β-catenin pathway involving NLRP12 during colorectal tumorigenesis

Abstract NLRP12, a member of the NOD-like receptor family, has been characterized as a negative regulator of NF-κB and MAPK pathways in immune cells. We previously demonstrated that Nlrp12-deficient mice are highly susceptible to azoxymethane plus dextran sodium sulfate induced colorectal tumorigenesis in mice. However, the precise mechanism of NLRP12-mediated protection against colorectal cancer (CRC) was poorly understood. RNA-seq analysis revealed that tumors of Nlrp12-deficient mice express higher levels of protooncogenes (cMyc, Ccnd1), Wnt target genes (Ctnnb1, Axin2, Yap1, Tcf3, Lgr5), matrix metalloproteinases, and epithelial to mesenchymal transition markers (Vim, Fn1, Foxc2, Zeb2, Ezh2) compared to wild-type tumor. Interestingly, higher expression of these genes in Nlrp12-deficient tumors was not linked to any inflammatory signaling pathways as there was no difference in the activation of NF-kB, ERK, JNK, AKT, and STAT3 signaling pathways between Nlrp12-/- and wild-type tumors. However, we observed higher activation of β-catenin in Nlrp12-deficient tumors. Using intestinal epithelial cell specific Nlrp12-conditional knockout mice we showed that Nlrp12 deficiency in intestinal epithelial cells leads to increased tumorigenesis, metastasis, and β-catenin activation. To further understand the role of NLRP12 in the regulation of the Wnt/β-catenin, we overexpressed NLRP12 in HEK293T cells and HCT116 cells followed by stimulation with Wnt ligand Wnt3A. NLRP12 overexpressed cells showed significantly reduced activation of β-catenin and expression of Wnt target genes. Consistently, knocking down of NLRP12 in HEK293T and HCT116 cells caused higher activation of the Wnt/β-catenin pathway. Further biochemical analysis revealed that NLRP12-mediated suppression of β-catenin activation is associated with reduced phosphorylation of GSK3β. Interestingly, human and mouse colorectal tumors showed reduced expression of NLRP12 along with increased activation of β-catenin and GSK3β phosphorylation. Altogether, these data suggest that NLRP12 is a potent negative regulator of the Wnt/β-catenin pathway in colorectal tumor cells, and the NLRP12-GSK3β axis could be a novel target for CRC treatment. Citation Format: Shahanshah Khan, Lan Peng, Cheryl M. Lewis, Yunpeng Gao, Ram S. Mani, Hasan Zaki. A novel regulation of the Wnt/β-catenin pathway involving NLRP12 during colorectal tumorigenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2573.

Whole β-glucan particle attenuates AOM/DSS-induced colorectal tumorigenesis in mice via inhibition of intestinal inflammation.

Yeast β-glucan is a polysaccharide purified from the Saccharomyces cerevisiae cell wall, and its multiple biological activities are essential for immune regulation. However, the effect of β-glucan on the intestinal immune response during colitis-associated colorectal cancer (CAC) is unclear. Here, we explore the possible role of β-glucan in the development of CAC. Wild type (WT) mice with CAC induced by azoxmethane (AOM) and dextran sodium sulfate (DSS) had fewer tumors than untreated mice after oral β-glucan because of increased antitumor dendritic cells (DCs) in the tumor microenvironment, resulting in more CD8+ T cells and the production of related cytokines. β-glucan also increased resistance to DSS-induced chronic colitis by reshaping the inflammatory microenvironment. These data suggest that β-glucan improves experimental intestinal inflammation and delays the development of CAC. Therefore, β-glucan is feasible for treating chronic colitis and CAC in clinical practice.

BTNL2 promotes colitis-associated tumorigenesis in mice by regulating IL-22 production.

