scholarly journals Signaling pathways in intestinal homeostasis and colorectal cancer: KRAS at centre stage

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Camille Ternet ◽  
Christina Kiel
Keyword(s):  
Colorectal Cancer ◽  
Signaling Pathways ◽  
Intestinal Microbiota ◽  
Critical Role ◽  
Neuroendocrine Cells ◽  
Cell Junction ◽  
Intestinal Cell ◽  
Intestinal Homeostasis ◽  
Cell Functions ◽  
The Impact

AbstractThe intestinal epithelium acts as a physical barrier that separates the intestinal microbiota from the host and is critical for preserving intestinal homeostasis. The barrier is formed by tightly linked intestinal epithelial cells (IECs) (i.e. enterocytes, goblet cells, neuroendocrine cells, tuft cells, Paneth cells, and M cells), which constantly self-renew and shed. IECs also communicate with microbiota, coordinate innate and adaptive effector cell functions. In this review, we summarize the signaling pathways contributing to intestinal cell fates and homeostasis functions. We focus especially on intestinal stem cell proliferation, cell junction formation, remodelling, hypoxia, the impact of intestinal microbiota, the immune system, inflammation, and metabolism. Recognizing the critical role of KRAS mutants in colorectal cancer, we highlight the connections of KRAS signaling pathways in coordinating these functions. Furthermore, we review the impact of KRAS colorectal cancer mutants on pathway rewiring associated with disruption and dysfunction of the normal intestinal homeostasis. Given that KRAS is still considered undruggable and the development of treatments that directly target KRAS are unlikely, we discuss the suitability of targeting pathways downstream of KRAS as well as alterations of cell extrinsic/microenvironmental factors as possible targets for modulating signaling pathways in colorectal cancer.

scholarly journals Growth Factors, PI3K/AKT/mTOR and MAPK Signaling Pathways in Colorectal Cancer Pathogenesis: Where Are We Now?

2021 ◽  
Vol 22 (19) ◽  
pp. 10260
Author(s):  
Constantin Stefani ◽  
Daniela Miricescu ◽  
Iulia-Ioana Stanescu-Spinu ◽  
Remus Iulian Nica ◽  
Maria Greabu ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Growth Factors ◽  
Growth Factor ◽  
Protein Kinase ◽  
Signaling Pathways ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Cancer Pathogenesis ◽  
The Impact ◽  
Mapk Signaling Pathways

Colorectal cancer (CRC) is a predominant malignancy worldwide, being the fourth most common cause of mortality and morbidity. The CRC incidence in adolescents, young adults, and adult populations is increasing every year. In the pathogenesis of CRC, various factors are involved including diet, sedentary life, smoking, excessive alcohol consumption, obesity, gut microbiota, diabetes, and genetic mutations. The CRC tumor microenvironment (TME) involves the complex cooperation between tumoral cells with stroma, immune, and endothelial cells. Cytokines and several growth factors (GFs) will sustain CRC cell proliferation, survival, motility, and invasion. Epidermal growth factor receptor (EGFR), Insulin-like growth factor -1 receptor (IGF-1R), and Vascular Endothelial Growth Factor -A (VEGF-A) are overexpressed in various human cancers including CRC. The phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) and all the three major subfamilies of the mitogen-activated protein kinase (MAPK) signaling pathways may be activated by GFs and will further play key roles in CRC development. The main aim of this review is to present the CRC incidence, risk factors, pathogenesis, and the impact of GFs during its development. Moreover, the article describes the relationship between EGF, IGF, VEGF, GFs inhibitors, PI3K/AKT/mTOR-MAPK signaling pathways, and CRC.

scholarly journals Association between Altered Oncogenic Signaling Pathways and Overall Survival of Patients with Metastatic Colorectal Cancer

Diagnostics ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2308
Author(s):  
Yi-Hsuan Huang ◽  
Peng-Chan Lin ◽  
Wu-Chou Su ◽  
Ren-Hao Chan ◽  
Po-Chuan Chen ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Overall Survival ◽  
Metastatic Colorectal Cancer ◽  
Signaling Pathways ◽  
Braf Mutation ◽  
The Cancer Genome Atlas ◽  
Cancer Center ◽  
Clinical Implications ◽  
Prognostic Impact ◽  
The Impact

