The expression and regulation of DFNA5 in human hepatocellular carcinoma DFNA5 in hepatocellular carcinoma

Construction of prognostic markers for gastric cancer and comprehensive analysis of pyroptosis-related long non-coding RNAs

BACKGROUND

China's most frequent malignancy is gastric cancer (GC), which has a very poor survival rate, and the survival rate for patients with advanced GC is dismal. Pyroptosis has been connected to the genesis and development of cancer. The function of pyroptosis-related long non-coding RNAs (PRLs) in GC, on the other hand, remains uncertain.

AIM

To explore the construction and comprehensive analysis of the prognostic characteristics of long non-coding RNA (lncRNA) related to pyroptosis in GC patients.

METHODS

The TCGA database provided us with 352 stomach adenocarcinoma samples, and we obtained 28 pyroptotic genes from the Reactome database. We examined the correlation between lncRNAs and pyroptosis using the Pearson correlation coefficient. Prognosis-related PRLs were identified through univariate Cox analysis. A predictive signature was constructed using stepwise Cox regression analysis, and its reliability and independence were assessed. To facilitate clinical application, a nomogram was created based on this signature. we analyzed differences in immune cell infiltration, immune function, and checkpoints between the high-risk group (HRG) and low-risk group (LRG).

RESULTS

Five hundred and twenty-three PRLs were screened from all lncRNAs (absolute correlation coefficient > 0.4, P < 0.05). Nine PRLs were included in the risk prediction signature that was created through stepwise Cox regression analysis. We determined the risk score for GC patients and employed the median value as the dividing line between HRG and LRG. The ability of the risk signature to predict the overall survival (OS) of GC is demonstrated by the Kaplan-Meier analysis, risk curve, receiver operating characteristic curve, and decision curve analysis curve. The risk signature was shown to be an independent prognostic factor for OS in both univariate and multivariate Cox regression analyses. HRG showed a more efficient local immune response or modulation compared to LRG, as indicated by the predicted signal pathway analysis and examination of immune cell infiltration, function, and checkpoints (P < 0.05).

CONCLUSION

In general, we have created a brand-new prognostic signature using PRLs, which may provide ideas for immunotherapy in patients with GC.

The Role and Therapeutic Potential of Pyroptosis in Colorectal Cancer: A Review

Colorectal cancer (CRC) is one of the leading causes of cancer-related mortality worldwide. The unlimited proliferation of tumor cells is one of the key features resulting in the malignant development and progression of CRC. Consequently, understanding the potential proliferation and growth molecular mechanisms and developing effective therapeutic strategies have become key in CRC treatment. Pyroptosis is an emerging type of regulated cell death (RCD) that has a significant role in cells proliferation and growth. For the last few years, numerous studies have indicated a close correlation between pyroptosis and the occurrence, progression, and treatment of many malignancies, including CRC. The development of effective therapeutic strategies to inhibit tumor growth and proliferation has become a key area in CRC treatment. Thus, this review mainly summarized the different pyroptosis pathways and mechanisms, the anti-tumor (tumor suppressor) and protective roles of pyroptosis in CRC, and the clinical and prognostic value of pyroptosis in CRC, which may contribute to exploring new therapeutic strategies for CRC.

Cpeb4-mediated Dclk2 promotes neuronal pyroptosis induced by chronic cerebral ischemia through phosphorylation of Ehf

Chronic cerebral ischemia (CCI) is a clinical syndrome characterised by brain dysfunction due to decreased chronic cerebral perfusion. CCI initiates several inflammatory pathways, including pyroptosis. RNA-binding proteins (RBPs) play important roles in CCI. This study aimed to explore whether the interaction between RBP-Cpeb4 and Dclk2 affected Ehf phosphorylation to regulate neuronal pyroptosis. HT22 cells and mice were used to construct oxygen glucose deprivation (OGD)/CCI models. We found that Cpeb4 and Dclk2 were upregulated in OGD-treated HT22 cells and CCI-induced hippocampal CA1 tissues. Cpeb4 upregulated Dclk2 expression by increasing Dclk2 mRNA stability. Knockdown of Cpeb4 or Dclk2 inhibited neuronal pyroptosis in OGD-treated HT22 cells and CCI-induced hippocampal CA1 tissues. By binding to the promoter regions of Caspase1 and Caspase3, the transcription factor Ehf reduced their promoter activities and inhibited the transcription. Dclk2 phosphorylated Ehf and changed its nucleoplasmic distribution, resulting in the exit of p-Ehf from the nucleus and decreased Ehf levels. It promoted the expression of Caspase1 and Caspase3 and stimulated neuronal pyroptosis of HT22 cells induced by OGD. Cpeb4/Dclk2/Ehf pathway plays an important role in the regulation of cerebral ischemia-induced neuronal pyroptosis.

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.

Pyroptosis in cancer treatment and prevention: the role of natural products and their bioactive compounds

Targeting programmed cell death (PCD) has been emerging as a promising therapeutic strategy in cancer. Pyroptosis, as a type of PCDs, leads to the cleavage of the gasdermin family and the secretion of pro-inflammatory factors. Gasdermin D (GSDMD) and gasdermin E (GSDME) are the two main executors of pyroptosis. Pyroptosis in tumor and immune cells is essential for tumor progression. Natural products, especially Chinese medicinal herb and their bioactive compounds have recently been regarded as anti-tumor agents that regulate cell pyroptosis under different circumstances. Here, we review the underlying mechanisms of natural products that activate pyroptosis in tumor cells and inhibit pyroptosis in immune cells. Pyroptosis activation in tumor cells leads to tumor cell death, yet pyroptosis inhibition in immune cells may prevent tumor occurrence. Elucidation of the signaling pathways involved in pyroptosis contributes to the understanding of the anti-tumor role of natural products and their potential clinical applications. Therefore, we outline a promising strategy for cancer therapy and prevention using natural products via modulation of pyroptosis.

Triggering pyroptosis enhances the antitumor efficacy of PARP inhibitors in prostate cancer

PURPOSE

PARP inhibitors have revolutionized the treatment landscape for advanced prostate cancer (PCa) patients who harboring mutations in homologous recombination repair (HRR) genes. However, the molecular mechanisms underlying PARP inhibitors function beyond DNA damage repair pathways remain elusive, and identifying novel predictive targets that favorably respond to PARP inhibitors in PCa is an active area of research.

METHODS

The expression of GSDME in PCa cell lines and human PCa samples was determined by western blotting. Targeted bisulfite sequencing, gene enrichment analysis (GSEA), clone formation, construction of the stably transfected cell lines, lactate dehydrogenase (LDH) assay, western blotting as well as a mouse model of subcutaneous xenografts were used to investigate the role of GSDME in PCa. The combinational therapeutic effect of olaparib and decitabine was determined using both in vitro and in vivo experiments.

RESULTS

We have found low expression of GSDME in PCa. Interestingly, we demonstrated that GSDME activity is robustly induced in olaparib-treated cells undergoing pyroptosis, and that high methylation of the GSDME promoter dampens its activity in PCa cells. Intriguingly, genetically overexpressing GSDME does not inhibit tumor cell proliferation but instead confers sensitivity to olaparib. Furthermore, pharmacological treatment with the combination of olaparib and decitabine synergistically induces GSDME expression and cleavage through caspase-3 activation, thus promoting pyroptosis and enhancing anti-tumor response, ultimately resulting in tumor remission.

CONCLUSION

Our findings highlight a novel therapeutic strategy for enhancing the long-term response to olaparib beyond HRR-deficient tumors in PCa, underscoring the critical role of GSDME in regulating tumorigenesis.

Pyroptosis: shedding light on the mechanisms and links with cancers

Pyroptosis, a novel form of programmed cell death (PCD) discovered after apoptosis and necrosis, is characterized by cell swelling, cytomembrane perforation and lysis, chromatin DNA fragmentation, and the release of intracellular proinflammatory contents, such as Interleukin (IL) 8, IL-1β, ATP, IL-1α, and high mobility group box 1 (HMGB1). Our understanding of pyroptosis has increased over time with an increase in research on the subject: gasdermin-mediated lytic PCD usually, but not always, requires cleavage by caspases. Moreover, new evidence suggests that pyroptosis induction in tumor cells results in a strong inflammatory response and significant cancer regression, which has stimulated great interest among scientists for its potential application in clinical cancer therapy. It's worth noting that the side effects of chemotherapy and radiotherapy can be triggered by pyroptosis. Thus, the intelligent use of pyroptosis, the double-edged sword for tumors, will enable us to understand the genesis and development of cancers and provide potential methods to develop novel anticancer drugs based on pyroptosis. Hence, in this review, we systematically summarize the molecular mechanisms of pyroptosis and provide the latest available evidence supporting the antitumor properties of pyroptosis, and provide a summary of the various antitumor medicines targeting pyroptosis signaling pathways.