Interleukin 22 (IL-22) has an important role in colorectal tumorigenesis and many colorectal diseases such as inflammatory bowel disease and certain infections. However, the regulation of IL-22 production in the intestinal system is still unclear. Here, we present evidence that butyrophilin-like protein 2 (BTNL2) is required for colorectal IL-22 production, and BTNL2 knockout mice show decreased colonic tumorigenesis and more severe colitis phenotypes than control mice due to defective production of IL-22. Mechanistically, BTNL2 acts on group 3 innate lymphoid cells (ILC3s), CD4+ T cells, and γδ T cells to promote the production of IL-22. Importantly, we find that a monoclonal antibody against BTNL2 attenuates colorectal tumorigenesis in mice and that the mBTNL2-Fc recombinant protein has a therapeutic effect in a dextran sulfate sodium (DSS)-induced colitis model. This study not only identifies a regulatory mechanism of IL-22 production in the colorectal system but also provides a potential therapeutic target for the treatment of human colorectal cancer and inflammatory bowel diseases.

Metformin Regulates Gut Microbiota Abundance to Suppress M2 Skewing of Macrophages and Colorectal Tumorigenesis in Mice.

The correlation of imbalanced gut microbiota with the onset and progression of colorectal cancer (CRC) has become clear. This work investigates the effect of metformin on gut microbiota and genesis of CRC in mice. Human fecal samples were collected from healthy control (HC) donors and CRC patients. Compared to HC donors, CRC patients had reduced abundance of gut microbiota; however, they had increased abundance of detrimental Bacteroidetes. Mice were injected with azomethane (AOM) to induce colorectal tumorigenesis models. Treatment of CRC patients-sourced fecal microbiota promoted tumorigenesis, and it increased the expression of Ki67, β-catenin, COX-2, and Cyclin D1 in mouse colon tissues. Further treatment of metformin blocked the colorectal tumorigenesis in mice. Fecal microbiota from the metformin-treated mice was collected, which showed decreased Bacteroidetes abundance and suppressed AOM-induced colorectal tumorigenesis in mice as well. Moreover, the metformin- modified microbiota promoted the M1 macrophage-related markers IL-6 and iNOS but suppressed the M2 macrophage-related markers IL-4R and Arg1 in mouse colon tissues. In conclusion, this study suggests that metformin-mediated gut microbiota alteration suppresses macrophage M2 polarization to block colorectal tumorigenesis.

Altered gut microbiome composition by appendectomy contributes to colorectal cancer

Appendectomy impacts the homeostasis of gut microbiome in patients. We aimed to study the role of appendectomy in colorectal cancer (CRC) risk through causing gut microbial dysbiosis. Population-based longitudinal study (cohort 1, n = 129,155) showed a 73.0% increase in CRC risk among appendectomy cases throughout 20 years follow-up (Adjusted sub-distribution hazard ratio (SHR) 1.73, 95% CI 1.49–2.01, P < 0.001). Shotgun metagenomic sequencing was performed on fecal samples from cohort 2 (n = 314). Gut microbial dysbiosis in appendectomy subjects was observed with significant enrichment of 7 CRC-promoting bacteria (Bacteroides vulgatus, Bacteroides fragilis, Veillonella dispar, Prevotella ruminicola, Prevotella fucsa, Prevotella dentalis, Prevotella denticola) and depletion of 5 beneficial commensals (Blautia sp YL58, Enterococcus hirae, Lachnospiraceae bacterium Choco86, Collinsella aerofaciens, Blautia sp SC05B48). Microbial network analysis showed increased correlation strengths among enriched bacteria and their enriched oncogenic pathways in appendectomy subjects compared to controls. Of which, B. fragilis was the centrality in the network of the enriched bacteria. We further confirmed that appendectomy promoted colorectal tumorigenesis in mice by causing gut microbial dysbiosis and impaired intestinal barrier function. Collectively, this study revealed appendectomy-induced microbial dysbiosis characterized by enriched CRC-promoting bacteria and depleted beneficial commensals, signifying that the gut microbiome may play a crucial role in CRC development induced by appendectomy.

