P2X7 receptor and NLRP3 inflammasome activation in head and neck cancer

SOAT1 Activates NLRP3 Inflammasome to Promote Cancer-Related Lymphangiogenesis and Metastasis via IL-1β/IL-1R-1 Axis in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is a prevalent type of cancer in the head and neck region, significantly impacting patient survival rates and quality of life. Lymph node (LN) metastasis is a lead contributor to the poor prognosis associated with OSCC. SOAT1 plays a critical role in cholesterol metabolism and has been implicated in various cancers, although its specific mechanisms in OSCC are poorly understood. Additionally, NLRP3 inflammasome has been identified as a factor that promotes cancer progression by influencing various processes involved in tumor development, with its activation linked to cancer metastasis. Lymphangiogenesis enhancing cancer metastasis has been identified in OSCC, while the molecule networks of regulating it remains unclear. In our study, we found that SOAT1 is overexpressed in OSCC and promotes proliferation, migration, and invasion of OSCC cells. Knockdown SOAT1 expression impaired OSCC progression both in vitro and in vivo, and reduced the rate of LN metastasis. RNA sequencing analysis revealed that NLRP3 is a downstream regulated by SOAT1, with NLRP3 inflammasome reactivation having recovered cancer malignancy inhibited by SOAT1 knockdown. Furthermore, we revealed that IL-1β, released by NLRP3 inflammasome activation, could directly bind to IL-1R-1 in lymphatic endothelial cells (LECs), and enhance tube formation capacity of LECs, indicating the potential role of NLRP3 inflammasome in promoting lymphangiogenesis and metastasis in OSCC. In conclusion, SOAT1 could promote OSCC malignancy and regulate the activation of NLRP3 inflammasome to increase the rate of lymphangiogenesis and cancer metastasis via IL-1β/IL-1R-1 axis in OSCC.

Therapeutic targeting of P2X receptors for orofacial pain

P2X receptors (P2XRs), membrane ion channels activated by extracellular adenosine 5' -triphosphate (ATP), play a pivotal role in nociception by directly promoting pain signaling. Currently, antagonists targeting P2XRs have taken effect in alleviating various pain. The therapeutic potential of the P2X receptor family has become a central focus. Consequently, numerous research groups and pharmaceutical companies are actively engaged in developing novel P2XR antagonists. Furthermore, an increasing number of clinical trials on P2XR antagonists have obtained encouraging results. This review provides an overview of the structural characteristics and cellular localization of P2XRs, their molecular mechanisms and signaling pathways implicated in orofacial pain. Additionally, it explores the development of P2XR antagonists and their therapeutic application for managing orofacial pain. In conclusion, this review highlights the promising role of P2XRs as therapeutic targets for orofacial pain treatment.

NLRP3 inflammasome-based therapies by natural products: a new development in the context of cancer therapy

The leucine-rich repeat containing protein (NLR) canonical inflammasome family includes Nod-like receptor protein 3 (NLRP3). Via the mediation of apoptosis proteins and immunological reactions, it controls the pathogenesis of malignancy. Experimental studies showed a relationship among lymphogenesis, cancer metastasis, and NLRP3 expression. Natural products have also been used as lead-based substances in a number of investigations to speed up the creation of novel, specific NLRP3 inhibitors. Via the mediation of apoptotic proteins and immunological responses, it controls the pathogenesis of malignancy. Moreover, it was recently noted that among human cancers, chemotherapy activates NLRP3. Induction of NLRP3 could encourage the generation of IL-1β and IL-22 to facilitate the propagation of malignancy. Additionally, prior research has demonstrated that the usage of NLRP3 in cancer therapy may result in resistance to drugs. The depletion of NLRP3 could affect the survival of cells. Natural products have been used as lead materials in a number of studies to help generate novel, specific NLRP3 antagonists more quickly. In the present review, we examine the mechanism behind the beneficial effects of the natural substances on the inhibition of cancer growth and progression, with special focus on NLRP3 regulation.

Conventional Chemotherapy and Inflammation: What Is the Role of the Inflammasome in the Tumor Microenvironment?

The link between inflammation and cancer has been extensively studied over the years. While the inflammatory process can facilitate tumor establishment and progression, on the other hand, current clinical approaches aim to boost the immune system against the tumor mass. In this scenario, the conventional chemotherapy has proven to induce immunogenic cell death in that the release of danger-associated alarmins can foster the cytotoxic immunity following the blockade of immune checkpoints. The release of alarmins can activate the inflammasome pathway. Thus, one of the questions is as follows: can conventional anti-tumor drugs lead to inflammasome activation? And if so, is the resulting effect anti- or pro-tumor? In this review, we provide an overview on the role of the inflammasome in cancer.

Breaking the barriers: Overcoming cancer resistance by targeting the NLRP3 inflammasome

Inflammation has a pivotal role in the initiation and progression of various cancers, contributing to crucial processes such as metastasis, angiogenesis, cell proliferation and invasion. Moreover, the release of cytokines mediated by inflammation within the tumour microenvironment (TME) has a crucial role in orchestrating these events. The activation of inflammatory caspases, facilitated by the recruitment of caspase-1, is initiated by the activation of pattern recognition receptors on the immune cell membrane. This activation results in the production of proinflammatory cytokines, including IL-1β and IL-18, and participates in diverse biological processes with significant implications. The NOD-Like Receptor Protein 3 (NLRP3) inflammasome holds a central role in innate immunity and regulates inflammation through releasing IL-1β and IL-18. Moreover, it interacts with various cellular compartments. Recently, the mechanisms underlying NLRP3 inflammasome activation have garnered considerable attention. Disruption in NLRP3 inflammasome activation has been associated with a spectrum of inflammatory diseases, encompassing diabetes, enteritis, neurodegenerative diseases, obesity and tumours. The NLRP3 impact on tumorigenesis varies across different cancer types, with contrasting roles observed. For example, colorectal cancer associated with colitis can be suppressed by NLRP3, whereas gastric and skin cancers may be promoted by its activity. This review provides comprehensive insights into the structure, biological characteristics and mechanisms of the NLRP3 inflammasome, with a specific focus on the relationship between NLRP3 and tumour-related immune responses, and TME. Furthermore, the review explores potential strategies for targeting cancers via NLRP3 inflammasome modulation. This encompasses innovative approaches, including NLRP3-based nanoparticles, gene-targeted therapy and immune checkpoint inhibitors.

Therapeutic Significance of NLRP3 Inflammasome in Cancer: Friend or Foe?

Besides various infectious and inflammatory complications, recent studies also indicated the significance of NLRP3 inflammasome in cancer progression and therapy. NLRP3-mediated immune response and pyroptosis could be helpful or harmful in the progression of cancer, and also depend on the nature of the tumor microenvironment. The activation of NLRP3 inflammasome could increase immune surveillance and the efficacy of immunotherapy. It can also lead to the removal of tumor cells by the recruitment of phagocytic macrophages, T-lymphocytes, and other immune cells to the tumor site. On the other hand, NLRP3 activation can also be harmful, as chronic inflammation driven by NLRP3 supports tumor progression by creating an environment that facilitates cancer cell proliferation, migration, invasion, and metastasis. The release of pro-inflammatory cytokines such as IL-1β and IL-18 can promote tumor growth and angiogenesis, while sustained inflammation may lead to immune suppression, hindering effective anti-tumor responses. In this review article, we discuss the role of NLRP3 inflammasome-mediated inflammatory response in the pathophysiology of various cancer types; understanding this role is essential for the development of innovative therapeutic strategies for cancer growth and spread.

