The association of aberrant expression of NLRP3 and p-S6K1 in colorectal cancer

Inflammasomes Are Influenced by Epigenetic and Autophagy Mechanisms in Colorectal Cancer Signaling

Inflammasomes contribute to colorectal cancer signaling by primarily inducing inflammation in the surrounding tumor microenvironment. Its role in inflammation is receiving increasing attention, as inflammation has a protumor effect in addition to inducing tissue damage. The inflammasome's function is complex and controlled by several layers of regulation. Epigenetic processes impact the functioning or manifestation of genes that are involved in the control of inflammasomes or the subsequent signaling cascades. Researchers have intensively studied the significance of epigenetic mechanisms in regulation, as they encompass several potential therapeutic targets. The regulatory interactions between the inflammasome and autophagy are intricate, exhibiting both advantageous and harmful consequences. The regulatory aspects between the two entities also encompass several therapeutic targets. The relationship between the activation of the inflammasome, autophagy, and epigenetic alterations in CRC is complex and involves several interrelated pathways. This article provides a brief summary of the newest studies on how epigenetics and autophagy control the inflammasome, with a special focus on their role in colorectal cancer. Based on the latest findings, we also provide an overview of the latest therapeutic ideas for this complex network.

Gut Microbiota, Inflammatory Bowel Disease, and Cancer: The Role of Guardians of Innate Immunity

Inflammatory bowel diseases (IBDs) are characterized by a persistent low-grade inflammation that leads to an increased risk of colorectal cancer (CRC) development. Several factors are implicated in this pathogenetic pathway, such as innate and adaptive immunity, gut microbiota, environment, and xenobiotics. At the gut mucosa level, a complex interplay between the immune system and gut microbiota occurs; a disequilibrium between these two factors leads to an alteration in the gut permeability, called 'leaky gut'. Subsequently, an activation of several inflammatory pathways and an alteration of gut microbiota composition with a proliferation of pro-inflammatory bacteria, known as 'pathobionts', take place, leading to a further increase in inflammation. This narrative review provides an overview on the principal Pattern Recognition Receptors (PRRs), including Toll-like receptors (TLRs) and NOD-like receptors (NLRs), focusing on their recognition mechanisms, signaling pathways, and contributions to immune responses. We also report the genetic polymorphisms of TLRs and dysregulation of NLR signaling pathways that can influence immune regulation and contribute to the development and progression of inflammatory disease and cancer.

Correlation and influencing factors analysis of colorectal polyps with Helicobacter pylori Infection and p-S6K1 expression

OBJECTIVE

To investigate the correlation between colorectal polyps (CRP) and Helicobacter pylori (H. pylori) infection, and the correlation between CRP and the expression of phosphorylated ribosomal protein S6 kinase (p-S6K1). Besides, its related influencing factors were determined in the present study.

METHODS

A total of 191 subjects who underwent colonoscopy in our hospital from January 2020 to February 2022 were selected for this study. Among them, 141 patients were diagnosed with CRP, and the other 50 subjects were no significant colorectal abnormalities. 141 CRP patients were divided into H. pylori-positive group (n = 89) and H. pylori-negative group (n = 52) according to the results of the H. pylori test. The expression of p-S6K1 in CRP tissue was detected. The relationship between the p-S6K1 expression and the clinicopathological characteristics of CRP patients was analyzed. The logistic analysis of factors influencing the occurrence of CRP was performed.

RESULTS

There were significant differences in pathological type, site of disease, the number and size of polyps between the H. pylori negative group and the H. pylori positive group (P < 0.001, P = 0.037, P = 0.042 and P = 0.039). The percentage of the p-S6K1 positive expression in polyp tissues was higher than that in normal tissue and parapolyp tissues (P < 0.001). The p-S6K1 negative group showed significant difference in the number and pathological type of polyps and the presence or absence of a pedicle as compared with the p-S6K1 positive group (P = 0.006, P < 0.001 and P = 0.012). Logistic multifactor analysis showed that BMI, H. pylori infection, smoking history, ApoB, Lp(a) and the p-S6K1 positive expression were all risk factors for the development of CRP (P = 0.025, P = 0.020, P = 0.010, P = 0.005, P = 0.043 and P < 0.001).