Systemic characterization of genomic alterations into signaling pathways helps to understand the molecular pathogenies of colorectal cancer; however, their clinical implications remain unclear. Here, 128 patients with metastatic colorectal cancer (mCRC) receiving targeted next generation sequencing were retrospectively enrolled to analyze the impact of altered oncogenic pathways on clinical outcome. The datasets from Memorial Sloan Kettering Cancer Center were used for validation. In 123 patients with non-MSI-high tumor, the most common mutated gene was TP53 (84.6%), followed by APC (78.0%), KRAS (49.6%), and SMAD4 (22.8%). When mutated genes were allocated into signaling pathways defined as The Cancer Genome Atlas Pan-Cancer Analysis Project, alterations of cell cycle, Wnt, p53, RTK-RAS, PI3K, TGF-β, Notch, and Myc pathways were identified in 88%, 87%, 85%, 75%, 28%, 26%, 17%, and 10% of mCRC tissues, respectively. The survival analyses revealed that Myc and TGF-β pathway alterations were associated with a shorter overall survival (OS) (hazard ratio [HR]: 2.412; 95% confidence interval [CI]: 1.139–5.109; p = 0.018 and HR: 2.754; 95% CI: 1.044–7.265; p = 0.033, respectively). The negative prognostic impact of altered TGF-β pathway was maintained in patients receiving an anti-EGFR antibody. The OS of patients with mCRC carrying MYC and BRAF mutation was shorter than those with either MYC or BRAF mutation (HR: 4.981, 95% CI: 0.296–83.92; p = 0.02). These findings have clinical implications, such as prognosis prediction, treatment guidance, and molecular-targeted therapy development.

scholarly journals Intestinal Microbiota Influences DNA Methylome and Susceptibility to Colorectal Cancer

Genes ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 808
Author(s):  
Aïcha Zouggar ◽  
Joshua R. Haebe ◽  
Yannick D. Benoit
Keyword(s):  
Colorectal Cancer ◽  
Inflammatory Bowel Disease ◽  
Inflammatory Response ◽  
Gut Microbiota ◽  
Intestinal Microbiota ◽  
Bowel Disease ◽  
Colorectal Tumorigenesis ◽  
Epigenetic Programming ◽  
Inflammatory Bowel ◽  
The Impact

In a recent publication, Ansari et al. identified gut microbiota as a critical mediator of the intestinal inflammatory response through epigenetic programming of host intestinal epithelium. Exposure to the microbiota induces Ten-Eleven-Translocation (TET)-dependent hypomethylation of genomic elements regulating genes associated with inflammatory response and colorectal cancer. Here, we discuss the impact of such a discovery on the understanding of how the intestinal microbiota may contribute to epigenetic reprogramming and influence the onset of colorectal tumorigenesis. Finally, we examine the prospect of TET inhibition strategies as a therapeutic and/or preventive approach for colorectal cancer in patients afflicted by inflammatory bowel disease.

scholarly journals Distinct roles of histamine H1- and H2-receptor signaling pathways in inflammation-associated colonic tumorigenesis

2019 ◽  
Vol 316 (1) ◽  
pp. G205-G216 ◽  
Author(s):  
Zhongcheng Shi ◽  
Robert S. Fultz ◽  
Melinda A. Engevik ◽  
Chunxu Gao ◽  
Anne Hall ◽  
...  
Keyword(s):  
Gene Expression ◽  
Colorectal Cancer ◽  
Colon Cancer ◽  
Signaling Pathways ◽  
Lactobacillus Reuteri ◽  
Intestinal Inflammation ◽  
Mapk Signaling ◽  
Histamine H2 Receptor ◽  
H2 Receptor ◽  
The Impact

Inflammatory bowel disease (IBD) is a well-known risk factor for the development of colorectal cancer. Prior studies have demonstrated that microbial histamine can ameliorate intestinal inflammation in mice. We tested the hypothesis whether microbe-derived luminal histamine suppresses inflammation-associated colon cancer in Apcmin/+ mice. Mice were colonized with the human-derived Lactobacillus reuteri. Chronic inflammation was induced by repeated cycles of low-dose dextran sulfate sodium (DSS). Mice that were given histamine-producing L. reuteri via oral gavage developed fewer colonic tumors, despite the presence of a complex mouse gut microbiome. We further demonstrated that administration of a histamine H1-receptor (H1R) antagonist suppressed tumorigenesis, while administration of histamine H2-receptor (H2R) antagonist significantly increased both tumor number and size. The bimodal functions of histamine include protumorigenic effects through H1R and antitumorigenic effects via H2R, and these results were supported by gene expression profiling studies on tumor specimens of patients with colorectal cancer. Greater ratios of gene expression of H2R ( HRH2) vs. H1R ( HRH1) were correlated with improved overall survival outcomes in patients with colorectal cancer. Additionally, activation of H2R suppressed phosphorylation of mitogen-activated protein kinases (MAPKs) and inhibited chemokine gene expression induced by H1R activation in colorectal cancer cells. Moreover, the combination of a H1R antagonist and a H2R agonist yielded potent suppression of lipopolysaccharide-induced MAPK signaling in macrophages. Given the impact on intestinal epithelial and immune cells, simultaneous modulation of H1R and H2R signaling pathways may be a promising therapeutic target for the prevention and treatment of inflammation-associated colorectal cancer. NEW & NOTEWORTHY Histamine-producing Lactobacillus reuteri can suppress development of inflammation-associated colon cancer in an established mouse model. The net effects of histamine may depend on the relative activity of H1R and H2R signaling pathways in the intestinal mucosa. Our findings suggest that treatment with H1R or H2R antagonists could yield opposite effects. However, by harnessing the ability to block H1R signaling while stimulating H2R signaling, novel strategies for suppression of intestinal inflammation and colorectal neoplasia could be developed.