Gasdermins and cancers

The identification of gasdermin as the executor of pyroptosis has opened new avenues for the study of this process. Although pyroptosis research has mainly focused on immune cells since it was discovered three decades ago, accumulating evidence suggests that pyroptosis plays crucial roles in many biological processes. One example is the discovery of gasdermin-mediated cancer cell pyroptosis (CCP) which has become an important and frontier field in oncology. Recent studies have shown that CCP induction can heat tumor microenvironment (TME) and thereby elicit the robust anti-tumor immunity to suppress tumor growth. As a newly discovered form of tumor cell death, CCP offers promising opportunities for improving tumor treatment and developing new drugs. Nevertheless, the research on CCP is still in its infancy, and the molecular mechanisms underlying the expression, regulation and activation of gasdermins are not yet fully understood. In this review, we summarize the recent progress of gasdermin research in cancer area, and propose that the anti-tumor effect of immune cell pyroptosis (ICP) and CCP depends on their duration, intensity, and the type of cells undergoing pyroptosis within TME.

Integrated analysis of diagnostic, prognostic value and potential drug treatment of GSDME in head and neck squamous cell carcinoma

BACKGROUND

Head and neck squamous cell carcinoma (HNSC) poses a global health challenge. Effective biomarkers for early detection are necessary to improve the survival rate of HNSC patient. The purpose of this study was using integrated bioinformatic analysis to investigate the potential biological roles of GSDME in HNSC.

METHODS

The Gene Expression Omnibus (GEO) and Cancer Gnome Atlas (TCGA) databases were used to analyze the expression of GSDME in different cancer types. The correlation between GSDME expression and immune cell infiltration or immune checkpoint genes was examined by Spearman correlation analysis. DNA methylation analysis of the GSDME gene was conducted using the MethSurv database. Kaplan-Meier (K-M) survival curves, diagnostic receiver operating characteristic (ROC) curves, nomogram model, and Cox regression analysis were chosen to evaluate the diagnostic and prognostic predictive value of GSDME. Connectivity Map (Cmap) online platform, Protein Data Bank (PDB) database and Chem3D, AutoDock Tool and PyMol software were used to predict and visualize potential molecular drugs aimed for GSDME.

RESULTS

GSDME expression level in HNSC was significantly higher than in the controls (p < 0.001). Differentially expressed genes (DEGs) correlation with GSDME were enriched in the GO pathways, such as protein activation cascade, complement activation and classical pathway (p < 0.05). According to GSEA, GSDME-associated differentially expressed genes were significantly enriched in KRAS signaling pathway and cytokine signaling molecule (p < 0.05). There is a significant relation between GSDME expression and immune cell infiltration in HNSC tissues, as well as immune checkpoint genes expression (p < 0.001). DNA methylation status of cg17790129 CpG islands of GSDME gene is correlated with HNSC prognosis (p < 0.05). Based on Cox regression analysis of HNSC patients, GSDME as a potential risk gene has high correlation with overall survival (OS) and disease specific survival (DSS) (p < 0.05). In a ROC curve analysis, HNSC tissues were differentiated from adjacent peritumoral tissues based on GSDME expression levels (AUC = 0.928). Totally six potential drugs targeted for GSDME were screened and the molecular docking tests between GSDME protein and candidate drugs were conducted.

CONCLUSIONS

GSDME is a promising therapeutic target as well as a potential clinical biomarker in HNSC patients.

Gasdermin E (GSDME)-A New Potential Marker of Psoriasis and Its Metabolic Complications: The First Combined Study on Human Serum, Urine and Tissue

Psoriasis is a frequent and incurable skin disease whose pathogenesis is still not fully understood. It is characterized by immune disturbances leading to hyperproliferation and improper differentiation of keratinocytes. Gasdermin E (GSDME) is a protein from the gasdermin family involved in the processes of inflammation and cell death based on apoptosis, necroptosis and pyroptosis. It has never been studied in psoriatics' sera or urine before. Our study enrolled 60 patients with psoriasis and 30 volunteers without dermatoses as controls. Serum and urinary GSDME concentrations were examined by ELISA and tissue expression of GSDME by immunohistochemistry. Serum GSDME concentration was significantly higher in patients than controls (p < 0.05). There were no differences in urinary GSDME concentrations between patients and controls. GSDME expression was significantly higher in the psoriatic plaque than non-lesional patients' skin and compared to controls (both p < 0.001). There was no correlation between serum GSDME or its lesional expression and psoriasis severity, age or disease duration. GSDME serum concentration was significantly negatively correlated with BMI, triglycerides and glucose concentrations. The obtained results suggest the engagement of GSDME in psoriasis pathogenesis. It could potentially become a new non-invasive psoriasis marker. Considering its pro-apoptotic influence, GSDME could be compensatively elevated to direct cells towards apoptosis, whereas under other circumstances, it may lead to pyroptosis and sustain inflammation. GSDME may exert a protective influence on the metabolic complications in psoriasis which requires further studies.

Role of pyroptosis in the pathogenesis and treatment of diseases

Programmed cell death (PCD) is regarded as a pathological form of cell death with an intracellular program mediated, which plays a pivotal role in maintaining homeostasis and embryonic development. Pyroptosis is a new paradigm of PCD, which has received increasing attention due to its close association with immunity and disease. Pyroptosis is a form of inflammatory cell death mediated by gasdermin that promotes the release of proinflammatory cytokines and contents induced by inflammasome activation. Recently, increasing evidence in studies shows that pyroptosis has a crucial role in inflammatory conditions like cardiovascular diseases (CVDs), cancer, neurological diseases (NDs), and metabolic diseases (MDs), suggesting that targeting cell death is a potential intervention for the treatment of these inflammatory diseases. Based on this, the review aims to identify the molecular mechanisms and signaling pathways related to pyroptosis activation and summarizes the current insights into the complicated relationship between pyroptosis and multiple human inflammatory diseases (CVDs, cancer, NDs, and MDs). We also discuss a promising novel strategy and method for treating these inflammatory diseases by targeting pyroptosis and focus on the pyroptosis pathway application in clinics.

Chemotherapeutic drugs-induced pyroptosis mediated by gasdermin E promotes the progression and chemoresistance of pancreatic cancer

Pyroptosis is closely associated with cancer development; however, the role of pyroptosis in pancreatic ductal adenocarcinoma (PDAC), a fatal malignant tumour with a poor overall survival rate, remains elusive. Here, we explored the mechanism of chemotherapy-induced pyroptosis and elucidated the role of pyroptosis in mediating PDAC progression and chemoresistance. The results demonstrated first- and second-line chemotherapeutic drugs against PDAC, including gemcitabine, irinotecan, 5-fluorouracil, paclitaxel, and cisplatin, induced concurrent pyroptosis and apoptosis. During this process, gasdermin E (GSDME) was cleaved by activated caspase-3, which was accompanied by pro-apoptotic caspase-7/8 activation. GSDME knockdown switched pyroptosis to apoptosis, decreased invasion and migration, and enhanced the sensitivity of PDAC cells to chemotherapy in vitro and in vivo. GSDME was highly expressed in PDAC tissues and positively correlated with histological differentiation and vascular invasion. Furthermore, cells that survived pyroptosis promoted proliferation and invasion and impaired the chemosensitivity of PDAC cells, which was attenuated by the GSDME knockdown. Our findings demonstrated that chemotherapeutics against PDAC induce GSDME-dependent pyroptosis, and GSDME expression positively correlated with PDAC progression and chemoresistance. Targeting GSDME may be a novel approach to overcoming chemoresistance in PDAC.