CONCLUSION

H. pylori infection was closely related to the pathological type, location, and the number and size of CRP. p-S6K1 was highly expressed in CRP, and was positively related to the number, the pathological type and pedicle of polyps. H. pylori infection and the positive p-S6K1 expression were independent risk factors for CRP. By exploring the association between H. pylori infection as well as p-S6K1 and CRP, it is hoped that it will help to formulate a more rigorous colorectal cancer screening program for H. pylori-positive individuals, and at the same time find a new direction for the prevention of CRP and colorectal cancer, and provide some help for future research.

NOD-like Receptor Signaling Pathway in Gastrointestinal Inflammatory Diseases and Cancers

Nucleotide-binding and oligomerization domain (NOD)-like receptors (NLRs) are intracellular proteins with a central role in innate and adaptive immunity. As a member of pattern recognition receptors (PRRs), NLRs sense specific pathogen-associated molecular patterns, trigger numerous signaling pathways and lead to the secretion of various cytokines. In recent years, cumulative studies have revealed the significant impacts of NLRs in gastrointestinal (GI) inflammatory diseases and cancers. Deciphering the role and molecular mechanism of the NLR signaling pathways may provide new opportunities for the development of therapeutic strategies related to GI inflammatory diseases and GI cancers. This review presents the structures and signaling pathways of NLRs, summarizes the recent advances regarding NLR signaling in GI inflammatory diseases and GI cancers and describes comprehensive therapeutic strategies based on this signaling pathway.

Divergent functions of NLRP3 inflammasomes in cancer: a review

The cancer is a serious health problem, which is The cancer death rate (cancer mortality) is 158.3 per 100,000 men and women per year (based on 2013-2017 deaths). Both clinical and translational studies have demonstrated that chronic inflammation is associated with Cancer progression. However, the precise mechanisms of inflammasome, and the pathways that mediate this phenomenon are not fully characterized. One of the most recently identified signaling pathways, whose activation seems to affect many metabolic disorders, is the "inflammasome" a multiprotein complex composed of NLRP3 (nucleotide-binding domain and leucine-rich repeat protein 3), ASC (apoptosis associated speck-like protein containing a CARD), and procaspase-1. NLRP3 inflammasome activation leads to the processing and secretion of the proinflammatory cytokines interleukin-1β (IL-1β) and IL-18. The goal of this paper is to review new insights on the effects of the NLRP3 inflammasome activation in the complex mechanisms of crosstalk between different organs, for a better understanding of the role of chronic inflammation in cancer pathogenesis. We will provide here a perspective on the current research on NLRP3 inflammasome, which may represent an innovative therapeutic target to reverse the malignancy condition consequences of the inflammation. Video Abstract.

Arctiin Inhibits Inflammation, Fibrosis, and Tumor Cell Migration in Rats With Ehrlich Solid Carcinoma

BACKGROUND AND OBJECTIVES

ESC or Ehrlich solid carcinoma is a type of tumor originating from a spontaneous mammary adenocarcinoma in mice. It is a highly aggressive and fast-growing carcinoma that can create a solid mass when inserted under the skin. Its solid, undifferentiated form makes it an ideal model for researching cancer biology, tumor immunology, and testing various anti-cancer treatments. Additionally, arctiin has multiple beneficial properties, such as anti-proliferative, anti-oxidative, anti-adipogenic, and anti-bacterial. This study aimed to explore the potential anti-cancer benefits of arctiin in rats with ESC while also analyzing its effects on cell fibrosis markers, tumor cell migration, and inflammasome pathways.

METHODS

Rats were given a tumor in their left hind limb via an intramuscular injection consisting of 2×106 cells. After eight days, some of the rats received a daily oral dose of 30 mg/kg of arctiin for three weeks. Muscle samples were observed under an electron microscope or stained with hematoxylin/eosin. Additionally, gene expression and protein levels of toll-like receptor 4 (TLR4), NLR family pyrin domain containing 3 (NLRP3), signal transducer and activator of transcription 3 (STAT3), transforming growth factor (TGF)-β, endothelial growth factor (VEGF), and cyclin D1 were assessed in another part of the muscle samples.

RESULTS

When ESC rats were given arctiin as a treatment, their mean survival time increased and their tumor volume and weight decreased. Additionally, when tumor tissue was examined under an electron microscope, it showed signs of pleomorphic cells, necrosis, nuclear fragmentation, membrane damage with cytoplasmic content spilling, and loss of cellular junction. The stained sections with hematoxylin/eosin showed a dense cellular mass and compressed, degenerated, and atrophied muscle. However, treatment with arctiin improved all these effects. Finally, the expression of TLR4, NLRP3, STAT3, TGF-β, VEGF, and cyclin D1 was significantly reduced with arctiin treatment.

