Rationale: The treatment of ulcerative colitis (UC) presents an ongoing clinical challenge. Emerging research has implicated that the cGAS-STING pathway promotes the progression of UC, but conflicting results have hindered the development of STING as a therapeutic target. In the current study, we aim to comprehensively elucidate the origins, downstream signaling and pathogenic roles of myeloid STING in colitis and colitis-associated carcinoma (CAC). Methods: Tmem173 fl/fl Lyz2-Cre ert2 mice were constructed for inducible myeloid-specific deletion of STING. RNA-sequencing, flow cytometry, and multiplex immunohistochemistry were employed to investigate immune responses in DSS-induced colitis or AOM/DSS-induced carcinogenesis. Colonic organoids, primary bone marrow derived macrophages and dendritic cells, and splenic T cells were used for in vitro studies. Results: We observed that myeloid STING knockout in adult mice inhibited macrophage maturation, reduced DC cell activation, and suppressed pro-inflammatory Th1 and Th17 cells, thereby protecting against both acute and chronic colitis and CAC. However, myeloid STING deletion in neonatal or tumor-present mice exhibited impaired immune tolerance and anti-tumor immunity. Furthermore, we found that TFAM-associated mtDNA released from damaged colonic organoids, rather than bacterial products, activates STING in dendritic cells in an extracellular vesicle-independent yet endocytosis-dependent manner. Both IRF3 and NF-κB are required for STING-mediated expression of IL-12 family cytokines, promoting Th1 and Th17 differentiation and contributing to excessive inflammation in colitis. Conclusions: Detection of the TFAM-mtDNA complex from damaged intestinal epithelium by myeloid STING exacerbates colitis through IL-12 cytokines, providing new evidence to support the development of STING as a therapeutic target for UC and CAC.

Ulcerative colitis (UC) is a chronic inflammatory disorder of the colon, and its pathogenesis remains unclear. Polyamine metabolic enzymes play a crucial role in UC. In this study, we aimed to identify pivotal polyamine-related genes (PRGs) and explore the underlying mechanism between PRGs and the disease status and therapeutic response of UC. We analyzed mRNA-sequencing data and clinical information of UC patients from the GEO database and identified NNMT, PTGS2, TRIM22, TGM2, and PPARG as key PRGs associated with active UC using differential expression analysis and weighted gene co-expression network analysis (WCGNA). Receiver operator characteristic curve (ROC) analysis confirmed the accuracy of these key genes in UC and colitis-associated colon cancer (CAC) diagnosis, and we validated their relationship with therapeutic response in external verification sets. Additionally, single-cell analysis revealed that the key PRGs were specific to certain immune cell types, emphasizing the vital role of intestinal tissue stem cells in active UC. The results were validated in vitro and in vivo experiments, including the colitis mice model and CAC mice model. In conclusion, these key PRGs effectively predict the progression of UC patients and could serve as new pharmacological biomarkers for the therapeutic response of UC.

One of the factors contributing to colorectal cancer (CRC) development is inflammation, which is mostly hypoxia-associated. This study aimed to characterize the morphological and molecular biological features of colon tumors in mice that were tolerant and susceptible to hypoxia based on colitis-associated CRC (CAC). Hypoxia tolerance was assessed through a gasping time evaluation in a decompression chamber. One month later, the animals were experimentally modeled for colitis-associated CRC by intraperitoneal azoxymethane administration and three dextran sulfate sodium consumption cycles. The incidence of tumor development in the distal colon in the susceptible to hypoxia mice was two times higher and all tumors (100%) were represented by adenocarcinomas, while in the tolerant mice, only 14% were adenocarcinomas and 86% were glandular intraepithelial neoplasia. The tumor area assessed on serially stepped sections was statistically significantly higher in the susceptible animals. The number of macrophages, CD3-CD19+, CD3+CD4+, and NK cells in tumors did not differ between animals; however, the number of CD3+CD8+ and vimentin+ cells was higher in the susceptible mice. Changes in the expression of genes regulating the response to hypoxia, inflammation, cell cycle, apoptosis, and epithelial barrier functioning in tumors and the peritumoral area depended on the initial mouse\'s hypoxia tolerance, which should be taken into account for new CAC diagnostics and treatment approaches development.