scholarly journals Role of Primary Cilia in Odontogenesis

2017 ◽  
Vol 96 (9) ◽  
pp. 965-974 ◽  
Author(s):  
M. Hampl ◽  
P. Cela ◽  
H.L. Szabo-Rogers ◽  
M. Kunova Bosakova ◽  
H. Dosedelova ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Primary Cilium ◽  
Mammalian Cells ◽  
Primary Cilia ◽  
Tooth Development ◽  
Critical Role ◽  
Current Evidence ◽  
Developmental Defects ◽  
Dental Tissues ◽  
The Impact

Primary cilium is a solitary organelle that emanates from the surface of most postmitotic mammalian cells and serves as a sensory organelle, transmitting the mechanical and chemical cues to the cell. Primary cilia are key coordinators of various signaling pathways during development and maintenance of tissue homeostasis. The emerging evidence implicates primary cilia function in tooth development. Primary cilia are located in the dental epithelium and mesenchyme at early stages of tooth development and later during cell differentiation and production of hard tissues. The cilia are present when interactions between both the epithelium and mesenchyme are required for normal morphogenesis. As the primary cilium coordinates several signaling pathways essential for odontogenesis, ciliary defects can interrupt the latter process. Genetic or experimental alterations of cilia function lead to various developmental defects, including supernumerary or missing teeth, enamel and dentin hypoplasia, or teeth crowding. Moreover, dental phenotypes are observed in ciliopathies, including Bardet-Biedl syndrome, Ellis-van Creveld syndrome, Weyers acrofacial dysostosis, cranioectodermal dysplasia, and oral-facial-digital syndrome, altogether demonstrating that primary cilia play a critical role in regulation of both the early odontogenesis and later differentiation of hard tissue–producing cells. Here, we summarize the current evidence for the localization of primary cilia in dental tissues and the impact of disrupted cilia signaling on tooth development in ciliopathies.

scholarly journals Phytotherapy for colorectal cancer: about some phytochemicals and their mechanisms of action]

2020 ◽  
Vol 3 (4) ◽  
pp. 79-84
Author(s):  
Patricia Landazuri ◽  
◽  
Beatriz Restrepo ◽  
Nelsy Loango ◽  
◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Cancer Cells ◽  
Signaling Pathways ◽  
Intestinal Microbiota ◽  
Functional Foods ◽  
Molecular Targets ◽  
Mechanisms Of Action ◽  
Inflammatory Signaling ◽  
Men And Women ◽  
Prevention And Treatment

Colorectal cancer (CRC) is very common in both men and women. Phytochemicals such as polysaccharide alkaloids, polyphenols, diterpenoids among others, have been used for the prevention and treatment of cancer. The mechanisms of action of these compounds on cancer cells include molecular targets in the apoptosis, proliferation, metastasis and anti-inflammatory signaling pathways. At the level of the whole organism, they improve the intestinal microbiota, which plays an important role in the initiation and progression of CRC. Recent research is aimed at obtaining and modifying phytochemicals to improve their effectiveness, safety and their inclusion in functional foods, but more studies are needed to validate their properties.

scholarly journals The Therapeutic Potential of Tackling Tumor-Induced Dendritic Cell Dysfunction in Colorectal Cancer

2021 ◽  
Vol 12 ◽  
Author(s):  
Beatriz Subtil ◽  
Alessandra Cambi ◽  
Daniele V. F. Tauriello ◽  
I. Jolanda M. de Vries
Keyword(s):  
Colorectal Cancer ◽  
Cancer Metastasis ◽  
Therapeutic Potential ◽  
Current Knowledge ◽  
Critical Role ◽  
Locally Advanced ◽  
Standard Of Care ◽  
Future Research ◽  
The Impact

