Natural product triptolide induces GSDME-mediated pyroptosis in head and neck cancer through suppressing mitochondrial hexokinase-ΙΙ

LncRNA SLC9A3-AS1 knockdown increases the sensitivity of liver cancer cell to triptolide by regulating miR-449b-5p-mediated glycolysis

Triptolide (TP) is involved in the progression of liver cancer. However, the detailed molecular network regulated through TP is still unclear. Long non-coding RNA (LncRNA) SLC9A3 exerts roles in various pathological progresses. Nevertheless, whether SLC9A3 affects the sensitivity of liver cancer cells to TP have not been uncovered. The content of SLC9A3-AS1 and miR-449b-5p was estimated by utilizing quantitative real-time polymerase-chain reaction (qRT-PCR). Cell counting kit 8 (CCK-8) assay was introduced to assess cell viability. Additionally, cell viability as well as invasion was tested via transwell assay. The direct binding between miR-449b-5p and SLC9A3-AS1 or LDHA was confirmed through luciferase reporter gene assay. Moreover, glycolysis rate was tested by calculating the uptake of glucose in addition to the production of lactate in Huh7 cells. LncRNA SLC9A3-AS1 was up-regulated in liver cancer tissue samples and cells. Knockdown of SLC9A3-AS1 notably further inhibited viability, migration as well as invasion in Huh7 cells. MiR-449b-5p was the direct downstream miRNA of SLC9A3-AS1 and was down-regulated by SLC9A3-AS1 in Huh7 cells. In addition, miR-449b-5p was reduced in liver cancer tissues and cells. Overexpressed miR-449b-5p increased the sensitivity of Huh7 cells to TP remarkably. Moreover, miR-449b-5p negatively regulated LDHA expression in Huh7 cells. This work proved that SLC9A3-AS1 increased the sensitivity of liver cancer cells to TP by regulating glycolysis rate mediated via miR-449b-5p/LDHA axis. These findings implied that TP is likely to be a potent agent for treating patients diagnosed with liver cancer.

A novel pharmacological mechanism of anti-cancer drugs that induce pyroptosis

Pyroptosis is an inflammasome-induced lytic form of programmed cell death, and its main effect involves the release of inflammatory mediators when a cell dies, resulting in an inflammatory response in the body. The key to pyroptosis is the cleavage of GSDMD or other gasdermin families. Some drugs can cause cleavage GSDMD or other gasdermin members cause pyroptosis and suppress cancer growth and development. This review explores several drugs that may induce pyroptosis, thereby contributing to tumor treatment. Pyroptosis-inducing drugs, such as arsenic, platinum, and doxorubicin, were used originally in cancer treatment. Other pyroptosis-inducing drugs, such as metformin, dihydroartemisinin, and famotidine, were used to control blood glucose, treat malaria, and regulate blood lipid levels and are effective tumor treatments. By summarizing drug mechanisms, we provide a valuable basis for treating cancers by inducing pyroptosis. In future, the use of these drugs may contribute to new clinical treatments.

Friend or foe? The dual role of triptolide in the liver, kidney, and heart

Triptolide, a controversial natural compound due to its significant pharmacological activities and multiorgan toxicity, has gained much attention since it was isolated from the traditional Chinese herb Tripterygium wilfordii Hook F. However, in addition to its severe toxicity, triptolide also presents powerful therapeutic potency in the same organs, such as the liver, kidney, and heart, which corresponds to the Chinese medicine theory of You Gu Wu Yun (anti-fire with fire) and deeply interested us. To determine the possible mechanisms involved in the dual role of triptolide, we reviewed related articles about the application of triptolide in both physiological and pathological conditions. Inflammation and oxidative stress are the two main ways triptolide exerts different roles, and the cross-talk between NF-κB and Nrf2 may be one of the mechanisms responsible for the dual role of triptolide and may represent the scientific connotation of You Gu Wu Yun. For the first time, we present a review of the dual role of triptolide in the same organ and propose the possible scientific connotation of the Chinese medicine theory of You Gu Wu Yun, hoping to promote the safe and efficient use of triptolide and other controversial medicines.