Longitudinal cohort study highlights cancer-preventive benefits of lipid-lowering drugs

Cancer prevention is a serious global challenge. We aimed to investigate the relationship between lipid-lowering drugs and cancers. We included participants based on the UK Biobank. Lipid-lowering drug use was defined as new users before enrollment and the primary outcome was cancer incidence. The Cox proportional hazards regression model was used to evaluate the association between drug use and outcome. We also performed a meta-analysis. We found that lipid-lowering drugs were associated with decreased risk of 21 types of cancers, including melanoma, skin cancer, and reproductive, hematological, urinary, digestive, nervous, and endocrine system cancers (all p < 0.0010). Our meta-analysis documented that lipid-lowering drugs reduced the risk of prostate, liver, and gastric cancers, especially (all p < 0.050). Overall, lipid-lowering drugs had protective associations with cancer incidence, suggesting the possible cancer prevention effects even in the general population.

Unravelling the Significance of NLRP3 and IL-β1 in Oral Squamous Cell Carcinoma and Potentially Malignant Oral Disorders: A Diagnostic and Prognostic Exploration

BACKGROUND

Nucleotide-binding domain-like receptor protein 3 (NLRP3), an inflammasome, is reported to be dysregulated or aberrantly expressed in chronic inflammation, leading to a myriad of inflammatory disorders, autoimmune diseases, and cancer. This study aimed to explore the expression and role of NLRP3 protein and the secreted cytokine IL-β1 in oral squamous cell carcinoma (OSCC) and potentially malignant oral disorders (PMOD).

MATERIAL & METHODS

Tissue NLRP3 expression was quantified using sandwich ELISA in 30 cases each of OSCC, PMOD, and normal oral mucosa. Serum IL-β1 level was also measured by ELISA to determine their correlation. In surgically treated OSCC cases, pathological parameters such as tumor size, depth of invasion (DOI), pTNM stage, and perineural & lymphovascular invasion were assessed and correlated with NLRP3 & IL-β1 levels to investigate their roles in tumor progression, invasion, and metastasis.

RESULTS

Tissue NLRP3 expression was markedly elevated in OSCC, with significant IL-β1 levels observed in the serum of both OSCC and PMOD cases. Both markers showed a pronounced increase with the severity of dysplasia, indicating a strong association (p = 0.003%). The expression levels of tissue NLRP3 and serum IL-β1 were positively correlated with DOI and tumor size. Furthermore, their elevated levels, alongside higher histological grades, indicate roles in the dedifferentiation and progression of tumor cells.

CONCLUSION

The findings indicated that increased expression of NLRP3 and IL-β1 in PMOD correlates with higher transformation rates, along with tumor progression and dedifferentiation in OSCC. Consequently, these markers hold promise as valuable targets for prognostic assessment, diagnostics, and therapeutic strategies in OSCC.

Tumor-resident microbiota contributes to colorectal cancer liver metastasis by lactylation and immune modulation

The role of tumor-resident microbiota in modulating tumor immunity remains unclear. Here, we discovered an abundance of intra-tumoral bacteria, such us E.coli, residing and resulting in Colorectal cancer liver metastasis (CRLM). E.coli enhanced lactate production, which mediated M2 macrophage polarization by suppressing nuclear factor-κB -gene binding (NF-κB) signaling through retinoic acid-inducible gene 1 (RIG-I) lactylation. Lactylation of RIG-I suppressed recruitment of NF-κB to the Nlrp3 promoter in macrophages, thereby reducing its transcription. This loss of Nlrp3 affected the immunosuppressive activities of regulatory T cells (Tregs) and the antitumor activities of and CD8+ T cells. Small-molecule compound screening identified a RIG-I lactylation inhibitor that suppressed M2 polarization and sensitized CRLM to 5-fluorouracil (5-FU). Our findings suggest that tumor-resident microbiota may be a potential target for preventing and treating CRLM.

Tumor biomarkers for diagnosis, prognosis and targeted therapy

Tumor biomarkers, the substances which are produced by tumors or the body's responses to tumors during tumorigenesis and progression, have been demonstrated to possess critical and encouraging value in screening and early diagnosis, prognosis prediction, recurrence detection, and therapeutic efficacy monitoring of cancers. Over the past decades, continuous progress has been made in exploring and discovering novel, sensitive, specific, and accurate tumor biomarkers, which has significantly promoted personalized medicine and improved the outcomes of cancer patients, especially advances in molecular biology technologies developed for the detection of tumor biomarkers. Herein, we summarize the discovery and development of tumor biomarkers, including the history of tumor biomarkers, the conventional and innovative technologies used for biomarker discovery and detection, the classification of tumor biomarkers based on tissue origins, and the application of tumor biomarkers in clinical cancer management. In particular, we highlight the recent advancements in biomarker-based anticancer-targeted therapies which are emerging as breakthroughs and promising cancer therapeutic strategies. We also discuss limitations and challenges that need to be addressed and provide insights and perspectives to turn challenges into opportunities in this field. Collectively, the discovery and application of multiple tumor biomarkers emphasized in this review may provide guidance on improved precision medicine, broaden horizons in future research directions, and expedite the clinical classification of cancer patients according to their molecular biomarkers rather than organs of origin.

Coenzyme Q0 inhibited the NLRP3 inflammasome, metastasis/EMT, and Warburg effect by suppressing hypoxia-induced HIF-1α expression in HNSCC cells

Coenzyme Q0 (CoQ0), a quinone derivative from Antrodia camphorata, has antitumor capabilities. This study investigated the antitumor effect of noncytotoxic CoQ0, which included NLRP3 inflammasome inhibition, anti-EMT/metastasis, and metabolic reprogramming via HIF-1α inhibition, in HNSCC cells under normoxia and hypoxia. CoQ0 suppressed hypoxia-induced ROS-mediated HIF-1α expression in OECM-1 and SAS cells. Under normoxia and hypoxia, the inflammatory NLRP3, ASC/caspase-1, NFκB, and IL-1β expression was reduced by CoQ0. CoQ0 reduced migration/invasion by enhancing epithelial marker E-cadherin and suppressing mesenchymal markers Twist, N-cadherin, Snail, and MMP-9, and MMP-2 expression. CoQ0 inhibited glucose uptake, lactate accumulation, GLUT1 levels, and HIF-1α-target gene (HK-2, PFK-1, and LDH-A) expressions that are involved in aerobic glycolysis. Notably, CoQ0 reduced ECAR as well as glycolysis, glycolytic capability, and glycolytic reserve and enhanced OCR, basal respiration, ATP generation, maximal respiration, and spare capacity in OECM-1 cells. Metabolomic analysis using LC-ESI-MS showed that CoQ0 treatment decreased the levels of glycolytic intermediates, including lactate, 2/3-phosphoglycerate, fructose 1,6-bisphosphate, and phosphoenolpyruvate, and increased the levels of TCA cycle metabolites, including citrate, isocitrate, and succinate. HIF-1α silencing reversed CoQ0-mediated anti-metastasis (N-Cadherin, Snail, and MMP-9) and metabolic reprogramming (GLUT1, HK-2, and PKM-2) under hypoxia. CoQ0 prevents cancer stem-like characteristics (upregulated CD24 expression and downregulated CD44, ALDH1, and OCT4) under normoxia and/or hypoxia. Further, in IL-6-treated SG cells, CoQ0 attenuated fibrosis by inhibiting TGF-β and Collagen I expression and suppressed EMT by downregulating Slug and upregulating E-cadherin expression. Interesting, CoQ0 inhibited the growth of OECM-1 tumors in xenografted mice. Our results advocate CoQ0 for the therapeutic application against HNSCC.

P2X7 receptors: a bibliometric review from 2002 to 2023

For many years, there has been ongoing research on the P2X7 receptor (P2X7R). A comprehensive, systematic, and objective evaluation of the scientific output and status of P2X7R will be instrumental in guiding future research directions. This study aims to present the status and trends of P2X7R research from 2002 to 2023. Publications related to P2X7R were retrieved from the Web of Science Core Collection database. Quantitative analysis and visualization tools were Microsoft Excel, VOSviewer, and CiteSpace software. The analysis content included publication trends, literature co-citation, and keywords. 3282 records were included in total, with the majority of papers published within the last 10 years. Based on literature co-citation and keyword analysis, neuroinflammation, neuropathic pain, gastrointestinal diseases, tumor microenvironment, rheumatoid arthritis, age-related macular degeneration, and P2X7R antagonists were considered to be the hotspots and frontiers of P2X7R research. Researchers will get a more intuitive understanding of the status and trends of P2X7R research from this study.