Pyroptosis and its role in cancer

Programmed cell death (PCD) is mediated by specific genes that encode signals. It can balance cell survival and death. Pyroptosis is a type of inflammatory, caspase-dependent PCD mediated by gasdermin proteins, which function in pore formation, cell expansion, and plasma membrane rupture, followed by the release of intracellular contents. Pyroptosis is mediated by caspase-1/3/4/5/11 and is primarily divided into the classical pathway, which is dependent on caspase-1, and the non-classical pathway, which is dependent on caspase-4/5/11. Inflammasomes play a vital role in these processes. The various components of the pyroptosis pathway are related to the occurrence, invasion, and metastasis of tumors. Research on pyroptosis has revealed new options for tumor treatment. This article summarizes the recent research progress on the molecular mechanism of pyroptosis, the relationship between the various components of the pyroptosis pathway and cancer, and the applications and prospects of pyroptosis in anticancer therapy.

A pyroptosis-related gene signature for prognosis prediction in hepatocellular carcinoma

Introduction

Hepatocellular carcinoma (HCC) is one of the most invasive cancers with a low 5-year survival rate. Pyroptosis, a specialized form of cell death, has shown its association with cancer progression. However, its role in the prognosis of HCC has not been fully understood.

Methods

In our study, clinical information and mRNA expression for 1076 patients with HCC were obtained from the five public cohorts. Pyroptotic clusters were generated by unsupervised clustering based on 40 pyroptosis-related genes (PRGs) in the TCGA and ICGC cohort. A pyroptosis-related signature was constructed using least absolute shrinkage and selection operator (LASSO) regression according to differentially expressed genes (DEGs) of pyroptotic clusters. The signature was then tested in the validation cohorts (GES10142 and GSE14520) and subsequently validated in the CPTAC cohort (n=159) at both mRNA and protein levels. Response to sorafenib was explored in GSE109211.

Results

Three clusters were identified based on the 40 PRGs in the TCGA cohort. A total of 24 genes were selected based on DEGs of the above three pyroptotic clusters to construct the pyroptotic risk score. Patients with the high-risk score showed shorter overall survival (OS) compared to those with the low-risk score in the training set (P&lt;0.001; HR, 3.06; 95% CI, 2.22-4.24) and the test set (P=0.008; HR, 1.61; 95% CI, 1.13-2.28). The predictive ability of the risk score was further confirmed in the CPTAC cohort at both mRNAs (P&lt;0.001; HR, 2.99; 95% CI, 1.67-5.36) and protein levels (P&lt;0.001; HR, 2.97; 95% CI 1.66-5.31). The expression of the model genes was correlated with immune cell infiltration, angiogenesis-related genes, and sensitivity to antiangiogenic therapy (P&lt;0.05).

Discussion

In conclusion, we established a prognostic signature of 24 genes based on pyroptosis clusters for HCC patients, providing insight into the risk stratification of HCC.

Promoting GSDME expression through DNA demethylation to increase chemosensitivity of breast cancer MCF-7 / Taxol cells

OBJECTIVE

Breast cancer is the most common and high-incidence cancer in women. It is mainly treated by surgery combined with chemoradiation. The main challenge in treating breast cancer patients is developing resistance to chemotherapeutics, so it is urgent to find potential strategies that can improve the chemotherapy effect of patients. In this study, we aimed to explore the role of GSDME methylation in the sensitivity of chemotherapy for breast cancer.

METHODS

Here, we identified breast cancer MCF-7 / Taxol cells models using quantitative real-time PCR (qRT-PCR), Western blotting (WB), and cell counting kit-8 (CCK-8) analyses. Epigenetic changes in it were detected by Methylated DNA immunoprecipitation-sequencing and methylation-specific PCR. The expression level of GSDME in breast cancer cells was observed by qPCR and WB analyses. CCK-8 and colony formation assay were used to detect cell proliferation. Finally, pyroptosis was detected by LDH assay, flow cytometry, and WB analyses.

RESULTS

Our results indicate that ABCB1 mRNA and p-GP expression are significantly increased in breast cancer MCF-7 / Taxol cells. GSDME enhancer methylation was found in drug-resistant cells and was associated with the down-regulation of GSDME expression. After treatment with decitabine (5-Aza-2'-deoxycytidine), the demethylation of GSDME induced the occurrence of pyroptosis and thereby inhibited the proliferation of MCF-7 / Taxol cells. We found that the upregulation of GSDME enhances the chemosensitivity of MCF-7 / Taxol cells to paclitaxel by inducing pyroptosis.

CONCLUSION

Taken together, we identified decitabine increases GSDME expression through DNA demethylation and induces pyroptosis, thus increasing the chemosensitivity of MCF-7 / Taxol cells to Taxol. Use of decitabine / GSDME / pyroptosis-based treatment strategies may be a new way to overcome the resistance of breast cancer to paclitaxel chemotherapy.

Oncolytic Parapoxvirus induces Gasdermin E-mediated pyroptosis and activates antitumor immunity

The advantage of oncolytic viruses (OV) in cancer therapy is their dual effect of directly killing tumours while prompting anti-tumour immune response. Oncolytic parapoxvirus ovis (ORFV) and other OVs are thought to induce apoptosis, but apoptosis, being the immunogenically inert compared to other types of cell death, does not explain the highly inflamed microenvironment in OV-challenged tumors. Here we show that ORFV and its recombinant therapeutic derivatives are able to trigger tumor cell pyroptosis via Gasdermin E (GSDME). This effect is especially prominent in GSDME-low tumor cells, in which ORFV-challenge pre-stabilizes GSDME by decreasing its ubiquitination and subsequently initiates pyroptosis. Consistently, GSDME depletion reduces the proportion of intratumoral cytotoxic T lymphocytes, pyroptotic cell death and the success of tumor ORFV virotherapy. In vivo, the OV preferentially accumulates in the tumour upon systemic delivery and elicits pyroptotic tumor killing. Consequentially, ORFV sensitizes immunologically 'cold' tumors to checkpoint blockade. This study thus highlights the critical role of GSDME-mediated pyroptosis in oncolytic ORFV-based antitumor immunity and identifies combinatorial cancer therapy strategies.

Prognostic value and immune infiltration of the gasdermin family in lung adenocarcinoma

Background

The GSDM family includes six members, GSDMA, GSDMB, GSDMC, GSDMD, GSDME (DFNA5), and PJVK (Pejvakin, DFNB59), which can induce pyroptosis, thereby regulating the tumorigenesis of various cancers. However, the clinical characteristics and role of the GSDM family in LUAD are not well understood.

Methods

In this study, several important bioinformatics databases were used to integrate the analysis of the expression, prognostic value, and immune infiltration of GSDMs in LUAD. These databases include UALCAN, DiseaseMeth, GEPIA, THPA, cBioPortal, TIMER, WebGestalt, STRING database, and Cytoscape.

Results

The findings from the UALCAN database revealed that the expression of all six GSDMs based on the tumor stage in LUAD was increased (particularly GSDMD). Our IHC results verified it. Additionally, the DiseaseMeth database showed that the methylation levels of GSDMA, GSDMB, GSDMC, and GSDMD were decreased. The expression of six GSDMs was related to shorter overall survival in patients with LUAD, according to the GEPIA database. The cBioPortal database was further used to explore the alteration rate and correlated genes in LUAD. Subsequently, these genes were subjected to functional enrichment and protein-protein interaction network analyses. We identified that the GSDM family regulate several signaling pathways, including immune-associated signaling pathways. According to tumor-infiltrating immune cell analysis from the TIMER database, GSDM family members are associated with the infiltration of important immune cells and their signature markers.

Conclusions

GSDM family may be prognostic markers and novel strategies for the treatment of LUAD.

Mutation analysis of the GSDME gene in a Chinese family with non-syndromic hearing loss

Background

Hearing loss is considered one of the most common sensory nervous system defects, about 60% of which are caused by genetic factors. Mutations in the GSDME gene are responsible for post-lingual, progressive, autosomal dominant hearing loss. This study aimed to characterize the genetic mutations and clinical features of a Chinese GSDME family.

Methods

After clinical evaluations, high-throughput DNA sequencing was conducted using DNA samples from this family. Sanger sequencing was performed to verify the suspected variants. A detailed genotype and phenotype analysis were carried out. Gene set enrichment analysis (GSEA) was performed to identify the signaling pathway associated with GSDME expression.

