NLRP3 signaling drives macrophage-induced adaptive immune suppression in pancreatic carcinoma

Igniting hope: Harnessing NLRP3 inflammasome-GSDMD-mediated pyroptosis for cancer immunotherapy

In the contemporary landscape of oncology, immunotherapy, represented by immune checkpoint blockade (ICB) therapy, stands out as a beacon of innovation in cancer treatment. Despite its promise, the therapy's progression is hindered by suboptimal clinical response rates. Addressing this challenge, the modulation of the NLRP3 inflammasome-GSDMD-mediated pyroptosis pathway holds promise as a means to augment the efficacy of immunotherapy. In the pathway, the NLRP3 inflammasome serves as a pivotal molecular sensor that responds to inflammatory stimuli within the organism. Its activation leads to the release of cytokines interleukin 1β and interleukin 18 through the cleavage of GSDMD, thereby forming membrane pores and potentially resulting in pyroptosis. This cascade of processes exerts a profound impact on tumor development and progression, with its function and expression exhibiting variability across different tumor types and developmental stages. Consequently, understanding the specific roles of the NLRP3 inflammasome and GSDMD-mediated pyroptosis in diverse tumors is imperative for comprehending tumorigenesis and crafting precise therapeutic strategies. This review aims to elucidate the structure and activation mechanisms of the NLRP3 inflammasome, as well as the induction mechanisms of GSDMD-mediated pyroptosis. Additionally, we provide a comprehensive overview of the involvement of this pathway in various cancer types and its applications in tumor immunotherapy, nanotherapy, and other fields. Emphasis is placed on the feasibility of leveraging this approach to enhance ICB therapy within the field of immunotherapy. Furthermore, we discuss the potential applications of this pathway in other immunotherapy methods, such as chimeric antigen receptor T-cell (CAR-T) therapy and tumor vaccines.

Programmed cell death disrupts inflammatory tumor microenvironment (TME) and promotes glioblastoma evolution

Glioblastoma (GBM) is the most common malignant brain tumor and has a dismal prognosis even under the current first-line treatment, with a 5-year survival rate less than 7%. Therefore, it is important to understand the mechanism of treatment resistance and develop new anti-tumor strategies. Induction of programmed cell death (PCD) has become a promising anti-tumor strategy, but its effectiveness in treating GBM remains controversial. On the one hand, PCD triggers tumor cell death and then release mediators to draw in immune cells, creating a pro-inflammatory tumor microenvironment (TME). One the other hand, mounting evidence suggests that PCD and inflammatory TME will force tumor cells to evolve under survival stress, leading to tumor recurrence. The purpose of this review is to summarize the role of PCD and inflammatory TME in the tumor evolution of GBM and promising methods to overcome tumor evolution.

Targeting regulated cell death (RCD) in hematological malignancies: Recent advances and therapeutic potential

Regulated cell death (RCD) is a form of cell death that can be regulated by numerous biomacromolecules. Accumulating evidence suggests that dysregulated expression and altered localization of related proteins in RCD promote the development of cancer. Targeting subroutines of RCD with pharmacological small-molecule compounds is becoming a promising therapeutic avenue for anti-tumor treatment, especially in hematological malignancies. Herein, we summarize the aberrant mechanisms of apoptosis, necroptosis, pyroptosis, PANoptosis, and ferroptosis in hematological malignancies. In particular, we focus on the relationship between cell death and tumorigenesis, anti-tumor immunotherapy, and drug resistance in hematological malignancies. Furthermore, we discuss the emerging therapeutic strategies targeting different RCD subroutines. This review aims to summarize the significance and potential mechanisms of RCD in hematological malignancies, along with the development and utilization of pertinent therapeutic strategies.

Cell-specific nanoengineering strategy disrupts tolerogenic signaling from myeloid-derived suppressor cells to invigorate antitumor immunity in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is characterized by intratumoral abundance of neutrophilic/polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) which inhibit T-cell function through JAK2/STAT3-regulated arginase activity. To overcome limitations of systemic inhibition of PMN-MDSCs in cancer-bearing patients-i.e., neutropenia and compensatory myelopoietic adaptations-we develop a nanoengineering strategy to target cell-specific signaling exclusively in PMN-MDSCs without provoking neutropenia. We conjugate a chemically modified small-molecule inhibitor of MDSC-surface receptor CXCR2 (AZD5069) with polyethylene glycol (PEG) and chemically graft AZD5069-PEG constructs onto amphiphilic polysaccharide derivatives to engineer CXCR2-homing nanoparticles (CXCR2-NP). Cy5.5 dye-loaded CXCR2-NP showed near-exclusive uptake in PMN-MDSCs compared with PDAC tumor-cells, cancer-associated fibroblasts, and macrophages. Encapsulation of JAK2/STAT3i Ruxolitinib (CXCR2-NP Ruxo ) resulted in more durable attenuation in STAT3-regulated arginase activity from PMN-MDSCs and induction of cytolytic T-cell activity vs. free Ruxolitinib in-vitro and in-vivo . Cell-specific delivery of payloads via CXCR2-homing immunonanoparticles represents a novel strategy to disrupt MDSC-mediated immunosuppression and invigorate antitumor immunity in PDAC.

Single-cell RNA sequencing reveals the process of CA19-9 production and dynamics of the immune microenvironment between CA19-9 (+) and CA19-9 (-) PDAC

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is one of the main types of malignant tumor of the digestive system, and patient prognosis is affected by difficulties in early diagnosis, poor treatment response, and a high postoperative recurrence rate. Carbohydrate antigen 19-9 (CA19-9) has been widely used as a biomarker for the diagnosis and postoperative follow-up of PDAC patients. Nevertheless, the production mechanism and potential role of CA19-9 in PDAC progression have not yet been elucidated.

METHODS

We performed single-cell RNA sequencing on six samples pathologically diagnosed as PDAC (three CA19-9-positive and three CA19-9-negative PDAC samples) and two paracarcinoma samples. We also downloaded and integrated PDAC samples (three each from CA19-9-positive and CA19-9-negative patients) from an online database. The dynamics of the proportion and potential function of each cell type were verified through immunofluorescence. Moreover, we built an in vitro coculture cellular model to confirm the potential function of CA19-9.

RESULTS

Three subtypes of cancer cells with a high ability to produce CA19-9 were identified by the markers TOP2A, AQP5, and MUC5AC. CA19-9 production bypass was discovered on antigen-presenting cancer-associated fibroblasts (apCAFs). Importantly, the proportion of immature ficolin-1 positive (FCN1+) macrophages was high in the CA19-9-negative group, and the proportion of mature M2-like macrophages was high in the CA19-9-positive group. High proportions of these two macrophage subtypes were associated with an unfavourable clinical prognosis. Further experiments indicated that CA19-9 could facilitate the transformation of M0 macrophages into M2 macrophages in the tumor microenvironment.

CONCLUSIONS

Our study described CA19-9 production at single-cell resolution and the dynamics of the immune atlas in CA19-9-positive and CA19-9-negative PDAC. CA19-9 could promote M2 polarization of macrophage in the pancreatic tumor microenvironment.

Comprehensive Analysis of Predictive Value and the potential therapeutic target of NLRP3 inflammasome in glioma based on tumor microenvironment

BACKGROUND

Glioma exhibits high recurrence rates and poor prognosis. The nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome plays a crucial role in inflammation. There is a lack of research exploring the NLRP3 in glioma.

METHODS

We used several databases, networks, Western blotting, multiple immunofluorescence staining to analyze the role of NLRP3 in inflammatory tumor microenvironment (TME).

RESULTS

NLRP3 is higher-expression in glioma with a low mutation load. NLRP3 expression is linked to the infiltration of immune cells, chemokines, immunomodulators, and the TME. Signaling pathways, co-expression genes and interacting proteins contribute to the up-regulation of NLRP3. Patients responding to immunotherapy positively tend to have lower NLRP3 expression relating to the overall survival based on nomogram. Sensitivity to molecular medicines is observed in relation to NLRP3.

CONCLUSION

The NLRP3 inflammasome plays a pivotal role in TME which could serve as a higher predictive value biomarker and therapeutic target for glioma treatment.