Potential Impact of Bioactive Compounds as NLRP3 Inflammasome Inhibitors: An Update

The inflammasome NLRP3 comprises a caspase recruitment domain, a pyrin domain containing receptor 3, an apoptosis-linked protein like a speck containing a procaspase-1, and an attached nucleotide domain leucine abundant repeat. There are a wide variety of stimuli that can activate the inflammasome NLRP3. When activated, the protein NLRP3 appoints the adapter protein ASC. Adapter ASC protein then recruits the procaspase-1 protein, which causes the procaspase- 1 protein to be cleaved and activated, which induces cytokines. At the same time, abnormal activation of inflammasome NLRP3 is associated with many diseases, such as diabetes, atherosclerosis, metabolic syndrome, cardiovascular and neurodegenerative diseases. As a result, a significant amount of effort has been put into comprehending the mechanisms behind its activation and looking for their specific inhibitors. In this review, we primarily focused on phytochemicals that inhibit the inflammasome NLRP3, as well as discuss the defects caused by NLRP3 signaling. We conducted an in-depth research review by searching for relevant articles in the Scopus, Google Scholar, and PubMed databases. By gathering information on phytochemical inhibitors that block NLRP3 inflammasome activation, a complicated balance between inflammasome activation or inhibition with NLRP3 as a key role was revealed in NLRP3-driven clinical situations.

NLRP3 and cancer: Pathogenesis and therapeutic opportunities

More than a decade ago IL-1 blockade was suggested as an add-on therapy for the treatment of cancer. This proposal was based on the overall safety record of anti-IL-1 biologics and the anti-tumor properties of IL-1 blockade in animal models of cancer. Today, a new frontier in IL-1 activity regulation has developed with several orally active NLRP3 inhibitors currently in clinical trials, including cancer. Despite an increasing body of evidence suggesting a role of NLRP3 and IL-1-mediated inflammation driving cancer initiation, immunosuppression, growth, and metastasis, NLRP3 activation in cancer remains controversial. In this review, we discuss the recent advances in the understanding of NLRP3 activation in cancer. Further, we discuss the current opportunities for NLRP3 inhibition in cancer intervention with novel small molecules.

The 'speck'-tacular oversight of the NLRP3-pyroptosis pathway on gastrointestinal inflammatory diseases and tumorigenesis

The NLRP3 inflammasome is an intracellular sensor and an essential component of the innate immune system involved in danger recognition. An important hallmark of inflammasome activation is the formation of a single supramolecular punctum, known as a speck, per cell, which is the site where the pro-inflammatory cytokines IL-1β and IL-18 are converted into their bioactive form. Speck also provides the platform for gasdermin D protein activation, whose N-terminus domain perforates the plasma membrane, allowing the release of mature cytokines alongside with a highly inflammatory form of cell death, namely pyroptosis. Although controlled NLRP3 inflammasome-pyroptosis pathway activation preserves mucosal immunity homeostasis and contributes to host defense, a prolonged trigger is deleterious and could lead, in genetically predisposed subjects, to the onset of inflammatory bowel disease, including Crohn's disease and ulcerative colitis, as well as to gastrointestinal cancer. Experimental evidence shows that the NLRP3 inflammasome has both protective and pathogenic abilities. In this review we highlight the impact of the NLRP3-pyroptosis axis on the pathophysiology of the gastrointestinal tract at molecular level, focusing on newly discovered features bearing pro- and anti-inflammatory and neoplastic activity, and on targeted therapies tested in preclinical and clinical trials.

Unraveling the Anticancer Potential of Statins: Mechanisms and Clinical Significance

Statins are an essential medication class in the treatment of lipid diseases because they inhibit 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase. They reduce cholesterol levels and reduce the risk of cardiovascular disease in both primary and secondary prevention. In addition to their powerful pharmacologic suppression of cholesterol production, statins appear to have pleitropic effects in a wide variety of other diseases by modulating signaling pathways. In recent years, statins have seen a large increase in interest due to their putative anticancer effects. Statins appear to cause upregulation or inhibition in key pathways involved in cancer such as inhibition of proliferation, angiogenesis, and metastasis as well as reducing cancer stemness. Further, statins have been found to induce oxidative stress, cell cycle arrest, autophagy, and apoptosis of cancer cells. Interestingly, clinical studies have shown that statin use is associated with a decreased risk of cancer formation, lower cancer grade at diagnosis, reduction in the risk of local reoccurrence, and increasing survival in patients. Therefore, our objective in the present review is to summarize the findings of the publications on the underlying mechanisms of statins' anticancer effects and their clinical implications.

The roles of inflammasomes in cancer

Inflammation is a key characteristic of all stages of tumor development, including tumor initiation, progression, malignant transformation, invasion, and metastasis. Inflammasomes are an important component of the inflammatory response and an indispensable part of the innate immune system. Inflammasomes regulate the nature of infiltrating immune cells by signaling the secretion of different cytokines and chemokines, thus regulating the anti-tumor immunity of the body. Inflammasome expression patterns vary across different tumor types and stages, playing different roles during tumor progression. The complex diversity of the inflammasomes is determined by both internal and external factors relating to tumor establishment and progression. Therefore, elucidating the specific effects of different inflammasomes in anti-tumor immunity is critical for promoting the discovery of inflammasome-targeting drugs. This review focuses on the structure, activation pathway, and identification methods of the NLRP3, NLRC4, NLRP1 and AIM2 inflammasomes. Herein, we also explore the role of inflammasomes in different cancers and their complex regulatory mechanisms, and discuss current and future directions for targeting inflammasomes in cancer therapy. A detailed knowledge of inflammasome function and regulation may lead to novel therapies that target the activation of inflammasomes as well as the discovery of new drug targets.

The potential role of COVID-19 in progression, chemo-resistance, and tumor recurrence of oral squamous cell carcinoma (OSCC)

Numerous studies have revealed that cancer patients are more likely to develop severe Coronavirus disease-2019 (COVID-19), which can cause mortality, as well as cancer progression and treatment failure. Among these patients who may be particularly vulnerable to severe COVID-19 and COVID-19-associated cancer progression are those with oral squamous cell carcinoma (OSCC). In this regard, therapeutic approaches must be developed to lower the risk of cancer development, chemo-resistance, tumor recurrence, and death in OSCC patients with COVID-19. It may be helpful to comprehend the cellular and molecular mechanisms by which the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) contributes to these problems. In this line, in this review, we described the potential cellular and molecular mechanisms that SARS-CoV-2 can exert its role and based on them pharmacological targeted therapies were suggested. However, in this study, we encourage more investigations in the future to uncover other cellular and molecular mechanisms of action of SARS-CoV-2 to develop beneficial therapeutic strategies for such patients.

Nanovaccine that activates the NLRP3 inflammasome enhances tumor specific activation of anti-cancer immunity

Neoantigen cancer vaccines that target tumor specific mutations are emerging as a promising modality for cancer immunotherapy. To date, various approaches have been adopted to enhance efficacy of these therapies, but the low immunogenicity of neoantigens has hindered clinical application. To address this challenge, we developed a polymeric nanovaccine platform that activates the NLRP3 inflammasome, a key immunological signaling pathway in pathogen recognition and clearance. The nanovaccine is comprised of a poly (orthoester) scaffold engrafted with a small-molecule TLR7/8 agonist and an endosomal escape peptide that facilitates lysosomal rupture and NLRP3 inflammasome activation. Upon solvent transfer, the polymer self-assembles with neoantigens to form ∼50 nm nanoparticles that facilitate co-delivery to antigen-presenting cells. This polymeric activator of the inflammasome (PAI) was found to induce potent antigen-specific CD8+ T cell responses characterized by IFN-γ and GranzymeB secretion. Moreover, in combination with immune checkpoint blockade therapy, the nanovaccine stimulated robust anti-tumor immune responses against established tumors in EG.7-OVA, B16·F10, and CT-26 models. Results from our studies indicate that NLRP3 inflammasome activating nanovaccines demonstrate promise for development as a robust platform to enhance immunogenicity of neoantigen therapies.