Parvimonas micra promotes colorectal tumorigenesis and is associated with prognosis of colorectal cancer patients

Large-scale fecal shotgun metagenomic sequencing revealed the high abundance of Parvimonas micra in colorectal cancer (CRC) patients. We investigated the role and clinical significance of P. micra in colorectal tumorigenesis. The abundance of P. micra was examined in 309 fecal samples and 165 colon biopsy tissues of CRC patients and healthy subjects. P. micra was significantly enriched in fecal samples from 128 CRC patients compared to 181 healthy subjects (P < 0.0001); and in colon tissue biopsies from 52 CRC patients compared to 61 healthy subjects (P < 0.0001). Multivariate analysis showed that P. micra is an independent risk factor of poor survival in CRC patients (Hazard Ratio: 1.93). P. micra strain was isolated from feces of a CRC patient. Apcmin/+ mice gavaged with P. micra showed significantly higher tumor burden and tumor load (both P < 0.01). Consistently, gavage of P. micra significantly promoted colonocyte proliferation in conventional mice, which was further confirmed by germ-free mice. P. micra colonization up-regulated genes involved in cell proliferation, stemness, angiogenesis and invasiveness/metastasis; and enhanced Th17 cells infiltration and expression of Th17 cells-secreted cytokines (Il-17, Il-22, and Il-23) in the colon of Apcmin/+, conventional and germ-free mice. P. micra-conditioned medium significantly promoted the differentiation of CD4+ T cells to Th17 cells (IL-17+CD4+ phenotype) and enhanced the oncogenic Wnt signaling pathway. In conclusion, P. micra promoted colorectal tumorigenesis in mice by inducing colonocyte proliferation and altering Th17 immune response. P. micra may act as a prognostic biomarker for poor survival of CRC patients.

Atypical chemokine receptor 3 induces colorectal tumorigenesis in mice by promoting β-arrestin-NOLC1-fibrillarin-dependent rRNA biogenesis.

Atypical chemokine receptor 3 (ACKR3) has emerged as a key player in various biological processes. Its atypical "intercepting receptor" properties have established ACKR3 as the major regulator in the pathophysiological processes in many diseases. In this study, we investigated the role of ACKR3 activation in promoting colorectal tumorigenesis. We showed that ACKR3 expression levels were significantly increased in human colon cancer tissues, and high levels of ACKR3 predicted the increased severity of cancer. In Villin-ACKR3 transgenic mice with a high expression level of CKR3 in their intestinal epithelial cells, administration of AOM/DSS induced more severe colorectal tumorigenesis than their WT littermates. Cancer cells of Villin-ACKR3 transgenic mice were characterised by the nuclear β-arrestin-1 (β-arr1)-activated perturbation of rRNA biogenesis. In HCT116 cells, cotreatment with CXCL12 and AMD3100 selectively activated ACKR3 and induced nuclear translocation of β-arr1, leading to an interaction of β-arr1 with nucleolar and coiled-body phosphoprotein 1 (NOLC1). NOLC1, as the phosphorylated protein, further interacted with fibrillarin, a conserved nucleolar methyltransferase responsible for ribosomal RNA methylation in the nucleolus, thereby increasing the methylation in histone H2A and promoting rRNA transcription in ribosome biogenesis. In conclusion, ACKR3 promotes colorectal tumorigenesis through the perturbation of rRNA biogenesis by the β-arr1-induced interaction of NOLC1 with fibrillarin.

Ceramide-mediated gut dysbiosis enhances cholesterol esterification and promotes colorectal tumorigenesis in mice.