Persistent NLRP3 inflammasome activation is associated with delayed immunosuppression in septic patients

Sepsis triggers a complex response marked by the simultaneous presence of proinflammatory and immunosuppressive elements, disrupting the mechanisms intended to maintain homeostasis. While the NLRP3 inflammasome has been demonstrated to contribute to the inflammatory side, its connection with delayed sepsis-induced immunosuppression remains unexplored. The present objective was to concomitantly and prospectively assess NLRP3 activation (IL-1β, IL-18, and soluble receptors) and features of immune failure (IL-10, mHLA-DR, myeloid-derived suppressor cells) in septic patients. To validate our findings, we conducted a transcriptomic analysis of mRNA of NLRP3-related genes (IL-18R1, IL-1R2) on an additional cohort of 107 patients. Two distinct endotypes were identified. One cluster displayed moderate inflammation rapidly returning to normal values, while the other exhibited a higher inflammatory response persisting until day 28, which was associated with persistent marked immunosuppression and higher 28-d mortality. Identifying endotypes with different pro/anti-inflammatory trajectories could hold important clinical implications for the management of sepsis.

Harnessing innate immune pathways for therapeutic advancement in cancer

The innate immune pathway is receiving increasing attention in cancer therapy. This pathway is ubiquitous across various cell types, not only in innate immune cells but also in adaptive immune cells, tumor cells, and stromal cells. Agonists targeting the innate immune pathway have shown profound changes in the tumor microenvironment (TME) and improved tumor prognosis in preclinical studies. However, to date, the clinical success of drugs targeting the innate immune pathway remains limited. Interestingly, recent studies have shown that activation of the innate immune pathway can paradoxically promote tumor progression. The uncertainty surrounding the therapeutic effectiveness of targeted drugs for the innate immune pathway is a critical issue that needs immediate investigation. In this review, we observe that the role of the innate immune pathway demonstrates heterogeneity, linked to the tumor development stage, pathway status, and specific cell types. We propose that within the TME, the innate immune pathway exhibits multidimensional diversity. This diversity is fundamentally rooted in cellular heterogeneity and is manifested as a variety of signaling networks. The pro-tumor effect of innate immune pathway activation essentially reflects the suppression of classical pathways and the activation of potential pro-tumor alternative pathways. Refining our understanding of the tumor's innate immune pathway network and employing appropriate targeting strategies can enhance our ability to harness the anti-tumor potential of the innate immune pathway and ultimately bridge the gap from preclinical to clinical application.

Analysis of single nuclear chromatin accessibility reveals unique myeloid populations in human pancreatic ductal adenocarcinoma

BACKGROUND

A better understanding of the pancreatic ductal adenocarcinoma (PDAC) immune microenvironment is critical to developing new treatments and improving outcomes. Myeloid cells are of particular importance for PDAC progression; however, the presence of heterogenous subsets with different ontogeny and impact, along with some fluidity between them, (infiltrating monocytes vs. tissue-resident macrophages; M1 vs. M2) makes characterisation of myeloid populations challenging. Recent advances in single cell sequencing technology provide tools for characterisation of immune cell infiltrates, and open chromatin provides source and function data for myeloid cells to assist in more comprehensive characterisation. Thus, we explore single nuclear assay for transposase accessible chromatin (ATAC) sequencing (snATAC-Seq), a method to analyse open gene promoters and transcription factor binding, as an important means for discerning the myeloid composition in human PDAC tumours.

METHODS

Frozen pancreatic tissues (benign or PDAC) were prepared for snATAC-Seq using 10× Chromium technology. Signac was used for preliminary analysis, clustering and differentially accessible chromatin region identification. The genes annotated in promoter regions were used for Gene Ontology (GO) enrichment and cell type annotation. Gene signatures were used for survival analysis with The Cancer Genome Atlas (TCGA)-pancreatic adenocarcinoma (PAAD) dataset.

RESULTS

Myeloid cell transcription factor activities were higher in tumour than benign pancreatic samples, enabling us to further stratify tumour myeloid populations. Subcluster analysis revealed eight distinct myeloid populations. GO enrichment demonstrated unique functions for myeloid populations, including interleukin-1b signalling (recruited monocytes) and intracellular protein transport (dendritic cells). The identified gene signature for dendritic cells influenced survival (hazard ratio = .63, p = .03) in the TCGA-PAAD dataset, which was unique to PDAC.

CONCLUSIONS

These data suggest snATAC-Seq as a method for analysis of frozen human pancreatic tissues to distinguish myeloid populations. An improved understanding of myeloid cell heterogeneity and function is important for developing new treatment targets in PDAC.

The promising role of tumor-associated macrophages in the treatment of cancer

Macrophages are important components of the immune system. Mature macrophages can be recruited to tumor microenvironment that affect tumor cell proliferation, invasion and metastasis, extracellular matrix remodeling, immune suppression, as well as chemotherapy resistance. Classically activated type I macrophages (M1) exhibited marked tumor killing and phagocytosis. Therefore, using macrophages for adoptive cell therapy has attracted attention and become one of the most effective strategies for cancer treatment. Through cytokines and/or chemokines, macrophage can inhibit myeloid cells recruitment, and activate anti-tumor and immune killing functions. Applying macrophages for anti-tumor delivery is one of the most promising approaches for cancer therapy. This review article introduces the role of macrophages in tumor development and drug resistance, and the possible clinical application of targeting macrophages for overcoming drug resistance and enhancing cancer therapeutics, as well as its challenges.

Involvement of the Gut Microbiome in the Local and Systemic Immune Response to Pancreatic Ductal Adenocarcinoma

The systemic and local immunosuppression exhibited by pancreatic ductal adenocarcinoma (PDAC) contributes significantly to its aggressive nature. There is a need for a greater understanding of the mechanisms behind this profound immune evasion, which makes it one of the most challenging malignancies to treat and thus one of the leading causes of cancer death worldwide. The gut microbiome is now thought to be the largest immune organ in the body and has been shown to play an important role in multiple immune-mediated diseases. By summarizing the current literature, this review examines the mechanisms by which the gut microbiome may modulate the immune response to PDAC. Evidence suggests that the gut microbiome can alter immune cell populations both in the peripheral blood and within the tumour itself in PDAC patients. In addition, evidence suggests that the gut microbiome influences the composition of the PDAC tumour microbiome, which exerts a local effect on PDAC tumour immune infiltration. Put together, this promotes the gut microbiome as a promising route for future therapies to improve immune responses in PDAC patients.

Unraveling the Role of the NLRP3 Inflammasome in Lymphoma: Implications in Pathogenesis and Therapeutic Strategies

Inflammasomes are multimeric protein complexes, sensors of intracellular danger signals, and crucial components of the innate immune system, with the NLRP3 inflammasome being the best characterized among them. The increasing scientific interest in the mechanisms interconnecting inflammation and tumorigenesis has led to the study of the NLRP3 inflammasome in the setting of various neoplasms. Despite a plethora of data regarding solid tumors, NLRP3 inflammasome's implication in the pathogenesis of hematological malignancies only recently gained attention. In this review, we investigate its role in normal lymphopoiesis and lymphomagenesis. Considering that lymphomas comprise a heterogeneous group of hematologic neoplasms, both tumor-promoting and tumor-suppressing properties were attributed to the NLRP3 inflammasome, affecting neoplastic cells and immune cells in the tumor microenvironment. NLRP3 inflammasome-related proteins were associated with disease characteristics, response to treatment, and prognosis. Few studies assess the efficacy of NLRP3 inflammasome therapeutic targeting with encouraging results, though most are still at the preclinical level. Further understanding of the mechanisms regulating NLRP3 inflammasome activation during lymphoma development and progression can contribute to the investigation of novel treatment approaches to cover unmet needs in lymphoma therapeutics.

New prospects of cancer therapy based on pyroptosis and pyroptosis inducers

Pyroptosis is a gasdermin-mediated programmed cell death (PCD) pathway. It differs from apoptosis because of the secretion of inflammatory molecules. Pyroptosis is closely associated with various malignant tumors. Recent studies have demonstrated that pyroptosis can either inhibit or promote the development of malignant tumors, depending on the cell type (immune or cancer cells) and duration and severity of the process. This review summarizes the molecular mechanisms of pyroptosis, its relationship with malignancies, and focuses on current pyroptosis inducers and their significance in cancer treatment. The molecules involved in the pyroptosis signaling pathway could serve as therapeutic targets for the development of novel drugs for cancer therapy. In addition, we analyzed the potential of combining pyroptosis with conventional anticancer techniques as a promising strategy for cancer treatment.