Results

A known hotspot heterozygous splice-site variation (c.991-15_991_13delTTC) was identified and shown to segregate with the hearing loss phenotype in the family. This pathogenic splice-site variant results in skipping of exon 8. GSEA analysis identified changes in regulation of the cell cycle checkpoint, peroxisome, and amino acid metabolism signaling pathways.

Conclusions

We identified a reported mutation in the GSDME gene. Our findings support the 3 bp deletion (c.991-15_991-13del) was a hotspot variation, and it emerged as an essential contributor to autosomal dominant progressive hearing loss in East Asians. GSDME gene is closely associated with a range of signaling pathways. These characterized findings may provide new evidence for pathogenesis.

Role of gasdermin family proteins in the occurrence and progression of hepatocellular carcinoma

Primary liver cancer is the sixth most common cancer and the third leading cause of cancer mortality worldwide, hepatocellular carcinoma (HCC) is the most common type of liver cancer, accounting for 75%–85% of cases. The occurrence and progression of HCC involve multiple events. Pyroptosis is a gasdermins mediated programmed cell death and is intricately associated with cancerogenesis, including HCC. This review mainly concerns the recent research advances of the gasdermin family members in HCC. The biological roles and specific expression patterns of the family members are discussed, especially those that are involved in the regulatory pathways in the occurrence and progression of HCC. We provide the latest progress into the distinct molecular mechanisms of gasdermin family members involved in the occurrence and development of HCC.

The emerging role of pyroptosis in pediatric cancers: from mechanism to therapy

Pediatric cancers are the driving cause of death for children and adolescents. Due to safety requirements and considerations, treatment strategies and drugs for pediatric cancers have been so far scarcely studied. It is well known that tumor cells tend to progressively evade cell death pathways, which is known as apoptosis resistance, one of the hallmarks of cancer, dominating tumor drug resistance. Recently, treatments targeting nonapoptotic cell death have drawn great attention. Pyroptosis, a newly specialized form of cell death, acts as a critical physiological regulator in inflammatory reaction, cell development, tissue homeostasis and stress response. The action in different forms of pyroptosis is of great significance in the therapy of pediatric cancers. Pyroptosis could be induced and consequently modulate tumorigenesis, progression, and metastasis if treated with local or systemic therapies. However, excessive or uncontrolled cell death might lead to tissue damage, acute inflammation, or even cytokine release syndrome, which facilitates tumor progression or recurrence. Herein, we aimed to describe the molecular mechanisms of pyroptosis, to highlight and discuss the challenges and opportunities for activating pyroptosis pathways through various oncologic therapies in multiple pediatric neoplasms, including osteosarcoma, neuroblastoma, leukemia, lymphoma, and brain tumors.

Pyroptosis in development, inflammation and disease

In the early 2000s, caspase-1, an important molecule that has been shown to be involved in the regulation of inflammation, cell survival and diseases, was given a new function: regulating a new mode of cell death that was later defined as pyroptosis. Since then, the inflammasome, the inflammatory caspases (caspase-4/5/11) and their substrate gasdermins (gasdermin A, B, C, D, E and DFNB59) has also been reported to be involved in the pyroptotic pathway, and this pathway is closely related to the development of various diseases. In addition, important apoptotic effectors caspase-3/8 and granzymes have also been reported to b involved in the induction of pyroptosis. In our article, we summarize findings that help define the roles of inflammasomes, inflammatory caspases, gasdermins, and other mediators of pyroptosis, and how they determine cell fate and regulate disease progression.

Zika virus causes placental pyroptosis and associated adverse fetal outcomes by activating GSDME

Zika virus (ZIKV) can be transmitted from mother to fetus during pregnancy, causing adverse fetal outcomes. Several studies have indicated that ZIKV can damage the fetal brain directly; however, whether the ZIKV-induced maternal placental injury contributes to adverse fetal outcomes is sparsely defined. Here, we demonstrated that ZIKV causes the pyroptosis of placental cells by activating the executor gasdermin E (GSDME) in vitro and in vivo. Mechanistically, TNF-α release is induced upon the recognition of viral genomic RNA by RIG-I, followed by activation of caspase-8 and caspase-3 to ultimately escalate the GSDME cleavage. Further analyses revealed that the ablation of GSDME or treatment with TNF-α receptor antagonist in ZIKV-infected pregnant mice attenuates placental pyroptosis, which consequently confers protection against adverse fetal outcomes. In conclusion, our study unveils a novel mechanism of ZIKV-induced adverse fetal outcomes via causing placental cell pyroptosis, which provides new clues for developing therapies for ZIKV-associated diseases.

DFNA5 inhibits colorectal cancer proliferation by suppressing the mTORC1/2 signaling pathways via upregulation of DEPTOR

The human deafness, autosomal dominant 5 gene (DFNA5), a newly discovered executor of pyroptosis, has been strongly implicated in the tumorigenesis of several human cancers. However, an understanding of the functional role of DFNA5 in the development and progression of colorectal cancer (CRC) is limited. In this study, we demonstrated that DFNA5 was downregulated in CRC tissues. Ectopic expression of DFNA5 inhibited tumor cell growth in vitro, retarded tumor formation in vivo, and blocked a cell-cycle transition from the G0/G1 to the S phase, whereas a DFNA5 knockdown promoted cell proliferation. Western blotting showed that the levels of cell cycle-related proteins, including cyclin D1, cyclin E, CDK2, and p21, were accordingly altered upon DFNA5 overexpression or DFNA5 knockdown. Mechanistic studies indicated that DFNA5 exerted its tumor suppressor functions by antagonizing mTORC1/2 signaling via upregulation of DEPTOR. In addition, blockage of mTORC1/2 signaling by Torin-1 abolished the accelerative proliferation by DFNA5 knockdown. In conclusion, these results indicated that DFNA5 inhibits the proliferation and tumor formation of colon cancer cells by suppressing mTORC1/2 signaling.

Emerging mechanisms of pyroptosis and its therapeutic strategy in cancer

Pyroptosis, a type of inflammatory programmed cell death, is triggered by caspase cleavage of gasdermin family proteins. Based on accumulating evidence, pyroptosis is closely associated with tumour development, but the molecular mechanism underlying pyroptosis activation and the signalling pathways regulated by pyroptosis remain unclear. In this review, we first briefly introduce the definition, morphological characteristics, and activation pathways of pyroptosis and the effect of pyroptosis on anticancer immunity. Then we review recent progress concerning the complex role of pyroptosis in various tumours. Importantly, we summarise various FDA-approved chemotherapy drugs or natural compounds that exerted antitumor properties by inducing pyroptosis of cancer cells. Moreover, we also focus on the current application of nanotechnology-induced pyroptosis in tumour therapy. In addition, some unsolved problems and potential future research directions are also raised.

The natural compound from Garcinia bracteata mainly induces GSDME-mediated pyroptosis in esophageal cancer cells

BACKGROUND

Pyroptosis, an inflammatory form of programmed cell death (PCD), is reported to play important roles in the treatment of tumors. In our previous studies, we found that neobractatin (NBT), a caged prenylxanthone isolated from edible fruits of Garcinia bracteata C. Y. Wu ex Y. H. Li, showed anticancer effects against different cancer cells. However, the effect of NBT on pyroptosis is not well understood.

PURPOSE

This study aims to investigate whether and how GSDME-mediated pyroptosis contributes to NBT-induced antitumor effects in esophageal cancer (EC) cells.

METHODS

Cell viability assay and colony formation assay were used to determine the anticancer effects of NBT in esophageal cancer cells. Lactate dehydrogenase (LDH) release assay and microscopy imaging were used to detect the main characteristic of pyroptosis. CRISPR-Cas9 knockout and siRNA knockdown were performed to verify the roles of GSDME and caspase-3 in NBT-induced pyroptosis. Flow cytometry was used to measure the reactive oxygen species (ROS) level and cell apoptosis. The changes of related protein level were detected by Western blot. Furthermore, animal experiments were used to verify the in vivo effect of NBT.