A comprehensive analysis of PANoptosome to prognosis and immunotherapy response in pan-cancer

PANoptosis, a programmed cell death, shares key characteristics of apoptosis, pyroptosis, and necroptosis. Accumulating evidence suggests that PANoptosis plays a crucial role in tumorigenesis. However, the respective regulation mechanisms in cancer are so far unclear. Using various bioinformatic approaches, we comprehensively analyzed the expression patterns, genetic alterations, prognostic value, and immunological role of PANoptosis genes in pan-cancer. Expression of the PANoptosis gene, PYCARD, was validated based on the Human Protein Atlas database and real-time quantitative reverse transcription polymerase chain reaction (RT-PCR). We found that PANoptosis genes were aberrantly expressed in most cancer types, which was consistent with the validation of PYCARD expression. Concurrently, PANoptosis genes and PANoptosis scores were significantly associated with patient survival in 21 and 14 cancer types, respectively. Pathway analysis showed that PANoptosis score was positively correlated with pathways linked to immune and inflammatory responses in pan-cancer, such as IL6-JAK-STAT3 signaling, the interferon-gamma response, and IL2-STAT5 signaling. In addition, the PANoptosis score was significantly correlated with the tumor microenvironment, the infiltration levels of most immune cells (i.e.NK cells, CD8+ T cells, CD4+ T cells, DC cells), and immune-related genes. Furthermore, it was a predictive indicator of immunotherapy response in patients with tumors. These insights substantially improve our understanding of PANoptosis components in cancers and may inspire the discovery of novel prognostic and immunotherapy response biomarkers.

Effect of Aspergillus fumigatus on infection in immunosuppressed rats

Background

Immunosuppression is believed to increase the risk of invasive pulmonary aspergillosis (IPA), but information on the mechanism is limited. Therefore, we analyze the effect and mechanism of the pathogenesis and disease progression of IPA in a combined immunosuppressed rat model.

Methods

The immunosuppressed rat model was established by intraperitoneal injection of cyclophosphamide (CTX) and dexamethasone (DXM). IPA was established by nasal inoculation of Aspergillus fumigatus spore suspension. Pathological sections and tissue homogenate culture were used to evaluate the lung tissue. Routine blood and inflammatory indexes were dynamically observed. The expressions of NLRP3/caspase-1/GSDMD protein and gene were determined using western blot and quantitative polymerase chain reaction (q-PCR) respectively. T-test or one-way repeated measures analysis were used to do statistical analysis on the groups.

Results

Following intraperitoneal of CTX and DXM injections, the rats showed depression, weight loss, and significant decreases in the numbers of leukocytes and classified cells. Pathological sections revealed more severe lung lesions in the immunosuppressed rats infected with Aspergillus fumigatus. The expression of NLRP3/caspase-1/GSDMD protein increased significantly in both the aspergillosis and immunosuppressed plus aspergillosis groups.

Conclusions

The pathological development of IPA in the immunosuppressed rats had the most serious effects, and the findings strongly implicated NLRP3/caspase-1/GSDMD pathway involvement.

NLRP1 in Cutaneous SCCs: An Example of the Complex Roles of Inflammasomes in Cancer Development

Protein complexes termed inflammasomes ensure tissue protection from pathogenic and sterile stressors by induction of inflammation. This is mediated by different caspase-1-induced downstream pathways, including activation of the pro-inflammatory cytokines proIL-1β and -18, induction of a lytic type of cell death, and regulation of the release of other pro-inflammatory molecules. Aberrant inflammasome activation underlies the pathology of numerous (auto)inflammatory diseases. Furthermore, inflammasomes support or suppress tumor development in a complex cell-type- and stage-dependent manner. In human keratinocytes and skin, NLRP1 is the central inflammasome sensor activated by cellular perturbation induced, for example, by UVB radiation. UVB represents the main inducer of skin cancer, which is the most common type of malignancy in humans. Recent evidence demonstrates that activation of NLRP1 in human skin supports the development of cutaneous squamous cell carcinomas (cSCCs) by inducing skin inflammation. In contrast, the NLRP1 inflammasome pathway is restrained in established cSCCs, suggesting that, at this stage, the protein complex has a tumor suppressor role. A better understanding of the complex functions of NLRP1 in the development of cSCCs and in general of inflammasomes in cancer might pave the way for novel strategies for cancer prevention and therapy. These strategies might include stage-specific modulation of inflammasome activation or its downstream pathways by mono- or combination therapy.

AIM2 upregulation promotes metastatic progression and PD-L1 expression in lung adenocarcinoma

Cancer metastasis leading to the dysfunction of invaded organs is the main cause of the reduced survival rates in lung cancer patients. However, the molecular mechanism for lung cancer metastasis remains unclear. Recently, the increased activity of inflammasome appeared to correlate with the metastatic progression and immunosuppressive ability of various cancer types. Our results showed that the mRNA levels of absence in melanoma 2 (AIM2), one of the inflammasome members, are extensively upregulated in primary tumors compared with normal tissues derived from the TCGA lung adenocarcinoma (LUAD) database. Moreover, Kaplan-Meier analysis demonstrated that a higher mRNA level of AIM2 refers to a poor prognosis in LUAD patients. Particularly, AIM2 upregulation is closely correlated with smoking history and the absence of EGFR/KRAS/ALK mutations in LUAD. We further showed that the endogenous mRNA levels of AIM2 are causally associated with the metastatic potentials of the tested LUAD cell lines. AIM2 knockdown suppressed but overexpression promoted the migration ability and lung colony-forming ability of tested LUAD cells. In addition, we found that AIM2 upregulation is closely associated with an increased level of immune checkpoint gene set, as well as programmed cell death-ligand 1 (PD-L1) transcript, in TCGA LUAD samples. AIM2 knockdown predominantly repressed but overexpression enhanced PD-L1 expression via altering the activity of PD-L1 transcriptional regulators NF-κB/STAT1 in LUAD cells. Our results not only provide a possible mechanism underlying the AIM2-promoted metastatic progression and immune evasion of LUAD but also offer a new strategy for combating metastatic/immunosuppressive LUAD via targeting AIM2 activity.

Azithromycin and Ceftriaxone Differentially Activate NLRP3 in LPS Primed Cancer Cells

Background: Cancer patients are prescribed antibiotics, such as macrolides and lactamides, for infection treatment. However, the effect of these antibiotics on NLRP3 activation remains largely unknown. Method: Lung cancer (A549) and prostate cancer (PC3) cell lines were primed with lipopolysaccharide (LPS) to activate NLRP3 transcription. Cells were then treated with azithromycin (Az) or ceftriaxone (Cf). NLRP3 activation was analyzed by qPCR, Western blot, and ELISA. Cell growth and viability were assessed by real-time cell analysis and Annexin V expression. Levels of 41 cytokines were also analyzed using a multiplex assay. Results: LPS-Az activated transcription of NLRP3, Pro-CASP-1, and Pro-IL-1β in A549 cells, while failing to upregulate NLRP3 and Pro-IL-1β in PC3 cells. LPS-Az decreased the secretion of pro-inflammatory cytokines while it induced the pro-angiogenic factors in A549 and PC3 cells. In contrast, LPS-Cf suppressed the expression of NLRP3-associated genes, NLRP3 protein expression, the inflammatory cytokine secretion in A549 and PC3 cells. LPS-Az and LPS-Cf had a limited effect on cell growth and viability. Discussion: Our data suggest that Cf could suppress LPS induced NLRP3, which should be considered when selecting antibiotics for cancer treatment. In contrast, the effect of Az on LPS primed NLRP3 and the inflammatory cytokines production appears to depend on the cancer cell origin. Therefore, these data indicate that considerations are required when selecting Az for the treatment of cancer patients.