The effects of NOD-like receptors on adaptive immune responses

It has long been appreciated that cues from the innate immune system orchestrate downstream adaptive immune responses. Although previous work has focused on the roles of Toll-like receptors in this regard, relatively little is known about how Nod-like receptors instruct adaptive immunity. Here we review the functions of different members of the Nod-like receptor family in orchestrating effector and anamnestic adaptive immune responses. In particular, we address the ways in which inflammasome and non-inflammasome members of this family affect adaptive immunity under various infectious and environmental contexts. Furthermore, we identify several key mechanistic questions that studies in this field have left unaddressed. Our aim is to provide a framework through which immunologists in the adaptive immune field may view their questions through an innate-immune lens and vice-versa.

Mechanisms and effects of NLRP3 in digestive cancers

Inflammasomes are thought to be important mediators of host defense against microbial pathogens and maintenance of gastrointestinal tract homeostasis. They can modulate caspase-1 to promote IL-18 and IL-1β secretion and promote phagocytosis induced by bacterial pathogens. NLRP3 is an inflammasome comprising a multiprotein complex assembled by pattern recognition receptors in the cell cytoplasm. It is a crucial component of the innate immune system. Dysregulation of NLRP3 may contribute to inflammatory diseases and intestinal cancers. Recent research suggests that NLRP3 plays an essential role in tumor development; therefore, intensive study of its mechanism is warranted as it could play a key role in the treatment of digestive system tumors. In this review, we discuss the mechanism and role of NLRP3 in tumors of the digestive system and response strategies to modulate NLRP3 for potential use in tumor treatment.

Determinants for Antitumor and Protumor Effects of Programmed Cell Death

Cytotoxic anticancer therapies activate programmed cell death in the context of underlying stress and inflammatory signaling to elicit the emission of danger signals, cytokines, and chemokines. In a concerted manner, these immunomodulatory secretomes stimulate antigen presentation and T cell-mediated anticancer immune responses. In some instances, cell death-associated secretomes attract immunosuppressive cells to promote tumor progression. As it stands, cancer cell death-induced changes in the tumor microenvironment that contribute to antitumor or protumor effects remain largely unknown. This is complicated to examine because cell death is often subverted by tumors to circumvent natural, and therapy-induced, immunosurveillance. Here, we provide insights into important but understudied aspects of assessing the contribution of cell death to tumor elimination or cancer progression, including the role of tumor-associated genetics, epigenetics, and oncogenic factors in subverting immunogenic cell death. This perspective will also provide insights on how future studies may address the complex antitumor and protumor immunologic effects of cell death, while accounting for variations in tumor genetics and underlying microenvironment.

The BCL-2 inhibitor APG-2575 resets tumor-associated macrophages toward the M1 phenotype, promoting a favorable response to anti-PD-1 therapy via NLRP3 activation

The main challenges in the use of immune checkpoint inhibitors (ICIs) are ascribed to the immunosuppressive tumor microenvironment and the lack of sufficient infiltration of activated CD8+ T cells. Transforming the tumor microenvironment (TME) from "cold" to "hot" and thus more likely to potentiate the effects of ICIs is a promising strategy for cancer treatment. We found that the selective BCL-2 inhibitor APG-2575 can enhance the antitumor efficacy of anti-PD-1 therapy in syngeneic and humanized CD34+ mouse models. Using single-cell RNA sequencing, we found that APG-2575 polarized M2-like immunosuppressive macrophages toward the M1-like immunostimulatory phenotype with increased CCL5 and CXCL10 secretion, restoring T-cell function and promoting a favorable immunotherapy response. Mechanistically, we demonstrated that APG-2575 directly binds to NF-κB p65 to activate NLRP3 signaling, thereby mediating macrophage repolarization and the activation of proinflammatory caspases and subsequently increasing CCL5 and CXCL10 chemokine production. As a result, APG-2575-induced macrophage repolarization could remodel the tumor immune microenvironment, thus improving tumor immunosuppression and further enhancing antitumor T-cell immunity. Multiplex immunohistochemistry confirmed that patients with better immunotherapeutic efficacy had higher CD86, p-NF-κB p65 and NLRP3 levels, accompanied by lower CD206 expression on macrophages. Collectively, these data provide evidence that further study on APG-2575 in combination with immunotherapy for tumor treatment is required.

Decreased survival in patients with pancreatic cancer may be associated with an increase in histopathological expression of inflammasome marker NLRP3

Pancreatic cancer is a malignant neoplasm that, despite its low frequency, has a 5-year survival rate of less than 10%. The study of different histopathological markers has allowed a better understanding of the onset and development of this type of tumor as well as facilitating an approach to clinical variables based on their diagnostic, prognostic, and predictive value. In this sense, the NLRP3 protein of the inflammasome has been shown to be a component of great relevance in the initiation and progression of pancreatic cancer, although the value of this biomarker in patients has not yet been clarified. In this study, we selected 41 patients with pancreatic cancer and followed them for 60 months (5 years), evaluating their NLRP3 expression using immunohistochemical techniques. Furthermore, by performing Kaplan-Meier curves, we evaluated the survival of these patients in relation to their NLRP3 expression. Our results show that a significant percentage of our cohort had high expression of this component (90.74%) and that there is an inverse relationship between the expression of NLRP3 and patient survival. High levels of NLRP3 expression are related to lower survival and worse prognosis in these patients, possibly due to an ineffective immune system response and increased tumor-promoted inflammation. Future studies should be aimed at confirming these results in larger groups and evaluating various clinical strategies based on this knowledge.

The entanglement of DNA damage and pattern recognition receptor signaling

Cells are under constant pressure to suppress DNA damage originating from both exogenous and endogenous sources. Cellular responses to DNA damage help to prevent mutagenesis and cell death that arises when DNA damage is either left unrepaired or repaired inaccurately. During the "acute phase" of DNA damage signaling, lesions are recognized, processed, and repaired to restore the primary DNA sequence whilst cell cycle checkpoints delay mitotic progression, cell death and the propagation of errors to daughter cells. Increasingly, there is recognition of a "chronic phase" of DNA damage signaling, exemplified by the secretion of dozens of cytokines days after the inciting damage event. In this review, we focus on the cellular origin of these chronic responses, the molecular pathways that control them and the increasing appreciation for the interconnection between acute and chronic DNA damage responses.

Harnessing the innate immune system by revolutionizing macrophage-mediated cancer immunotherapy

Immunotherapy is a promising and safer alternative to conventional cancer therapies. It involves adaptive T-cell therapy, cancer vaccines, monoclonal antibodies, immune checkpoint blockade (ICB), and chimeric antigen receptor (CAR) based therapies. However, most of these modalities encounter restrictions in solid tumours owing to a dense, highly hypoxic and immune-suppressive microenvironment as well as the heterogeneity of tumour antigens. The elevated intra-tumoural pressure and mutational rates within fastgrowing solid tumours present challenges in efficient drug targeting and delivery. The tumour microenvironment is a dynamic niche infiltrated by a variety of immune cells, most of which are macrophages. Since they form a part of the innate immune system, targeting macrophages has become a plausible immunotherapeutic approach. In this review, we discuss several versatile approaches (both at pre-clinical and clinical stages) such as the direct killing of tumour-associated macrophages, reprogramming pro-tumour macrophages to anti-tumour phenotypes, inhibition of macrophage recruitment into the tumour microenvironment, novel CAR macrophages, and genetically engineered macrophages that have been devised thus far. These strategies comprise a strong and adaptable macrophage-toolkit in the ongoing fight against cancer and by understanding their significance, we may unlock the full potential of these immune cells in cancer therapy.