RESULTS

The results showed that NBT reduced the viability of EC cells mainly through GSDME-mediated pyroptosis. Morphologically, NBT induced cell swelling and formed large bubbles emerging from plasma membrane in wild type EC cells. Furthermore, NBT induced the cleavage of GSDME by activating caspase-3 in EC cells. On the other hand, caspase-3 activated by NBT also induced apoptosis especially at high dosage. Knocking down GSDME switched NBT-induced cell death from mainly pyroptosis to apoptosis in vivo and in vitro. Mechanistic studies indicated that NBT led to accumulation of ROS, which then regulated the phosphorylation of both JNK and MEK/ERK. In the absence of ROS or caspase-3, NBT-induced pyroptosis and apoptosis were completely reversed. Moreover, NBT showed a significant antitumor effect in both the KYSE150 and GSDME knockout KYSE150-/- xenograft models by inducing pyroptosis and apoptosis, respectively.

CONCLUSION

Our results indicated that natural compound NBT could induce GSDME-mediated pyroptosis and apoptosis in esophageal cancer cells, making it a potential therapeutic drug in clinical treatment.

Novel Pyroptosis-Related Gene Signatures Identified as the Prognostic Biomarkers for Bladder Carcinoma

Background

Bladder carcinoma (BLCA) is a common malignant tumor with high morbidity and mortality in the urinary system. Pyroptosis is a pattern of programmed cell death that is closely associated with progression of tumors. Therefore, it is significant to probe the expression of pyroptosis-related genes (PRGs) in BLCA.

Methods

The differentially expressed genes in normal and BLCA tissues were first obtained from the Cancer Genome Atlas (TCGA) database analysis, as well as PRGs from the National Center for Biotechnology Information (NCBI) database, intersecting to obtain differentially expressed pyroptosis-related genes (DEPRGs) in BLCA. With the construction of a prognostic model of pyroptosis by regression analysis, we derived and validated key genes, which were ascertained as a separate prognostic marker by individual prognostic and clinical relevance analysis. In addition, we gained six immune cells from the Tumor Immune Evaluation Resource (TIMER) website and analyzed the relationship between pyroptosis prognostic genes and immune infiltration.

Result

Our results revealed that 31 DEPRGs were available by comparing normal and BLCA tissues with |log2 (fold change, FC)| &gt; 0.5 and FDR &lt;0.05. Four key genes (CRTAC1, GSDMB, AIM2, and FOXO3) derived from the pyroptosis prognostic model were experimentally validated for consistent expression in BLCA patients. Following risk scoring, the low-risk group of BLCA patients had noticeably higher overall survival (OS) than the high-risk group (p &lt; 0.001). Risk score was still an independent prognostic factor (HR = 1.728, 95% CI =1.289–2.315, p &lt; 0.001). In addition, we found remarkable correlations among the expression of pyroptosis-related prognostic genes and the immune infiltration of CD4+ T cells, CD8+ T cells, B cells, dendritic cells, macrophages, and neutrophils.

Conclusion

Genes (CRTAC1, GSDMB, AIM2, and FOXO3) associated with pyroptosis are potential BLCA prognostic biomarkers that act as an essential part in the predictive prognosis of survival and immunotherapy of BLCA.

Role of Pyroptosis in Inflammatory Bowel Disease (IBD): From Gasdermins to DAMPs

Pyroptosis is a pro-inflammatory cell death executed by gasdermin family proteins that involve the formation of pores on cells, recognition of danger signals, and release of pro-inflammatory cytokines IL-1β and IL-18. Pyroptosis modulates mucosal innate immunity and enteropathogenic bacterial infection. Similarly, the gasdermin family has been reported to be involved in the defense of the intestinal epithelium against bacterial infection and in the regulation of intestinal inflammation. Pyroptosis initiates damage signals that activate multiple pathways to cause inflammation, which may be a potential cause of chronic intestinal inflammation. In this review, we discuss the impact of pyroptosis on inflammatory bowel disease (IBD), with a focus on the executive proteins of pyroptosis (GSDMB, GADMD, and GSDME) and IBD-related endogenous damage-associated molecular patterns (DAMPs) produced by pyroptosis.

Gasdermin E: A Prospective Target for Therapy of Diseases

Gasdermin E (GSDME) is a member of the gasdermin protein family, which mediates programmed cell death including apoptosis and pyroptosis. Recently, it was suggested that GSDME is activated by chemotherapeutic drugs to stimulate pyroptosis of cancer cells and trigger anti-tumor immunity, which is identified as a tumor suppressor. However, GSDME-mediated pyroptosis contributes to normal tissue damage, leading to pathological inflammations. Inhibiting GSDME-mediated pyroptosis might be a potential target in ameliorating inflammatory diseases. Therefore, targeting GSDME is a promising option for the treatment of diseases in the future. In this review, we introduce the roles of GSDME-driven programmed cell death in different diseases and the potential targeted therapies of GSDME, so as to provide a foundation for future research.

Blocking GSDME-mediated pyroptosis in renal tubular epithelial cells alleviates disease activity in lupus mice

An increase in apoptosis and/or defects in the clearance of apoptotic cells resulting in massive secondary necrosis have been recognized as the main causes of systemic lupus erythematosus (SLE). Recent findings have revealed that gasdermin E (GSDME)-mediated pyroptosis is a mechanism associated with secondary necrosis. We aimed to investigate the effects of GSDME-mediated pyroptosis on disease activity in lupus mice. In vivo, high levels of GSDME expression were observed in the renal tubules of pristane-induced lupus (PIL) mice and SLE patients. In lupus mice, GSDME knockout or SP600125 administration effectively ameliorated lupus-like features by inhibiting GSDME-mediated renal tubular epithelial cell pyroptosis. In vitro, treatment with tumour necrosis factor-α (TNF-α) plus cycloheximide (CHX) or SLE sera induced HK2 cells to undergo pyroptosis in a caspase-3- and GSDME-dependent manner. Likewise, SP600125 significantly reduced GSDME expression and decreased pyroptosis in HK2 cells. GSDME-mediated pyroptosis may be associated with SLE pathogenesis, and targeting GSDME may be a potential strategy for treating SLE.

Pyroptosis-related molecular classification and immune microenvironment infiltration in breast cancer: A novel therapeutic target

The underlying role of pyroptosis in breast cancer (BC) remains unknown. Herein, we investigated the correlations of 33 pyroptosis‐related genes (PRGs) with immune checkpoints and immune cell infiltrations in BC patients based on The Cancer Genome Atlas cohort (n = 996) and Gene Expression Omnibus cohort (n = 3,262). Enrichment analysis revealed that these PRGs mainly functioned in pyroptosis, inflammasomes and regulation of autophagy pathway. Four prognostic independent PRGs (CASP9, TIRAP, GSDMC and IL18) were identified. Then, cluster 1/2 was recognized using consensus clustering for these four PRGs. Patients from cluster 1 had a favourable prognosis and diverse immune cell infiltrations. A nomogram was developed based on age, TNM stage, tumour subtype and pyroptosis score. Patients with the high‐risk group exhibited worse 5‐year OS, and the result was consistent in the external cohort. Additionally, high‐risk group patients were associated with downregulated immune checkpoint expression. Further analysis suggested that the high‐risk group patients were associated with a higher IC50 of paclitaxel, doxorubicin, cisplatin, methotrexate and vinorelbine. In summarizing, the pyroptosis score‐based nomogram might serve as an independent prognostic predictor and could guide medication for chemotherapy. Additionally, it may bring novel insight into the regulation of tumour immune microenvironment in BC and help to achieve precision immunotherapy.

Prognostic Implications of Pyroptosis-Related Gene Signatures in Lung Squamous Cell Carcinoma

Background: Lung squamous cell carcinoma (LUSC) has been a highly malignant tumor with very poor prognosis. It is confirmed that pyroptosis refers to the deaths of cells in a programmed and inflammatory manner. Nevertheless, the correlation between expression of genes related with pyroptosis and their prognosis remains uncertain in LUSC. Methods: Utilization of The Cancer Genome Atlas (TCGA) cohort has been done for evaluating the prognostics of pyroptosis-related genes for survival and constructing a signature with multiple genes. The least absolute shrinkage and selection operator (LASSO) Cox regression was performed for establishing such pyroptosis-related gene signature. Results: Eventually, identification of 28 genes in relation to pyroptosis was made in LUSC and healthy lung tissues. Upon the basis of these differentially-expressed genes (DEGs), the patients of LUSC can be divided into two subtypes. Nine gene signatures were established using LASSO. The surviving rate for low-risk group was apparently greater in contrast with the high-risk group (p < .001). According to our finding, risk score worked as an independent predictive factor of OS among LUSC sufferers in combination with clinical characteristics. In line with Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, the enrichment of immunity-related genes and decreasing immunity status among the high-risk group. Conclusion: Genes in relation with pyroptosis played an essential role in tumor immunity, which is capable of predicting the prognosis for LUSCs.