Activation of Host-NLRP3 Inflammasome in Myeloid Cells Dictates Response to Anti-PD-1 Therapy in Metastatic Breast Cancers

Tumor-associated inflammation leads to dysregulated cytokine production that promotes tumor immune evasion and anti-tumor immunity dysfunction. In advanced stage breast cancer, the proinflammatory cytokine IL-1β is overexpressed due to large proportions of activated myeloid cells in the tumor microenvironment (TME). Here, we demonstrate the role of the host nucleotide-binding domain, leucine-rich containing family, pyrin domain-containing 3 (NLRP3) inflammasome in metastatic breast cancer. In vitro, we show that stimulation of THP-1 cells with conditioned media collected from MDA-MB-468 cells induced NLRP3 activation and increased Pdcd1l1 expression. In vivo, mice deficient in NLRP3 orthotopically implanted with metastatic breast cancer cell line (E0771) showed significant reduction in tumor growth (p < 0.05) and increased survival (p < 0.01). Inhibition of NLRP3 with the small molecule OLT1177® reduced expression of Pdcd1l1 (p < 0.001), Casp1 (p < 0.01) and Il1b (p < 0.01) in primary tumors. Furthermore, tumor-bearing mice receiving OLT1177® showed reduced infiltration of myeloid-derived suppressor cells (MDSCs) (p < 0.001) and increased CD8+ T cells (p < 0.05) and NK cells (p < 0.05) in the TME. NLRP3 inhibition in addition to anti-PD-1 treatment significantly reduced tumor growth from the monotherapies (p < 0.05). These data define NLRP3 activation as a key driver of immune suppression in metastatic breast cancers. Furthermore, this study suggests NLRP3 as a valid target to increase efficacy of immunotherapy with checkpoint inhibitor in metastatic breast cancers.

Inflammatory profile in cervical cancer: influence of purinergic signaling and possible therapeutic targets

INTRODUCTION AND OBJECTIVE

Cervical cancer is the fourth most prevalent type of cancer in the world. The tumor microenvironment of this disease is associated with the production of several cytokines, pro and anti-inflammatory, and with the purinergic signaling system so that changes in these components are observed throughout the pathological process. The aim of this review is to understand the pathophysiology of cervical cancer based on immunological processes and purinergic signaling pathways, in addition to suggesting possibilities of therapeutic targets.

MATERIALS AND METHODS

To make up this review, studies covering topics of cervical cancer, inflammation and purinergic system were selected from the Pubmed.

RESULTS

The main pro-inflammatory cytokines involved are IL-17, IL-1β, IL-6, and IL-18, and among the anti-inflammatory ones, IL-10 and TGF-β stand out. As new therapeutic targets, P2X7 and A2A receptors have been suggested, since blocking P2X7 would lead to reduced release of pro-inflammatory cytokines, and blocking A2A would increase activation of cytotoxic T lymphocytes in the context of tumor combat. The association between the immune system and the purinergic system, already known in other types of disease, also presents possibilities for a better understanding of biomolecular processes and therapeutic possibilities in the context of cervical cancer.

Daphnes Cortex and its licorice-processed products suppress inflammation via the TLR4/NF-κB/NLRP3 signaling pathway and regulation of the metabolic profile in the treatment of rheumatoid arthritis

ETHNOPHARMACOLOGICAL RELEVANCE

Daphnes Cortex (Daphne Giraldii Nitsche, DGN) is a popular traditional Chinese herbal medicine for traumatic injuries and rheumatoid arthritis (RA) in the Shaanxi and Gansu provinces of China. Due to skin irritation caused by raw DGN (RDGN), licorice-processed DGN products are usually used in clinical practice. However, the efficacy and mechanisms of action between DGN and its licorice-processed DGN products in treating RA have not been compared.

AIMS

This study compared the efficacy and elucidated the mechanisms in vitro and in vivo between RDGN and its licorice-processed DGN products in treating RA.

MATERIALS AND METHODS

A collagen-induced RA rat model was established, and treated with different doses of RDGN and its licorice-processed DGN products for 4 weeks to explore the therapeutic effects. The anti-inflammatory effects were assessed in RAW 264.7 macrophages stimulated by lipopolysaccharide (LPS). Analyses of the differential quality markers (DQMs) between DGN and its licorice-processed DGN products using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry, and non-targeted metabolomics analyses of rat synovial tissues were used to systematically explore correlations between DGN processing and its efficacy.

RESULTS

Licorice-processed DGN products significantly ameliorated RA symptoms in CIA rats. Licorice-processed DGN products also regulated inflammatory cytokines, matrix metalloproteinases, and vascular endothelial growth factor in the serum and cell supernatants. Licorice-processed DGN products significantly inhibited Toll-like receptor 4/nuclear factor kappa B/NOD-like receptor family, pyrin domain containing 3 (TLR4/NF-κB/NLRP3) signaling in CIA rats and LPS-induced RAW264.7 cells. The DQMs between RDGN and its licorice-processed DGN products were identified, most of which were amino acids or energy-related metabolites present in licorice-processed DGN products. Correlations between DQMs with differential metabolites and differential metabolic pathways were established.

CONCLUSIONS

Licorice-processed DGN products displayed better anti-inflammatory effects via the TLR4/NF-κB/NLRP3 signaling pathway on CIA rats and LPS-induced RAW264.7 cells, and regulation of the metabolic profile in treating RA.

Genetically Predicted Circulating Levels of Cytokines and the Risk of Cancer

Background

Inflammation plays a pivotal role in the pathogenesis of cancer. Though previous studies have reported a link between several inflammatory biomarkers and risk of certain types of cancer, there is a lack of systematic investigation. Therefore, we aimed to assess the role of circulating cytokines on the risk of cancer using a two-sample Mendelian randomization (MR) approach.

Method

We used genetic variants associated with circulating levels of cytokines from a meta-analysis of genome-wide association studies (GWASs) of 8,293 Finns as instrumental variables. Summary level data of 20 site-specific cancer were obtained from the UK BioBank including up to 456,348 participants of European ancestry. We performed two-sample MR analyses using inverse-variance weighted (IVW) method as the main method, followed by weighted-median and likelihood-based methods as sensitivity analysis. Pleiotropic and outlier variants were assessed by MR-Egger regression and MR Pleiotropy RESidual Sum and Outlier (MR-PRESSO) test.

Results

224 genetic variants associated with 27 circulating cytokines achieving genome-wide significance (P<5×10^-8) were used as IVs. After Bonferroni correction, genetically predicted high levels of interleukin-18 (IL-18) were associated with a decreased risk of acute myeloid leukemia (odds ratio (OR) per 1 standard deviation (SD) increase = 0.55, 95% confidence interval (CI):0.43-0.69, P=5.39×10^-7), and circulating levels of IL-17 were associated with altered stomach cancer risk (OR per 1 SD increase = 0.15, 95% CI: 0.07-0.36, P=1.25×10^-5) by IVW. Results were stable across sensitivity analyses, and MR-Egger regression did not suggest the presence of directional pleiotropy. Additionally, we found suggestive evidence for 48 cytokine-cancer associations including tumor necrosis factor related apoptosis-inducing ligand (TRAIL) and cutaneous T-cell attracting chemokine (CTACK) with the risk of several types of cancer (9.26×10^-5≤P<0.05).

Conclusions

By using a genetic epidemiological approach, our study systematically evaluated the role of circulating cytokines on the risk of cancer, and provided clues for potential therapeutic targets. However, the exact underlying biological mechanism warrants further investigation.