Lipopolysaccharide (LPS) stimulation of Pancreatic Ductal Adenocarcinoma (PDAC) and macrophages activates the NLRP3 inflammasome that influences the levels of pro-inflammatory cytokines in a co-culture model

Modified macrophages, tumor-associated macrophages (TAMs), are key contributors to the survival, growth, and metastatic behavior of pancreatic ductal adenocarcinoma (PDAC) cells. Central to the role of inflammation and TAMs lies the NLRP3 inflammasome. This study investigated the effects of LPS-stimulated inflammation on cell proliferation, levels of pro-inflammatory cytokines, and the NLRP3 inflammasome pathway in a co-culture model using PDAC cells and macrophages in the presence or absence of MCC950, a NLRP3-specific inhibitor. The effects of LPS-stimulated inflammation were tested on two PDAC cell lines (Panc 10.05 and SW 1990) co-cultured with RAW 264.7 macrophages. Cell proliferation was determined using the MTT assay. Levels of pro-inflammatory cytokines, IL-1β, and TNF-α were determined by ELISA. Western blot analyses were used to examine the expression of NLRP3 in both PDAC cells and macrophages. The co-culture and interaction between PDAC cell lines and macrophages led to pro-inflammatory microenvironment under LPS stimulation as evidenced by high levels of secreted IL-1β and TNF-α. Inhibition of the NLRP3 inflammasome by MCC950 counteracted the effects of LPS stimulation on the regulation of the NLRP3 inflammasome and pro-inflammatory cytokines in PDAC and macrophages. However, MCC950 differentially modified the viability of the metastatic vs primary PDAC cell lines. LPS stimulation increased PDAC cell viability by regulating the NLRP3 inflammasome and pro-inflammatory cytokines in the tumor microenvironment of PDAC cells/macrophages co-cultures. The specific inhibition of the NLRP inflammasome by MCC950 effectively counteracted the LPS-stimulated inflammation.

Interplay between inflammasomes and PD-1/PD-L1 and their implications in cancer immunotherapy

The inflammasomes play crucial roles in inflammation and cancer development, while the PD-1/PD-L1 pathway is critical for immune suppression in the tumor microenvironment (TME). Recent research indicates a reciprocal regulatory relationship between inflammasomes and PD-1/PD-L1 signaling in cancer development and PD-1 blockade treatment. By activating in diverse cells in tumor tissues, inflammasome upregulates PD-L1 level in the TME. Moreover, the regulation of PD-1/PD-L1 activity by inflammasome activation involves natural killer cells, tumor-associated macrophages and myeloid-derived suppressor cells. Conversely, PD-1 blockade can activate the inflammasome, potentially influencing treatment outcomes. The interplay between inflammasomes and PD-1/PD-L1 has profound and intricate effects on cancer development and treatment. In this review, we discuss the crosstalk between inflammasomes and PD-1/PD-L1 in cancers, exploring their implications for tumorigenesis, metastasis and immune checkpoint inhibitor (ICI) resistance. The combined therapeutic strategies targeting both inflammasomes and checkpoint molecules hold promising potential as treatments for cancer.

Astaxanthin alleviates fine particulate matter (PM2.5)-induced lung injury in rats by suppressing ferroptosis and apoptosis

Objectives: Fine particulate matter (PM2.5), a small molecule particulate pollutant, can reach the lungs via respiration and cause lung damage. Currently, effective strategies and measures are lacking to prevent and treat the pulmonary toxicity of PM2.5. Astaxanthin (ASX), a natural xanthophyll carotenoid, has attracted attention due to its unique biological activity. Our research aims to probe into the prevention and treatment of ASX on PM2.5-induced lung injury and clarify its potential mechanism. Methods: Sprague-Dawley (SD) rats were given olive oil and different concentrations of ASX orally daily for 21 days. PM2.5 suspension was instilled into the trachea of rats every two days for one week to successfully develop the PM2.5 exposure model in the PM2.5-exposed and ASX-treated groups of rats. The bronchoalveolar lavage fluid (BALF) was collected, and the content of lung injury-related markers was detected. Histomorphological changes and expression of markers associated with oxidative stress, inflammation, iron death, and apoptosis were detected in lung tissue. Results: PM2.5 exposure can cause changes in lung histochemistry and increase the expression levels of TP, AKP, ALB, and LDH in the BALF. Simultaneously, inflammatory responses and oxidative stress were promoted in rat lung tissue after exposure to particulate matter. Additionally, ASX preconditioning can alleviate histomorphological changes, oxidative stress, and inflammation caused by PM2.5 and reduce PM2.5-related ferroptosis and apoptosis. Conclusion: ASX preconditioning can alleviate lung injury after PM2.5 exposure by inhibiting ferroptosis and apoptosis.

Inflammasomes cross-talk with lymphocytes to connect the innate and adaptive immune response

BACKGROUND

Innate and adaptive immunity are two different parts of the immune system that have different characteristics and work together to provide immune protection. Inflammasomes are a major part of the innate immune system that are expressed widely in myeloid cells and are responsible for inflammatory responses. Recent studies have shown that inflammasomes are also expressed and activated in lymphocytes, especially in T and B cells, to regulate the adaptive immune response. Activation of inflammasomes is also under the control of lymphocytes. Therefore, we propose that inflammasomes act as a bridge and they provide crosstalk between the innate and adaptive immune systems to obtain a fine balance in immune responses.

AIM OF REVIEW

This review systematially summarizes the interaction between inflammasomes and lymphocytes and describes the crosstalk between the innate and adaptive immune systems induced by inflammasomes, with the aim of providing new directions and important areas for further research.

KEY SCIENTIFIC CONCEPTS OF REVIEW

When considering the novel function of inflammasomes in various lymphocytes, attention should be given to the activity of specific inflammasomes in studies of lymphocyte function. Moreover, research on the function of various inflammasomes in lymphocytes will help advance knowledge on the mechanisms and treatment of various diseases, including autoimmune diseases and tumors. In addition, when studying inflammatory responses, inflammasomes in both lymphocytes and myeloid cells need to be considered.

NLRP3/IL-1β induced myeloid-derived suppressor cells recruitment and PD-L1 upregulation promotes oxaliplatin resistance of hepatocellular carcinoma

Oxaliplatin is commonly used as the first-line chemotherapeutic agent for advanced hepatocellular carcinoma (HCC). Unfortunately, the acquired resistance, limits the effectiveness of oxaliplatin and the underlying mechanisms remain unknown. Therefore, we explored the role of NOD-like receptor protein 3 (NLRP3)/IL-1β in mediating oxaliplatin resistance in HCC. We observed that NLRP3/IL-1β expression was much higher in oxaliplatin-resistant HCC cells. To further understand its impact on drug resistance, we knocked down NLRP3 and observed that it sensitized HCC cells to the growth-inhibitory effects of oxaliplatin and induced cell apoptosis. NLRP3/IL-1β overexpressing tumor cells also attracted polymorphonuclear myeloid-derived suppressor cells. Using mouse models, we demonstrated that NLRP3/IL-1β inhibition by short hairpin RNA or MCC950 effectively overcame oxaliplatin resistance. Furthermore, NLRP3/IL-1β inhibition resulted in reduced expression of PD-L1. We also found that PD-L1 antibody combined with NLRP3/IL-1β blockade displayed significant antitumor effect in HCC. Overall, our study provides compelling evidence supporting the essential role of NLRP3/IL-1β in conferring resistance to oxaliplatin and reshaping the immunosuppressive microenvironment in HCC. Targeting NLRP3/IL-1β presents a potential therapeutic target for overcoming oxaliplatin resistance and reshaping microenvironment of HCC.

Canonical and non-canonical functions of NLRP3

BACKGROUND

Since its discovery, NLRP3 is almost never separated from its major role in the protein complex it forms with ASC, NEK7 and Caspase-1, the inflammasome. This key component of the innate immune response mediates the secretion of proinflammatory cytokines IL-1β and IL-18 involved in immune response to microbial infection and cellular damage. However, NLRP3 has also other functions that do not involve the inflammasome assembly nor the innate immune response. These non-canonical functions have been poorly studied. Nevertheless, NLRP3 is associated with different kind of diseases probably through its inflammasome dependent function as through its inflammasome independent functions.

AIM OF THE REVIEW

The study and understanding of the canonical and non-canonical functions of NLRP3 can help to better understand its involvement in various pathologies. In parallel, the description of the mechanisms of action and regulation of its various functions, can allow the identification of new therapeutic strategies.