Brassinin Induces Apoptosis, Autophagy, and Paraptosis via MAPK Signaling Pathway Activation in Chronic Myelogenous Leukemia Cells

Brassinin (BSN), a potent phytoalexin found in cruciferous vegetables, has been found to exhibit diverse anti-neoplastic effects on different cancers. However, the impact of BSN on chronic myelogenous leukemia (CML) cells and the possible mode of its actions have not been described earlier. We investigated the anti-cytotoxic effects of BSN on the KBM5, KCL22, K562, and LAMA84 CML cells and its underlying mechanisms of action in inducing programmed cell death. We noted that BSN could induce apoptosis, autophagy, and paraptosis in CML cells. BSN induced PARP cleavage, subG1 peak increase, and early apoptosis. The potential action of BSN on autophagy activation was confirmed by an LC3 expression and acridine orange assay. In addition, BSN induced paraptosis through increasing the reactive oxygen species (ROS) production, mitochondria damage, and endoplasmic reticulum (ER) stress. Moreover, BSN promoted the activation of the MAPK signaling pathway, and pharmacological inhibitors of this signaling pathway could alleviate all three forms of cell death induced by BSN. Our data indicated that BSN could initiate the activation of apoptosis, autophagy, and paraptosis through modulating the MAPK signaling pathway.

Developing a pyroptosis-related gene signature to better predict the prognosis and immune status of patients with head and neck squamous cell carcinoma

Chronic inflammation may promote the incidence and development of neoplasms. As a pro-inflammatory death pathway, pyroptosis could induce normal cells to transform into cancerous cells, but the potential effect of pyroptosis in head and neck squamous cell carcinoma (HNSCC) remains unclear. This study developed and evaluated a pyroptosis-related gene signature to predict the prognosis and immune status of patients with HNSCC. The gene expression, mutation information, and clinical characteristics of HNSCC were extracted from TCGA to establish a comprehensive genome database (GEO). Based on LASSO Cox regression model, nine pyroptosis-related genes (TTLL1, TRIML2, DYNC1I1, KLHL35, CAMK2N1, TNFRSF18, GLDC, SPINK5, and DKK1) were used to construct a pyroptosis-related gene signature, which had good ability to predict the prognosis of HNSCC. Furthermore, the expression of nine pyroptosis-related genes in HNSCC and paracancerous tissues was detected by quantitative real-time PCR (qRT-PCR). The potential immunotherapeutic features and drug sensitivity prediction of this signature were also explored. Because pyroptosis regulators play an important role in HNSCC development and prognoses, further exploration might assist in identifying new biomarkers and predictors of prognosis to benefit clinical identification and management.

Alantolactone induces concurrent apoptosis and GSDME-dependent pyroptosis of anaplastic thyroid cancer through ROS mitochondria-dependent caspase pathway

BACKGROUND

Anaplastic thyroid cancer (ATC) is one of the fatal cancers and has not effective treatments. Alantolactone (ATL), a terpenoid extracted from traditional Chinese medicinal herb Inula helenium L., confers significant anti-inflammatory, antibacterial and antitumor activity. However, the activity and mechanisms of ATL in ATC remain unclear.

PURPOSE

To investigate the potential anti-ATC effects in vitro and in vivo and the mechanisms involved.

METHODS

The anti-proliferative activity of Alantolactone (ATL) against ATC cells was analyzed through CCK-8 and colony formation assays. Flow cytometry assay was performed to assess the cell cycle, cell apoptosis, ROS, and mitochondrial membrane potential (ΔΨm), whereas the cellular localization of cytochrome c and calreticulin were determined using cellular immunofluorescence assays. The lactate dehydrogenase (LDH) enzyme activity in the cell culture medium was measured using a commercial LDH kit, whereas ELISA was conducted to assess the secretory function of IL-1β. Western blot assays were conducted to determine the expression or regulation of proteins associated with apoptosis and pyroptosis. Subcutaneous tumor model of nude mice was established to evaluate the anticancer activity of ATL in vivo. The expression of Ki67, cyclin B1, cleaved-PARP, cleaved-caspase 3, and IL-1β in the animal tumor tissues was profiled using immunohistochemistry analyses.