CONCLUSIONS

Through the use of arctiin, tumor size and weight were effectively reduced, leading to an increase in the average survival time of rats and an improvement in muscle structure. Additional research has shown that arctiin is able to suppress inflammation, fibrosis, and the migration of tumor cells by inhibiting STAT3, TGF-β1, TLR4, NLRP3, VEGF, and cyclin D1.

The Multifaceted Role and Regulation of Nlrp3 Inflammasome in Colitis-Associated Colo-Rectal Cancer: A Systematic Review

Colitis-associated colo-rectal cancer remains the leading cause of mortality in inflammatory bowel diseases, with inflammation remaining one of the bridging points between the two pathologies. The NLRP3 inflammasome complex plays an important role in innate immunity; however, its misregulation can be responsible for the apparition of various pathologies such as ulcerative colitis. Our review focuses on the potential pathways of upregulation or downregulation of the NLRP3 complex, in addition to evaluating its role in the current clinical setting. Eighteen studies highlighted the potential pathways of NLRP3 complex regulation as well as its role in the metastatic process in colo-rectal cancer, with promising results. Further research is, however, needed in order to validate the results in a clinical setting.

IL-37 alleviates Coxsackievirus B3-induced viral myocarditis via inhibiting NLRP3 inflammasome-mediated pyroptosis

Our study aims to verify the potential effects and underlying mechanisms of IL-37 in Coxsackievirus B3 (CVB3)-induced viral myocarditis (VMC). VMC model was established by intraperitoneal injection of CVB3 into 6-week-old male balb-c mice on day 0. Each mouse of the IL-37-control group and IL-37-VMC CVB3 groups was intraperitoneally injected with IL-37 on day 4 and day 7. The cardiac function was evaluated by transthoracic echocardiography including LVEF, LVFE, IVSs and IVSd. Myocardial injury was measured by Elisa for serum cTnI. The inflammation infiltration and fibrosis were evaluated by hematoxylin and eosin (HE) staining and Masson staining. The expression levels of NLRP3 inflammasome components in pyroptosis were determined by western blot, Elisa, and immunofluorescent analysis. We also detected the expression of IL-37-IL-1R8 in PBMCs by immunofluorescence after injection with CVB3 and IL-37. Compared with the VMC group, mice received CVB3 and IL-37 have improved cardiac function, reduced inflammation infiltration and fibrosis, and with lower expression of cTnI, IL-1β, IL-18 and NLRP3 inflammasome component. IL-37 weakened the upregulation of GSDMD and phosphorylation of NF-κB p65 induced by CVB3. Exogenous addition of IL-37 with CVB3 further increases the production of IL-37-IL-1R8 -IL-18RA complex in vitro. Our findings indicate that IL-37 alleviates CVB3-induced VMC, which may be produced by inhibiting NLRP3 inflammasome-mediated pyroptosis, NF-κB signaling pathway, and IL-37-IL-1R8 -IL-18RA complex.

The role of NLRP3 inflammasome in colorectal cancer: potential therapeutic target

All phases of carcinogenesis are affected by inflammation. Activation of the inflammasome is a crucial signaling mechanism that leads to acute and chronic inflammation. When specific nucleotide-binding domains, leucine-rich repeat-containing proteins (NLRs) are activated, inflammasomes are formed. The NLRP3 is one of the NLR family members with the most functional characterization. NLRP3 can modulate the immune systems, apoptosis, growth, and/or the gut microbiome to impact cancer development. Colorectal cancer (CRC) is one of the most common cancers, and it begins as a tissue overgrowth on the internal part of the rectum or colon. In vivo and in vitro studies showed that the NLRP3 inflammasome has a role in CRC development due to its broad activity in shaping immune responses. Here, onwards, we focus on the NLRP3 inflammasome role in CRC development, as well as the therapeutic prospective of modifying NLRP3 inflammasome in the context of anti-cancer therapy.

The Ala134Thr variant in TMEM176B exerts a beneficial role in colorectal cancer prognosis by increasing NLRP3 inflammasome activation

PURPOSE

TMEM176B was recently described as a negative modulator of Nlrp3 inflammasome activation in mice. In the mouse model, the inhibition of TMEM176B leads to an increased anti-tumoral activity which is dependent on Nlrp3. Since we have recently shown that single nucleotide variants (SNPs) in inflammasome genes, including NLRP3, significantly affect colorectal cancer (CRC) prognosis, we proposed to investigate here the association between genetic variants in TMEM176B and CRC prognosis.