Colorectal cancer (CRC) is the third most diagnosed malignancy and the second leading cause of cancer-related deaths worldwide. Locally advanced and metastatic disease exhibit resistance to therapy and are prone to recurrence. Despite significant advances in standard of care and targeted (immuno)therapies, the treatment effects in metastatic CRC patients have been modest. Untreatable cancer metastasis accounts for poor prognosis and most CRC deaths. The generation of a strong immunosuppressive tumor microenvironment (TME) by CRC constitutes a major hurdle for tumor clearance by the immune system. Dendritic cells (DCs), often impaired in the TME, play a critical role in the initiation and amplification of anti-tumor immune responses. Evidence suggests that tumor-mediated DC dysfunction is decisive for tumor growth and metastasis initiation, as well as for the success of immunotherapies. Unravelling and understanding the complex crosstalk between CRC and DCs holds promise for identifying key mechanisms involved in tumor progression and spread that can be exploited for therapy. The main goal of this review is to provide an overview of the current knowledge on the impact of CRC-driven immunosuppression on DCs phenotype and functionality, and its significance for disease progression, patient prognosis, and treatment response. Moreover, present knowledge gaps will be highlighted as promising opportunities to further understand and therapeutically target DC dysfunction in CRC. Given the complexity and heterogeneity of CRC, future research will benefit from the use of patient-derived material and the development of in vitro organoid-based co-culture systems to model and study DCs within the CRC TME.

scholarly journals The Impact of Dietary Sphingolipids on Intestinal Microbiota and Gastrointestinal Immune Homeostasis

2021 ◽  
Vol 12 ◽  
Author(s):  
Johanna Rohrhofer ◽  
Benjamin Zwirzitz ◽  
Evelyne Selberherr ◽  
Eva Untersmayr
Keyword(s):  
Immune Response ◽  
Gut Microbiota ◽  
Intestinal Microbiota ◽  
Barrier Function ◽  
Intestinal Cell ◽  
Immune Homeostasis ◽  
Low Grade ◽  
Vast Number ◽  
The Impact ◽  
Low Grade Inflammation

The large surfaces of gastrointestinal (GI) organs are well adapted to their diverse tasks of selective nutritional uptake and defense against the external environment. To maintain a functional balance, a vast number of immune cells is located within the mucosa. A strictly regulated immune response is required to impede constant inflammation and to maintain barrier function. An increasing prevalence of GI diseases has been reported in Western societies over the past decades. This surge in GI disorders has been linked to dietary changes followed by an imbalance of the gut microbiome, leading to a chronic, low grade inflammation of the gut epithelium. To counteract the increasing health care costs associated with diseases, it is paramount to understand the mechanisms driving immuno-nutrition, the associations between nutritional compounds, the commensal gut microbiota, and the host immune response. Dietary compounds such as lipids, play a central role in GI barrier function. Bioactive sphingolipids (SLs), e.g. sphingomyelin (SM), sphingosine (Sph), ceramide (Cer), sphingosine-1- phosphate (S1P) and ceramide-1-phosphate (C1P) may derive from dietary SLs ingested through the diet. They are not only integral components of cell membranes, they additionally modulate cell trafficking and are precursors for mediators and second messenger molecules. By regulating intracellular calcium levels, cell motility, cell proliferation and apoptosis, SL metabolites have been described to influence GI immune homeostasis positively and detrimentally. Furthermore, dietary SLs are suggested to induce a shift in the gut microbiota. Modes of action range from competing with the commensal bacteria for intestinal cell attachment to prevention from pathogen invasion by regulating innate and immediate defense mechanisms. SL metabolites can also be produced by gut microorganisms, directly impacting host metabolic pathways. This review aims to summarize recent findings on SL signaling and functional variations of dietary SLs. We highlight novel insights in SL homeostasis and SL impact on GI barrier function, which is directly linked to changes of the intestinal microbiota. Knowledge gaps in current literature will be discussed to address questions relevant for understanding the pivotal role of dietary SLs on chronic, low grade inflammation and to define a balanced and healthy diet for disease prevention and treatment.

The Laryngeal Epithelium in Reflux

2011 ◽  
Vol 21 (3) ◽  
pp. 112-117 ◽  
Author(s):  
Elizabeth Erickson-Levendoski ◽  
Mahalakshmi Sivasankar
Keyword(s):  
Laryngopharyngeal Reflux ◽  
Critical Role ◽  
Structure And Function ◽  
Laryngeal Disease ◽  
Health And Disease ◽  
And Function ◽  
The Impact

The epithelium plays a critical role in the maintenance of laryngeal health. This is evident in that laryngeal disease may result when the integrity of the epithelium is compromised by insults such as laryngopharyngeal reflux. In this article, we will review the structure and function of the laryngeal epithelium and summarize the impact of laryngopharyngeal reflux on the epithelium. Research investigating the ramifications of reflux on the epithelium has improved our understanding of laryngeal disease associated with laryngopharyngeal reflux. It further highlights the need for continued research on the laryngeal epithelium in health and disease.

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