RESULTS

Our data showed that ATL significantly inhibited the proliferation and colony formation activity of ATC cells. ATL induced ATC cell cycle arrest at G2/M phase, and downregulated the expression of cyclin B1 and CDC2. Furthermore, ATL induced concurrent apoptosis and pyroptosis in the ATC cells, and the cleavage of PARP and GSDME. It also significantly increased the release of LDH and IL-1β. Mechanically, ATL-mediated increase in ROS suppressed the Bcl-2/Bax ratio, downregulated the mitochondrial membrane potential and increased the release of cytochrome c, leading to caspase 9 and caspase 3 cleavage. We also found that ATL induced the translocation of an immunogenic cell death marker (calreticulin) to the cell membrane. In addition, it inhibited the growth of the ATC subcutaneous xenograft model, and activated proteins associated with apoptosis and pyroptosis, with a high safety profile.

CONCLUSION

Taken together, these results firstly demonstrated that ATL exerted an anti-ATC activity by inducing concurrent apoptosis and GSDME-dependent pyroptosis through ROS-mediated mitochondria-dependent caspase activation. Meanwhile, these cell deaths exhibited obvious characteristics of immunogenic cell death, which may synergistically increase the potential of cancer immunotherapy in ATC. Further studies are needed to explore deeper mechanisms for the anti- ATC activity of ATL.

Downregulation of lncRNA SLC7A11-AS1 decreased the NRF2/SLC7A11 expression and inhibited the progression of colorectal cancer cells

Colorectal cancer (CRC) is ranked as the second leading cause of cancer-related death worldwide. Many abnormally expressed long non-coding RNAs (lncRNAs) in CRC were identified with the development of next-generation sequencing, most functions of which are largely unclear. In this study, we report that the lncRNA SLC7A11-AS1 was significantly overexpressed in CRC by analyzing TCGA database and 6 pairs of clinical samples. High SLC7A11-AS1 level was related to poor CRC overall survival and SLC7A11-AS1 knockdown could inhibit the proliferation, migration and invasion of CRC cell lines. Furthermore, we found there was a positive correlation between the expression of SLC7A11-AS1 and its' sense transcript SLC7A11. In HCT-8 cells, SLC7A11-AS1 knockdown decreased expression of both SLC7A11 and the nuclear level of NRF2, which happens to be the activator of SLC7A11 transcription. Interestingly, in SLC7A11-AS1 overexpressed CRC tissues, SLC7A11 and NRF2 were also upregulated. Moreover, the ROS levels increased with SLC7A11-AS1 knockdown in HCT-8 cells. And the down regulated expression of SLC7A11 and lower ROS level causing by SLC7A11-AS1 knocked down could be relieved by overexpressed NRF2. These results suggested that upregulated SLC7A11-AS1 might promote the formation and progression of CRC by increasing the expression of NRF2 and SLC7A11, which decreases the ROS level in cancer cells. Therefore, SLC7A11-AS1 could be a potential therapeutic target and diagnostic marker of CRC.

Shikonin triggers GSDME-mediated pyroptosis in tumours by regulating autophagy via the ROS-MAPK14/p38α axis

BACKGROUND

Shikonin (SK), a botanical drug extracted from Lithospermum erythrorhizon, has been shown to inhibit tumour growth through apoptosis and necrosis. However, whether SK induces pyroptosis in cancer cells is still unknown.

PURPOSE

This study aims to investigated the mechanisms of SK-induced pyroptosis in tumour cells and mice.