KEY SCIENTIFIC CONCEPTS OF THE REVIEW

NLRP3 functions have mainly been studied in the context of the inflammasome, in myeloid cells and in totally deficient transgenic mice. However, for several year, the work of different teams has proven that NLRP3 is also expressed in other cell types where it has functions that are independent of the inflammasome. If these studies suggest that NLRP3 could play different roles in the cytoplasm or the nucleus of the cells, the mechanisms underlying NLRP3 non-canonical functions remain unclear. This is why we propose in this review an inventory of the canonical and non-canonical functions of NLRP3 and their impact in different pathologies.

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.

Impact of NLRP3 gene polymorphisms (rs10754558 and rs10733113) on HPV infection and cervical cancer in southern Chinese population

OBJECTIVE

Mutations in the NLRP3gene have previously been linked to certain forms of cancer, but there have not been any specific studies examining the association between NLRP3 polymorphisms and cervical cancer (CC). This study was therefore designed to investigate the effect of NLRP3 gene polymorphisms on HPV infection and cervical cancer in southern Chinese population.

METHODS

Multiplex PCR and next-generation sequencing approaches were used to assess the NLRP3 rs10754558 and rs10733113 polymorphisms in 404 cervical lesion patients, including 227 diagnosed with CC and 177 diagnosed with cervical intraepithelial neoplasia(CIN), with 419 healthy female controls being included for comparison. Correlations between the rs10754558 and rs10733113 genotypes and alleles in these patients and CC and CIN were then analyzed.

RESULTS

No correlations were found between NLRP3 rs10754558 and rs10733113 and human papillomavirus(HPV) infection status. Relative to the healthy control group, the NLRP3 rs10754558 GG genotype, CG + GG genotype, and G allele frequencies were significantly increased among patients with cervical lesions (CC and CIN) (OR = 1.815,P = 0.013;OR = 1.383, P = 0.026; OR = 1.284, P = 0.014,respectively), whereas no such differences were observed for rs10733113. A higher cervical lesion risk was detected for patients over the age of 45 exhibiting the rs10754558 GG genotype (OR = 1.848, P = 0.040). Additionally, the risk of CC was elevated in patients with the rs10754558 GG genotype or the G allele relative to patients with the CC genotype or the C allele(OR = 1.830, P = 0.029; OR = 1.281, P = 0.039). The rs10733113 genotypes or alleles were not significantly associated with CC risk (P > 0.05). No association between rs10754558 and rs10733113 genotypes and CC patient clinicopathological features were observed (P > 0.05). Serum NLRP3, IL-1β, and IL-18 levels were significantly elevated in CC patients relative to healthy controls(P < 0.05). Relative to the CC genotype, CC patients harboring the rs10754558 GG genotype exhibited significantly elevated IL-1β and IL-18 levels(P < 0.05).

CONCLUSION

The rs10754558 polymorphism in the NLRP3 gene may contribute to an elevated risk of CC, although it is not significantly correlated with HPV infection and CC progression.

Systems Biology and Cytokines Potential Role in Lung Cancer Immunotherapy Targeting Autophagic Axis

Lung cancer accounts for the highest number of deaths among men and women worldwide. Although extensive therapies, either alone or in conjunction with some specific drugs, continue to be the principal regimen for evolving lung cancer, significant improvements are still needed to understand the inherent biology behind progressive inflammation and its detection. Unfortunately, despite every advancement in its treatment, lung cancer patients display different growth mechanisms and continue to die at significant rates. Autophagy, which is a physiological defense mechanism, serves to meet the energy demands of nutrient-deprived cancer cells and sustain the tumor cells under stressed conditions. In contrast, autophagy is believed to play a dual role during different stages of tumorigenesis. During early stages, it acts as a tumor suppressor, degrading oncogenic proteins; however, during later stages, autophagy supports tumor cell survival by minimizing stress in the tumor microenvironment. The pivotal role of the IL6-IL17-IL23 signaling axis has been observed to trigger autophagic events in lung cancer patients. Since the obvious roles of autophagy are a result of different immune signaling cascades, systems biology can be an effective tool to understand these interconnections and enhance cancer treatment and immunotherapy. In this review, we focus on how systems biology can be exploited to target autophagic processes that resolve inflammatory responses and contribute to better treatment in carcinogenesis.

Potential effects of gut microbiota on host cancers: focus on immunity, DNA damage, cellular pathways, and anticancer therapy

The symbiotic bacteria that live in the human gut and the metabolites they produce have long influenced local and systemic physiological and pathological processes of the host. The gut microbiota are increasingly being recognized for its impact on a range of human diseases, including cancer, it may play a key role in the occurrence, progression, treatment, and prognosis of many types of cancer. Understanding the functional role of the gut microbiota in cancer is crucial for the development of the era of personalized medicine. Here, we review recent advances in research and summarize the important associations and clear experimental evidence for the role of the gut microbiota in a variety of human cancers, focus on the application and possible challenges associated with the gut microbiota in antitumor therapy. In conclusion, our research demonstrated the multifaceted mechanisms of gut microbiota affecting human cancer and provides directions and ideas for future clinical research.

Pancreatic Ductal Adenocarcinoma Cells Regulate NLRP3 Activation to Generate a Tolerogenic Microenvironment

Defining feature of pancreatic ductal adenocarcinoma (PDAC) that participates in the high mortality rate and drug resistance is the immune-tolerant microenvironment which enables tumors to progress unabated by adaptive immunity. In this study, we report that PDAC cells release CSF-1 to induce nucleotide-binding domain, leucine-rich containing family, pyrin domain-containing-3 (NLRP3) activation in myeloid cells. Increased NLRP3 expression was found in the pancreas of patients with PDAC when compared with normal pancreas which correlated with the formation of the NLRP3 inflammasome. Using human primary cells and an orthotopic PDAC mouse model, we show that NLRP3 activation is responsible for the maturation and release of the inflammatory cytokine IL1β which selectively drives Th2-type inflammation via COX2/PGE2 induction. As a result of this inflammation, primary tumors were characterized by reduced cytotoxic CD8+ T-cell activation and increased tumor expansion. Genetic deletion and pharmacologic inhibition of NLRP3 enabled the development of Th1 immunity, increased intratumoral levels of IL2, CD8+ T cell–mediated tumor suppression, and ultimately limited tumor growth. In addition, we observed that NLRP3 inhibition in combination with gemcitabine significantly increased the efficacy of the chemotherapy. In conclusion, this study provides a mechanism by which tumor-mediated NLRP3 activation exploits a distinct adaptive immunity response that facilitates tumor escape and progression. Considering the ability to block NLRP3 activity with safe and small orally active molecules, this protein represents a new promising target to improve the limited therapeutic options in PDAC.

SIGNIFICANT

This study provides novel molecular insights on how PDAC cells exploit NLRP3 activation to suppress CD8 T-cell activation. From a translational perspective, we demonstrate that the combination of gemcitabine with the orally active NLRP3 inhibitor OLT1177 increases the efficacy of monotherapy.

Anticancer mechanisms on pyroptosis induced by Oridonin: New potential targeted therapeutic strategies

Pyroptosis is a type of inflammatory cell death that is triggered by the formation of pores on the cell membrane by gasdermin (GSDM) family proteins. This process activates inflammasomes and leads to the maturation and release of proinflammatory cytokines such as interleukin-1β (IL-1β) and interleukin-18 (IL-18). Pyroptosis, a form of programmed cell death, has been found to be associated with various biomolecules such as caspases, granzymes, non-coding RNA (lncRNA), reactive oxygen species (ROS), and NOD-like receptor protein 3 (NLRP3). These biomolecules have been shown to play a dual role in cancer by affecting cell proliferation, metastasis, and the tumor microenvironment (TME), resulting in both tumor promotion and anti-tumor effects. Recent studies have found that Oridonin (Ori) has anti-tumor effects by regulating pyroptosis through various pathways. Ori can inhibit pyroptosis by inhibiting caspase-1, which is responsible for activating pyroptosis of the canonical pathway. Additionally, Ori can inhibit pyroptosis by inhibiting NLRP3, which is responsible for activating pyroptosis of the noncanonical pathway. Interestingly, Ori can also activate pyroptosis by activating caspase-3 and caspase-8, which are responsible for activating pyroptosis of the emerging pathway; Ori has been found to be effective in inhibiting pyroptosis by blocking the action of perforin, which is responsible for facilitating the entry of granzyme into cells and activating pyroptosis. Additionally, Ori plays a crucial role in regulating pyroptosis by promoting the accumulation of ROS while inhibiting the ncRNA and NLRP3 pathways. It is worth noting that all of these pathways ultimately regulate pyroptosis by influencing the cleavage of GSDM, which is a key factor in the process. These studies concludes that Ori has extensive anti-cancer effects that are related to its potential regulatory function on pyroptosis. The paper summarizes several potential ways in which Ori participates in the regulation of pyroptosis, providing a reference for further study on the relationship between Ori, pyroptosis, and cancer.