GSDME Is Related to Prognosis and Response to Chemotherapy in Oral Cancer

Gasdermin E (GSDME), as the major executive protein of pyroptosis, has been considered to be linked to antitumor immunity in recent years. However, the role of GSDME in oral squamous cell carcinoma (OSCC) remains to be elucidated. Here, by using a human OSCC tissue microarray, human OSCC tissue, and Tgfbr1/Pten conditional knockout mice, we found that GSDME was strongly expressed in OSCC and that GSDME expression in primary tumors was higher than that in metastatic lymph nodes. In addition, GSDME expression in OSCC was positively related to better prognosis. Moreover, GSDME-mediated pyroptosis occurred upon stimulation with chemotherapy drugs, and functional knockdown of GSDME attenuated the cisplatin-induced antitumor effect. Consistent with these results, bioinformatic analysis indicated that GSDME expression was positively correlated with the sensitivity of a number of antitumor drugs approved by the US Food and Drug Administration. Inhibition of GSDME expression by small interfering RNA in SCC7 cells significantly increased the expression of the cancer stem cell markers, CD44 and ALDH1. Furthermore, multiplexed immunohistochemistry and flow cytometry indicated that the expression of GSDME positively correlated with tumor-infiltrating CD8⁺ T cells, granzyme B, and M1 phenotype macrophages. Collectively, these findings demonstrated that GSDME is a potential positive prognostic factor of OSCC, and GSDME-mediated pyroptosis induced by chemotherapy plays a role in antitumor response.

A Pyroptosis-Based Prognostic Model for Immune Microenvironment Estimation of Hepatocellular Carcinoma

Background

Hepatocellular carcinoma (HCC), an aggressive malignant tumor, has a high incidence and unfavorable prognosis. Recently, the synergistic effect of pyroptosis in antitumor therapy and regulation of tumor immune microenvironment has made it possible to become a novel therapeutic method, but its potential mechanism still needs further exploration.

Methods

Differentially expressed genes with prognostic value in Liver Hepatocellular Carcinoma Project of The Cancer Genome Atlas (TCGA-LIHC) cohort were screened and incorporated into the risk signature by Cox proportional hazards regression model and least absolute shrinkage and selection operator. Kaplan-Meier (KM) curves and receiver operating characteristic (ROC) curves were applied to conduct survival comparisons and estimate prediction ability. The dataset of Liver Cancer-RIKEN, Japan Project from International Cancer Genome Consortium (ICGC-LIRI-JP) cohort was used to verify the reliability of the signature. Correlation analysis between clinicopathological characteristics, immune infiltration, drug sensitivities, and risk scores was conducted. Functional annotation analyses were performed for the genes differentially expressed between high-risk and low-risk groups.

Results

A risk signature consisting of 6 pyroptosis-related genes in HCC was developed and validated. KM curves and ROC curves revealed its considerable predictive accuracy. Higher risk scores meant more advanced grade, higher alpha-fetoprotein level, and stronger invasive ability. Overexpressed genes in high-risk population were more enriched in the immune-associated pathways, and these patients might be more sensitive to immune checkpoint inhibitors instead of Sorafenib. Intriguingly, 6 identified genes were promising to be prognostic biomarkers and therapeutic targets of HCC.

Conclusions

The signature may have crucial clinical significance in predicting survival prognosis, immune infiltration, and drug efficacy based on pyroptosis-related genes.

Epithelial-Mesenchymal Transition Induces GSDME Transcriptional Activation for Inflammatory Pyroptosis

GSDME is a newly recognized executor of cellular pyroptosis, and has been recently implicated in tumor growth and immunity. However, knowledge about the molecular regulators underlying GSDME abundance remains limited. Here, we performed integrative bioinformatics analyses and identified that epithelial-mesenchymal transition (EMT) gene signatures exhibited positive correlation with GSDME levels across human cancers. A causal role was supported by the observation that EMT dictated GSDME reversible upregulation in multiple experimental models. Mechanistically, transcriptional activation of GSDME was directly driven by core EMT-activating transcription factors ZEB1/2, which bound to the GSDME promoter region. Of functional importance, elevated GSDME in mesenchymally transdifferentiated derivatives underwent proteolytic cleavage upon antineoplastic drug exposure, leading to pyroptotic cell death and consequent cytokine release. Taken together, our findings pinpointed a key transcriptional machinery controlling GSDME expression and indicated potential therapeutic avenues to exploit GSDME-mediated inflammatory pyroptosis for the treatment of mesenchymal malignancies.

A Novel Pyroptosis-Related Gene Signature for Prognostic Prediction of Head and Neck Squamous Cell Carcinoma

Background

Head and neck squamous cell carcinoma (HNSCC) is an extremely heterogeneous malignant cancer with poor prognosis. Pyroptosis is defined as a novel inflammation-dependent programmed cell death. However, the pyroptosis-associated gene expression in HNSCC and their relationship with prognosis are still indistinct.

Material and Methods

We acquired the mRNA expression information of HNSCC patients from publicly available TCGA and GEO databases. We compared the tumor issues and adjacent normal tissues in terms of the gene expression for the purpose of identifying differentially expressed genes (DEGs). Based on these genes, we established a risk signature by the LASSO Cox regression in the TCGA cohort and validated the results in a GEO cohort. We also verified the levels of relevant mRNA expression in the model by RT-qPCR analysis. Eventually, functional enrichment approach was carried out to explore the potential mechanisms.

Results

Our team found a total of 18 differentially expressed genes (DEGs) between the HNSCC and healthy samples, and 4 DEGs displayed a remarkable association with the overall survival (OS) (P < 0.05). A 4-gene signature was constructed, presenting beneficial forecast power in both TCGA and GEO cohorts. Our team categorized patients into a group with high risk and another group with low risk as per the average risk value of the 4-gene feature. The individuals in the low risk group displayed a notably greater OS compared with the high risk one (P < 0.01). The Cox regression study demonstrated the independent forecast capability of the risk score. The receiver operating characteristic approach facilitated the verification of the forecast function of the gene signature. Posterior to verification, 4 genes were aberrantly expressed in the HNSCC and healthy samples. Functional study displayed that these groups presented diverse immunity conditions.

Conclusion

Pyroptosis-associated genes are pivotal for the prognosis of HNSCC and can serve as potential therapeutic targets.

The multifaceted roles of gasdermins in cancer biology and oncologic therapies

The involvement of the Gasdermin (GSDM) protein family in cancer and other pathologies is one of the hottest topics in biomedical research. There are six GSDMs in humans (GSDMA, B, C, D, GSDME/DFNA5 and PJVK/DFNB59) and, except PJVK, they can trigger cell death mostly by pyroptosis (a form of lytic and pro-inflammatory cell death) but also other mechanisms. The exact role of GSDMs in cancer is intricate, since depending on the biological context, these proteins have diverse cell-death dependent and independent functions, exhibit either pro-tumor or anti-tumor functions, and promote either sensitization or resistance to oncologic treatments. In this review we provide a comprehensive overview on the multifaceted roles of the GSDMs in cancer, and we critically discuss the possibilities of exploiting GSDM functions as determinants of anti-cancer treatment and as novel therapeutic targets, with special emphasis on innovative GSDM-directed nano-therapies. Finally, we discuss the issues to be resolved before GSDM-mediated oncologic therapies became a reality at the clinical level.