METHODS

In vivo and in vitro methods were used in this study. Cell deaths were analysed by LDH and CCK-8 assay and western blotting. To investigated the signalling pathway of SK-induced pyroptosis, various genes expressions were supressed by shRNA or inhibitors. High-sensitivity mass spectrometry assay was used to identified potential factors that regulate GSDME-mediated pyroptosis. Finally, a mouse model was used to investigate the effect of SK administration on tumour growth in vivo.

RESULTS

The activation of BAX/caspase-3 signalling was essential for GSDME-mediated pyroptosis by SK. Mechanistically, the intracellular reactive oxygen species (ROS) generation induced by SK treatment initiated GSDME-dependant pyroptosis. SK stimulation induced protective autophagy in a ROS-dependant manner, and repressed autophagy significantly enhanced SK-induced pyroptosis. Moreover, MAPK14/p38α, a ROS sensor, modulated SK-induced autophagy and ultimately affected GSDME-dependant pyroptosis.

CONCLUSION

Here, for the first time we demonstrated that SK treatment induced GSDME-dependant pyroptosis in tumour cells. Our results demonstrated that SK initiates ROS signalling to drive pyroptosis in cancer cells.

Targeting cell death pathways for cancer therapy: recent developments in necroptosis, pyroptosis, ferroptosis, and cuproptosis research

Many types of human cells self-destruct to maintain biological homeostasis and defend the body against pathogenic substances. This process, called regulated cell death (RCD), is important for various biological activities, including the clearance of aberrant cells. Thus, RCD pathways represented by apoptosis have increased in importance as a target for the development of cancer medications in recent years. However, because tumor cells show avoidance to apoptosis, which causes treatment resistance and recurrence, numerous studies have been devoted to alternative cancer cell mortality processes, namely necroptosis, pyroptosis, ferroptosis, and cuproptosis; these RCD modalities have been extensively studied and shown to be crucial to cancer therapy effectiveness. Furthermore, evidence suggests that tumor cells undergoing regulated death may alter the immunogenicity of the tumor microenvironment (TME) to some extent, rendering it more suitable for inhibiting cancer progression and metastasis. In addition, other types of cells and components in the TME undergo the abovementioned forms of death and induce immune attacks on tumor cells, resulting in enhanced antitumor responses. Hence, this review discusses the molecular processes and features of necroptosis, pyroptosis, ferroptosis, and cuproptosis and the effects of these novel RCD modalities on tumor cell proliferation and cancer metastasis. Importantly, it introduces the complex effects of novel forms of tumor cell death on the TME and the regulated death of other cells in the TME that affect tumor biology. It also summarizes the potential agents and nanoparticles that induce or inhibit novel RCD pathways and their therapeutic effects on cancer based on evidence from in vivo and in vitro studies and reports clinical trials in which RCD inducers have been evaluated as treatments for cancer patients. Lastly, we also summarized the impact of modulating the RCD processes on cancer drug resistance and the advantages of adding RCD modulators to cancer treatment over conventional treatments.

Roles of Mitochondria in Oral Squamous Cell Carcinoma Therapy: Friend or Foe?

Oral squamous cell carcinoma (OSCC) therapy is unsatisfactory, and the prevalence of the disease is increasing. The role of mitochondria in OSCC therapy has recently attracted increasing attention, however, many mechanisms remain unclear. Therefore, we elaborate upon relative studies in this review to achieve a better therapeutic effect of OSCC treatment in the future. Interestingly, we found that mitochondria not only contribute to OSCC therapy but also promote resistance, and targeting the mitochondria of OSCC via nanoparticles is a promising way to treat OSCC.

