Colorectal carcinogenesis: Review of human and experimental animal studies

Studies on the ameliorative potential of Rheum webbianum rhizome extracts on 1,2-dimethylhydrazine (DMH) induced colorectal cancer and associated hepatic and haematological abnormalities in swiss albino rats

ETHNOPHARMACOLOGICAL RELEVANCE

Rheum webbianum Royle (RW) holds significant ethnopharmacological importance owing to its 5000-year history of cultivation for medicinal and culinary purposes. Demonstrating therapeutic advantages in traditional and contemporary medical practices, RW exhibits key pharmacological effects including anticancer activity, gastrointestinal control, anti-inflammatory properties, and suppression of fibrosis. Despite its recognized vast bioactivities in ethnopharmacology, its efficacy against the colorectal cancer (CRC) remains incompletely understood.

AIM OF THE STUDY

This study for the first time aims to investigate the chemo-preventive capabilities of various extracts derived from RW rhizomes against CRC development.

MATERIALS AND METHODS

Four types of RW extracts were prepared by using different solvents viz: Hexane, Ethy-acetate, Ethanol and Methanol. All the four extracts were evaluated for cytotoxicity on HCT-116 human CRC cells. Promising extracts were further investigated in-vivo at varying doses using 1,2-dimethylhydrazine (DMH) induced rat CRC model to assess the anti-oxidant and anticancer properties as well as their effects on the associated hepatic deterioration and hematological alterations.

RESULTS

Cell viability: In-vitro assessments demonstrated a dose and time-dependent reduction in HCT-116 cell viability following treatment with methanolic and ethanolic extracts of RW, reducing viability by up to 85% and 90%, respectively, at 200 μg/ml.

HISTOPATHOLOGY

Histopathological analyses revealed significant improvements in colon tissue morphology in RW extract-treated groups compared to DMH-only treated animals. RW-treated groups showed reduced structural abnormalities, congestion, inflammatory cell infiltration, crypt abscess formation, and dysplasia. In contrast, the DMH-only group exhibited irregular glandular structure, mucosal destruction, extensive inflammatory cell infiltration, crypt abscess formation, and dysplasia. These results highlight the potential of RW methanolic and ethanolic extracts in mitigating colon cancer-related histopathological alterations. Haematological, and hepatic parameters: In the DMH-induced colorectal cancer rat model, significant hematological imbalances were evident, including a 49.13% decrease in erythrocytes, 32.18% in hemoglobin, and 26.79% in hematocrit, along with a 79.62% increase in white blood cells and 68.96% rise in platelets. Administration of RW rhizome extracts effectively restored these hematological parameters to levels comparable to those in the control group. Furthermore, RW treatment significantly reduced serum ALT and AST levels, which had increased by 36.78% and 33.12%, respectively, due to DMH exposure. RW intervention also mitigated the onset of atherosclerosis, evidenced by notable reductions in serum total cholesterol and triglyceride levels. Comparative analysis indicated that RW-treated DMH groups effectively restored lipid profiles, contrasting with the DMH-only group which exhibited markers indicative of colon cancer. Oxidative stress: The DMH-treated group showed a significant increase in MDA levels by 195.59%, indicative of heightened free radical production, coupled with decreased levels of SOD (33%), CAT (48%), GSH (58%), and GR activity (49%), signifying oxidative stress. Treatment with RW extracts in DMH-treated rats markedly reduced MDA levels and enhanced SOD, CAT, GSH, and GR activities. These results underscore the antioxidant efficacy of RW extracts.

CONCLUSION

This study underscores the significant potential of RW rhizome extracts in inhibiting colorectal cancer development. Further investigations are warranted to identify the active constituents responsible for these promising outcomes, positioning RW as a natural and potential agent in combating colon cancer.

Molecular analysis to identify novel potential biomarkers as drug targets in colorectal cancer therapy: an integrated bioinformatics analysis

Colorectal cancer (CRC) is a heterogeneous disease that requires new diagnostic and prognostic markers. Integrated bioinformatics approach to identify novel therapeutic targets associated with CRC. Using GEO2R identified DEGs in CRC, and Funrich software facilitated the visualization of DEGs through Venn diagrams. From a total of 114 enhanced DEGs, potential hub genes were further filtered based on their nodal strength and edges using STRING database. To gain insights into the functional roles of these hub genes, gene ontology and pathway enrichment were conducted thorough g: profiler web server. Subsequently, overall survival plots from GEPIA and oncogenic predictive functions like mRNA expressions for stages and nodal metastasis were employed to identify hub genes in CRC patient samples. Additionally, the cBioPortal and HPA databases also revealed genetic alterations and expression levels in these hub genes in CRC patients, further supporting their involvement in colorectal cancer. Gene expression by RT-PCR shows upregulation of hub genes in HT-29 cells. Finally, our integrated bioinformatic analysis revealed that ABCE1, AURKA, HSPD1, PHKA1, CDK4, and YWHAE as hub genes with potential oncogenic roles in CRC. These genes hold promise as diagnostic and prognostic markers for colorectal tumorigenesis, providing insights into targeted therapies for improved patient outcomes.

Enhancement of colorectal cancer therapy through interruption of the HSF1-HSP90 axis by p53 activation or cell cycle inhibition

The stress-associated molecular chaperone system is an actionable target in cancer therapies. It is ubiquitously upregulated in cancer tissues and enables tumorigenicity by stabilizing hundreds of oncoproteins and disturbing the stoichiometry of protein complexes. Most inhibitors target the key component heat-shock protein 90 (HSP90). However, although classical HSP90 inhibitors are highly tumor-selective, they fail in phase 3 clinical oncology trials. These failures are at least partly due to an interference with a negative feedback loop by HSP90 inhibition, known as heat-shock response (HSR): in response to HSP90 inhibition there is compensatory synthesis of stress-inducible chaperones, mediated by the transcription factor heat-shock factor 1 (HSF1). We recently identified that wildtype p53 (p53) actively reduces the HSR by repressing HSF1 via a p21-CDK4/6-MAPK-HSF1 axis. Here we test the hypothesis that in HSP90-based therapies simultaneous p53 activation or direct cell cycle inhibition interrupts the deleterious HSF1-HSR axis and improves the efficiency of HSP90 inhibitors. Indeed, we find that the clinically relevant p53 activator Idasanutlin suppresses the HSF1-HSR activity in HSP90 inhibitor-based therapies. This combination synergistically reduces cell viability and accelerates cell death in p53-proficient colorectal cancer (CRC) cells, murine tumor-derived organoids and patient-derived organoids (PDOs). Mechanistically, upon combination therapy human CRC cells strongly upregulate p53-associated pathways, apoptosis, and inflammatory immune pathways. Likewise, in the chemical AOM/DSS CRC model in mice, dual HSF1-HSP90 inhibition strongly represses tumor growth and remodels immune cell composition, yet displays only minor toxicities in mice and normal mucosa-derived organoids. Importantly, inhibition of the cyclin dependent kinases 4 and 6 (CDK4/6) under HSP90 inhibition phenocopies synergistic repression of the HSR in p53-proficient CRC cells. Even more important, in p53-deficient (mutp53-harboring) CRC cells, an HSP90 inhibition in combination with CDK4/6 inhibitors similarly suppresses the HSF1-HSR system and reduces cancer growth. Likewise, p53-mutated PDOs strongly respond to dual HSF1-HSP90 pathway inhibition and thus, providing a strategy to target CRC independent of the p53 status. In sum, activating p53 (in p53-proficient cancer cells) or inhibiting CDK4/6 (independent of the p53 status) provide new options to improve the clinical outcome of HSP90-based therapies and to enhance colorectal cancer therapy.

Targeted Nanoparticles: the Smart Way for the Treatment of Colorectal Cancer

Colorectal cancer (CRC) is a widespread cancer that starts in the digestive tract. It is the third most common cause of cancer deaths around the world. The World Health Organization (WHO) estimates an expected death toll of over 1 million cases annually. The limited therapeutic options as well as the drawbacks of the existing therapies necessitate the development of non-classic treatment approaches. Nanotechnology has led the evolution of valuable drug delivery systems thanks to their ability to control drug release and precisely target a wide variety of cancers. This has also been extended to the treatment of CRC. Herein, we shed light on the pertinent research that has been performed on the potential applications of nanoparticles in the treatment of CRC. The various types of nanoparticles in addition to their properties, applications, targeting approaches, merits, and demerits are discussed. Furthermore, innovative therapies for CRC, including gene therapies and immunotherapies, are also highlighted. Eventually, the research gaps, the clinical potential of such delivery systems, and a future outlook on their development are inspired.