Colorectal cancer (CRC) severely threatens human health and life span. An effective therapeutic strategy has not been established because we do not clearly know its pathogenesis. Here, we report that ceramide and sterol O-acyltransferase 1 (SOAT1) have roles in both spontaneous and chemical-induced intestinal cancers. We first found that miRNA-148a deficiency dramatically increased mouse gut dysbiosis through upregulating ceramide synthase 5 (Cers5) expression, which promoted ceramide synthesis afterward. The newly generated ceramide further promoted both azoxymethane/dextran sodium sulfate–induced (AOM/DSS-induced) and ApcMin/+ spontaneous intestinal tumorigenesis via increasing mouse gut dysbiosis. Meanwhile, increased level of ceramide correlated with the significant enhancements of both β-catenin activity and colorectal tumorigenesis in a TLR4-dependent fashion. Next, we found a direct binding of β-catenin to SOAT1 promoter to activate transcriptional expression of SOAT1, which further induced cholesterol esterification and colorectal tumorigenesis. In human patients with CRC, the same CERS5/TLR4/β-catenin/SOAT1 axis was also found to be dysregulated. Finally, the SOAT1 inhibitor (avasimibe) showed significant levels of therapeutic effects on both AOM/DSS-induced and ApcMin/+ spontaneous intestinal cancer. Our study clarified that ceramide promoted CRC development through increasing gut dysbiosis, further resulting in the increase of cholesterol esterification in a SOAT1-dependent way. Treatment with avasimibe to specifically decrease cholesterol esterification could be considered as a clinical strategy for effective CRC therapy in a future study.

KMT9 Controls Stemness and Growth of Colorectal Cancer.

Colorectal cancer is among the leading causes of cancer-associated deaths worldwide. Treatment failure and tumor recurrence due to survival of therapy-resistant cancer stem/initiating cells represent major clinical issues to overcome. In this study, we identified lysine methyltransferase 9 (KMT9), an obligate heterodimer composed of KMT9α and KMT9β that monomethylates histone H4 at lysine 12 (H4K12me1), as an important regulator in colorectal tumorigenesis. KMT9α and KMT9β were overexpressed in colorectal cancer and colocalized with H4K12me1 at promoters of target genes involved in the regulation of proliferation. Ablation of KMT9α drastically reduced colorectal tumorigenesis in mice and prevented the growth of murine as well as human patient-derived tumor organoids. Moreover, loss of KMT9α impaired the maintenance and function of colorectal cancer stem/initiating cells and induced apoptosis specifically in this cellular compartment. Together, these data suggest that KMT9 is an important regulator of colorectal carcinogenesis, identifying KMT9 as a promising therapeutic target for the treatment of colorectal cancer. SIGNIFICANCE: The H4K12 methyltransferase KMT9 regulates tumor cell proliferation and stemness in colorectal cancer, indicating that targeting KMT9 could be a useful approach for preventing and treating this disease.

Combined Supplementation with Vitamin B-6 and Curcumin is Superior to Either Agent Alone in Suppressing Obesity-Promoted Colorectal Tumorigenesis in Mice