Identification of a Prognostic Pyroptostic-Related Model for Head and Neck Squamous Cell Carcinoma Based on LASSO-Cox Regression Analysis

Pyroptosis is associated with the biological behavior of the tumor and with tumor immunity. We investigated the effect of pyroptosis on the tumor microenvironment and tumor immunity in head and neck squamous cell carcinoma (HNSCC). RNA sequencing data and clinical information of HNSCC were downloaded from TCGA. Differentially expressed pyroptosis-related genes in HNSCC were identified between HNSCC and normal tissue. Pyroptosis-related classification of HNSCC was conducted based on consensus clustering analysis. LASSO-Cox regression analysis was used to construct a prognostic risk model-based pyroptosis-related gene. Evaluation of the immune microenvironment was conducted in prognostic risk signature based on pyroptosis-related genes. Total 22 differentially expressed pyroptosis-related genes were identified in HNSCC. Six prognostic-related genes were included to construct a LASSO regression model with a prognostic risk score = (0.133 ∗ GSDME (DFNA5) + 0.084 ∗ NOD1 + 0.039 ∗ IL6 + 0.003 ∗ IL1B + 0.084 ∗ CASP3 + 0.028 ∗ NLRP2). Higher fraction of resting memory CD4+ T cells and macrophages M1 was infiltrated in the high-risk group compared with the low-risk group in HNSCC. Furthermore, the PI3K-Akt signaling pathway and the IL-17 signaling pathways were identified to be involved in the development of high-risk HNSCC. Our study constructed a prognostic risk signature based on pyroptosis-related genes, which emphasizes the critical importance of pyroptosis in HNSCC and provided a novel perspective of HNSCC therapy.

m6A demethylase FTO renders radioresistance of nasopharyngeal carcinoma via promoting OTUB1-mediated anti-ferroptosis

Radiotherapy is a valid treatment for nasopharyngeal carcinoma (NPC), and radioresistance is the main cause of local NPC treatment failure. However, the underlying mechanisms and valuable markers of radioresistance for NPC remain have not been established. In this study, we observed that the m6A mRNA demethylase fat mass and obesity-associated protein (FTO) was significantly upregulated in radioresistant NPC tissues and cells relative to parental radiosensitive NPC tissues and cells. FTO enhances radioresistance by repressing radiation-induced ferroptosis in NPC. Mechanistically, FTO acts as an m6A demethylase to erase the m6A modification of the OTUB1 transcript and promote the expression of OTUB1, thereby inhibiting the ferroptosis of cells induced by radiation and finally triggering the radiotherapy resistance of NPC. Furthermore, our in vivo experiment results showed that the FTO inhibitor, FB23-2, and the ferroptosis activator, erastin, altered tumor responsiveness to radiotherapy in NPC cell lines and patient-derived xenografts. Our findings reveal, for the first time, that FTO enhances NPC radiotherapy resistance by withstanding radiation-induced ferroptosis, suggesting that FTO may serve as a potential therapeutic target and valuable prognostic biomarker in patients with NPC.

Breaking the Bottleneck in Anticancer Drug Development: Efficient Utilization of Synthetic Biology

Natural products have multifarious bioactivities against bacteria, fungi, viruses, cancers and other diseases due to their diverse structures. Nearly 65% of anticancer drugs are natural products or their derivatives. Thus, natural products play significant roles in clinical cancer therapy. With the development of biosynthetic technologies, an increasing number of natural products have been discovered and developed as candidates for clinical cancer therapy. Here, we aim to summarize the anticancer natural products approved from 1950 to 2021 and discuss their molecular mechanisms. We also describe the available synthetic biology tools and highlight their applications in the development of natural products.

Natural products targeting glycolytic signaling pathways-an updated review on anti-cancer therapy

Glycolysis is a complex metabolic process that occurs to convert glucose into pyruvate to produce energy for living cells. Normal cells oxidized pyruvate into adenosine triphosphate and carbon dioxide in the presence of oxygen in mitochondria while cancer cells preferentially metabolize pyruvate to lactate even in the presence of oxygen in order to maintain a slightly acidic micro-environment of PH 6.5 and 6.9, which is beneficial for cancer cell growth and metastasis. Therefore targeting glycolytic signaling pathways provided new strategy for anti-cancer therapy. Natural products are important sources for the treatment of diseases with a variety of pharmacologic activities. Accumulated studies suggested that natural products exhibited remarkable anti-cancer properties both in vitro and in vivo. Plenty of studies suggested natural products like flavonoids, terpenoids and quinones played anti-cancer properties via inhibiting glucose metabolism targets in glycolytic pathways. This study provided an updated overview of natural products controlling glycolytic pathways, which also provide insight into druggable mediators discovery targeting cancer glucose metabolism.