METHODS

Considering that, up to now, no genetic study analyzing this gene in humans exists, we selected possible functional SNPs and genotyped them in a cohort of CRC patients submitted to surgery and followed up for more than 10 years. Genotype-guided assays were realized to evaluate the effect of the variant on NLRP3 inflammasome activation. Gene expression from The Cancer Genome Atlas (TCGA) cohort was analyzed to valid possible prognostic and predictive features.

RESULTS

We identified the Ala134Thr variant (rs2072443) in TMEM176B as a protective factor for CRC prognosis. This SNP is associated with decreased gene expression and with an increased activation of NLRP3 inflammasome, at least in monocytes and dendritic cells. Furthermore, low TMEM176B expression is associated with higher overall survival.

CONCLUSION

Altogether, these findings supported the role of TMEM176B in NLRP3 inflammasome biology and for the first time demonstrated the genetic association between rs2072443 and CRC in humans.

Dual Role of Chitin as the Double Edged Sword in Controlling the NLRP3 Inflammasome Driven Gastrointestinal and Gynaecological Tumours

The role of NLRP3 in the tumour microenvironment is elusive. In some cancers, the activation of NLRP3 causes a worse prognosis and in some cancers, NLRP3 increases chances of survivability. However, in many cases where NLRP3 has a protumorigenic role, inhibition of NLRP3 would be a crucial step in therapy. Consequently, activation of NLRP3 would be of essence when inflammation is required. Although many ways of inhibiting and activating NLRP3 in cancers have been discussed before, not a lot of focus has been given to chitin and chitosan in this context. The availability of these marine compounds and their versatility in dealing with inflammation needs to be investigated further in relation with cancers, along with other natural extracts. In this review, the effects of NLRP3 on gastrointestinal and gynaecological cancers and the impact of different natural extracts on NLRP3s with special emphasis on chitin and chitosan is discussed. A research gap in using chitin derivatives as anti/pro-inflammatory agents in cancer treatment has been highlighted.

Downstream Signaling of Inflammasome Pathway Affects Patients' Outcome in the Context of Distinct Molecular Breast Cancer Subtypes

Inflammasomes are protein complexes involved in the regulation of different biological conditions. Over the past few years, the role of NLRP3 in different tumor types has gained interest. In breast cancer (BC), NLRP3 has been associated with multiple processes including epithelia mesenchymal transition, invasion and metastization. Little is known about molecular modifications of NLRP3 up-regulation. In this study, in a cohort of BCs, the expression levels of NLRP3 and PYCARD were analyzed in combination with CyclinD1 and MYC ones and their gene alterations. We described a correlation between the NLRP3/PYCARD axis and CyclinD1 (p < 0.0001). NLRP3, PYCARD and CyclinD1’s positive expression was observed in estrogen receptor (ER) and progesterone receptor (PgR) positive cases (p < 0.0001). Furthermore, a reduction of NLRP3 and PYCARD expression has been observed in triple negative breast cancers (TNBCs) with respect to the Luminal phenotypes (p = 0.017 and p = 0.0015, respectively). The association NLRP3+/CCND1+ or PYCARD+/CCND1+ was related to more aggressive clinicopathological characteristics and a worse clinical outcome, both for progression free survival (PFS) and overall survival (OS) with respect to NLRP3+/CCND1− or PYCARD+/CCND1− patients, both in the whole cohort and also in the subset of Luminal tumors. In conclusion, our study shows that the NLRP3 inflammasome complex is down-regulated in TNBC compared to the Luminal subgroup. Moreover, the expression levels of NLRP3 and PYCARD together with the alterations of CCND1 results in Luminal subtype BC’ss poor prognosis.

p70 S6 kinase as a therapeutic target in cancers: More than just an mTOR effector

p70 S6 kinase (p70^S6K) is best-known for its regulatory roles in protein synthesis and cell growth by phosphorylating its primary substrate, ribosomal protein S6, upon mitogen stimulation. The enhanced expression/activation of p70^S6K has been correlated with poor prognosis in some cancer types, suggesting that it may serve as a biomarker for disease monitoring. p70^S6K is a critical downstream effector of the oncogenic PI3K/Akt/mTOR pathway and its activation is tightly regulated by an ordered cascade of Ser/Thr phosphorylation events. Nonetheless, it should be noted that other upstream mechanisms regulating p70^S6K at both the post-translational and post-transcriptional levels also exist. Activated p70^S6K could promote various aspects of cancer progression such as epithelial-mesenchymal transition, cancer stemness and drug resistance. Importantly, novel evidence showing that p70^S6K may also regulate different cellular components in the tumor microenvironment will be discussed. Therapeutic targeting of p70^S6K alone or in combination with traditional chemotherapies or other microenvironmental-based drugs such as immunotherapy may represent promising approaches against cancers with aberrant p70^S6K signaling. Currently, the only clinically available p70^S6K inhibitors are rapamycin analogs (rapalogs) which target mTOR. However, there are emerging p70^S6K-selective drugs which are going through active preclinical or clinical trial phases. Moreover, various screening strategies have been used for the discovery of novel p70^S6K inhibitors, hence bringing new insights for p70^S6K-targeted therapy.