Genetic Alterations of NF-κB and Its Regulators: A Rich Platform to Advance Colorectal Cancer Diagnosis and Treatment

Colorectal cancer (CRC) is the third leading cause of cancer mortality in the United States, with an estimated 52,000 deaths in 2023. Though significant progress has been made in both diagnosis and treatment of CRC in recent years, genetic heterogeneity of CRC-the culprit for possible CRC relapse and drug resistance, is still an insurmountable challenge. Thus, developing more effective therapeutics to overcome this challenge in new CRC treatment strategies is imperative. Genetic and epigenetic changes are well recognized to be responsible for the stepwise development of CRC malignancy. In this review, we focus on detailed genetic alteration information about the nuclear factor (NF)-κB signaling, including both NF-κB family members, and their regulators, such as protein arginine methyltransferase 5 (PRMT5), and outer dynein arm docking complex subunit 2 (ODAD2, also named armadillo repeat-containing 4, ARMC4), etc., in CRC patients. Moreover, we provide deep insight into different CRC research models, with a particular focus on patient-derived xenografts (PDX) and organoid models, and their potential applications in CRC research. Genetic alterations on NF-κB signaling components are estimated to be more than 50% of the overall genetic changes identified in CRC patients collected by cBioportal for Cancer Genomics; thus, emphasizing its paramount importance in CRC progression. Consequently, various genetic alterations on NF-κB signaling may hold great promise for novel therapeutic development in CRC. Future endeavors may focus on utilizing CRC models (e.g., PDX or organoids, or isogenic human embryonic stem cell (hESC)-derived colonic cells, or human pluripotent stem cells (hPSC)-derived colonic organoids, etc.) to further uncover the underpinning mechanism of these genetic alterations in NF-κB signaling in CRC progression. Moreover, establishing platforms for drug discovery in dishes, and developing Biobanks, etc., may further pave the way for the development of innovative personalized medicine to treat CRC in the future.

Murine models of colorectal cancer: the azoxymethane (AOM)/dextran sulfate sodium (DSS) model of colitis-associated cancer

Background

Colorectal cancer (CRC) is the third most common cancer. It is a heterogeneous disease, including both hereditary and sporadic types of tumors. CRC results from complex interactions between various genetic and environmental factors. Inflammatory bowel disease is an important risk factor for developing CRC. Despite growing understanding of the CRC biology, preclinical models are still needed to investigate the etiology and pathogenesis of the disease, as well as to find new methods of treatment and prevention.

Objectives

The purpose of this review is to describe existing murine models of CRC with a focus on the models of colitis-associated CRC. This manuscript could be relevant for experimental biologists and oncologists.

Methodology

We checked PubMed and Google from 01/2018 to 05/2023 for reviews of CRC models. In addition, we searched PubMed from 01/2022 to 01/2023 for articles using the azoxymethane (AOM)/dextran sulfate sodium (DSS) CRC model.

Results

Existing murine models of CRC include spontaneous, genetically engineered, transplantation, and chemically induced models. For the study of colitis-associated cancer (CAC), the AOM/DSS model is predominantly used. This model is very similar in histological and molecular characteristics to the human CAC, and is highly reproducible, inexpensive, and easy to use. Despite its popularity, the AOM/DSS model is not standardized, which makes it difficult to analyze and compare data from different studies.

Conclusions

Each model demonstrates particular advantages and disadvantages, and allows to reproduce different subtypes or aspects of the pathogenesis of CRC.

Creating a Surgical Biobank: The Hershey Medical Center Experience

BACKGROUND

Tissue harvesting at the time of surgery offers surgeons and scientists a unique opportunity to discover and better understand disease pathophysiology. Tissue biobanking presents challenges in patient consents, specimen collection, preparation, and storage, but the potential for scientific discovery justifies the effort. Although the number of tissue biobanks is increasing worldwide, information regarding necessary infrastructure, process flow, and management of expected obstacles is lacking.

OBJECTIVE

To provide a framework and motivation for clinician scientists intending to start an intestinal tissue biobank under their direction.

DATA SOURCES

The Carlino Family Inflammatory Bowel and Colorectal Diseases Biobank is housed at the Milton S. Hershey Medical Center.

STUDY SELECTION

Review.

INTERVENTION

Implementation of a surgical tissue biobank at a large tertiary care institution.

MAIN OUTCOME MEASURES

Assess critical challenges and obstacles over the years as well as keys to the success of the program.

RESULTS

Over 2 decades, the institutional biobank grew from an IBD biobank to one which now incorporates thousands of surgical specimens representing numerous colorectal diseases. This was done through a process of refinement focusing on patient recruitment and an efficient consenting and specimen management process. The biobank's success is further insured by institutional, external, and philanthropic support; scientific collaborations; and sharing of biological specimens with other groups of dedicated researchers.

LIMITATIONS

This is a single-center experience in collecting surgically resected colorectal specimens.

CONCLUSIONS

Surgical specimen biobanks are essential in studying disease cause using genomics, transcriptomics, and proteomic technologies. Therefore, surgeons, clinicians, and scientists should build biobanks at their institutions to promote further scientific discovery and improve specimen diversity.

Antitumor activity of 5-fluorouracil polymeric nanogel synthesized by gamma radiation on a rat model of colon carcinoma: a proposed mechanism

The use of 5-fluorouracil (5-FU) is associated with multifaceted challenges and poor pharmacokinetics. Accordingly, our study was designed to prepare 5-FU nanogel as a new form of the colon cancer chemotherapeutic drug 5-FU using polyacrylic acid and gelatin hybrid nanogel as efficient drug carriers. Alongside the in vivo chemotherapeutic evaluation, the anti-proliferative and anti-apoptotic efficacy were carried out for 5-FU nanogel against 1,2-dimethylhydrazine (DMH, 20 mg/kg) and γ-radiation (4 Gy)-prompted colon dysplasia in rats compared to 5-FU. The morphology and size of 5-FU nanogel were characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS) in addition to cytotoxicity assay. The expression of phosphoinositide-3-kinase (PI3K)/Akt, mammalian target of rapamycin (mTOR); Toll-like receptor2 (TLR2)/nuclear factor kappa B), adenosine monophosphate (AMP)-activated protein kinase (AMPK) and its downstream autophagy-related genes in addition to apoptotic markers were measured in colon tissues. Results: 5-FU nanogel reduced the levels of the TLR2/ NF-κβ as well as the expression of PI3K/AKT/mTOR. Moreover, it promoted autophagy through the activation of the AMPK and its downstream targets which consequently augmented the intrinsic and extrinsic apoptotic pathways. Conclusion: Collectively, these data might strengthen the therapeutic potential of 5-FU nanogel which can be used as an antitumor product for colon cancer.

A Short-Term Model of Colitis-Associated Colorectal Cancer That Suggests Initial Tumor Development and the Characteristics of Cancer Stem Cells

The mechanisms underlying the transition from colitis-associated inflammation to carcinogenesis and the cell origin of cancer formation are still unclear. The azoxymethane (AOM)/dextran sodium sulfate (DSS) mouse model reproduces human colitis-associated colorectal cancer. To elucidate the mechanisms of cancer development and dynamics of the linker threonine-phosphorylated Smad2/3 (pSmad2/3L-Thr)-positive cells, we explored the early stages of colitis-associated colorectal cancer in AOM/DSS mice. The AOM/DSS mice were sacrificed at 4 to 6 weeks following AOM administration. To analyze the initial lesions, immunofluorescence staining for the following markers was performed: β-catenin, Ki67, CDK4, Sox9, Bmi1, cyclin D1, and pSmad2/3L-Thr. Micro-neoplastic lesions were flat and unrecognizable, and the uni-cryptal ones were either open to the surfaces or hidden within the mucosae. These neoplastic cells overexpressed β-catenin, Sox9, Ki67, and Cyclin D1 and had large basophilic nuclei in the immature atypical cells. In both the lesions, pSmad2/3L-Thr-positive cells were scattered and showed immunohistochemical co-localization with β-catenin, CDK4, and Bmi1 but never with Ki67. More β-catenin-positive neoplastic cells of both lesions were detected at the top compared to the base or center of the mucosae. We confirmed initial lesions in the colitis-associated colorectal cancer model mice and observed results that suggest that pSmad2/3L-Thr is a biomarker for tissue stem cells and cancer stem cells.

Interaction of lncRNAs with mTOR in colorectal cancer: a systematic review

Colorectal cancer (CRC) is the third most widespread cancer and the fourth leading lethal disease among different societies. It is thought that CRC accounts for about 10% of all newly diagnosed cancer cases with high-rate mortality. lncRNAs, belonging to non-coding RNAs, are involved in varied cell bioactivities. Emerging data have confirmed a significant alteration in lncRNA transcription under anaplastic conditions. This systematic review aimed to assess the possible influence of abnormal mTOR-associated lncRNAs in the tumorigenesis of colorectal tissue. In this study, the PRISMA guideline was utilized based on the systematic investigation of published articles from seven databases. Of the 200 entries, 24 articles met inclusion criteria and were used for subsequent analyses. Of note, 23 lncRNAs were prioritized in association with the mTOR signaling pathway with up-regulation (79.16%) and down-regulation (20.84%) trends. Based on the obtained data, mTOR can be stimulated or inhibited during CRC by the alteration of several lncRNAs. Determining the dynamic activity of mTOR and relevant signaling pathways via lncRNAs can help us progress novel molecular therapeutics and medications.

The Association of Human Cytomegalovirus Infection and Colorectal Cancer: A Clinical Analysis

Background

Human cytomegalovirus (HCMV) commonly infects humans and establishes lifelong infection. It causes disease and increased mortality rates in patients with immunosuppression. HCMV gene products are found to be present in multiple human malignancies and target cellular functions involved in tumor development; additionally, a tumor-cytoreductive role of CMV has also been observed. The purpose of this study was to evaluate the correlation between CMV infection and the incidence of colorectal cancer (CRC).