Development of a prognostic prediction model based on a combined multi-omics analysis of head and neck squamous cell carcinoma cell pyroptosis-related genes

This study aimed to understand the prognosis of patients with head and neck squamous cell carcinoma (HNSCC) and to develop and validate a prognostic model for HNSCC based on pyroptosis-associated genes (PAGs) in nasopharyngeal carcinoma. The Cancer Genome Atlas database was used to identify differentially expressed PAGs. These genes were analyzed using the Kyoto Encyclopedia of Genes and Genomes functional annotation analyses and Gene Ontology analyses. The NLR family pyrin domain containing 1 (NLRP1) gene, charged multivesicular body protein 7 (CHMP7) gene, and cytochrome C (CYCS) gene were used to create a prognostic model for HNSCC. The results of the Kaplan-Meier (K-M) and Cox regression analyses indicated that the developed model served as an independent risk factor for HNSCC. According to the K-M analysis, the overall survival of high-risk patients was lower than that of low-risk patients. The hazard ratios corresponding to the risk scores determined using the multivariate and univariate Cox regression analyses were 1.646 (95% confidence interval (CI): 1.189–2.278) and 1.724 (95% CI: 1.294–2.298), respectively, and the area under the receiver operator characteristic curve was 0.621. The potential mechanisms associated with the functions of the identified genes were then identified, and the tumor microenvironment and levels of immune cell infiltration achieved were analyzed. The immune infiltration analysis revealed differences in the distribution of Th cells, tumor-infiltrating lymphocytes, regulatory T cells, follicular helper T cells, adipose-derived cells, interdigitating dendritic cells, CD8⁺ T cells, and B cells. However, validating bioinformatics analyses through biological experiments is still recommended. This study developed a prognostic model for HNSCC that included NLRP1, CHMP7, and CYCS.

Ferroptosis and its emerging role in esophageal cancer

The occurrence and development of tumors involve a series of life activities of cells, among which cell death has always been a crucial part in the research of tumor mechanisms and treatment methods. Ferroptosis is a non-apoptotic form of cell death, which is characterized by lipid peroxidation accumulation and further cell membrane rupture caused by excessive production of intracellular oxygen free radicals dependent on iron ions. Esophageal cancer is one of the common digestive tract tumors. Patients in the early stage are mainly treated with surgery, and the curative effect is awe-inspiring. However, surgery is far from enough for terminal patients, and it is the best choice to combine radiotherapy and chemotherapy before the operation or during the perioperative period. Although the treatment plan for patients with advanced esophageal cancer is constantly being optimized, we are disappointed at the still meager 5-year survival rate of patients and the poor quality of life. A series of complex problems, such as increased chemotherapy drug resistance and decreased radiotherapy sensitivity of esophageal cancer cells, are waiting for us to tackle. Perhaps ferroptosis can provide practical and feasible solutions and bring new hope to patients with advanced esophageal cancer. The occurrence of ferroptosis is related to the dysregulation of iron metabolism, lipid metabolism, and glutamate metabolism. Therefore, these dysregulated metabolic participant proteins and signaling pathways are essential entry points for using cellular ferroptosis to resist the occurrence and development of cancer cells. This review first introduced the main regulatory mechanisms of ferroptosis. It then summarized the current research status of ferroptosis in esophageal cancer, expecting to provide ideas for the research related to ferroptosis in esophageal cancer.