BACKGROUND: Ulcerative colitis is a well-known inflammatory bowel disease. Patients have an increased risk of developing colitis associated carcinoma (CAC). It is important for patient management to be able to distinguish between ulcerative colitis associated carcinoma and sporadic carcinoma (sCRC). However, this distinction is frequently very challenging. It is not readily possible to differentiate this histologically. However, the diagnosis is crucial for the patient\'s further treatment and follow-up. An attempt was therefore made to develop a diagnostic regime that would enable a reliable distinction between sCRC and CAC.
METHODS: We screened 96 patients analyzing more than 850,000 methylation hotspots, to detect distinct epigenetic patterns between both types of carcinomas. Patients with sporadic carcinoma and colitis-associated carcinoma as well as patients with normal colon and patients with confirmed ulcerative colitis without neoplasia were used for the analysis. By extensively filtering the results, methylation sites relevant to distinguish between CAC and sCRC were identified.
RESULTS: After the results were filtered, three methylation sites relevant to distinguish between CAC and sCRC were identified. For this purpose, methylation limit values were defined, which favor the samples as CAC or sCRC up to a certain methylation value of the methylation sites. The combination of three methylation sites allows a correct assignment to CAC or sCRC in 94.5% of the cases.
CONCLUSIONS: The results show that these three methylation sites are promising markers in the diagnosis of CAC vs sCRC. Nevertheless, the diagnosis should always be made in conjunction with histomorphological analyses.

Microcystins (MCs) are secondary metabolites generated by cyanobacterial blooms, among which microcystin-LR (MC-LR) stands out as the most widely distributed variant in aquatic environments. However, the effects of MC-LR on the colorectum and its role in promoting colorectal tumor progression remain unclear. Therefore, this study aims to scrutinize the impact of MC-LR on a mice model of colitis-associated colorectal cancer and elucidate the potential underlying molecular mechanisms. In this study, we used AOM/DSS mice and orally administered MC-LR at doses of 40 µg/kg or 200 µg/kg. Exposure to MC-LR increased tumor burden, promoted tumor growth, shortened colon size, and decreased goblet cell numbers and tight junction protein levels in intestinal tissues. Additionally, exposure to MC-LR induced alterations in the structure of gut microbiota in the mouse colon, characterized by an increase in the relative abundance of Escherichia_coli and Shigella_sonnei, and a decline in the relative abundance of Akkermansia_muciniphila. Transcriptomic analysis revealed that MC-LR exposure activated the IL-17 signaling pathway in mouse colorectal tissues and participated in inflammation regulation and immune response. Immunofluorescence results demonstrated an increase in T-helper 17 (Th17) cell levels in mouse colorectal tumors following MC-LR exposure. The results from RT-qPCR revealed that MC-LR induced the upregulation of IL-6, IL-1β, IL-10, IL-17A, TNF-α, CXCL1, CXCL2, CXCL5 and CCL20. The novelty of this study lies in its comprehensive approach to understanding the mechanisms by which MC-LR may contribute to CRC progression, offering new perspectives and valuable reference points for establishing guidance standards regarding MC-LR in drinking water. Our findings suggest that even at guideline value, MC-LR can have profound effects on susceptible mice, emphasizing the need for a reevaluation of guideline value and a deeper understanding of the role of environmental toxins in cancer progression.