P2X7 receptor: the regulator of glioma tumor development and survival

P2X7 is an ionotropic nucleotide receptor, forming the cation channel upon ATP stimulation. It can also function as a large membrane pore as well as transmit ATP-dependent signal without forming a channel at all. P2X7 activity in somatic cells is well-known, but remains poorly studied in glioma tumors. The current paper presents the comprehensive study of P2X7 activity in C6 and glioma cell line showing the wide range of effects the receptor has on glioma biology. We observed that P2X7 stimulation boosts glioma cell proliferation and increases cell viability. P2X7 activation promoted cell adhesion, mitochondria depolarization, and reactive oxygen species overproduction in C6 cells. P2X7 receptor also influenced glioma tumor growth in vivo via activation of pro-survival signaling pathways and ATP release. Treatment with Brilliant Blue G, a selective P2X7 antagonist, effectively inhibited glioma tumor development; decreased the expression of negative prognostic cancer markers pro-survival and epithelial-mesenchymal transition (EMT)-related proteins; and modulated the immune response toward glioma tumor in vivo. Finally, pathway-specific enrichment analysis of the microarray data from human patients also showed an upregulation of P2X7 receptor in gliomas from grades I to III. The presented results shed more light on the role of P2X7 receptor in the biology of this disease.

Therapeutic Influence on Important Targets Associated with Chronic Inflammation and Oxidative Stress in Cancer Treatment

Chronic inflammation and oxidative stress are the interconnected pathological processes, which lead to cancer initiation and progression. The growing level of oxidative and inflammatory damage was shown to increase cancer severity and contribute to tumor spread. The overproduction of reactive oxygen species (ROS), which is associated with the reduced capacity of the endogenous cell defense mechanisms and/or metabolic imbalance, is the main contributor to oxidative stress. An abnormal level of ROS was defined as a predisposing factor for the cell transformation that could trigger pro-oncogenic signaling pathways, induce changes in gene expression, and facilitate accumulation of mutations, DNA damage, and genomic instability. Additionally, the activation of transcription factors caused by a prolonged oxidative stress, including NF-κB, p53, HIF1α, etc., leads to the expression of several genes responsible for inflammation. The resulting hyperactivation of inflammatory mediators, including TNFα, TGF-β, interleukins, and prostaglandins can contribute to the development of neoplasia. Pro-inflammatory cytokines were shown to trigger adaptive reactions and the acquisition of resistance by tumor cells to apoptosis, while promoting proliferation, invasion, and angiogenesis. Moreover, the chronic inflammatory response leads to the excessive production of free radicals, which further aggravate the initiated reactions. This review summarizes the recent data and progress in the discovery of mechanisms that associate oxidative stress and chronic inflammation with cancer onset and metastasis. In addition, the review provides insights for the development of therapeutic approaches and the discovery of natural substances that will be able to simultaneously inhibit several key oncological and inflammation-related targets.

Immunological and clinical immunotherapy implications of NLRP3 mutations in melanoma

Recent studies have demonstrated the role of Nod-like receptor protein 3 (NLRP3) inflammasome in promoting melanoma progression. Immune checkpoint inhibitors (ICI) treatment dramatically extended the survival outcomes for advanced melanoma patients. Nevertheless, immunologic and immunotherapy implications of NLRP3 mutations in melanoma were obscure. Herein, we utilized publicly genomic data of 750 melanoma patients to explore the association of NLRP3 mutations with immunologic and genomic features. In addition, we curated 336 advanced/metastatic melanoma patients treated with ICI agents from 6 published studies to analyze the response rate and survival outcome in relation to NLRP3 mutations. We observed that patients with NLRP3 mutations had a significantly higher tumor mutation burden (P < 0.001) and neoantigen burden (P < 0.001). Moreover, significantly lower tumor heterogeneity (P = 0.048) and purity (P = 0.022) were also observed in this mutated subgroup. Elevated infiltration of immune-response cells, decreased enrichment of immune-suppressive cells, and immune response-related circuits were markedly enriched in patients with NLRP3 mutations. In the pooled ICI-treated cohort, NLRP3 mutations were linked with the higher response rate (P = 0.031) and preferable survival outcome (P = 0.006). NLRP3 mutations were identified to associate with the elevated mutational burden, favorable immune infiltration, and preferable ICI efficacy. Findings derived from our study suggest that NLRP3 mutations may serve as a potential biomarker for evaluating melanoma immunotherapy response.

Statins: a repurposed drug to fight cancer

As competitive HMG-CoA reductase (HMGCR) inhibitors, statins not only reduce cholesterol and improve cardiovascular risk, but also exhibit pleiotropic effects that are independent of their lipid-lowering effects. Among them, the anti-cancer properties of statins have attracted much attention and indicated the potential of statins as repurposed drugs for the treatment of cancer. A large number of clinical and epidemiological studies have described the anticancer properties of statins, but the evidence for anticancer effectiveness of statins is inconsistent. It may be that certain molecular subtypes of cancer are more vulnerable to statin therapy than others. Whether statins have clinical anticancer effects is still an active area of research. Statins appear to enhance the efficacy and address the shortcomings associated with conventional cancer treatments, suggesting that statins should be considered in the context of combined therapies for cancer. Here, we present a comprehensive review of the potential of statins in anti-cancer treatments. We discuss the current understanding of the mechanisms underlying the anti-cancer properties of statins and their effects on different malignancies. We also provide recommendations for the design of future well-designed clinical trials of the anti-cancer efficacy of statins.

NLRP3 Inflammasome Promotes the Progression of Acute Myeloid Leukemia via IL-1β Pathway

NLRP3 inflammasome has been reported to be associated with the pathogenesis of multiple solid tumors. However, the role of NLRP3 inflammasome in acute myeloid leukemia (AML) remains unclear. We showed that NLRP3 inflammasome is over-expressed and highly activated in AML bone marrow leukemia cells, which is correlated with poor prognosis. The activation of NLRP3 inflammasome in AML cells promotes leukemia cells proliferation, inhibits apoptosis and increases resistance to chemotherapy, while inactivation of NLRP3 by caspase-1 or NF-κB inhibitor shows leukemia-suppressing effects. Bayesian networks analysis and cell co-culture tests further suggest that NLRP3 inflammasome acts through IL-1β but not IL-18 in AML. Knocking down endogenous IL-1β or anti-IL-1β antibody inhibits leukemia cells whereas IL-1β cytokine enhances leukemia proliferation. In AML murine model, up-regulation of NLRP3 increases the leukemia burden in bone marrow, spleen and liver, and shortens the survival time; furthermore, knocking out NLRP3 inhibits leukemia progression. Collectively, all these evidences demonstrate that NLRP3 inflammasome promotes AML progression in an IL-1β dependent manner, and targeting NLRP3 inflammasome may provide a novel therapeutic option for AML.

The P2X7 Receptor in the Maintenance of Cancer Stem Cells, Chemoresistance and Metastasis

Metastasis is the worst prognosis predictor in the clinical course of cancer development. Features of metastatic cancer cells include migratory ability, low degree of differentiation, self-renewal and proliferation potentials, as well as resistance to therapies. Metastatic cells do not present all of the necessary characteristics at once. Indeed, they have a unique phenotypic plasticity, allowing the acquisition of features that make them successful in all steps of metastasis. Cancer stem cells (CSC), the most undifferentiated cells in the tumor mass, display highest metastatic potential and resistance to radio- and chemotherapy. Growing tumors exhibit marked upregulation of P2X7 receptor expression and secrete ATP. Since the P2X7 receptor plays an important role in the maintenance of undifferentiated state of pluripotent cells, its importance on cell fate regulation in the tumor mass is suggested. Considering the extensive crosstalk between CSCs, epithelial-mesenchymal transition, drug resistance and metastasis, current knowledge implicating P2X7 receptor function in these phenomena and new avenues for therapeutic strategies to control metastasis are reviewed.

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.