Potential roles and molecular mechanisms of phytochemicals against cancer

Increasing evidence has been reported regarding phytochemicals, plant secondary metabolites, having therapeutic functions against numerous human diseases. Recently, phytochemicals (flavonoids, polyphenols, terpenoids, alkaloids, saponins, coumarins and so on) have shown promising anti-cancer efficacy with their distinct advantages of high efficiency and low toxicity. They regulate programmed cell death (apoptosis, pyroptosis, and autophagy), migration and senescence-related signaling pathways of cancer via the modulation of reactive oxygen species (ROS), mitogen activated protein kinase (MAPK) pathway, deleted in liver cancer 1 (DLC1), nuclear factor κ light-chain-enhancer of activated B cell (NF-κB) pathways and glycolytic enzymes. Here, we review the molecular mechanisms by which phytochemicals prevent the development of cancer. Furthermore, phytochemicals combined with chemotherapeutic agents could target the crosstalk among multiple signal cascades to block chemoresistance and attenuate carcinogenic properties, and can be considered as a novel and potential therapeutic strategy. Our review highlights that the mechanisms and promising applications are required to be understood to decisively establish the anti-cancer efficacy of natural phytochemicals.

Regulation of dietary polyphenols on cancer cell pyroptosis and the tumor immune microenvironment

Cancer is a major public health problem that threatens human life worldwide. In recent years, immunotherapy has made great progress in both clinical and laboratory research. But the high heterogeneity and dynamics of tumors makes immunotherapy not suitable for all cancers. Dietary polyphenols have attracted researchers' attention due to their ability to induce cancer cell pyroptosis and to regulate the tumor immune microenvironment (TIME). This review expounds the regulation of dietary polyphenols and their new forms on cancer cell pyroptosis and the TIME. These dietary polyphenols include curcumin (CUR), resveratrol (RES), epigallocatechin gallate (EGCG), apigenin, triptolide (TPL), kaempferol, genistein and moscatilin. New forms of dietary polyphenols refer to their synthetic analogs and nano-delivery, liposomes. Studies in the past decade are included. The result shows that dietary polyphenols induce pyroptosis in breast cancer cells, liver cancer cells, oral squamous cells, carcinoma cells, and other cancer cells through different pathways. Moreover, dietary polyphenols exhibit great potential in the TIME regulation by modulating the programmed cell death protein 1(PD-1)/programmed death-ligand 1 (PD-L1) axis, enhancing antitumor immune cells, weakening the function and activity of immunosuppressive cells, and targeting tumor-associated macrophages (TAMs) to reduce their tumor infiltration and promote their polarization toward the M1 type. Dietary polyphenols are also used with radiotherapy and chemotherapy to improve antitumor immunity and shape a beneficial TIME. In conclusion, dietary polyphenols induce cancer cell pyroptosis and regulate the TIME, providing new ideas for safer cancer cures.

FOXA1 prevents nutrients deprivation induced autophagic cell death through inducing loss of imprinting of IGF2 in lung adenocarcinoma

Lung cancer remains one of the most common malignancies and the leading cause of cancer-related death worldwide. Forkhead box protein A1 (FOXA1) is a pioneer factor amplified in lung adenocarcinoma (LUAD). However, its role in LUAD remains elusive. In this study, we found that expression of FOXA1 enhanced LUAD cell survival in nutrients deprived conditions through inhibiting autophagic cell death (ACD). FOXA1 bound to the imprinting control region of insulin-like growth factor 2 (IGF2) and interacted with DNA methyltransferase 1 (DNMT1), leading to initiation of DNMT1-mediated loss of imprinting (LOI) of IGF2 and autocrine of IGF2. Blockage of IGF2 and its downstream insulin-like growth factor 1 receptor (IGF1R) abolished the protective effect of FOXA1 on LUAD cells in nutrients deprived conditions. Furthermore, FOXA1 suppressed the expression of the lysosomal enzyme glucocerebrosidase 1 (GBA1), a positive mediator of ACD, through ubiquitination of GBA1 enhanced by IGF2. Notably, FOXA1 expression in A549 cells reduced the efficacy of the anti-angiogenic drug nintedanib to inhibit xenograft tumor growth, whereas a combination of nintedanib with IGF1R inhibitor linsitinib or mTORC1 inhibitor rapamycin enhanced tumor control. Clinically, high expression level of FOXA1 protein was associated with unfavorable prognosis in LUAD patients of advanced stage who received bevacizumab treatment. Our findings uncovered a previously unrecognized role of FOXA1 in mediating loss of imprinting of IGF2, which confer LUAD cells enhanced survival ability against nutrients deprivation through suppressing autophagic cell death.