BackgroundObesity increases the colorectal cancer risk, in part by elevating colonic proinflammatory cytokines. Curcumin (CUR) and supplemental vitamin B-6 each suppress colonic inflammation. ObjectivesWe examined whether the combination of CUR and vitamin B-6 amplifies each supplement's effects and thereby suppress obesity-promoted tumorigenesis. MethodsMale Friend Virus B (FVB) mice (4-week-old; n = 110) received 6 weekly injections of azoxymethane beginning 1 week after arrival. Thereafter, they were randomized to receive a low-fat diet (10% energy from fat), a high-fat diet (HFD; 60% energy from fat), a HFD containing 0.2% CUR, a HFD containing supplemental vitamin B-6 (24 mg pyridoxine HCl/kg), or a HFD containing both CUR and supplemental vitamin B-6 (C + B) for 15 weeks. Colonic inflammation, assessed by fecal calprotectin, and tumor metrics were the primary endpoints. The anti-inflammatory efficacy of the combination was also determined in human colonic organoids. ResultsHFD-induced obesity produced a 2.6-fold increase in plasma IL-6 (P < 0.02), a 1.9-fold increase in fecal calprotectin (P < 0.05), and a 2.2-fold increase in tumor multiplicity (P < 0.05). Compared to the HFD group, the C + B combination, but not the individual agents, decreased fecal calprotectin (66%; P < 0.01) and reduced tumor multiplicity and the total tumor burden by 60%–80% (P < 0.03) in an additive fashion. The combination of C + B also significantly downregulated colonic phosphatidylinositol-4,5-bisphosphate 3-kinase, Wnt, and NF-κB signaling by 31%–47% (P < 0.05), effects largely absent with the single agents. Observations that may explain how the 2 agents work additively include a 2.8-fold increased colonic concentration of 3-hydroxyanthranillic acid (P < 0.05) and a 1.3-fold higher colonic concentration of the active coenzymatic form of vitamin B-6 (P < 0.05). In human colonic organoids, micromolar concentrations of CUR, vitamin B-6, and their combination suppressed secreted proinflammatory cytokines by 41%–93% (P < 0.03), demonstrating relevance to humans. ConclusionsIn this mouse model, C + B is superior to either agent alone in preventing obesity-promoted colorectal carcinogenesis. Augmented suppression of procancerous signaling pathways may be the means by which this augmentation occurs.

ZNF545 loss promotes ribosome biogenesis and protein translation to initiate colorectal tumorigenesis in mice

Ribosome biogenesis plays a pivotal role in tumorigenesis by supporting robust protein translation. We investigate the functional and molecular mechanism of Zinc finger protein 545 (ZNF545), a transcriptional repressor for ribosomal RNA (rRNA), in colorectal cancer (CRC). ZNF545 was silenced in CRC compared to adjacent normal tissues (P < 0.0001), implying a tumor-suppressive role. Colon-specific Znf545 knockout in mice accelerated CRC in ApcMin/+ and azoxymethane/dextran sulfate sodium-induced CRC. Mechanistically, we demonstrated that ZNF545 uses its two zinc finger clusters to bind to minimal rDNA promoter, where it assembled transcriptional repressor complex by interacting with KAP1. Znf545 deletion in mouse embryonic fibroblasts not only increased rRNA transcription rate and the nucleolar size and number but also altered the nucleolar composition and architecture with an increased number of fibrillar centers surrounded by net-like dense fibrillar components. Consequently, Znf545 deletion promoted the gene expression of translation machinery, protein translation, and cell growth. Consistent with its tumor-suppressive role, ZNF545 overexpression in CRC cells induced growth arrest and apoptosis. Finally, administration of rRNA synthesis inhibitor, CX-5461, inhibited CRC development in Znf545Δ/ΔApcMin/+ mice. In conclusion, ZNF545 suppresses CRC through repressing rRNA transcription and protein translation. Targeting rRNA biosynthesis in ZNF545-silenced tumors is a potential therapeutic strategy for CRC.

Tanshinone IIA attenuates AOM/DSS-induced colorectal tumorigenesis in mice via inhibition of intestinal inflammation