BACKGROUND: Huangqin Tang (HQT), a traditional Chinese medicine formula, is commonly used in clinical practice for the treatment of inflammatory bowel diseases. It has been reported that HQT exerts antitumor effects on colitis-associated colorectal cancer (CAC). However, the mechanism by which HQT interferes with the inflammation-to-cancer transformation remains unclear.
OBJECTIVE: The purpose of this study was to dynamically evaluate the efficacy of HQT in alleviating or delaying CAC and to reveal the underlying mechanism.
METHODS: We established a mouse model of CAC using azoxymethane combined with 1.5% dextran sodium sulphate. The efficacy of HQT was evaluated based on pathological sections and serum biochemical indices. Subsequently, amino acids (AAs) metabolism analyses were performed using ultra-performance liquid chromatography-tandem mass spectrometry, and the phosphatidylinositol 3 kinase/protein kinase B/mechanistic target of rapamycin (PI3K/AKT/mTOR) pathway was detected by western blotting.
RESULTS: The data demonstrated that HQT could alleviate the development of CAC in the animal model. HQT effectively reduced the inflammatory response, particularly interleukin-6 (IL-6), in the inflammation induction stage, as well as in the stages of proliferation initiation and tumorigenesis. During the proliferation initiation and tumorigenesis stages, immunohistochemistry staining showed that the expression of the proliferation marker Ki67 was reduced, while apoptosis was increased in the HQT group. Accordingly, HQT substantially decreased the levels of specific AAs in the colon with CAC, including glutamic acid, glutamine, arginine, and isoleucine. Furthermore, HQT significantly inhibited the activated PI3K/AKT/mTOR pathway, which may contribute to suppression of cell proliferation and enhancement of apoptosis.
CONCLUSIONS: HQT is effective in alleviating and delaying the colon \"inflammation-to-cancer\". The mechanism of action may involve HQT maintained AAs metabolism homeostasis and regulated PI3K/AKT/mTOR pathway, so as to maintain the balance between proliferation and apoptosis, and then interfere in the occurrence and development of CAC.

BACKGROUND: Based on the core pathogenesis of hepatosplenic disorder and qi transformation disorder in ulcerative colitis, Tong-Xie-Yao-Fang (TXYF) is a classical traditional Chinese medicine commonly used to treat ulcerative colitis. Our study revealed that it has the potential to prevent colitis-associated colorectal cancer, which embodies the academic concept in traditional Chinese medicine of treating the disease before it develops.
OBJECTIVE: This study was aimed at evaluating the therapeutic role of TXYF in treating colitis-associated colorectal cancer and exploring its possible underlying mechanisms.
METHODS: A colitis-associated colorectal cancer model was established in mice using azoxymethane and dextran sulfate sodium salt to examine the therapeutic effect of TXYF. The mouse body weights were observed. Hematoxylin-eosin staining was used to evaluate mouse colon histopathology. Colon cancer cells and colon epithelial cells were used to explore the potential molecular mechanisms. The proliferation and apoptosis of cells were detected by CCK8 and cell colony assays, flow cytometry and western blotting. The epithelial-mesenchymal transition (EMT) and mitophagy markers were examined by immunohistochemistry, western blotting, quantitative real-time PCR and immunofluorescence staining.
RESULTS: TXYF inhibited the tumorigenesis of mice with colitis-associated colorectal cancer and the growth of inflammatory colon cells. TXYF induced mitophagy in colon cancer cells through the PTEN-induced putative kinase 1 (PINK1)/Parkin pathway to reverse EMT, which was consistent with the results in mice with colitis-associated colorectal cancer.
CONCLUSIONS: The results of the present study demonstrated that TXYF effectively inhibited the progression of colitis-associated colorectal cancer through the PINK1/Parkin pathway, which provides new evidence for prevention strategies for this disease.

Colitis-associated cancer (CAC) is an aggressive subtype of colorectal cancer that can develop in ulcerative colitis patients and is driven by chronic inflammation and oxidative stress. Current chemotherapy for CAC, based on 5-fluorouracil and oxalipltin, is not fully effective and displays severe side effects, prompting the search for alternative therapies. Dimethylfumarate (DMF), an activator of the nuclear factor erythroid 2-related factor 2 (NRF2), is a potent antioxidant and immunomodelatrory drug used in the treatment of multiple sclerosis and showed a strong anti-inflammatory effect on experimental colitis. Here, we investigated the chemotherapeutic effect of DMF on an experimental model of CAC. Male NMRI mice were given two subcutaneous injections of 1,2 Dimethylhydrazine (DMH), followed by three cycles of dextran sulfate sodium (DSS). Low-dose (DMF30) and high-dose of DMF (DMF100) or oxaliplatin (OXA) were administered from the 8th to 12th week of the experiment, and then the colon tissues were analysed histologically and biochemically. DMH/DSS induced dysplastic aberrant crypt foci (ACF), oxidative stress, and severe colonic inflammation, with a predominance of pro-inflammatory M1 macrophages. As OXA, DMF30 reduced ACF multiplicity and crypt dysplasia, but further restored redox status, and reduced colitis severity by shifting macrophages towards the anti-inflammatory M2 phenotype. Surprisingly, DMF100 exacerbated ACF multiplicity, oxidative stress, and colon inflammation, likely through NRF2 and p53 overexpression in colonic inflammatory cells. DMF had a dual effect on CAC. At low dose, DMF is chemotherapeutic and acts as an antioxidant and immunomodulator, whereas at high dose, DMF is pro-oxidant and exacerbates colitis-associated cancer.