Activation of the Adipose Tissue NLRP3 Inflammasome Pathway in Cancer Cachexia

Background

Cachexia is a paraneoplastic syndrome that accompanies and compromises cancer treatment, especially in advanced stages, affecting the metabolism and function of several organs. The adipose tissue is the first to respond to the presence of the tumor, contributing to the secretion of factors which drive the systemic inflammation, a hallmark of the syndrome. While inflammation is a defensive innate response, the control mechanisms have been reported to be disrupted in cachexia. On the other hand, little is known about the role of NLRP3 inflammasome in this scenario, a multiprotein complex involved in caspase-1 activation and the processing of the cytokines IL-1β and IL-18.

Aim

based on the evidence from our previous study with a rodent model of cachexia, we examined the activation of the NLRP3 inflammasome pathway in two adipose tissue depots obtained from patients with colorectal cancer and compared with that another inflammatory pathway, NF-κB.

Results

For CC we found opposite modulation in ScAT and PtAT for the gene expression of TLR4, Caspase-1 (cachectic group) and for NF-κB p50, NF-κB p65, IL-1β. CD36, expression was decreased in both depots while that of NLRP3 and IL-18 was higher in both tissues, as compared with controls and weight stable patients (WSC). Caspase-1 basal protein levels in the ScAT culture supernatant were higher in WSC and (weight stable patients) CC, when compared to controls. Basal ScAT explant culture medium IL-1β and IL-18 protein content in ScAT supernatant was decreased in the WSC and CC as compared to CTL explants.

Conclusions

The results demonstrate heterogeneous responses in the activation of genes of the NLRP3 inflammasome pathway in the adipose tissue of patients with cancer cachexia, rendering this pathway a potential target for therapy aiming at decreasing chronic inflammation in cancer.

Overcoming Immunotherapy Resistance by Targeting the Tumor-Intrinsic NLRP3-HSP70 Signaling Axis

Simple Summary

The tumor-intrinsic NLRP3 inflammasome is a newly recognized player in the regulation of tumor-directed immune responses and promises to provide fresh insight into how tumors respond to immunotherapy. This brief review discusses recent data describing how activation of the tumor-intrinsic NLRP3 inflammasome contributes to immune evasion and what this pathway may provide to the field of immuno-oncology both in terms of pharmacologic targets capable of boosting responses to checkpoint inhibitor therapies and predictive biomarkers indicating which tumors may be most susceptible to these new therapeutic strategies.

Abstract

The tumor-intrinsic NOD-like receptor family, pyrin-domain-containing-3 (NLRP3) inflammasome, plays an important role in regulating immunosuppressive myeloid cell populations in the tumor microenvironment (TME). While prior studies have described the activation of this inflammasome in driving pro-tumorigenic mechanisms, emerging data is now revealing the tumor NLRP3 inflammasome and the downstream release of heat shock protein-70 (HSP70) to regulate anti-tumor immunity and contribute to the development of adaptive resistance to anti-PD-1 immunotherapy. Genetic alterations that influence the activity of the NLRP3 signaling axis are likely to impact T cell-mediated tumor cell killing and may indicate which tumors rely on this pathway for immune escape. These studies suggest that the NLRP3 inflammasome and its secreted product, HSP70, represent promising pharmacologic targets for manipulating innate immune cell populations in the TME while enhancing responses to anti-PD-1 immunotherapy. Additional studies are needed to better understand tumor-specific regulatory mechanisms of NLRP3 to enable the development of tumor-selective pharmacologic strategies capable of augmenting responses to checkpoint inhibitor immunotherapy while minimizing unwanted off-target effects. The execution of upcoming clinical trials investigating this strategy to overcome anti-PD-1 resistance promises to provide novel insight into the role of this pathway in immuno-oncology.