Integration of Single-Cell RNA Sequencing and Bulk RNA Sequencing Reveals That TAM2-Driven Genes Affect Immunotherapeutic Response and Prognosis in Pancreatic Cancer

Tumor-associated macrophages M2 (TAM2), which are highly prevalent infiltrating immune cells in the stroma of pancreatic cancer (PC), have been found to induce an immunosuppressive tumor microenvironment, thus enhancing tumor initiation and progression. However, the immune therapy response and prognostic significance of regulatory genes associated with TAM2 in PC are currently unknown. Based on TCGA transcriptomic data and single-cell sequencing data from the GEO database, we identified TAM2-driven genes using the WGCNA algorithm. Molecular subtypes based on TAM2-driven genes were clustered using the ConsensusClusterPlus algorithm. The study constructed a prognostic model based on TAM2-driven genes through Lasso-COX regression analysis. A total of 178 samples obtained by accessing TCGA were accurately categorized into two molecular subtypes, including the high-TAM2 infiltration (HMI) cluster and the low-TAM2 infiltration (LMI) cluster. The HMI cluster exhibits a poor prognosis, a malignant tumor phenotype, immune-suppressive immune cell infiltration, resistance to immunotherapy, and a high number of genetic mutations, while the LMI cluster is the opposite. The prognostic model composed of six hub genes from TAM2-driven genes exhibits a high degree of accuracy in predicting the prognosis of patients with PC and serves as an independent risk factor. The induction of TAM2 was employed as a means of verifying these six gene expressions, revealing the significant up-regulation of BCAT1, BST2, and MERTK in TAM2 cells. In summary, the immunophenotype and prognostic model based on TAM2-driven genes offers a foundation for the clinical management of PC. The core TAM2-driven genes, including BCAT1, BST2, and MERTK, are involved in regulating tumor progression and TAM2 polarization, which are potential targets for PC therapy.

Molecular mechanisms of pyroptosis and its role in anti-tumor immunity

Pyroptosis is a form of cell death that is characterized by the destruction of the cell, and it has implications in both the immune system and cancer immunotherapy. The gasdermin family is responsible for the activation of pyroptosis, which involves the formation of pores in the cellular membrane that permit the discharge of inflammatory factors. The inflammasome response is a powerful mechanism that helps to eliminate bacteria and cancer cells when cellular damage occurs. As tumor cells become more resilient to apoptosis, other treatments for cancer are becoming more popular. It is essential to gain a thorough understanding of pyroptosis in order to use it in cancer treatment, considering the intricate association between pyroptosis and the immune system's defensive reaction against tumors. This review offers an overview of the mechanisms of pyroptosis, the relationship between the gasdermin family and pyroptosis, and the interplay between pyroptosis and anti-tumor immunity. In addition, the potential implications of pyroptosis in cancer immunotherapy are discussed. Additionally, we explore future research possibilities and introduce a novel approach to tumor treatment.

Defining the spatial distribution of extracellular adenosine revealed a myeloid-dependent immunosuppressive microenvironment in pancreatic ductal adenocarcinoma

BACKGROUND

The prognosis for patients with pancreatic ductal adenocarcinoma (PDAC) remains extremely poor. It has been suggested that the adenosine pathway contributes to the ability of PDAC to evade the immune system and hence, its resistance to immuno-oncology therapies (IOT), by generating extracellular adenosine (eAdo).

METHODS

Using genetically engineered allograft models of PDAC in syngeneic mice with defined and different immune infiltration and response to IOT and autochthonous tumors in KPC mice we investigated the impact of the adenosine pathway on the PDAC tumor microenvironment (TME). Flow cytometry and imaging mass cytometry (IMC) were used to characterize the subpopulation frequency and spatial distribution of tumor-infiltrating immune cells. Mass spectrometry imaging (MSI) was used to visualize adenosine compartmentalization in the PDAC tumors. RNA sequencing was used to evaluate the influence of the adenosine pathway on the shaping of the immune milieu and correlate our findings to published data sets in human PDAC.

RESULTS

We demonstrated high expression of adenosine pathway components in tumor-infiltrating immune cells (particularly myeloid populations) in the murine models. MSI demonstrated that extracellular adenosine distribution is heterogeneous in tumors, with high concentrations in peri-necrotic, hypoxic regions, associated with rich myeloid infiltration, demonstrated using IMC. Protumorigenic M2 macrophages express high levels of the Adora2a receptor; particularly in the IOT resistant model. Blocking the in vivo formation and function of eAdo (Adoi), using a combination of anti-CD73 antibody and an Adora2a inhibitor slowed tumor growth and reduced metastatic burden. Additionally, blocking the adenosine pathway improved the efficacy of combinations of cytotoxic agents or immunotherapy. Adoi remodeled the TME, by reducing the infiltration of M2 macrophages and regulatory T cells. RNA sequencing analysis showed that genes related to immune modulation, hypoxia and tumor stroma were downregulated following Adoi and a specific adenosine signature derived from this is associated with a poorer prognosis in patients with PDAC.

CONCLUSIONS

The formation of eAdo promotes the development of the immunosuppressive TME in PDAC, contributing to its resistance to conventional and novel therapies. Therefore, inhibition of the adenosine pathway may represent a strategy to modulate the PDAC immune milieu and improve therapy response in patients with PDAC.

NR1D1 deficiency in the tumor microenvironment promotes lung tumor development by activating the NLRP3 inflammasome

Nuclear receptor Rev-erbα (NR1D1) is a major negative regulator of the circadian clock. Numerous studies have investigated the role of circadian clock-related factors in the tumorigenesis of multiple cancer types, but little is known about the role of NR1D1 in cancer development. In this study, we identified the role of NR1D1 in lung tumorigenesis using genetically engineered mouse models of Nr1d1. Although NR1D1 overexpression or knockdown had little effect on the proliferation of NSCLC cells in vitro, NR1D1 deficiency in the tumor microenvironment increased lung cancer development compared with the control in the orthotopic model. NR1D1-deficient mice showed increased NACHT, LRR, and PYD domain-containing protein 3 (NLRP3) inflammasome activation, and conditioned medium (CM) from NR1D1-deficient macrophages increased the proliferation and epithelial-mesenchymal transition (EMT) of lung cancer cells. Treatment with MCC950, a specific inhibitor of NLRP3 inflammasome, blocked tumorigenesis in NR1D1-deficient mice in an orthotopic lung cancer model. In addition, MCC950 treatment blocked the increased proliferation and EMT of cancer cells induced by CM from NR1D1-deficient macrophages in vitro. Our results showed that NR1D1 in the tumor microenvironment functions as a tumor suppressor by negatively regulating the NLRP3 inflammasome, suggesting that the NLRP3 inflammasome blockade via NR1D1 activation could be a therapeutic strategy to overcome lung cancer.

Cell type-specific roles of NLRP3, inflammasome-dependent and -independent, in host defense, sterile necroinflammation, tissue repair, and fibrosis

The NLRP3 inflammasome transforms a wide variety of infectious and non-infectious danger signals that activate pro-inflammatory caspases, which promote the secretion of IL-1β and IL-18, and pyroptosis, a pro-inflammatory form of cell necrosis. Most published evidence documents the presence and importance of the NLRP3 inflammasome in monocytes, macrophages, and neutrophils during host defense and sterile forms of inflammation. In contrast, in numerous unbiased data sets, NLRP3 inflammasome-related transcripts are absent in non-immune cells. However, an increasing number of studies report the presence and functionality of the NLRP3 inflammasome in almost every cell type. Here, we take a closer look at the reported cell type-specific expression of the NLRP3 inflammasome components, review the reported inflammasome-dependent and -independent functions, and discuss possible explanations for this discrepancy.