NLRP3 inflammasome in cancer and metabolic diseases

The NLRP3 inflammasome is a multimeric cytosolic protein complex that assembles in response to cellular perturbations. This assembly leads to the activation of caspase-1, which promotes maturation and release of the inflammatory cytokines interleukin-1β (IL-1β) and IL-18, as well as inflammatory cell death (pyroptosis). The inflammatory cytokines contribute to the development of systemic low-grade inflammation, and aberrant NLRP3 activation can drive a chronic inflammatory state in the body to modulate the pathogenesis of inflammation-associated diseases. Therefore, targeting NLRP3 or other signaling molecules downstream, such as caspase-1, IL-1β or IL-18, has the potential for great therapeutic benefit. However, NLRP3 inflammasome-mediated inflammatory cytokines play dual roles in mediating human disease. While they are detrimental in the pathogenesis of inflammatory and metabolic diseases, they have a beneficial role in numerous infectious diseases and some cancers. Therefore, fine tuning of NLRP3 inflammasome activity is essential for maintaining proper cellular homeostasis and health. In this Review, we will cover the mechanisms of NLRP3 inflammasome activation and its divergent roles in the pathogenesis of inflammation-associated diseases such as cancer, atherosclerosis, diabetes and obesity, highlighting the therapeutic potential of targeting this pathway.

A438079 affects colorectal cancer cell proliferation, migration, apoptosis, and pyroptosis by inhibiting the P2X7 receptor

BACKGROUND

Our previous study identified elevated expression of the P2X7 receptor (P2X7R) in colorectal cancer (CRC) patients, suggesting the receptor is a target for predicting poor disease prognosis. A438079 is a highly selective P2X7R antagonist, however, no studies have identified A438079 effects and mechanisms toward the biological behavior of CRC cells, and its therapeutic in vivo potential in CRC nude mice.

METHODS

The CRC cell lines, HCT-116 and SW620 were treated with 10 μM A438079, after which proliferation, migration, invasion, and apoptosis were assessed. SW620 cell xenografted BALB/c nude male mice were randomly divided into control, 5-FU, and A438079 groups. Mouse weight and tumor dimensions were also measured every two days. Furthermore, the expression of apoptosis related indicators (P2X7R, Bcl-2, Bax, caspase9, cleaved caspase9, caspase3, and cleaved caspase3) and pyroptosis related indicators (NLRP3, ASC, cleaved caspase1, and interleukin (IL)-β) were investigated in vitro and in vivo.

RESULTS

A438079 inhibited HCT-116 and SW620 cell proliferation, invasion and migration, and inhibited the growth of CRC xenografts in nude mice. A438079 promoted apoptosis via the Bcl-2/caspase9/caspase3 pathway and inhibited pyroptosis through the NLRP3/caspase1 pathway by inhibiting P2X7R in vitro and in vivo.

CONCLUSIONS

We preliminarily confirmed the therapeutic potential of A438079 toward CRC, and we provide a sound theoretical basis for A438079 as a new drug for the clinical treatment of CRC.

Roles of Inflammasomes in Epstein-Barr Virus-Associated Nasopharyngeal Cancer

Epstein-Barr virus (EBV) infection is recognised as one of the causative agents in most nasopharyngeal carcinoma (NPC) cases. Expression of EBV viral antigens can induce host's antiviral immune response by activating the inflammasomes to produce pro-inflammatory cytokines, such as interleukin-1β (IL-1β) and IL-18. These cytokines are known to be detrimental to a wide range of virus-infected cells, in which they can activate an inflammatory cell death program, called pyroptosis. However, aberrant inflammasome activation and production of its downstream cytokines lead to chronic inflammation that may contribute to various diseases, including NPC. In this review, we summarise the roles of inflammasomes during viral infection, how EBV evades inflammasome-mediated immune response, and progress into tumourigenesis. The contrasting roles of inflammasomes in cancer, as well as the current therapeutic approaches used in targeting inflammasomes, are also discussed in this review. While the inflammasomes appear to have dual roles in carcinogenesis, there are still many questions that remain unanswered. In particular, the exact molecular mechanism responsible for the regulation of the inflammasomes during carcinogenesis of EBV-associated NPC has not been explored thoroughly. Furthermore, the current practical application of inflammasome inhibitors is limited to specific tumour types, hence, further studies are warranted to discover the potential of targeting the inflammasomes for the treatment of NPC.

The Hallmarks of Flavonoids in Cancer

Flavonoids represent an important group of bioactive compounds derived from plant-based foods and beverages with known biological activity in cells. From the modulation of inflammation to the inhibition of cell proliferation, flavonoids have been described as important therapeutic adjuvants against several diseases, including diabetes, arteriosclerosis, neurological disorders, and cancer. Cancer is a complex and multifactor disease that has been studied for years however, its prevention is still one of the best known and efficient factors impacting the epidemiology of the disease. In the molecular and cellular context, some of the mechanisms underlying the oncogenesis and the progression of the disease are understood, known as the hallmarks of cancer. In this text, we review important molecular signaling pathways, including inflammation, immunity, redox metabolism, cell growth, autophagy, apoptosis, and cell cycle, and analyze the known mechanisms of action of flavonoids in cancer. The current literature provides enough evidence supporting that flavonoids may be important adjuvants in cancer therapy, highlighting the importance of healthy and balanced diets to prevent the onset and progression of the disease.

Effect of P2X purinergic receptors in tumor progression and as a potential target for anti-tumor therapy

The development of tumors is a complex pathological process involving multiple factors, multiple steps, and multiple genes. Their prevention and treatment have always been a difficult problem at present. A large number of studies have proved that the tumor microenvironment plays an important role in the progression of tumors. The tumor microenvironment is the place where tumor cells depend for survival, and it plays an important role in regulating the growth, proliferation, apoptosis, migration, and invasion of tumor cells. P2X purinergic receptors, which depend on the ATP ion channel, can be activated by ATP in the tumor microenvironment, and by mediating tumor cells and related cells (such as immune cells) in the tumor microenvironment. They play an important regulatory role on the effects of the skeleton, membrane fluidity, and intracellular molecular metabolism of tumor cells. Therefore, here, we outlined the biological characteristics of P2X purinergic receptors, described the effect of tumor microenvironment on tumor progression, and discussed the effect of ATP on tumor. Moreover, we explored the role of P2X purinergic receptors in the development of tumors and anti-tumor therapy. These data indicate that P2X purinergic receptors may be used as another potential pharmacological target for tumor prevention and treatment.

Cell death in head and neck cancer pathogenesis and treatment

Many cancer therapies aim to trigger apoptosis in cancer cells. Nevertheless, the presence of oncogenic alterations in these cells and distorted composition of tumour microenvironment largely limit the clinical efficacy of this type of therapy. Luckily, scientific consensus describes about 10 different cell death subroutines with different regulatory pathways and cancer cells are probably not able to avoid all of cell death types at once. Therefore, a focused and individualised therapy is needed to address the specific advantages and disadvantages of individual tumours. Although much is known about apoptosis, therapeutic opportunities of other cell death pathways are often neglected. Molecular heterogeneity of head and neck squamous cell carcinomas (HNSCC) causing unpredictability of the clinical response represents a grave challenge for oncologists and seems to be a critical component of treatment response. The large proportion of this clinical heterogeneity probably lies in alterations of cell death pathways. How exactly cells die is very important because the predominant type of cell death can have multiple impacts on the therapeutic response as cell death itself acts as a second messenger. In this review, we discuss the different types of programmed cell death (PCD), their connection with HNSCC pathogenesis and possible therapeutic windows that result from specific sensitivity to some form of PCD in some clinically relevant subgroups of HNSCC.

Therapeutic regulation of the NLRP3 inflammasome in chronic inflammatory diseases

Inflammasomes are cytosolic pattern recognition receptors that recognize pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs) derived from invading pathogens and damaged tissues, respectively. Upon activation, the inflammasome forms a complex containing a receptor protein, an adaptor, and an effector to induce the autocleavage and activation of procaspase-1 ultimately culminating in the maturation and secretion of IL-1β and IL-18 and pyroptosis. Inflammasome activation plays an important role in host immune responses to pathogen infections and tissue repair in response to cellular damage. The NLRP3 inflammasome is a well-characterized pattern recognition receptor and is well known for its critical role in the regulation of immunity and the development and progression of various inflammatory diseases. In this review, we summarize recent efforts to develop therapeutic applications targeting the NLRP3 inflammasome to cure and prevent chronic inflammatory diseases. This review extensively discusses NLRP3 inflammasome-related diseases and current development of small molecule inhibitors providing beneficial information on the design of therapeutic strategies for NLRP3 inflammasome-related diseases. Additionally, small molecule inhibitors are classified depending on direct or indirect targeting mechanism to describe the current status of the development of pharmacological inhibitors.