Methods

The data were provided by a national database that is compliant with Health Insurance Portability and Accountability Act (HIPAA). Using International Classification of Disease (ICD)-10 and ICD-9 diagnostic codes, the data were filtered to evaluate patients infected with HCMV versus patients never infected with HCMV. Patient data from 2010 to 2019 were assessed. Access to the database was granted by Holy Cross Health, Fort Lauderdale for the purpose of academic research. Standard statistical methods were used.

Results

Between January 2010 and December 2019, the query was analyzed and resulted in 14,235 patients after matching in the infected and control groups. The groups were matched by age range, sex, Charlson Comorbidity Index (CCI) score, and treatment. The incidence of CRC was 1.159% (165 patients) in the HCMV group and 2.845% (405 patients) in the control group. The difference after matching was statistically significant by a P-value < 2.2 × 10^-16 with an odds ratio of 0.37 (95% confidence interval (CI) 0.32 - 0.42).

Conclusions

The study shows a statistically significant correlation between CMV infection and a reduced incidence of CRC. Further evaluation is recommended to assess the potential of CMV in reducing CRC incidence.

Molecular and cellular pathways in colorectal cancer: apoptosis, autophagy and inflammation as key players

BACKGROUND

Colorectal carcinogenesis (CRC) is one of the most aggressive forms of cancer, particularly in developing countries. It accounts for the second and third-highest reason for cancer-induced lethality in women and men respectively. CRC involves genetic and epigenetic modifications in colonic epithelium, leading to colon adenocarcinoma. The current review highlights the pathogenic mechanisms and multifactorial etiology of CRC, influenced by apoptosis, inflammation, and autophagy pathways.

METHODS

We have carried out a selective literature review on mechanisms contributing to the pathogenesis of CRC.

RESULTS

Resistance to senescence and apoptosis of the mesenchymal cells, which play a key role in intestinal organogenesis, morphogenesis and homeostasis, appears important for sporadic CRC. Additionally, inflammation-associated tumorigenesis is a key incident in CRC, supported by immune disruptors, adaptive and innate immune traits, environmental factors, etc. involving oxidative stress, DNA damage and epigenetic modulations. The self-digesting mechanism, autophagy, also plays a twin role in CRC through the participation of LC3/LC3-II, Beclin-1, ATG5, other autophagy proteins, and Inflammatory Bowel Disease (IBD) susceptibility genes. It facilitates the promotion of effective surveillance pathways and stimulates the generation of malignant tumor cells. The autophagy and apoptotic pathways undergo synergistic or antagonistic interactions in CRC and bear a critical association with IBD that results from the pro-neoplastic effects of persistent intestinal inflammation. Conversely, pro-inflammatory factors stimulate tumor growth and angiogenesis and inhibit apoptosis, suppressing anti-tumor activities.

CONCLUSION

Hence, research attempts for the development of potential therapies for CRC are in progress, primarily based on combinatorial approaches targeting apoptosis, inflammation, and autophagy.

Hesperetin alleviates DMH induced toxicity via suppressing oxidative stress and inflammation in the colon of Wistar rats

1,2-Dimethylhydrazine (DMH), a colon-specific environmental toxicant is one among the carcinogen responsible for the cause of colon cancer. The present study was designed to evaluate the protective effect of Hesperetin (HST) against colon toxicity induced by DMH in Wistar rats. HST, a flavonoid widely found in citrus fruits possesses several biological activities including anti-microbial, anti-oxidant properties among others. A single dose of DMH (40 mg/kg body weight) was administered subcutaneously on 1st day for induction of colon toxicity followed by oral treatment with HST at a dose of 20 mg/kg bodyweight for 14 consecutive days. DMH administration leads to excessive ROS generation, resulting in an imbalance in redox homeostasis and causing membrane lipid peroxidation, which is also partly due to the decrease in the level of tissue antioxidant machinery. Our result showed HST significantly ameliorates DMH-induced lipid peroxidation and also substantially increases the activity/level of various anti-oxidant proteins (GR, GPx, GST, GSH, and SOD). HST was also found to reduce the expression of inflammatory proteins (TNF-α, IL-6, i-NOS, COX-2, NF-kB-p65), goblet cell disintegration as well as mucin depletion (sulfo and sialomucin) in the colon that was found to be elevated upon administration of DMH. Our histological results further provide confirmation of the protective role of HST against DMH-induced pathological alterations. The results of the present study demonstrate supplementation of HST is beneficial in ameliorating DMH-induced toxicity by suppressing oxidative stress, inflammation, goblet cell disintegration as well mucin depletion in the colon of Wistar rats.

Survivin in Breast Cancer: A Review

Breast cancer is the most frequently diagnosed cancer in women and ranks second among causes for cancer-related death in women. Gene technology has led to the recognition that breast cancer is a heterogeneous disease composed of different biological subtypes, and genetic profiling enables the response to chemotherapy to be predicted. This fact emphasizes the importance of selecting sensitive diagnostic and prognostic markers in the early disease stage and more efficient targeted treatments for this disease. One such prognostic marker appears to be survivin. Many studies have shown that survivin is strongly expressed in different types of cancers. Its overexpression has been demonstrated in breast cancer, and high activity of the survivin gene has been associated with a poor prognosis and worse survival rates.

Effects of glycolysis and polyamine predation on intestinal epithelial barrier in colorectal cancer

Colorectal cancer (CRC) is the second most lethal cancer and the third most common cancer in the world, and its prognosis is severely affected by high intestinal mucosal permeability and increasing tumor burden. Studies have shown that the expression of hypoxia induce factor 1α (HIF1α) is up-regulated in a variety of tumor tissues, which is related to multiple metabolic reprogramming of tumor cells. However, the role of HIF1α in CRC tumor growth, tumor polyamine metabolism and intestinal mucosal barrier damage has not been studied. Here, we constructed different types of CRC tumor-bearing mice models by inoculating HCT116 cells with different levels of HIF1α expression (knockdown, wild type, overexpression) in the armpits of mice to explore the upstream and downstream regulators of HIF1α, the effects of HIF1α on the growth of CRC, and the CRC polyamine metabolism and its effect on the intestinal mucosal barrier. We found that with the increase of HIF1 gene expression, tumor growth was promoted and intestinal mucosal permeability was increased. The expression of glycolysis-related proteins was up-regulated, the rate-limiting enzyme ODC of polyamine synthesis was decreased, and the transfer protein of polyamine was increased. HPLC showed that the polyamine content in the tumor tissue of the overexpression group HIF1α OE was higher than that of the wild group HIF1α (+/+), and higher than that of the knockdown group HIF1α (-/-), but the content of polyamines in intestinal mucosa was the opposite. After supplementation of exogenous polyamines, the content of polyamines in intestinal mucosa and tumor tissue increased, and the damage of intestinal mucosa was alleviated. In conclusion, upon activation of the MYC/HIF1 pathway, tumor glycolysis is enhanced, tumors require more energy and endogenous polyamine synthesis is reduced. Therefore, in order to meet its growth needs, tumor will rob polyamines in the intestinal mucosa, resulting in intestinal mucosal epithelial barrier dysfunction.

Colorectal Cancer Chemoprevention by S-Allyl Cysteine–Caffeic Acid Hybrids: In Vitro Biological Activity and In Silico Studies

Conventional chemotherapy for colorectal cancer (CRC) gives only a small increase in patient survival, since it is often diagnosed at late stages, when the tumor has disseminated to other organs. Moreover, it is common to observe that malignant cells may acquire resistance to conventional chemotherapies through different mechanisms, including reducing drug activation or accumulation (by enhancing efflux), inducing alterations in molecular targets, and inhibiting the DNA damage response, among other strategies. Considering these facts, the discovery of new molecules with therapeutic potential has become an invaluable tool in chemoprevention. In this context, we previously evaluated two hybrids (SAC-CAFA-MET and SAC-CAFA-PENT) that exhibited selective cytotoxicity against SW480 cells, with better results than the conventional chemotherapeutic agent (5-fluorouracil; 5-FU). Here, we investigated the possible mechanisms of these molecules in greater depth, to identify whether they could be valuable therapeutic scaffolds in the search for new molecules with chemopreventive potential for the treatment of CRC. Both compounds reduced ROS formation, which could be related to antioxidant effects. Further evaluations showed that SAC-CAFA-MET induces cell death independent of caspases and the tumor-suppressor protein p53, but probably mediated by the negative regulation of the pro-apoptotic Bcl-2. In addition, the lack of activation of caspase-8 and the positive regulation of caspase-3 induced by SAC-CAFA-PENT suggest that this compound acts through an apoptotic mechanism, probably initiated by intrinsic pathways. Furthermore, the downregulation of IL-6 by SAC-CAFA-PENT suggests that it also induces a significant anti-inflammatory process. In addition, docking studies would suggest caspase-3 modulation as the primary mechanism by which SAC-CAFA-PENT elicits apoptosis in SW480human colorectal adenocarcinoma cells. Meanwhile, density functional theory (DFT) calculations suggest that both hybrids would produce effects in the modulation of ROS in SW480 cells via the hydrogen atom transfer (HAT) pathway. The present work notes that SAC-CAFA-MET and SAC-CAFA-PENT could be potential candidates for further investigations in the search for potential chemopreventive agents.

Interpretation of P16 expression as a marker of HPV in colorectal cancer

BACKGROUND

Colorectal cancer is one of the most prevalent types of tumors worldwide. P16ᴵᴺᴷ⁴ᵃ is a widely used immunohistochemical marker for high-risk HPV infection. The purpose of this study is to explore the relationship between P16 expression as an indicator of HPV infection and colorectal cancer in Egyptian patients, as well as its association with histopathological characteristics.