Pyroptosis in Steatohepatitis and Liver Diseases

Pyroptosis is an inflammatory form of regulated cell death, which functions in the clearance of intracellularly replicating pathogens by cell lysis in order to induce further immune response. Since the discovery of the gasdermin (GSDM) family, pyroptosis has attracted attention in a wide range of inflammatory diseases such as nonalcoholic steatohepatitis and other liver diseases. Due to the cleavage of GSDMs by different caspases, the amino-terminal GSDM fragments form membrane pores essential for pyroptosis that facilitate the release of inflammatory cytokines by loss of ionic gradient and membrane rupture. In this review, we address the key molecular and cellular processes that induce pyroptosis in the liver and its significance in the pathogenesis of common liver diseases in different human and experimental mice studies.

p53-GSDME Elevation: A Path for CDK7 Inhibition to Suppress Breast Cancer Cell Survival

Higher cyclin-dependent kinase (CDK7) expression is a character of breast cancer and indicates poor prognosis. Inhibiting CDK7 exhibited effective cancer cell suppression which implies the potential of CDK7 inhibition to be a method for anti-cancer treatment. Our study aimed to explore a novel mechanism of CDK7 inhibition for suppressing breast cancer cell survival. Here, we proved inhibiting CDK7 repressed breast cancer cell proliferation and colony formation and increased the apoptotic cell rate, with p53 and GSDME protein level elevation. When p53 was suppressed in MCF-7 cells, the decline of GSDME expression and associated stronger proliferation and colony formation could be observed. Since downregulation of GSDME was of benefit to breast cancer cells, p53 inhibition blocked the elevation of GSDME induced by CDK7 inhibition and retrieved cells from the tumor suppressive effect of CDK7 inhibition. Therefore, CDK7 inhibition exerted a negative effect on breast cancer cell proliferation and colony formation in a p53–GSDME dependent manner. These results revealed the CDK7–p53–GSDME axis could be a pathway affecting breast cancer cell survival.

Inflammation-related pyroptosis, a novel programmed cell death pathway, and its crosstalk with immune therapy in cancer treatment

In recent decades, chemotherapies targeting apoptosis have emerged and demonstrated remarkable achievements. However, emerging evidence has shown that chemoresistance is mediated by impairing or bypassing apoptotic cell death. Several novel types of programmed cell death, such as ferroptosis, necroptosis, and pyroptosis, have recently been reported to play significant roles in the modulation of cancer progression and are considered a promising strategy for cancer treatment. Thus, the switch between apoptosis and pyroptosis is also discussed. Cancer immunotherapy has gained increasing attention due to breakthroughs in immune checkpoint inhibitors; moreover, ferroptosis, necroptosis, and pyroptosis are highly correlated with the modulation of immunity in the tumor microenvironment. Compared with necroptosis and ferroptosis, pyroptosis is the primary mechanism for host defense and is crucial for bridging innate and adaptive immunity. Furthermore, recent evidence has demonstrated that pyroptosis exerts benefits on cancer immunotherapies, including immune checkpoint inhibitors (ICIs) and chimeric antigen receptor T-cell therapy (CAR-T). Hence, in this review, we elucidate the role of pyroptosis in cancer progression and the modulation of immunity. We also summarize the potential small molecules and nanomaterials that target pyroptotic cell death mechanisms and their therapeutic effects on cancer.

Pyroptosis in Cancer: Friend or Foe?

Simple Summary

Pyroptosis is a new form of programmed cell death that differs from apoptosis in terms of its release of inflammatory factors and its characteristic bubble-like morphology. Pyroptosis was first discovered in the process of immune defense against bacterial infection, but the field of research soon spread to other inflammatory diseases and cancer. As cancer constitutes a serious risk for public health, numerous studies investigating pyroptosis in cancer have been carried out during these years. Tumorigenesis and new therapeutic treatments have been the focus of much recent research. This review discusses the role of pyroptosis in tumorigenesis and its influence on tumor immunity.

Abstract

Pyroptosis is an inflammatory form of programmed cell death that is mediated by pore-forming proteins such as the gasdermin family (GSDMs), including GSDMA-E. Upon cleavage by activated caspases or granzyme proteases, the N-terminal of GSDMs oligomerizes in membranes to form pores, resulting in pyroptosis. Though all the gasdermin proteins have been studied in cancer, the role of pyroptosis in cancer remains mysterious, with conflicting findings. Numerous studies have shown that various stimuli, such as pathogen-associated molecular patterns (PAMPs), damage-associated molecular patterns (DAMPs), and chemotherapeutic drugs, could trigger pyroptosis when the cells express GSDMs. However, it is not clear whether pyroptosis in cancer induced by chemotherapeutic drugs or CAR T cell therapy is beneficial or harmful for anti-tumor immunity. This review discusses the discovery of pyroptosis as well as its role in inflammatory diseases and cancer, with an emphasis on tumor immunity.

Triclabendazole Induces Pyroptosis by Activating Caspase-3 to Cleave GSDME in Breast Cancer Cells

Pyroptosis is a form of programmed cell death, in which gasdermin E (GSDME) plays an important role in cancer cells, which can be induced by activated caspase-3 on apoptotic stimulation. Triclabendazole is a new type of imidazole in fluke resistance and has been approved by the FDA for the treatment of fascioliasis and its functions partially acting through apoptosis-related mechanisms. However, it remains unclear whether triclabendazole has obvious anti-cancer effects on breast cancer cells. In this study, to test the function of triclabendazole on breast cancer, we treated breast cancer cells with triclabendazole and found that triclabendazole induced lytic cell death in MCF-7 and MDA-MB-231, and the dying cells became swollen with evident large bubbles, a typical sign of pyroptosis. Triclabendazole activates apoptosis by regulating the apoptoic protein levels including Bax, Bcl-2, and enhanced cleavage of caspase-8/9/3/7 and PARP. In addition, enhanced cleavage of GSDME was also observed, which indicates the secondary necrosis/pyroptosis is further induced by active caspase-3. Consistent with this, triclabendazole-induced GSDME-N-terminal fragment cleavage and pyroptosis were reduced by caspase-3-specific inhibitor (Ac-DEVD-CHO) treatment. Moreover, triclabendazole induced reactive oxygen species (ROS) elevation and increased JNK phosphorylation and lytic cell death, which could be rescued by the ROS scavenger (NAC), suggesting that triclabendazole-induced GSDME-dependent pyroptosis is related to the ROS/JNK/Bax-mitochondrial apoptotic pathway. Besides, we showed that triclabendazole significantly reduced the tumor volume by promoting the cleavage of caspase-3, PARP, and GSDME in the xenograft model. Altogether, our results revealed that triclabendazole induces GSDME-dependent pyroptosis by caspase-3 activation at least partly through augmenting the ROS/JNK/Bax-mitochondrial apoptotic pathway, providing insights into this on-the-market drug in its potential new application in cancer treatment.

Gasdermin E-mediated programmed cell death: An unpaved path to tumor suppression

Hearing loss-associated protein gasdermin E (GSDME), an effector of secondary necrosis, has been identified in a new pathway of programmed cell death (PCD). GSDME epigenetic silencing and mutations resulting in loss-of-function have been reported in cancer tissues. Additionally, GSDME upregulation inhibits tumor proliferation as well as colony forming ability, and reduces the incidence of lymphatic metastasis, demonstrating that GSDME may act as a tumor suppressor. Here, we have focused on the molecular mechanisms of GSDME-mediated PCD, and tried to reveal the crosstalk between this cell death pathway and apoptosis, autophagy, GSDMD-mediated pyroptosis. Moreover, we concluded the anti-cancer activity of GSDME include forming permeable membranes, and triggering anti-cancer immunity. Thus, GSDME was potential to be a novel target for cancer prevention and treatment.

Pyroptosis: mechanisms and diseases

Currently, pyroptosis has received more and more attention because of its association with innate immunity and disease. The research scope of pyroptosis has expanded with the discovery of the gasdermin family. A great deal of evidence shows that pyroptosis can affect the development of tumors. The relationship between pyroptosis and tumors is diverse in different tissues and genetic backgrounds. In this review, we provide basic knowledge of pyroptosis, explain the relationship between pyroptosis and tumors, and focus on the significance of pyroptosis in tumor treatment. In addition, we further summarize the possibility of pyroptosis as a potential tumor treatment strategy and describe the side effects of radiotherapy and chemotherapy caused by pyroptosis. In brief, pyroptosis is a double-edged sword for tumors. The rational use of this dual effect will help us further explore the formation and development of tumors, and provide ideas for patients to develop new drugs based on pyroptosis.