Role of the NLRP3 Inflammasome: Insights Into Cancer Hallmarks

In response to a variety of stresses, mammalian cells activate the inflammasome for targeted caspase-dependent pyroptosis. The research community has recently begun to deduce that the activation of inflammasome is instigated by several known oncogenic stresses and metabolic perturbations; nevertheless, the role of inflammasomes in the context of cancer biology is less understood. In manipulating the expression of inflammasome, researchers have found that NLRP3 serves as a deterministic player in conducting tumor fate decisions. Understanding the mechanistic underpinning of pro-tumorigenic and anti-tumorigenic pathways might elucidate novel therapeutic onco-targets, thereby providing new opportunities to manipulate inflammasome in augmenting the anti-tumorigenic activity to prevent tumor expansion and achieve metastatic control. Accordingly, this review aims to decode the complexity of NLRP3, whereby summarizing and clustering findings into cancer hallmarks and tissue contexts may expedite consensus and underscore the potential of the inflammasome in drug translation.

P2X7 Variants in Oncogenesis

The P2X7 receptor for extracellular ATP is a well-established mediator of tumoral development and progression both in solid cancers and hematological malignancies. The human P2X7 gene is highly polymorphic, and several splice variants of the receptor have been identified in time. P2X7 single-nucleotide polymorphisms (SNPs) have been broadly analyzed by studies relating them to pathologies as different as infectious, inflammatory, nervous, and bone diseases, among which cancer is included. Moreover, in the last years, an increasing number of reports concentrated on P2X7 splice variants’ different roles and their implications in pathological conditions, including oncogenesis. Here, we give an overview of established and recent literature demonstrating a role for human P2X7 gene products in oncological conditions, mainly focusing on current data emerging on P2X7 isoform B and nfP2X7. We explored the role of these and other genetic variants of P2X7 in cancer insurgence, dissemination, and progression, as well as the effect of chemotherapy on isoforms expression. The described literature strongly suggests that P2X7 variants are potential new biomarkers and therapeutical targets in oncological conditions and that their study in carcinogenesis deserves to be further pursued.

P2Y receptors for extracellular nucleotides: Contributions to cancer progression and therapeutic implications

Purinergic receptors for extracellular nucleotides and nucleosides contribute to a vast array of cellular and tissue functions, including cell proliferation, intracellular and transmembrane ion flux, immunomodulation and thrombosis. In mammals, the purinergic receptor system is composed of G protein-coupled P1 receptors A₁, A_2A, A_2B and A₃ for extracellular adenosine, P2X1-7 receptors that are ATP-gated ion channels and G protein-coupled P2Y_{1,2,4,6,11,12,13 and 14} receptors for extracellular ATP, ADP, UTP, UDP and/or UDP-glucose. Recent studies have implicated specific P2Y receptor subtypes in numerous oncogenic processes, including cancer tumorigenesis, metastasis and chemotherapeutic drug resistance, where G protein-mediated signaling cascades modulate intracellular ion concentrations and activate downstream protein kinases, Src family kinases as well as numerous mitogen-activated protein kinases. We are honored to contribute to this special issue dedicated to the founder of the field of purinergic signaling, Dr. Geoffrey Burnstock, by reviewing the diverse roles of P2Y receptors in the initiation, progression and metastasis of specific cancers with an emphasis on pharmacological and genetic strategies employed to delineate cell-specific and P2Y receptor subtype-specific responses that have been investigated using in vitro and in vivo cancer models. We further highlight bioinformatic and empirical evidence on P2Y receptor expression in human clinical specimens and cover clinical perspectives where P2Y receptor-targeting interventions may have therapeutic relevance to cancer treatment.

Inflammasomes in cancer: Effect of epigenetic and autophagic modulations

Tumour-promoting inflammation is a critical hallmark in cancer development, and inflammasomes are well-known regulators of inflammatory processes within the tumour microenvironment. Different inflammasome components along with the adaptor, apoptosis-associated speck-like protein containing caspase activation and recruitment domain (ASC), and the effector, caspase-1, have a significant influence on tumorigenesis but in a tissue-specific and stage-dependent manner. The downstream products of inflammasome activation, that is the proinflammatory cytokines such as IL-1β and IL-18, regulate tissue homeostasis and induce antitumour immune responses, but in contrast, they can also favour cancer growth and proliferation by directing various oncogenic signalling pathways in cancer cells. Moreover, different epigenetic mechanisms, including DNA methylation, histone modification and noncoding RNAs, control inflammasomes and their components by regulating gene expression during cancer progression. Furthermore, autophagy, a master controller of cellular homeostasis, targets inflammasome-induced carcinogenesis by maintaining cellular homeostasis and removing potential cancer risk factors that promote inflammasome activation in support of tumorigenesis. Here, in this review, we summarize the effect of inflammasome activation in cancers and discuss the role of epigenetic and autophagic regulatory mechanisms in controlling inflammasomes. A proper understanding of the interactions among these key processes will be useful for developing novel therapeutic regimens for targeting inflammasomes in cancer.

Nod-like receptor protein 3 inflammasome in head-and-neck cancer

Activation of inflammasomes has a decisive role in host defense mechanism against pathogens and other intracellular risk factors, but recently, it has been revealed that they play a significant role in the pathogenesis of several diseases, including cancer. Nod-like receptor protein 3 (NLRP3) inflammasome, the best-studied inflammasome, has contrasting roles in cancer development and progressions. In head-and-neck cancers, the upregulated level of NLRP3 promotes tumor progression. The main objective of this review is to provide current knowledge on the involvement of NLRP3 inflammasome in head-and-neck cancers. Deeper understanding of the biology of this dynamic protein complex provides new scope for the development of more effective anticancer therapies.

The interplay between α7 nicotinic acetylcholine receptors, pannexin-1 channels and P2X7 receptors elicit exocytosis in chromaffin cells

Pannexin-1 (Panx1) forms plasma membrane channels that allow the exchange of small molecules between the intracellular and extracellular compartments, and are involved in diverse physiological and pathological responses in the nervous system. However, the signaling mechanisms that induce their opening still remain elusive. Here, we propose a new mechanism for Panx1 channel activation through a functional crosstalk with the highly Ca²⁺ permeable α7 nicotinic acetylcholine receptor (nAChR). Consistent with this hypothesis, we found that activation of α7 nAChRs induces Panx1-mediated dye uptake and ATP release in the neuroblastoma cell line SH-SY5Y-α7. Using membrane permeant Ca²⁺ chelators, total internal reflection fluorescence microscopy in SH-SY5Y-α7 cells expressing a membrane-tethered GCAMP3, and Src kinase inhibitors, we further demonstrated that Panx1 channel opening depends on Ca²⁺ signals localized in submembrane areas, as well as on Src kinases. In turn, Panx1 channels amplify cytosolic Ca²⁺ signals induced by the activation of α7 nAChRs, by a mechanism that seems to involve ATP release and P2X7 receptor activation, as hydrolysis of extracellular ATP with apyrase or blockage of P2X7 receptors with oxidized ATP significantly reduces the α7 nAChR-Ca²⁺ signal. The physiological relevance of this crosstalk was also demonstrated in neuroendocrine chromaffin cells, wherein Panx1 channels and P2X7 receptors contribute to the exocytotic release of catecholamines triggered by α7 nAChRs, as measured by amperometry. Together these findings point to a functional coupling between α7 nAChRs, Panx1 channels and P2X7 receptors with physiological relevance in neurosecretion.