MATERIAL AND METHODS

The study was performed on 59 cases of colorectal carcinoma cases and 30 specimens of normal colonic mucosa.

RESULTS

p16 protein was detected in 22% (13 of 59) of patients with colorectal carcinoma. No evidence of P16 expression in all 30 cases of non-neoplastic colonic mucosa was found. More frequent expression of P16 was seen in distal carcinomas.

CONCLUSION

our study demonstrated that P16 protein is expressed in a reasonable percent of colorectal carcinoma cases, suggesting a role of HPV in colorectal carcinogenesis. The present study highlights the role of p16 protein expression which is important in the pathogenesis in colorectal carcinoma, especially regarding distal tumors.

The P2X7 Receptor Promotes Colorectal Inflammation and Tumorigenesis by Modulating Gut Microbiota and the Inflammasome

Background: Given the role of the P2X7 receptor (P2X7R) in inflammatory bowel diseases (IBD), we investigated its role in the development and progression of colitis-associated colorectal cancer (CA-CRC). Methods: CA-CRC was induced in P2X7R^+/+ and P2X7R^−/− mice with azoxymethane (AOM) combined with dextran sodium sulfate (DSS). In a therapeutic protocol, P2X7R^+/+ mice were treated with a P2X7R-selective inhibitor (A740003). Mice were evaluated with follow-up video endoscopy with endoluminal ultrasound biomicroscopy. Colon tissue was analyzed for histological changes, densities of immune cells, expression of transcription factors, cytokines, genes, DNA methylation, and microbiome composition of fecal samples by sequencing for 16S rRNA. Results: The P2X7R^+/+ mice displayed more ulcers, tumors, and greater wall thickness, than the P2X7R^−/− and the P2X7R^+/+ mice treated with A740003. The P2X7R^+/+ mice showed increased accumulation of immune cells, production of proinflammatory cytokines, activation of intracellular signaling pathways, and upregulation of NLRP3 and NLRP12 genes, stabilized after the P2X7R-blockade. Microbial changes were observed in the P2X7R^−/− and P2X7R^+/+-induced mice, partially reversed by the A740003 treatment. Conclusions: Regulatory mechanisms activated downstream of the P2X7R in combination with signals from a dysbiotic microbiota result in the activation of intracellular signaling pathways and the inflammasome, amplifying the inflammatory response and promoting CA-CRC development.

o-Aminoazotoluene, 7,12-dimethylbenz[a]anthracene, and N-ethyl-N-nitrosourea, which are mutagenic but not carcinogenic in the colon, rapidly induce colonic tumors in mice with dextran sulfate sodium-induced colitis

BACKGROUND

Several rodent models with chemically induced colon cancer have been developed. Among these models, dextran sulfate sodium (DSS), a colitis inducer, combined with azoxymethane as a colon mutagenic carcinogen, is commonly used. We previously reported that although benzo [a] pyrene (BP) is mutagenic but not carcinogenic in the colon, it rapidly develops colon tumors at a high incidence/multiplicity after treatment with DSS. In the present study, we examined whether other colon-mutagenic non-carcinogens (CMNCs) induced colon tumors after treatment with DSS.

RESULTS

o-Aminoazotoluene, 7,12-dimethylbenz[a]anthracene, and N-ethyl-N-nitrosourea were selected as CMNCs. Male CD2F1 mice were orally administered CMNC for 5 consecutive days. After a 9-day dose-free period, mice were treated with 4% DSS in drinking water for 1 week. Three months after DSS treatment, colon samples were collected for histopathology and β-catenin immunohistochemistry analyses. All CMNCs in combination with DSS induced colonic adenocarcinomas at a high incidence/multiplicity in the distal and middle parts of the colon, coinciding with the location of colitis. Unlike in normal cells where β-catenin is exclusively located on the cell membrane, in adenocarcinoma cells, it was translocated to both the nucleus and cytoplasm or only to cytoplasm. The translocation of β-catenin is closely associated with colon carcinogenesis in rodents and humans. No colonic tumors or dysplastic lesions were found after exposure to either CMNC or DSS alone.

CONCLUSION

We provided further evidence clearly showing that CMNCs can rapidly induce colonic tumors in mice with DSS-induced colitis, even if they are not colonic carcinogens.

Comprehensive analysis of N6-methylandenosine regulators and m6A-related RNAs as prognosis factors in colorectal cancer

Colorectal cancer (CRC) is one of the most common malignancies and has been a leading cause of cancer-related death worldwide in recent years. N6-methyladenosine (m6A) methylation is the most abundant epigenetic modification of various types of RNAs, and it plays a vital role in promoting cancer development. Here, we obtained SNV and transcriptome data of CRC from The Cancer Genome Atlas (TCGA). We demonstrated that most m6A methylation regulators were aberrantly expressed in individuals with CRC. The abnormal expression of m6A regulators was caused by their different copy number variation (CNV) patterns, and alteration of m6A regulators was significantly correlated with prognosis and tumor stage. By using weighted coexpression network analysis (WGCNA), we identified m6A-related long noncoding RNAs (lncRNAs) and mRNAs; then we used least absolute shrinkage and selection operator (LASSO) Cox regression analysis to construct m6A-related lncRNA and mRNA prognostic signatures in the TCGA dataset. Furthermore, a nomogram with clinicopathological features, lncRNA risk scores, and mRNA risk scores was established, which showed a strong ability to forecast the overall survival of the individuals with CRC in training and testing sets. In conclusion, m6A methylation regulators played a vital role in affecting the prognosis of subjects with CRC, and m6A-related lncRNAs and mRNAs revealed underlying mechanisms in CRC tumorigenesis and progression.

An Integrative Approach to Characterize the Early Phases of Dimethylhydrazine-Induced Colorectal Carcinogenesis in the Rat

This study aimed to characterize an animal model of colorectal cancer (CRC) in the early stages of disease development. Twenty-nine male Wistar rats were divided into two control groups (CTRL1 and CTRL2), receiving EDTA–saline injections and two induced groups (CRC1 and CRC2), receiving 1,2-dimethylhydrazine (DMH) injections for seven consecutive weeks. CRC1 and CTRL1 were euthanized at the 11th week, while CRC2 and CTRL2 were euthanized at the 17th week. DMH treatment decreased microhematocrit values and IL-6, ghrelin, and myostatin serum levels. Histopathological analysis of intestinal sections showed that DMH-treated rats were characterized by moderate to severe epithelial dysplasia. An adenoma was observed in one animal (CRC2 group), and the presence of inflammatory infiltrate at the intestinal level was primarily observed in DMH-treated animals. DMH also induced Ki-67 immunoexpression. The gut microbiota analysis showed a higher abundance of Firmicutes, Clostridia, Clostridiales, Peptostreptococcaceae, Blautia, Romboutsia, and Clostridium sensu stricto in CRC than CTRL rats, whereas Prevotellaceae, Prevotella, Akkermansia, and Lactobacillus levels were more prevalent in CTRL animals. Our results suggest that this model could be helpful to investigate chemoprevention in the early stages of CRC.

The Pro-tumor and Anti-tumor Effects of NLRP3 Inflammasome as a New Therapeutic Option for Colon Cancer: a Meta-analysis of Pre-clinical Studies

In this review, we aimed to elaborate on these findings and explore how NLRP3 inflammasome affects CRC and which mechanism could be a potential therapeutic target. For this purpose, major indexing databases consist of Cochrane central, ISI web of science (WOS), PubMed/Medline, Scopus, and EMBASE were systematically searched using standard terms without any language, study region, or type restrictions. After applying the exclusion criteria, the main properties of 12 articles on 326 animals included in this meta-analysis. Of 12, eight were about an anti-tumoral effect, and four were on a pro-tumoral effect of the inflammasome. NLRP3 inhibition reduced IL-1β (SMD: -4.14, 95% CI: -5.49, -2.79, P < 0.00001, I² = 76%), TNFα (SMD: -2.18, 95% CI: -3.23, -1.13, P < 0.00001, I² = 82%), and IL-18 (SMD: -2.27, 95% CI: -3.38, -1.16, P = 0.0002, I² = 74%) significantly contrasted with the model controls. Colons harvested from NLRP3 inhibition groups showed significant truncation compared with the model controls (SMD: -1.75, 95% CI: -2.69, -0.81, P = 0.0003, I² = 60%). We demonstrated significantly decreased tumorigenesis following NLRP3 inactivation, as well as an increased survival rate compared with the model controls. To translate anti-cancer agents based on anti-NLRP3 from bench to bedside, it is necessary to identify the molecules that selectively target NLRP3 or its downstream pathways in malignant cells, as well as considering metabolic heterogeneity and the mechanisms causing such cancer-connected heterogeneity. Other studies are needed to separate the molecular and functional complexity of this network.SummarySecretion of IL-1β is contingent upon activation of the inflammasome complex of NLRP3. It has been suggested that activation of this complex necessitates two signals. One of these signals is made available by activation of toll-like-receptor (TLR)-mediated NF-kappa and actuates the IL-1β precursor synthesis and NLRP3 assembly. Another signal is conceivable to be mediated by hazard signals e.g., the purinergic P2X7 receptor stimulated by Adenosine triphosphate or other stimuli resulting in the efflux of potassium.