Prognostic Value of NLRP3 Inflammasome and TLR4 Expression in Breast Cancer Patients

Inflammasome complexes play a pivotal role in different cancer types. NOD-like receptor protein 3 (NLRP3) inflammasome is one of the most well-studied inflammasomes. Activation of the NLRP3 inflammasome induces abnormal secretion of soluble cytokines, generating advantageous inflammatory surroundings that support tumor growth. The expression levels of the NLRP3, PYCARD and TLR4 were determined by immunohistochemistry in a cohort of primary invasive breast carcinomas (BCs). We observed different NLRP3 and PYCARD expressions in non-tumor vs tumor areas (p<0.0001). All the proteins were associated to more aggressive clinicopathological characteristics (tumor size, grade, tumor proliferative activity etc.). Univariate analyses were carried out and related Kaplan-Meier curves plotted for NLRP3, PYCARD and TLR4 expression. Patients with higher NLRP3 and TLR4 expression had worse 5-year disease-free survival (DFS) compared to patients with lower NLRP3 and TLR4 expression (p =0.021 and p = 0.009, respectively). In multivariate analysis, TLR4 was confirmed as independent prognostic factors for DFS (HR = 2.03, 95% CI 1.16–3.57, p = 0.014), and high NLRP3 expression showed a slight association with DFS (HR = 1.75, 95% CI 0.98–3.15, p = 0.06). In conclusion, we showed TLR4 expression as independent prognostic factors and we highlighted for the first time that high expression of NLRP3 is linked to a poor prognosis in BC patients. These results suggest that NLRP3 and TLR4 could be two new good prognostic factor for BC patients.

Inflammasomes and Colorectal Cancer

Inflammasomes are important intracellular multiprotein signaling complexes that modulate the activation of caspase-1 and induce levels of the proinflammatory cytokines interleukin-1β (IL-1β) and IL-18 in response to pathogenic microorganisms and molecules that originated from host proteins. Inflammasomes play contradictory roles in the development of inflammation-induced cancers. Based on several findings, inflammasomes can initiate and promote carcinogenesis. On the contrary, inflammasomes also exhibit anticancer effects by triggering pyroptosis and immunoregulatory functions. Herein, we review extant studies delving into different functions of inflammasomes in colorectal cancer development.

Targeting the NLRP3 Inflammasome as a New Therapeutic Option for Overcoming Cancer

Inflammasomes are multiprotein complexes that regulate the maturation and secretion of the proinflammatory cytokines interleukin-1beta (IL-1β and interleukin-18 (IL-18) in response to various intracellular stimuli. As a member of the inflammasomes family, NLRP3 is the most studied and best characterized inflammasome and has been shown to be involved in several pathologies. Recent findings have made it increasingly apparent that the NLRP3 inflammasome may also play a central role in tumorigenesis, and it has attracted attention as a potential anticancer therapy target. In this review, we discuss the role of NLRP3 in the development and progression of cancer, offering a detailed summary of NLRP3 inflammasome activation (and inhibition) in the pathogenesis of various forms of cancer. Moreover, we focus on the therapeutic potential of targeting NLRP3 for cancer therapy, emphasizing how understanding NLRP3 inflammasome-dependent cancer mechanisms might guide the development of new drugs that target the inflammatory response of tumor-associated cells.

Does NLRP3 Inflammasome and Aryl Hydrocarbon Receptor Play an Interlinked Role in Bowel Inflammation and Colitis-Associated Colorectal Cancer?

Inflammation is a hallmark in many forms of cancer; with colitis-associated colorectal cancer (CAC) being a progressive intestinal inflammation due to inflammatory bowel disease (IBD). While this is an exemplification of the negatives of inflammation, it is just as crucial to have some degree of the inflammatory process to maintain a healthy immune system. A pivotal component in the maintenance of such intestinal homeostasis is the innate immunity component, inflammasomes. Inflammasomes are large, cytosolic protein complexes formed following stimulation of microbial and stress signals that lead to the expression of pro-inflammatory cytokines. The NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome has been extensively studied in part due to its strong association with colitis and CAC. The aryl hydrocarbon receptor (AhR) has recently been acknowledged for its connection to the immune system aside from its role as an environmental sensor. AhR has been described to play a role in the inhibition of the NLRP3 inflammasome activation pathway. This review will summarise the signalling pathways of both the NLRP3 inflammasome and AhR; as well as new-found links between these two signalling pathways in intestinal immunity and some potential therapeutic agents that have been found to take advantage of this link in the treatment of colitis and CAC.