OBJECTIVE: Huangqin decoction (HQD) is a Chinese medicine used to treat colitis and colorectal cancer (CRC). However, the specific compounds and mechanisms of HQD remain unclear despite its good curative clinical results. Through bioinformatics, network pharmacology, and experiments, this study aims to explore the progressive mechanisms of colitis-associated colorectal cancer (CAC) from ulcerative colitis (UC) while examining the protective effects of HQD and its compounds against this.
METHODS: Bioinformatics was utilized to identify the hub genes between UC and CRC, and their clinical predictive significance, function, and expression were validated. Employing network pharmacology in combination with hub genes, key targets of HQD for preventing the development of UC into CAC were identified. Molecular docking and molecular dynamics (MD) were utilized to procure compounds that effectively bind to these targets and their transcription factors (TFs). Finally, the expression and mechanism of key targets were demonstrated in mice with UC or CAC.
RESULTS: (1) Joint analysis of UC and CRC gene sets resulted in 14 hub genes, mainly related to extracellular matrix receptor binding, biological processes in the extracellular matrix, focal adhesion and neutrophil migration; (2) Network pharmacology results show HQD has 133 core targets for treating UC and CRC, acting on extracellular matrix, inflammatory bowel disease, chemical carcinogen receptor activation and other pathways; (3) The intersection of hub genes and core targets yielded two key targets, MMP1 and MMP3; (4) STAT3 is a shared TF of MMP1 and MMP3. (5) Molecular docking and MD verified that the dockings between Glabridin and STAT3/MMP1/MMP3 are stable and reliable; (6) In murine vivo experiments verified that Glabridin reduces inflammation, extracellular matrix degradation, and the occurrence of epithelial-mesenchymal transition to prevent UC transforming into CAC by inhibiting the phosphorylation of STAT3 and regulating the activity of MMP1/3.

Aim: To elucidate dynamics and functions in colonic macrophage subsets, and their regulation by Bifidobacterium breve (B. breve) and its associated metabolites in the initiation of colitis-associated colorectal cancer (CAC). Methods: Azoxymethane (AOM) and dextran sodium sulfate (DSS) were used to create a CAC model. The tumor-suppressive effect of B. breve and variations of macrophage subsets were evaluated. Intestinal macrophages were ablated to determine their role in the protective effects of B. breve. Efficacious molecules produced by B. breve were identified by non-targeted and targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The molecular mechanism was further verified in murine bone marrow-derived macrophages (BMDMs), macrophages derived from human peripheral blood mononuclear cells (hPBMCs), and demonstrated in CAC mice. Results: B. breve alleviated colitis symptoms, delayed colonic tumorigenesis, and promoted phenotypic differentiation of immature inflammatory macrophages into mature homeostatic macrophages. On the contrary, the ablation of intestinal macrophages largely annulled the protective effects of B. breve. Microbial analysis of colonic contents revealed the enrichment of probiotics and the depletion of potential pathogens following B. breve supplementation. Moreover, indole-3-lactic acid (ILA) was positively correlated with B. breve in CAC mice and highly enriched in the culture supernatant of B. breve. Also, the addition of ILA directly promoted AKT phosphorylation and restricted the pro-inflammatory response of murine BMDMs and macrophages derived from hPBMCs in vitro. The effects of ILA in murine BMDMs and macrophages derived from hPBMCs were abolished by the aryl hydrocarbon receptor (AhR) antagonist CH-223191 or the AKT inhibitor MK-2206. Furthermore, ILA could protect against tumorigenesis by regulating macrophage differentiation in CAC mice; the AhR antagonist largely abrogated the effects of B. breve and ILA in relieving colitis and tumorigenesis. Conclusion: B. breve-mediated tryptophan metabolism ameliorates the precancerous inflammatory intestinal milieu to inhibit tumorigenesis by directing the differentiation of immature colonic macrophages.