Context Tanshinone IIA is a natural extract derived from a Chinese medicinal herb with multiple bioactivities; however, whether and how tanshinone IIA protects against colorectal cancer (CRC) are uncertain. Objective We investigated the potential beneficial effects of tanshinone IIA in a colitis-associated colorectal tumorigenesis mouse model and its underlying mechanisms. Materials and methods Male C57BL/6 mice were treated with azoxymethane (AOM) 10 mg/kg body weight and dextran sulphate sodium (2.5% DSS) to induce a colitis-associated cancer model. Tanshinone IIA (200 mg/kg body weight) was given to the mice intraperitoneally. After 12 weeks, all mice were sacrificed to measure tumour formation, intestinal permeability, neutrophil infiltration, and colonic inflammation. In addition, whether tanshinone IIA has inhibitory effects on neutrophil activation was determined through in vitro investigations. Results We observed that tanshinone IIA significantly decreased tumour formation in AOM/DSS-treated mice compared to AOM/DSS-treated alone mice (0.266 ± 0.057 vs. 0.78 ± 0.153, p = 0.013). Tanshinone IIA also decreased intestinal permeability compared to that in AOM/DSS-treated alone mice (3.12 ± 0.369 vs. 5.06 ± 0.597, p = 0.034) and consequently reduced neutrophil infiltration of the colonic mucosa (53.25 ± 8.85 vs. 107.6 ± 13.09, p = 0.014) as well as intestinal inflammation in mice. Mechanistically, tanshinone IIA downregulated the NF-κB signalling pathway in the colonic tumours of AOM/DSS-treated mice. In vitro assays further validated that tanshinone IIA suppressed LPS-induced neutrophil activation. Conclusion These data suggest that tanshinone IIA alleviates colorectal tumorigenesis through inhibition of intestinal inflammation. Tanshinone IIA may have a therapeutic potential for CRC in clinical practice.

Effects of Huaier Extract on Ameliorating Colitis-Associated Colorectal Tumorigenesis in Mice.

BackgroundHuaier extract has been a part of traditional Chinese medicine (TCM) for roughly 1600 years and may serve as a potential anti-cancer drug as it is associated with good efficacy and low toxicity. Individuals with inflammatory bowel disease (IBD) are at a higher chance of being diagnosed with colorectal cancer (CRC) and as Huaier extract may potentially influence tumorigenesis, we set out to determine the effect of Huaier extract on colitis-associated CRC.MethodsThe CRC mouse model, established through azoxymethane (AOM) and dextran sulfate sodium (DSS), was administered Huaier extract. Weight loss, colon length, tumor number and tumor size were evaluated macroscopically. Pro-inflammatory cytokine expression and STAT3 phosphorylation were assessed in the colon using ELISA, Western blot and/or immunohistochemistry.ResultsHuaier extract improved the severity of colitis-associated tumorigenesis compared with control group, with attenuated weight loss and longer colons. Tumor number, size and load were drastically decreased in mice treated with Huaier. Histological assessment suggested that Huaier could decrease histological injury of the colon tissue. Additionally, Huaier extract treatment led to reduced pro-inflammatory cytokine levels (TNF-α, IL-6, IFN-γ and IL-1β) and a decrease of STAT3 phosphorylation in colon tissue. Additionally, present findings demonstrated that Huaier extract inhibited cell proliferation and induced apoptosis in CRC cells HCT116 and HCT8. The migration and invasion of CRC cells were markedly inhibited upon exposure to Huaier treatment. The apoptosis-associated protein levels (P53, Bax, Bcl-2, pro-caspase-3 and cleavage caspase-3) showed significant differences after the administration of Huaier extract in HCT116 and HCT8 cells. In vivo, the administration of Huaier extract to mice inhibited tumor growth and yielded a similar profile of apoptotic proteins expression p53, Bcl-2, pro-caspase-3 and cleaved caspase-3 while no significant differences in Bax were observed. Moreover, the ratio of TUNEL-positive/apoptotic cells was markedly increased in the Huaier-treated mice.ConclusionHuaier extract may reduce the IBD-associated tumor development by suppressing pro-inflammatory cytokine levels and STAT3 stimulation.

Parabacteroides distasonis attenuates tumorigenesis, modulates inflammatory markers and promotes intestinal barrier integrity in azoxymethane-treated A/J mice.