The trigger for pancreatic disease: NLRP3 inflammasome

NLRP3 inflammasome is a multiprotein complex expressed in a variety of cells to stimulate the production of inflammatory factors. Activation of NLRP3 inflammasome depends on a complex regulatory mechanism, and its pro-inflammatory function plays an important role in pancreatic diseases. In this literature review, we summarize the activation mechanism of NLRP3 and analyze its role in each of the four typical pancreatic diseases. Through this article, we provide a relatively comprehensive summary to the researchers in this field, and provide some targeted therapy routes.

NLRX1 functions as a tumor suppressor in Pan02 pancreatic cancer cells

Pancreatic cancer is a deadly malignancy with limited treatment options. NLRX1 is a unique, understudied member of the Nod-like Receptor (NLR) family of pattern recognition receptors that regulates a variety of biological processes that are highly relevant to pancreatic cancer. The role of NLRX1 in cancer remains highly enigmatic, with some studies defining its roles as a tumor promoter, while others characterize its contributions to tumor suppression. These seemingly contradicting roles appear to be due, at least in part, to cell type and temporal mechanisms. Here, we define roles for NLRX1 in regulating critical hallmarks of pancreatic cancer using both gain-of-function and loss-of-function studies in murine Pan02 cells. Our data reveals that NLRX1 increases susceptibility to cell death, while also suppressing proliferation, migration, and reactive oxygen species production. We also show that NLRX1 protects against upregulated mitochondrial activity and limits energy production in the Pan02 cells. Transcriptomics analysis revealed that the protective phenotypes associated with NLRX1 are correlated with attenuation of NF-κB, MAPK, AKT, and inflammasome signaling. Together, these data demonstrate that NLRX1 diminishes cancer-associated biological functions in pancreatic cancer cells and establishes a role for this unique NLR in tumor suppression.

The Role of IL-18 in P2RX7-Mediated Antitumor Immunity

Cancer is the leading cause of death worldwide despite the variety of treatments that are currently used. This is due to an innate or acquired resistance to therapy that encourages the discovery of novel therapeutic strategies to overcome the resistance. This review will focus on the role of the purinergic receptor P2RX7 in the control of tumor growth, through its ability to modulate antitumor immunity by releasing IL-18. In particular, we describe how the ATP-induced receptor activities (cationic exchange, large pore opening and NLRP3 inflammasome activation) modulate immune cell functions. Furthermore, we recapitulate our current knowledge of the production of IL-18 downstream of P2RX7 activation and how IL-18 controls the fate of tumor growth. Finally, the potential of targeting the P2RX7/IL-18 pathway in combination with classical immunotherapies to fight cancer is discussed.

Harnessing the Microbiome to Reduce Pancreatic Cancer Burden

Pancreatic cancer mortality is expected to rise in the next decades. This aggressive malignancy has a dismal prognosis due to late diagnosis and resistance to treatment. Increasing evidence indicates that host-microbiome interactions play an integral role in pancreatic cancer development, suggesting that harnessing the microbiome might offer promising opportunities for diagnostic and therapeutic interventions. Herein, we review the associations between pancreatic cancer and the intratumoral, gut and oral microbiomes. We also explore the mechanisms with which microbes influence cancer development and the response to treatment. We further discuss the potentials and limitations of using the microbiome as a target for therapeutic interventions, in order to improve pancreatic cancer patient outcomes.

Construction and validation of programmed cell death-based molecular clusters for prognostic and therapeutic significance of clear cell renal cell carcinoma

As the dominant histological subtype of kidney cancer, clear cell renal cell carcinoma (ccRCC) poorly responds to conventional chemotherapy and radiotherapy. Although novel immunotherapies such as immune checkpoint inhibitors could have a durable effect in treating ccRCC patients, the limited availability of dependable biomarkers has restricted their application in clinic. In the study of carcinogenesis and cancer therapies, there has been a recent emphasis on researching programmed cell death (PCD). In the current study, we discovered the enriched and prognostic PCD in ccRCC utilizing gene set enrichment analysis (GSEA) and investigate the functional status of ccRCC patients with different PCD risks. Then, genes related to PCD that had prognostic value in ccRCC were identified for the conduction of non-negative matrix factorization to cluster ccRCC patients. Next, the tumor microenvironment, immunogenicity, and therapeutic response in different molecular clusters were analyzed. Among PCD, apoptosis and pyroptosis were enriched in ccRCC and correlated with prognosis. Patients with high PCD levels were related to poor prognosis and a rich but suppressive immune microenvironment. PCD-based molecular clusters were identified to differentiate the clinical status and prognosis of ccRCC. Moreover, the molecular cluster with high PCD levels may correlate with high immunogenicity and a favorable therapeutic response to ccRCC. Furthermore, a simplified PCD-based gene classifier was established to facilitate clinical application and used transcriptome sequencing data from clinical ccRCC samples to validate the applicability of the gene classifier. We thoroughly extended the understanding of PCD in ccRCC and constructed a PCD-based gene classifier for differentiation of the prognosis and therapeutic efficacy in ccRCC.

Progress in the study of molecular mechanisms of cell pyroptosis in tumor therapy

Pyroptosis, also known as cellular inflammatory necrosis, is a programmed cell death mediated by the Gasdermin family of proteins. The mechanisms by which pyroptosis occurs are divided into the GSDMD-mediated Caspase-1 and Caspase-4/-5/-11-dependent classical inflammatory vesicle pathway and the GSDME-mediated Caspase-3 and granzyme-dependent non-classical inflammatory vesicle pathways, among others. Recent studies have shown that pyroptosis has both inhibitory and promotive effects on tumor development. Pyroptosis induction also plays a dual role in antitumor immunotherapy: on the one hand, it suppresses antitumor immunity by promoting the release of inflammatory factors, and on the other hand, it inhibits tumor cell proliferation by triggering antitumor inflammatory responses. In addition, cell scorching plays an essential role in chemotherapy. It has been found that natural drugs modulating the induction of cell scorch are necessary to treat tumors. Therefore, studying the specific mechanisms of cell pyroptosis in different tumors can provide more ideas for developing oncology drugs. In this paper, we review the molecular mechanisms of pyroptosis and the role of pyroptosis in tumor development and treatment to provide new targets for clinical tumor treatment, prognosis, and antitumor drug development.

NLRP3 inflammasome-induced pyroptosis in digestive system tumors

Programmed cell death (PCD) refers to cell death in a manner that depends on specific genes encoding signals or activities. PCD includes apoptosis, pyroptosis, autophagy and necrosis (programmed necrosis). Among these mechanisms, pyroptosis is mediated by the gasdermin family and is accompanied by inflammatory and immune responses. When pathogens or other danger signals are detected, cytokine action and inflammasomes (cytoplasmic multiprotein complexes) lead to pyroptosis. The relationship between pyroptosis and cancer is complex and the effect of pyroptosis on cancer varies in different tissue and genetic backgrounds. On the one hand, pyroptosis can inhibit tumorigenesis and progression; on the other hand, pyroptosis, as a pro-inflammatory death, can promote tumor growth by creating a microenvironment suitable for tumor cell growth. Indeed, the NLRP3 inflammasome is known to mediate pyroptosis in digestive system tumors, such as gastric cancer, pancreatic ductal adenocarcinoma, gallbladder cancer, oral squamous cell carcinoma, esophageal squamous cell carcinoma, in which a pyroptosis-induced cellular inflammatory response inhibits tumor development. The same process occurs in hepatocellular carcinoma and some colorectal cancers. The current review summarizes mechanisms and pathways of pyroptosis, outlining the involvement of NLRP3 inflammasome-mediated pyroptosis in digestive system tumors.

Loss of NLRP3 reduces oxidative stress and polarizes intratumor macrophages to attenuate immune attack on endometrial cancer

Introduction

The interaction between endometrial cancer (EMC) cells and intratumoral macrophages plays a significant role in the development of the disease. PYD domains-containing protein 3 (NLRP3) inflammasome formation triggers caspase-1/IL-1β signaling pathways and produces reactive oxygen species (ROS) in macrophages. However, the role of NLRP3-regulated ROS production in macrophage polarization and the subsequent growth and metastasis of EMC remains unknown.