Endoscopic treatment of early colorectal cancer

Early colorectal neoplasia is a localized precancerous lesion of the large intestine associated with negligible risk of lymphatic or systemic dissemination. Early neoplasia consists of adenoma with low- and high-grade dysplasia, intramucosal carcinoma and superficially invasive cancer without other high-risk features. In the majority of cases, early neoplastic lesions are detected by colonoscopy and treated by means of endoscopy resection replacing surgical treatment. Risk of invasive cancer should be stratified during diagnostic colonoscopy using morphological classifications and then, appropriate resection technique (endoscopic polypectomy, endoscopic mucosal resection, endoscopic submucosal dissection or full-thickness resection) is used. Success of endoscopic resection is assessed by histological examination of the resected specimen and in some cases, additional surgical resection with lymphadenectomy should be performed. Colonoscopic surveillance is needed due to the risk of local recurrence and metachronous lesions.

Bile acids as regulatory molecules and potential targets in metabolic diseases

Bile acids are important hydroxylated steroids that are synthesized in the liver from cholesterol for intestinal absorption of lipids and other fatty-nutrient. They also display remarkable and immense functions such as regulating immune responses, managing the apoptosis of cells, participating in glucose metabolism, and so on. Some bile acids were used for the treatment or prevention of diseases such as gallstones, primary biliary cirrhosis, and colorectal cancer. Meanwhile, the accumulation of toxic bile acids leads to apoptosis, necrosis, and inflammation. Alteration of bile acids metabolism, as well as the gut microbiota that interacted with bile acids, contributes to the pathogenesis of metabolic diseases. Therefore, the purpose of this review is to summarize the current functions and pre-clinical or clinical applications of bile acids, and to further discuss the alteration of bile acids in metabolic disorders as well as the manipulation of bile acids metabolism as potential therapeutic targets.

3-D Endoluminal Ultrasound Biomicroscopic Imaging and Volumetry of Mouse Colon Tumors

Currently, colonoscopy is considered the gold standard procedure for diagnosis of colorectal cancer (CRC), the third most common cancer in the United States. However, this technique fails to detect flat adenomas, serrated polyps and advanced adenomas, with miss rates of 34%, 27% and 14%, respectively. These miss rates, more frequent than previously supposed, suggest the need for new CRC screening tools. In the work described here, the potential application of a 40-MHz ultrasound system to generate a sequence of 2-D endoluminal ultrasound biomicroscopy (eUBM-2-D) images of a mouse model of colon cancer was investigated, and this image sequence was used to render eUBM-3-D images and to measure tumor volume. The technique was validated with tissue-mimicking phantoms and used in vivo with mice bearing colon polypoid tumors. Estimated volumes ranged from 0.174-7.909 mm³ for targets in validation phantoms and from 0.066-6.082 mm³ for mouse colon tumors.

Potential Use of Senolytics for Pharmacological Targeting of Precancerous Lesions

Senescence is a cell state that contributes to several homeostatic and pathologic processes. In addition to being induced in somatic cells in response to replicative exhaustion (replicative senescence) as part of organismal aging, senescence can also be triggered prematurely by oncogene hyperactivation or tumor suppressor dysfunction [oncogene-induced senescence (OIS)]. Consequently, senescent cells comprise a major component of precancerous lesions of skin, oral mucosa, nasopharynx, prostate, gut, and lung. Unfortunately, invasive (or minimally invasive) interventions are currently the only available approach employed to eradicate premalignant lesions that carry the potential for cancer progression. Senolytics are a newly emerging drug class capable of selectively eliminating senescent cells. Although senolytics have been successfully demonstrated to mitigate a myriad of aging-related pathologies and to cull senescent cancer cells, there is a paucity of evidence for the potential use of senolytics as a novel approach to eliminate oncogene-induced senescent cells. This Emerging Concepts commentary will 1) summarize evidence in established models of OIS including B-Raf-induced nevi, transgenic lung cancer, and pancreatic adenocarcinoma models, as well as evidence from clinical precancerous lesions; 2) suggest that OIS is targetable; and 3) propose the utilization of senolytic agents as a revolutionary means to interfere with the ability of senescent premalignant cells to progress to cancer in vitro and in vivo If proven to be effective, senolytics will represent an emerging tool to pharmacologically treat precancerous lesions. SIGNIFICANCE STATEMENT: The treatment of premalignant lesions is largely based on the utilization of invasive (or minimally invasive) measures. Oncogene-induced senescence (OIS) is one form of senescence that occurs in response to oncogene overexpression in somatic cells and is present in precancerous lesions. Although the contribution of OIS to disease progression is undetermined, recent evidence suggests that senescent cells are permissive for malignant transformation. Accordingly, the pharmacological targeting of oncogene-induced senescent cells could potentially provide a novel, less invasive, means for the treatment of premalignant disease.

Transcriptomic and Proteomic Study on the High-Fat Diet Combined With AOM/DSS-Induced Adenomatous Polyps in Mice

Objective

To screen and identify molecular targets and bacteria genus leading to adenomatous polyps in mouse induced by high-fat diet (HFD) +AOM/DSS using omics technology.

Methods

The molecular targets of colorectal adenoma disease were obtained from the GeneCards and OMIM database. The SPF C57BL mice were randomly divided into blank (Control) and AOM/DSS+HFD colorectal adenoma model (ADH) groups. The ADH model group was intraperitoneally injected with AOM reagent. Then, mice were given with 2.5% DSS (in free drinking water) and high-fat diet to establish the mouse model. During this period, the changes of physical signs of mice in each group were observed. After the end of modeling, HE staining was used to evaluate the histopathological change of mice. The differentially expressed genes and proteins in the Control group and ADH group were detected by RNA-seq transcriptome sequencing and Tandem Mass Tags (TMT) quantitative proteomics. The histological results were analyzed by intersection with the intestinal adenoma molecular targets obtained from the database. Moreover, the changes of intestinal flora in the two groups were examined. The correlation between targets and differential bacteria was analyzed and verified by Parallel Reaction Monitoring (PRM) to comprehensively evaluate the mouse model of adenomatous polyp induced by AOM/DSS+HFD.

Results

The general condition and histopathological results of mice confirmed that the ADH mouse model was successfully established and tubular adenoma was formed. A total of 604 genes and 42 proteins related to intestinal adenoma were obtained by histological analysis and database intersection analysis. The intestinal microflora of ADH mice was different from that of normal mice, and the constituents and abundance of intestinal flora were similar to those of human intestinal adenoma. GATA4 and LHPP were selected as potential pathological markers of the model mice by correlation analysis of targets and intestinal flora. The results of PRM verification were highly consistent with the results of RNA-Seq transcriptome sequencing and TMT analysis.

Conclusion

The pathological results, molecular pathological markers and the changes of intestinal flora suggest that the mouse ADH model is ideal for studying the transformation of inflammatory cancer. The ADH model will be helpful for understanding the occurrence and development of human colorectal cancer at the transcriptomic and proteomic level.

Microbiome in drug resistance to colon cancer

Metagenomic analyses have revealed microbial dysbiosis in the gut of patients with colorectal cancer (CRC). The gut microbiota influences CRC via a variety of mechanisms, including microbial-derived factors such as metabolites or genotoxins. Pathogenic drivers and opportunistic passenger bacteria may underlie direct effect of the gut microbiota on carcinogenesis. We posit that metabolites generated by gut microbiota can influence CRC through a multitude of epigenetic or genetic effects on malignant transformation. A closer look at the cross talks between the commensals, epithelial cells, immune regulators etc., needs to be established with more substantiated studies. The recurrence of chemoresistant disease following therapy undoubtedly provides the impetus for morbidity and mortality; yet, the role of gut microbiome in drug resistance remains to be fully investigated. We review the current literature on microbial dysbiosis during CRC and discuss the mechanistic basis of CRC-associated bacteria in tumor initiation, progression and drug resistance.

Identification of Two Novel CIL-102 Upregulations of ERP29 and FUMH to Inhibit the Migration and Invasiveness of Colorectal Cancer Cells by Using the Proteomic Approach

CIL-102 (1-[4-(furo[2,3-b]quinolin-4-ylamino) phenyl]ethanone) is a major active agent of Camptotheca acuminata’s alkaloid derivative, and its anti-tumorigenic activity, a valuable biological property of the agent, has been reported in many types of cancer. In this study, we researched the novel CIL-102-induced protein for either the induction of cell apoptosis or the inhibition of cell migration/invasiveness in colorectal cancer cells (CRC) and their molecular mechanism. Firstly, our data showed that CIL-102 treatment not only increased the cytotoxicity of cells and the production of Reactive Oxygen Species (ROS), but it also decreased cell migration and invasiveness in DLD-1 cells. In addition, many cellular death-related proteins (cleavage caspase 9, cleavage caspase 3, Bcl-2, and TNFR1 and TRAIL) and JNK MAPK/p300 pathways were increased in a time-dependent manner. Using the proteomic approach with a MALDI-TOF-TOF analysis, CIL-102-regulated differentially expressed proteins were identified, including eight downregulated and 11 upregulated proteins. Among them, upregulated Endoplasmic Reticulum resident Protein 29 (ERP29) and Fumarate Hydratase (FUMH) by CIL-102 were blocked by the inhibition of ROS production, JNK activity, and p300/CBP (CREB binding protein) signaling pathways. Importantly, the knockdown of ERP29 and FUMH expression by shRNA abolished the inhibition of cell migration and invasion by CIL-102 in DLD-1 cells. Together, our findings demonstrate that ERP29 and FUMH were upregulated by CIL102 via ROS production, JNK activity, and p300/CBP pathways, and that they were involved in the inhibition of the aggressive status of colorectal cancer cells.