Imbalance of the gut microbial community promotes inflammation and colorectal cancer (CRC). Previously, we demonstrated that freeze-dried Parabacteroides distasonis (Pd) suppressed obesity-driven colorectal tumorigenesis in mice. Here, we investigated if Pd could suppress the development of colon tumors in mice independent of obesity. Six-week-old male A/J mice were assigned to receive: (i) chow diet (CTR); (ii) chow with 0.04% wt/wt freeze-dried Pd (Pd-Early) or (iii) chow diet before switching to 0.04% Pd diet (Pd-Late). Mice remained on diet for 25 weeks with the switch for Pd-Late mice occurring after 19 weeks. All mice received 6 weekly injections of the colon carcinogen azoxymethane (AOM; 10 mg/kg I.P.) starting after 1 week on diet. Colon tumors were observed in 77, 55 and 40% in CTR, Pd-Early and Pd-Late mice, respectively (X2 = 0.047). Colonic expression of toll-like receptor 4, IL-4 and TNF-α was 40% (P < 0.01), 58% (P = 0.05) and 55% (P < 0.001) lower, respectively, in Pd-Early compared with CTR mice. Pd-Late mice displayed a 217% (P = 0.05) and 185% (P < 0.001) increase in colonic IL-10 and TGF-β expression, respectively, compared with CTR mice and similar increases in protein abundances were detected (47-145%; P < 0.05). Pd-Early and Pd-Late mice both demonstrated increased colonic expression of the tight junction proteins Zonula occludens-1 (P < 0.001) and occludin (P < 0.001) at the transcript (2-3-fold; P < 0.01) and protein level (30-50%; P < 0.05) relative to CTR. Our results support a protective role for Pd in colonic tumorigenesis and maintenance of intestinal epithelial barrier in AOM-treated mice.

Dynamic Regulation of ME1 Phosphorylation and Acetylation Affects Lipid Metabolism and Colorectal Tumorigenesis.

PGAM5 is a mitochondrial serine/threonine phosphatase that regulates multiple metabolic pathways and contributes to tumorigenesis in a poorly understood manner. We show here that PGAM5 inhibition attenuates lipid metabolism and colorectal tumorigenesis in mice. PGAM5-mediated dephosphorylation of malic enzyme 1 (ME1) at S336 allows increased ACAT1-mediated K337 acetylation, leading to ME1 dimerization and activation, both of which are reversed by NEK1 kinase-mediated S336 phosphorylation. SIRT6 deacetylase antagonizes ACAT1 function in a manner that involves mutually exclusive ME1 S336 phosphorylation and K337 acetylation. ME1 also promotes nicotinamide adenine dinucleotide phosphate (NADPH) production, lipogenesis, and colorectal cancers in which ME1 transcripts are upregulated and ME1 protein is hypophosphorylated at S336 and hyperacetylated at K337. PGAM5 and ME1 upregulation occur via direct transcriptional activation mediated by β-catenin/TCF1. Thus, the balance between PGAM5-mediated dephosphorylation of ME1 S336 and ACAT1-mediated acetylation of K337 strongly influences NADPH generation, lipid metabolism, and the susceptibility to colorectal tumorigenesis.

LINC00265 promotes colorectal tumorigenesis via ZMIZ2 and USP7-mediated stabilization of β-catenin.

Colorectal cancer (CRC) is the third most prevalent world cancer and oncogenic β-catenin is frequently dysregulated in CRC. Long noncoding RNAs (lncRNAs) play critical roles in colorectal tumorigenesis; however, the contributions of lncRNAs to human CRC remain largely unknown. In this study, we report that LINC00265 is upregulated and predicts poor clinical outcome in human patients with CRC. Depletion of LINC00265 and ZMIZ2 distinctly attenuates colorectal tumorigenesis in mice. Mechanistically, LINC00265 augments ZMIZ2 expression by acting as an endogenous sponge against several miRNAs, which directly target ZMIZ2 expression. Moreover, ZMIZ2 recruits the enzyme USP7, which deubiquitylates and stabilizes β-catenin, thereby facilitating colorectal tumorigenesis. In addition, β-catenin mediates LINC00265 and ZMIZ2 oncogenic phenotypes. Taken together, the LINC00265-ZMIZ2-β-catenin signaling axis plays a critical role in the colorectal tumorigenesis, which may be a potential therapeutic target.