Methods

We conducted bioinformatic analysis to compare NLRP3 levels in intratumoral macrophages from EMC and normal endometrium. In vitro experiments involved knocking out NLRP3 in macrophages to shift the polarization from an anti-inflammatory M1-like phenotype to a proinflammatory M2-like phenotype and reduce ROS production. The impact of NLRP3 depletion on the growth, invasion, and metastasis of co-cultured EMC cells was assessed. We also evaluated the effect of NLRP3 depletion in macrophages on the growth and metastasis of implanted EMC cells in mice.

Results

Our bioinformatic analysis showed significantly lower NLRP3 levels in intratumoral macrophages from EMC than those from normal endometrium. Knocking out NLRP3 in macrophages shifted their polarization to a proinflammatory M2-like phenotype and significantly reduced ROS production. NLRP3 depletion in M2-polarized macrophages increased the growth, invasion, and metastasis of co-cultured EMC cells. NLRP3 depletion in M1-polarized macrophages reduced phagocytic potential, which resulted in weakened immune defense against EMC. Additionally, NLRP3 depletion in macrophages significantly increased the growth and metastasis of implanted EMC cells in mice, likely due to compromised phagocytosis by macrophages and a reduction in cytotoxic CD8+ T cells.

Discussion

Our results suggest that NLRP3 plays a significant role in regulating macrophage polarization, oxidative stress, and immune response against EMC. NLRP3 depletion alters the polarization of intratumoral macrophages, leading to weakened immune defense against EMC cells. The reduction in ROS production by the loss of NLRP3 may have implications for the development of novel treatment strategies for EMC.

Mechanisms of obesity- and diabetes mellitus-related pancreatic carcinogenesis: a comprehensive and systematic review

Research on obesity- and diabetes mellitus (DM)-related carcinogenesis has expanded exponentially since these two diseases were recognized as important risk factors for cancers. The growing interest in this area is prominently actuated by the increasing obesity and DM prevalence, which is partially responsible for the slight but constant increase in pancreatic cancer (PC) occurrence. PC is a highly lethal malignancy characterized by its insidious symptoms, delayed diagnosis, and devastating prognosis. The intricate process of obesity and DM promoting pancreatic carcinogenesis involves their local impact on the pancreas and concurrent whole-body systemic changes that are suitable for cancer initiation. The main mechanisms involved in this process include the excessive accumulation of various nutrients and metabolites promoting carcinogenesis directly while also aggravating mutagenic and carcinogenic metabolic disorders by affecting multiple pathways. Detrimental alterations in gastrointestinal and sex hormone levels and microbiome dysfunction further compromise immunometabolic regulation and contribute to the establishment of an immunosuppressive tumor microenvironment (TME) for carcinogenesis, which can be exacerbated by several crucial pathophysiological processes and TME components, such as autophagy, endoplasmic reticulum stress, oxidative stress, epithelial-mesenchymal transition, and exosome secretion. This review provides a comprehensive and critical analysis of the immunometabolic mechanisms of obesity- and DM-related pancreatic carcinogenesis and dissects how metabolic disorders impair anticancer immunity and influence pathophysiological processes to favor cancer initiation.

A systematic evidence map of chronic inflammation and immunosuppression related to per- and polyfluoroalkyl substance (PFAS) exposure

BACKGROUND

The ability to induce chronic inflammation and immunosuppression are two key characteristics of carcinogens and important forms of immunotoxicity. The National Toxicology Program (NTP) evaluated the immunotoxicity of two per- and polyfluoroalkyl substances (PFASs), PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonate), in 2016. However, the potential pro-inflammatory and immunosuppressive effects of other PFASs remain largely uncharacterized.

METHODS

We developed an expanded set of search terms pertaining to the chronic inflammatory and immunosuppressive effects of PFASs based on those of the International Agency for Research on Cancer (IARC) and NTP. To confirm searching effectiveness and scope, we compared our search term results with those of IARC and NTP for both PFASs and two other known carcinogens, chromium (VI) and benzene. Systematic evidence maps (SEMs) were also produced using Tableau to visualize the distribution of study numbers and types reporting immunotoxic effects and specific biomarkers elicited by PFAS exposures.

RESULTS

In total, 1155 PFAS studies were retrieved, of which 321 qualified for inclusion in our dataset. Using our search terms, we identified a greater number of relevant studies than those obtained using IARC and NTP's search terms. From the SEM findings, increased cytokine production strengthened an association between PFAS exposure and chronic inflammation, and decreased B-cell activation and altered levels of T-cell subtypes and immunoglobulins confirmed PFAS-induced immunosuppression.

CONCLUSION

Our SEM findings confirm that several PFASs commonly found in both in the environment, including those that are lesser-known, may induce immunosuppression and chronic inflammation, two key characteristics of carcinogens. This approach, including development of search terms, study screening process, data coding, and evidence mapping visualizations, can be applied to other key characteristics of chemical carcinogens.

Role of gut microbiota in tumorigenesis and antitumoral therapies: an updated review

Gut microbiota plays a prominent role in regulation of host nutrientmetabolism, drug and xenobiotics metabolism, immunomodulation and defense against pathogens. It synthesizes numerous metabolites thatmaintain the homeostasis of host. Any disbalance in the normalmicrobiota of gut can lead to pathological conditions includinginflammation and tumorigenesis. In the past few decades, theimportance of gut microbiota and its implication in various diseases, including cancer has been a prime focus in the field of research. Itplays a dual role in tumorigenesis, where it can accelerate as wellas inhibit the process. Various evidences validate the effects of gutmicrobiota in development and progression of malignancies, wheremanipulation of gut microbiota by probiotics, prebiotics, dietarymodifications and faecal microbiota transfer play a significant role.In this review, we focus on the current understanding of theinterrelationship between gut microbiota, immune system and cancer,the mechanisms by which they play dual role in promotion andinhibition of tumorigenesis. We have also discussed the role ofcertain bacteria with probiotic characteristics which can be used tomodulate the outcome of the various anti-cancer therapies under theinfluence of the alteration in the composition of gut microbiota.Future research primarily focusing on the microbiota as a communitywhich affect and modulate the treatment for cancer would benoteworthy in the field of oncology. This necessitates acomprehensive knowledge of the roles of individual as well asconsortium of microbiota in relation to physiology and response ofthe host.

Tripartite motif containing 69 elicits ERK2-dependent EYA4 turnover to impart pancreatic tumorigenesis

Eyes absent homologue 4 (EYA4) is silenced in pancreatic ductal adenocarcinoma (PDAC) and functions as a tumor suppressor to restrain PDAC development, albeit the molecular mechanism underlying its downregulation remains enigmatic. Methods: Functional studies were determined by immunohistochemistry of PDAC samples from patients and Pdx1-Cre; LSL-Kras^G12D/+; Trp53^fl/+ (KPC) mice, three-dimensional spheroid culture, flow cytometry, MTT and subcutaneous xenograft experiments. Mechanistical studies were examined by cellular ubiquitination, cycloheximide (CHX) pulse-chase, co-immunoprecipitation, chromatin immunoprecipitation, GST-pulldown, in vitro protein kinase assay, immunofluorescence and luciferase reporter assays. Results: We screen E3 ligase that is negatively correlated with EYA4 and uncover a mutually exclusive interaction of tripartite motif containing 69 (TRIM69) with EYA4 in human PDAC. TRIM69 elicits EYA4 polyubiquitylation and turnover independent of P53 and impedes the EYA4-driven deactivation of β-catenin/ID2 cascade, fueling PDAC cell proliferation in vitro and tumor development in mice. Expression of TRIM69 is upregulated in PDAC samples from independent cohorts of patients and the Pdx1-Cre; LSL-Kras^G12D/+; Trp53^fl/+ (KPC) mice, and associated with unfavorable prognosis. Depleting TRIM69 preferentially induces lethality in the EYA4-deficient PDAC cells. We further unearth that ERK2 directly binds to the D-site of mitogen-activated protein kinase (MAPK) docking groove in EYA4 Leu512/514 and phosphorylates EYA4 at Ser37, which is instrumental for EYA4 polyubiquitylation and turnover by TRIM69. Conclusion: Our results define a previously unappreciated role of TRIM69-EYA4 axis in pancreatic tumorigenesis and underscore that targeting TRIM69 might be an effective therapeutic approach for PDAC harboring EYA4 deficiency.