Biological Functions of Gasdermins in Cancer: From Molecular Mechanisms to Therapeutic Potential

Pyroptosis is a type of lytic programmed cell death triggered by various inflammasomes that sense danger signals. Pyroptosis has recently attracted great attention owing to its contributory role in cancer. Pyroptosis plays an important role in cancer progression by inducing cancer cell death or eliciting anticancer immunity. The participation of gasdermins (GSDMs) in pyroptosis is a noteworthy recent discovery. GSDMs have emerged as a group of pore-forming proteins that serve important roles in innate immunity and are composed of GSDMA-E and Pejvakin (PJVK) in human. The N-terminal domains of GSDMs, expect PJVK, can form pores on the cell membrane and function as effector proteins of pyroptosis. Remarkably, it has been found that GSDMs are abnormally expressed in several forms of cancers. Moreover, GSDMs are involved in cancer cell growth, invasion, metastasis and chemoresistance. Additionally, increasing evidence has indicated an association between GSDMs and clinicopathological features in cancer patients. These findings suggest the feasibility of using GSDMs as prospective biomarkers for cancer diagnosis, therapeutic intervention and prognosis. Here, we review the progress in unveiling the characteristics and biological functions of GSDMs. We also focus on the implication and molecular mechanisms of GSDMs in cancer pathogenesis. Investigating the relationship between GSDMs and cancer biology could assist us to explore new therapeutic avenues for cancer prevention and treatment.

GSDME and its role in cancer: From behind the scenes to the front of the stage

Gasdermin E (GSDME), a gene originally involved in hereditary hearing loss, has been associated with several types of cancer in the last two decades. Recently, GSDME was identified as a pore-forming molecule, which is activated following caspase-3-mediated cleavage resulting in so-called secondary necrosis following apoptotic cell death, or in primary necrotic cell death without an apoptotic phase, so-called pyroptosis-like. This implication in cell death execution suggests its potential role as a tumor suppressor. GSDME also exhibited a cancer type-specific differential methylation pattern between tumor tissues and normal cells, implying GSDME gene methylation as both a pan-cancer and cancer type-specific detection biomarker. A bit paradoxically, GSDME protein expression is considered to be less suited as biomarker, and although its ablation does not protect the cell against eventual cell death, its protein expression might still operate in tumor immunogenicity due to its capacity to induce (secondary) necrotic cell death, which has enhanced immunogenic properties. Additionally, GSDME gene expression has been shown to be associated with favorable prognosis following chemotherapy, and it could therefore be a potential predictive biomarker. We provide an overview of the different associations between GSDME gene methylation, gene expression and tumorigenesis, and explore their potential use in the clinic. Our review only focuses on GSDME and summarizes the current knowledge and most recent advances on GSDME's role in cancer formation, its potential as a biomarker in cancer and on its promising role in immunotherapies and antitumor immune response.

Gasdermine E-Dependent Mitochondrial Pyroptotic Pathway in Dermatomyositis: A Possible Mechanism of Perifascicular Atrophy

Different mechanisms have been proposed to explain the pathological basis of perifascicular atrophy (PFA), a pathognomonic histologic feature of dermatomyositis (DM); however, the detailed mechanisms remain to be elucidated. There is mitochondrial dysfunction in PFA and expression of mitochondrial apoptosis molecules has been reported in DM. Overexpression of gasdermin E (GSDME) can turn mitochondrial apoptosis to mitochondrial pyroptosis, a newly characterized form of programmed cell death. We determined the expression of proteins involved in the caspase-3- and GSDME-dependent mitochondrial pyroptotic pathway, including BAX, BAK, cytochrome C, caspase-9, caspase-3, GSDME, and IL-1α, in biopsied muscles from DM and control patients. Immunohistochemical analysis showed that those markers were expressed in most fibers in PFA in DM. GSDME-positive and IL-1α-positive staining was mainly localized around punched-out vacuoles or sarcolemma. These markers were significantly upregulated at the protein and mRNA levels in DM versus controls. Our results suggest that caspase-3- and GSDME-dependent mitochondrial pyroptosis are involved in the pathogenetic mechanisms of PFA in DM and that targeting GSDME-dependent mitochondrial pyroptosis may be an effective therapeutic approach for this condition.

Role of GSDMB in Pyroptosis and Cancer

Gasdermin B (GSDMB) belongs to the gasdermin (GSDM) family which may adopt different mechanisms of intramolecular domain interactions to modulate their lipid-binding and pore-forming activities. The GSDM family has regulatory functions in cell proliferation and differentiation, especially in pyroptosis process. Pyroptosis is a pro-inflammatory form of regulated cell death and is designed to attract a nonspecific innate response to the site of infection. For cancer cells, the activation of pyroptosis may promote cell death and exert anticancer properties. Also, recent studies have observed the pyroptosis-like features in GSDMB and some researches have shown that GSDMB overexpression occurred in several kinds of cancers; these findings bring a contradiction with the participation of GSDMB in pyroptosis. Although people pay less attention to GSDMB, it still has some essential research value. It is a paradox that GSDMB might participate in programmed cell death, which might put forward a research direction of therapeutic targets for cancer. Here, we review the possible progress of how GSDMB participated in this inflammatory regulation mechanistically and the potential functions of GSDMB in cancer.

Distinct characteristics of dasatinib-induced pyroptosis in gasdermin E-expressing human lung cancer A549 cells and neuroblastoma SH-SY5Y cells

Dasatinib, a multikinase inhibitor, is used in the treatment of chronic myeloid leukemia and was developed to overcome imatinib resistance. Its mechanism of action involves the induction of apoptosis, autophagy and necroptosis. However, it remains unclear whether dasatinib can induce pyroptosis. In the present study, gasdermin E (GSDME)-expressing SH-SY5Y and A549 cells were chosen for investigation. Typical pyroptotic features, such as cleavage of GSDME protein, leakage of lactate dehydrogenase and large bubbled morphology, were observed in both cell lines after exposure to dasatinib. The generation of GSDME fragments was inhibited by specific caspase-3 inhibitor zDEVD in SH-SY5Y cells and pan-caspase inhibitor zVAD in A549 cells. Moreover, distinct characteristics of pyroptosis were observed in A549 cells, which occurred only with a high percentage of Annexin V/propidium iodide double-stained cells and low level of GSDME protein cleavage. The sensitivity of A549 cells to dasatinib is significantly reduced by increasing cell numbers. The elevation of GSDMD and GSDME protein levels was induced by low concentrations of dasatinib, which was not influenced by the reduction of p53 protein with RNA interference. In conclusion, to the best of our knowledge, this is the first study to report that dasatinib can induce pyroptosis in tumor cells and increase the protein levels of GSDMD and GSDME in a p53-independent manner.

Granzyme A from cytotoxic lymphocytes cleaves GSDMB to trigger pyroptosis in target cells

Cytotoxic lymphocyte-mediated immunity relies on granzymes. Granzymes are thought to kill target cells by inducing apoptosis, although the underlying mechanisms are not fully understood. Here, we report that natural killer cells and cytotoxic T lymphocytes kill gasdermin B (GSDMB)-positive cells through pyroptosis, a form of proinflammatory cell death executed by the gasdermin family of pore-forming proteins. Killing results from the cleavage of GSDMB by lymphocyte-derived granzyme A (GZMA), which unleashes its pore-forming activity. Interferon-γ (IFN-γ) up-regulates GSDMB expression and promotes pyroptosis. GSDMB is highly expressed in certain tissues, particularly digestive tract epithelia, including derived tumors. Introducing GZMA-cleavable GSDMB into mouse cancer cells promotes tumor clearance in mice. This study establishes gasdermin-mediated pyroptosis as a cytotoxic lymphocyte-killing mechanism, which may enhance antitumor immunity.

Research progresses of molecular mechanism of pyroptosis and its related diseases

Pyroptosis is a newly discovered untypical form of programmed cell death by inflammatory response, which is dependent on the classic pathway of Caspase-1 and the non-canonical pathway of Caspase-11 in mice or orthologue Caspase-4/-5 in Humans. It has been found that the Gasdermin family of protein is a key molecule in the formation of membrane pores of pyroptosis. After being cleaved by inflammatory caspases, it releases a N-terminal fragment with perforating activity to trigger pyroptosis. That pyroptosis is closely related to the occurrence and development of certain diseases. Now, the molecular mechanism of pyroptosis and pyroptosis-related diseases are reviewed.