Tumor-on-chip modeling of organ-specific cancer and metastasis

Every year, cancer claims millions of lives around the globe. Unfortunately, model systems that accurately mimic human oncology - a requirement for the development of more effective therapies for these patients - remain elusive. Tumor development is an organ-specific process that involves modification of existing tissue features, recruitment of other cell types, and eventual metastasis to distant organs. Recently, tissue engineered microfluidic devices have emerged as a powerful in vitro tool to model human physiology and pathology with organ-specificity. These organ-on-chip platforms consist of cells cultured in 3D hydrogels and offer precise control over geometry, biological components, and physiochemical properties. Here, we review progress towards organ-specific microfluidic models of the primary and metastatic tumor microenvironments. Despite the field's infancy, these tumor-on-chip models have enabled discoveries about cancer immunobiology and response to therapy. Future work should focus on the development of autologous or multi-organ systems and inclusion of the immune system.

Metformin and Gastrointestinal Cancer Development in Newly Diagnosed Type 2 Diabetes: A Population-Based Study in Korea

INTRODUCTION

Clinical studies have produced conflicting results on the effects of metformin on gastrointestinal cancer development. We aimed to investigate the association between metformin use and stomach, colon, liver, and pancreatic cancer development among patients with newly diagnosed, drug-naïve type 2 diabetes.

METHODS

This retrospective study evaluated propensity score-matched patients with newly diagnosed type 2 diabetes from the Korean National Health Insurance Service database. Metformin users were categorized into tertiles according to the cumulative dose or duration of metformin treatment, and the risks of gastrointestinal cancers were compared.

RESULTS

Metformin users had reduced risks of developing stomach cancer (hazard ratio [HR]: 0.841, 95% confidence interval [CI]: 0.797-0.887), colon cancer (HR: 0.865, 95% CI: 0.822-0.91), and liver cancer (HR: 0.709, 95% CI: 0.675-0.746; P < 0.001). However, metformin users did not have a reduced overall risk of pancreatic cancer (HR: 1.335, 95% CI: 1.209-1.475; P < 0.001). The risks tended to decrease at higher cumulative doses and durations of metformin use, with significantly reduced risks of all 4 cancers at the highest cumulative dose (≥1,200,000 mg) and the longest duration (≥2,000 days) of metformin use.

DISCUSSION

This population-based data suggest that metformin could be associated with reductions in the risks of stomach, colon, and liver cancers, as well a reduced risk of pancreatic cancer in some subgroups. Metformin has benefit as a first-line treatment for type 2 diabetes mellitus. A further role in cancer risk reduction could be studied in controlled trials.

A Review of Colorectal Cancer in Terms of Epidemiology, Risk Factors, Development, Symptoms and Diagnosis

This review article contains a concise consideration of genetic and environmental risk factors for colorectal cancer. Known risk factors associated with colorectal cancer include familial and hereditary factors and lifestyle-related and ecological factors. Lifestyle factors are significant because of the potential for improving our understanding of the disease. Physical inactivity, obesity, smoking and alcohol consumption can also be addressed through therapeutic interventions. We also made efforts to systematize available literature and data on epidemiology, diagnosis, type and nature of symptoms and disease stages. Further study of colorectal cancer and progress made globally is crucial to inform future strategies in controlling the disease's burden through population-based preventative initiatives.

Design, Synthesis, Characterization, and Crystal Structure Studies of Nrf2 Modulators for Inhibiting Cancer Cell Growth In Vitro and In Vivo

Nrf2 is one of the important therapeutic targets studied extensively in several cancers including the carcinomas of the colon and rectum. However, to date, not many Nrf2 inhibitors showed promising results for retarding the growth of colorectal cancers (CRCs). Therefore, in this study, first, we have demonstrated the therapeutic effect of siRNA-mediated downmodulation of Nrf2 on the proliferation rate of CRC cell lines. Next, we have designed, synthesized, characterized, and determined the crystal structures for a series of tetrahydrocarbazoles (THCs) and assessed their potential to modulate the activity of Nrf2 target gene NAD(P)H:quinone oxidoreductase (NQO1) activity by treating colorectal carcinoma cell line HCT-116. Later, the cytotoxic potential of compounds was assessed against cell lines expressing varying amounts of Nrf2, viz., breast cancer cell lines MDA-MB-231 and T47D (low functionally active Nrf2), HCT-116 (moderately active Nrf2), and lung cancer cell line A549 (highly active Nrf2), and the lead compound 5b was tested for its effect on cell cycle progression in vitro and for retarding the growth of Ehrlich ascites carcinomas (EACs) in mice. Data from our study demonstrated that among various compounds 5b exhibited better therapeutic index and retarded the growth of EAC cells in mice. Therefore, compound 5b is recommended for further development to target cancers.

The dysbiosis signature of Fusobacterium nucleatum in colorectal cancer-cause or consequences? A systematic review

Colorectal cancer (CRC) is the third most common cause of cancer globally and the fourth attributable cause of mortality and morbidity due to cancer. An emerging factor contributing to CRC is the gut microbiota and the cellular changes associated with it. Further insights on this may help in the prevention, diagnosis and new therapeutic approaches to colorectal cancer. In most cases of CRC, genetic factors appear to contribute less to its aetiology than environmental and epigenetic factors; therefore, it may be important to investigate these environmental factors, their effects, and the mechanisms that may contribute to this cancer. The gut microbiota has recently been highlighted as a potential risk factor that may affect the structural components of the tumor microenvironment, as well as free radical and enzymatic metabolites directly, or indirectly. Many studies have reported changes in the gut microbiota of patients with colorectal cancer. What is controversial is whether the cancer is the cause or consequence of the change in the microbiota. There is strong evidence supporting both possibilities. The presence of Fusobacterium nucleatum in human colorectal specimens has been demonstrated by RNA-sequencing. F. nucleatum has been shown to express high levels of virulence factors such as FadA, Fap2 and MORN2 proteins. Our review of the published data suggest that F. nucleatum may be a prognostic biomarker of CRC risk, and hence raises the potential of antibiotic treatment of F. nucleatum for the prevention of CRC.

Animal Models of Colorectal Cancer: From Spontaneous to Genetically Engineered Models and Their Applications

Colorectal cancer is one of the most common gastrointestinal malignancies in humans, affecting approximately 1.8 million people worldwide. This disease has a major social impact and high treatment costs. Animal models allow us to understand and follow the colon cancer progression; thus, in vivo studies are essential to improve and discover new ways of prevention and treatment. Dietary natural products have been under investigation for better and natural prevention, envisioning to show their potential. This manuscript intends to provide the readers a review of rodent colorectal cancer models available in the literature, highlighting their advantages and disadvantages, as well as their potential in the evaluation of several drugs and natural compounds’ effects on colorectal cancer.

Heterozygous APC germline mutations impart predisposition to colorectal cancer

Familial adenomatous polyposis (FAP) is an inherited syndrome caused by a heterozygous adenomatous polyposis coli (APC) germline mutation, associated with a profound lifetime risk for colorectal cancer. While it is well accepted that tumorigenic transformation is initiated following acquisition of a second mutation and loss of function of the APC gene, the role of heterozygous APC mutation in this process is yet to be discovered. This work aimed to explore whether a heterozygous APC mutation induces molecular defects underlying tumorigenic transformation and how different APC germline mutations predict disease severity. Three FAP-human embryonic stem cell lines (FAP1/2/3-hESC lines) carrying germline mutations at different locations of the APC gene, and two control hESC lines free of the APC mutation, were differentiated into colon organoids and analyzed by immunohistochemistry and RNA sequencing. In addition, data regarding the genotype and clinical phenotype of the embryo donor parents were collected from medical records. FAP-hESCs carrying a complete loss-of-function of a single APC allele (FAP3) generated complex and molecularly mature colon organoids, which were similar to controls. In contrast, FAP-hESCs carrying APC truncation mutations (FAP1 and FAP2) generated only few cyst-like structures and cell aggregates of various shape, occasionally with luminal parts, which aligned with their failure to upregulate critical differentiation genes early in the process, as shown by RNA sequencing. Abnormal disease phenotype was shown also in non-pathological colon of FAP patients by the randomly distribution of proliferating cells throughout the crypts, compared to their focused localization in the lower part of the crypt in healthy/non-FAP patients. Genotype/phenotype analysis revealed correlations between the colon organoid maturation potential and FAP severity in the carrier parents. In conclusion, this study suggest that a single truncated APC allele is sufficient to initiate early molecular tumorigenic activity. In addition, the results hint that patient-specific hESC-derived colon organoids can probably predict disease severity among FAP patients.

Variation rs9929218 and risk of the colorectal Cancer and adenomas: A meta-analysis

BACKGROUNDS

Genome-wide association studies (GWAS) have identified multiple common CRC-related (colorectal cancer) SNPs (single nucleotide polymorphisms) including the Cadherin 1(CDH1) rs9929218 may act by increasing the risk of colorectal cancer, colorectal adenoma, or both. These studies, however, reported inconsistent associations.

METHODS

To derive a more accurate approximation of the connection, we carried out a meta-analysis of 12 published pieces of research including 11,590 controls and 8192 cases. We used odds ratios (ORs) and 95% confidence intervals (CIs) to evaluate the associations' strength.

RESULTS

Meta-analysis implied considerable association between CRC and rs9929218 (OR = 1.21, 95%CI 1.04-1.42 for GG versus AA; OR = 1.22, 95%CI 1.05-1.42 for GG/AG versus AA). In the subgroup analyses, significantly increased risks were found among Europeans.

CONCLUSIONS

In summary, our meta-analysis studies in different populations confirmed that SNP rs9929218 is significantly associated with CRC risk and that this variant may have a greater impact on Europeans.

A review of experimental models in colorectal carcinogenesis

Colorectal cancer is the leading cause of malignancy of the gastrointestinal tract. A better understanding of the molecular and cellular changes that lead to the disease is necessary to develop early diagnosis and optimal treatment modalities. Rodent models are rapid, reproducible and exhibit an adenoma-carcinoma sequence similar to that found in humans. The objective of this manuscript is to review the most common chemical carcinogens used to induce experimental tumors and the usual methods of evaluation.

H. El-kannishy S, Gardouh AR, K. Tawfik M, Faisal S, El-Mistekawy A, Salama A, Alomar SY, H. Eltrawy A, Yagub Aloyouni S, Zaitone SA. Chemopreventive Effect of 5-Flurouracil Polymeric Hybrid PLGA-Lecithin Nanoparticles against Colon Dysplasia Model in Mice and Impact on p53 Apoptosis

The use of 5-fluorouracil (5FU) is associated with multifaceted challenges and poor pharmacokinetics. Poly(lactic-co-glycolic acid)-lipid hybrid nanoparticles (PLNs)-based therapy has received attention as efficient carriers for a diversity of drugs. This study evaluated the in vivo chemotherapeutic and anti-proliferative efficacy of 5FU-loaded PLNs against 1,2-dimethylhydrazine (Di-MH) prompted colon dysplasia in mice compared to free 5FU. 5FU PLNs were prepared. Male Swiss albino mice were distributed to six experimental groups. Group 1: Saline group. All the other groups were injected weekly with Di-MH [20 mg/kg, s.c.]. Group 2: Di-MH induced colon dysplasia control group. Groups 3 and 4: Di-MH + free 5FU treated group [2.5 and 5 mg/kg]. Groups 5 and 6: Di-MH + 5FU-PLNs treated group [2.5 and 5 mg/kg]. Free 5FU and 5FU-PLNs doses were administered orally, twice weekly. Treatment with 5FU-PLNs induced a higher cytoprotective effect compared to free 5FU as indicated by lower mucosal histopathologic score and reduction in number of Ki-67 immunpositive proliferating nuclei. Additionally, there was significant upregulation of p53 and caspase 3 genes in colon specimens. Our results support the validity of utilizing the PLNs technique to improve the chemopreventive action of 5FU in treating colon cancer.

Vitamin E delta-tocotrienol and metabolite 13'-carboxychromanol inhibit colitis-associated colon tumorigenesis and modulate gut microbiota in mice

The gut microbiota play important roles in colon cancer. Vitamin E δ-tocotrienol (δTE) and its metabolite δTE-13'-carboxychromanol (δTE-13') are known to have cancer-preventive effects, but their impact on gut flora during tumorigenesis and the role of the metabolite in δTE's beneficial effects remain to be determined. In the murine colitis-associated colon cancer (CAC) induced by azoxymethane (AOM) and dextran sulfate sodium (DSS), we show that δTE and δTE-13' inhibited the multiplicity of large adenomas (>2 mm²) by 34% (P<.05) and 55% (P<.01), respectively, compared to the control diet. δTE-13' diminished AOM/DSS-increased GM-CSF and MCP-1, and δTE decreased IL-1β. Using 16S rRNA gene sequencing of fecal DNAs, we observe that δTE and δTE-13' modulated the composition but not the richness of gut microbes compared to the control. Both δTE and δTE-13' enhanced potentially beneficial Lactococcus and Bacteroides. The elevation of Lactococcus positively correlated with fecal concentrations of δTE-13' and its hydrogenated metabolite, suggesting that the metabolite may contribute to δTE's modulation of gut microbes. Furthermore, δTE-13' counteracted AOM/DSS-induced depletion of Roseburia that is known to be decreased in patients with inflammatory bowel diseases. δTE uniquely elevated (Eubacterium) coprostanoloigenes. Our study demonstrates that δTE and δTE-13' inhibited tumorigenesis, suppressed pro-inflammatory cytokines and modulated gut microbiota in a murine CAC model. These findings uncover new and distinct activities of δTE and δTE-13' and support the notion that the metabolite may play a role in δTE's anticancer and modulation of gut microbes.

Intestinal Growth in Glucagon Receptor Knockout Mice Is Not Associated With the Formation of AOM/DSS-Induced Tumors

Treatment with exogenous GLP-2 has been shown to accelerate the growth of intestinal adenomas and adenocarcinomas in experimental models of colonic neoplasia, however, the role of endogenous GLP-2 in tumor promotion is less well known. Mice with a global deletion of the glucagon receptor (Gcgr^-/-) display an increase in circulating GLP-1 and GLP-2. Due to the intestinotrophic nature of GLP-2, we hypothesized that Gcgr^-/- mice would be more susceptible to colonic dysplasia in a model of inflammation-induced colonic carcinogenesis. Female Gcgr^-/- mice were first characterized for GLP-2 secretion and in a subsequent study they were given a single injection with the carcinogen azoxymethane (7.5 mg/kg) and treated with dextran sodium sulfate (DSS) (3%) for six days (n=19 and 9). A cohort of animals (n=4) received a colonoscopy 12 days following DSS treatment and all animals were sacrificed after six weeks. Disruption of glucagon receptor signaling led to increased GLP-2 secretion (p<0.0001) and an increased concentration of GLP-2 in the pancreas of Gcgr^-/- mice, coinciding with an increase in small intestinal (p<0.0001) and colonic (p<0.05) weight. Increased villus height was recorded in the duodenum (p<0.001) and crypt depth was increased in the duodenum and jejunum (p<0.05 and p<0.05). Disruption of glucagon receptor signaling did not affect body weight during AOM/DSS treatment, neither did it affect the inflammatory score assessed during colonoscopy or the number of large and small adenomas present at the end of the study period. In conclusion, despite the increased endogenous GLP-2 secretion Gcgr^-/- mice were not more susceptible to AOM/DSS-induced tumors.

Chemopreventive activity of bioactive fungal fractions isolated from milk-supplemented cultures of Cerrena unicolor and Pycnoporus sanguineus on colon cancer cells

The biochemical properties and anti-tumorigenic activity of Cerrena unicolor (CU) and Pycnoporus sanguineus (PS) towards colon cancer cells and the effect of supplementation of the fungal culture medium with cow milk on these activities were examined. CU1-II and PS4-II exhibited anticancer properties through various mechanisms. The extracts at the 200 µg/mL concentration significantly decreased the viability of HT-29 and SW948 cells. They also exhibited pro-apoptotic properties towards the cancer cell lines (HT-29, LS 180, and SW948). Furthermore, culturing the studied fungi on milk-supplemented media may improve the pro-health properties of both milk and mushrooms. The extracts had a higher concentration of proteins, lower levels of free amino acids, and higher content of phenolic compounds than milk. They also exerted a free radical scavenging effect, which may be connected with the high activity of catalase and superoxide dismutase. The tested extracts exhibited anticancer activity: C. unicolor grown on the medium without milk and P. sanguineus grown on the medium with milk. The CU1-II and PS4-II extracts exhibited the strongest anticancer properties; however, PS4-II exerted a milder effect on normal CCD 841 CoTr cells than CU1-II. CU3-II exerted the mildest effect among all extracts on both normal and cancer cells.

Diagnosing colorectal abnormalities using scattering coefficient maps acquired from optical coherence tomography

Optical coherence tomography (OCT) has shown potential in differentiating normal colonic mucosa from neoplasia. In this study of 33 fresh human colon specimens, we report the first use of texture features and computer vision-based imaging features acquired from en face scattering coefficient maps to characterize colorectal tissue. En face scattering coefficient maps were generated automatically using a new fast integral imaging algorithm. From these maps, a gray-level cooccurrence matrix algorithm was used to extract texture features, and a scale-invariant feature transform algorithm was used to derive novel computer vision-based features. In total, 25 features were obtained, and the importance of each feature in diagnosis was evaluated using a random forest model. Two classifiers were assessed on two different classification tasks. A support vector machine model was found to be optimal for distinguishing normal from abnormal tissue, with 94.7% sensitivity and 94.0% specificity, while a random forest model performed optimally in further differentiating abnormal tissues (i.e., cancerous tissue and adenomatous polyp) with 86.9% sensitivity and 85.0% specificity. These results demonstrated the potential of using OCT to aid the diagnosis of human colorectal disease.

O-glycan recognition and function in mice and human cancers

Protein glycosylation represents a nearly ubiquitous post-translational modification, and altered glycosylation can result in clinically significant pathological consequences. Here we focus on O-glycosylation in tumor cells of mice and humans. O-glycans are those linked to serine and threonine (Ser/Thr) residues via N-acetylgalactosamine (GalNAc), which are oligosaccharides that occur widely in glycoproteins, such as those expressed on the surfaces and in secretions of all cell types. The structure and expression of O-glycans are dependent on the cell type and disease state of the cells. There is a great interest in O-glycosylation of tumor cells, as they typically express many altered types of O-glycans compared with untransformed cells. Such altered expression of glycans, quantitatively and/or qualitatively on different glycoproteins, is used as circulating tumor biomarkers, such as CA19-9 and CA-125. Other tumor-associated carbohydrate antigens (TACAs), such as the Tn antigen and sialyl-Tn antigen (STn), are truncated O-glycans commonly expressed by carcinomas on multiple glycoproteins; they contribute to tumor development and serve as potential biomarkers for tumor presence and stage, both in immunohistochemistry and in serum diagnostics. Here we discuss O-glycosylation in murine and human cells with a focus on colorectal, breast, and pancreatic cancers, centering on the structure, function and recognition of O-glycans. There are enormous opportunities to exploit our knowledge of O-glycosylation in tumor cells to develop new diagnostics and therapeutics.

FAM3D is essential for colon homeostasis and host defense against inflammation associated carcinogenesis

The physiological homeostasis of gut mucosal barrier is maintained by both genetic and environmental factors and its impairment leads to pathogenesis such as inflammatory bowel disease. A cytokine like molecule, FAM3D (mouse Fam3D), is highly expressed in mouse gastrointestinal tract. Here, we demonstrate that deficiency in Fam3D is associated with impaired integrity of colonic mucosa, increased epithelial hyper-proliferation, reduced anti-microbial peptide production and increased sensitivity to chemically induced colitis associated with high incidence of cancer. Pretreatment of Fam3D^−/− mice with antibiotics significantly reduces the severity of chemically induced colitis and wild type (WT) mice co-housed with Fam3D^−/− mice phenocopy Fam3D-deficiency showing increased sensitivity to colitis and skewed composition of fecal microbiota. An initial equilibrium of microbiota in cohoused WT and Fam3D^−/− mice is followed by an increasing divergence of the bacterial composition after separation. These results demonstrate the essential role of Fam3D in colon homeostasis, protection against inflammation associated cancer and normal microbiota composition.

The cytokine like protein FAM3D (Fam3D in mice) is highly expressed in the digestive tract with unknown role in colon pathophysiology. Here, by using gene deficient mice, the authors show that Fam3D is critically involved in colon homeostasis, host defense against colitis-associated carcinogenesis, and the balance of microbiota.

Colitis-induced IL11 promotes colon carcinogenesis

Colitis increases the risk of colorectal cancer; however, the mechanism of the association between colitis and cancer remains largely unknown. To identify colitis-associated cancer promoting factors, we investigated gene expression changes caused by dextran sulfate sodium (DSS)-induced colitis in mice. By analyzing gene expression profiles, we found that IL11 was upregulated in DSS-induced colitis tissue and 2-amino-1-methyl-6-phenylimidazo[4,5-b]-pyridine (PhIP)/DSS-induced colon tumours in mice as well as in human colorectal cancer. By characterizing the activation/phosphorylation of STAT3 (pSTAT3), we found that pSTAT3 was induced transiently in colitis, but maintained at higher levels from hyper-proliferative dysplastic lesions to tumours. Using the IL11 receptor (IL11Rα1) knockout mice, we found that pSTAT3 in the newly regenerated crypt epithelial cells in colitis is abolished in IL11Rα1+/- and -/- mice, suggesting that colitis-induced IL11 activates STAT3 in colon crypt epithelial cells. Moreover, colitis-promoted colon carcinogenesis was significantly reduced in IL11Rα1+/- and -/- mice. To determine the roles of the IL11 in colitis, we found that the inhibition of IL11 signalling by recombinant IL11 antagonist mutein during colitis was sufficient to attenuate colitis-promoted carcinogenesis. Together, our results demonstrated that colitis-induced IL11 plays critical roles in creating cancer promoting microenvironment to facilitate the development of colon cancer from dormant premalignant cells.

Licochalcone A, a licorice flavonoid: antioxidant, cytotoxic, genotoxic, and chemopreventive potential

Licochalcone A (LicoA) is a flavonoid derived from Glycyrrhiza spp. plants. The present study aimed to investigate the antioxidant, cytotoxic, genotoxic, and chemopreventive effects of LicoA in in vitro and in vivo systems. The results showed that LicoA (197.1 μM) scavenged 77.92% of free radicals. Concentrations of 147.75 µM or higher LicoA produced cytotoxicity in Chinese hamster ovary (CHO) fibroblasts. LicoA treatments of 4.43 to 10.34 µM did not exert genotoxic activity, but at 11.8 µM significantly lowered nuclear division indexes, compared to negative control, revealing cytotoxicity. Lower concentrations (1.85 to 7.39 µM) exhibited protective activity against chromosomal damage induced by doxorubicin (DXR) or methyl methanesulfonate (MMS) in CHO cells. LicoA exerted no marked influence on DXR-induced genotoxicity in mouse erythrocytes, but reduced pre-neoplastic lesions induced by 1,2-dimethylhydrazine (DMH) in rat colon at 3.12 to 50 mg/kg b.w. Biochemical markers and body weight indicated no apparent toxicity. These findings contribute to better understanding the mechanisms underlying LicoA-initiated activity as a promising chemopreventive compound.

ABBREVIATIONS

AC, aberrant crypts; ACF, aberrant crypt foci; ALT, alanine aminotransferase; AST, aspartate aminotransferase; BOD, biochemical oxygen demand; CHO, Chinese hamster ovary fibroblast; DMH, 1,2-dimethylhydrazine; DMSO, dimethyl sulfoxide; DPPH, 2,2-diphenyl-1-picrylhydrazyl; DXR, doxorubicin hydrochloride; EDTA, ethylenediaminetetraacetic acid; GA, gallic acid; LicoA, licochalcone A; MMS, methyl methanesulfonate; MNBC, micronucleated binucleated cells; MNPCE, micronucleated polychromatic erythrocyte; NCE, normochromatic erythrocyte; NDI, nuclear division index; PBS, phosphate-buffered saline; PCE, polychromatic erythrocyte; XTT, 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide.

Long-term model of colitis-associated colorectal cancer suggests tumor spread mechanism and nature of cancer stem cells

Although chemical-induced animal models of colorectal cancer (CRC) suggest a lot about the disease, more efforts are required to establish metastasis models. Azoxymethane (AOM) and dextran sodium sulfate (DSS)-treated (AOM/DSS) Crl:CD-1 mice were sacrificed after 10 or 20 weeks in our previous study, and most colon tumors exhibited intramucosal adenocarcinomas. Our observations were extended until 30 weeks to study a colitis-associated advanced CRC mouse model, and explore whether linker threonine-phosphorylated Smad2/3 (pSmad2/3L-Thr) immunostaining-positive cells were involved in the progressive course of colitis-associated CRC as cancer stem cells. AOM/DSS mice were sacrificed at 10, 20 and 30 weeks after AOM administration. Following the histopathological analysis, immunohistochemical staining was performed for the following markers: CD34, podoplanin, β-catenin, E-cadherin, Ki67, Bmi1 and pSmad2/3L-Thr. Compared with AOM/DSS mice at 10 and 20 weeks, submucosal tumor infiltration and tumor invasion into vessels were markedly increased at 30 weeks. In the parts of colon tumors from AOM/DSS mice, particularly in mice at 30 weeks, the positive signal of E-cadherin was clearly reduced in the cell membranes. The percentage of Ki67-positive tumor cells in mucosal areas of AOM/DSS mice was higher than that in the sites of submucosal infiltration. In mucosal areas of colon tumors, pSmad2/3L-Thr-positive cells were scattered among tumor cells. At sites of submucosal infiltration and vessel invasion of these tumors, pSmad2/3L-Thr-positive cells were also observed among tumor cells. In colon tumors from AOM/DSS mice at 30 weeks, the percentage of pSmad2/3L-Thr-positive cells among the nuclear β-catenin-positive tumor cells was higher than that among the cytoplasmic β-catenin-positive tumor cells. For both non-neoplastic and neoplastic epithelial cells, pSmad2/3L-Thr-positive cells exhibited immunohistochemical co-localization with Bmi1. The present study developed an advanced CRC mouse model that exhibited tumor infiltration into the submucosa and invasion into vessels. The present study re-confirmed the theory that pSmad2/3L-Thr-positive cells may be cancer stem cells.

A Focused Review on Advances in Risk Stratification of Malignant Polyps

Colorectal cancer is the third most common cancer in both men and women in the United States, with most cases arising from precursor adenomatous polyps. Colorectal malignant polyps are defined as cancerous polyps that consist of tumor cells invading through the muscularis mucosae into the underlying submucosa (pT1 tumor). It has been reported that approximately 0.5-8.3% of colorectal polyps are malignant polyps, and the potential for lymph node metastasis in these polyps ranges from 8.5% to 16.1%. Due to their clinical significance, recognition of malignant polyps is critical for clinical teams to make treatment decisions and establish appropriate surveillance schedules after local excision of the polyps. There is a rapidly developing interest in malignant polyps within the literature as a result of an increasing number of identifiable adverse histologic features and recent advancements in endoscopic treatment techniques. The purpose of this paper is to have a focused review of the recent histopathologic literature of malignant polyps.