A novel pyroptosis-related gene signature for predicting laryngeal carcinoma prognosis

Pyroptosis, a newly-defined mode of cell death related to inflammation, is closely related to cancers but has not yet been studied in laryngeal carcinoma (LC). We investigated pyroptosis in LC and constructed a prognostic model. Using RNA sequencing data, we identified differentially expressed genes (DEGs) in LC and normal tissues to construct a prognostic risk model. The model's accuracy and independent prognostic value were evaluated using survival- and receiver operating characteristic (ROC)- curves; and univariate and multivariate Cox regression analyses, respectively. Gene Expression Omnibus (GEO) data was utilized as a model validation set. Differential analysis revealed 37 DEGs, and consistent clustering showed that pyroptosis-related genes could predict LC prognosis. Six genes (CHMP7, GSDME, GZMB, CASP9, IL6, and NLRP1) were obtained by Lasso Cox regression analysis to construct a prognostic model. The high-risk group had a poor prognosis with areas under the ROC curve at 1-, 3-, and 5-years of 0.619, 0.692, and 0.656, respectively. Univariate and multivariate Cox analyses showed that the risk score was an independent prognostic factor. Enrichment analysis of GO and KEGG pathways revealed that differentially expressed genes may be related to infection, T cell differentiation, immunity, and inflammation. It was further found that the low survival rate of the high-risk group may be related to the significant reduction of immune cell infiltration and immune function. With the bioinformatic method, six genes related to pyroptosis affecting LC prognosis were screened and a prognostic risk model was constructed, which laid a foundation for pyroptosis study in LC.

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.

The NLRP3 Inflammasome as a Novel Therapeutic Target for Cardiac Fibrosis

Cardiac fibrosis often has adverse cardiovascular effects, including heart failure, sudden death, and malignant arrhythmias. However, there is no targeted therapy for cardiac fibrosis. Inflammation is known to play a crucial role in the disorder, and the NLR pyrin domain-containing-3 (NLRP3) inflammasome is closely associated with innate immunity. Therefore, further understanding the pathophysiological role of the inflammasome in cardiac fibrosis may provide novel strategies for the prevention and treatment of the disorder. The aim of this review was to summarize the present knowledge of NLRP3 inflammasome-related mechanisms underlying cardiac fibrosis and to suggest potential targeted therapy that could be used to treat the condition.

Cyclophilin D: Guardian or Executioner for Tumor Cells?

Cyclophilin D (CypD) is a peptide-proline cis-trans isomerase (PPIase) distributed in the mitochondrial matrix. CypD regulates the opening of the mitochondrial permeability conversion pore (mPTP) and mitochondrial bioenergetics through PPIase activity or interaction with multiple binding partners in mitochondria. CypD initially attracted attention due to its regulation of mPTP overopening-mediated cell death. However, recent studies on the effects of CypD on tumors have shown conflicting results. Although CypD has been proven to promote the aerobic glycolysis in tumor cells, its regulation of malignant characteristics such as the survival, invasion and drug resistance of tumor cells remains controversial. Here, we elaborate the main biological functions of CypD and its relationships with tumor progression identified in recent years, focusing on the dual role of CypD in tumors.

Effects of kefir lactic acid bacteria-derived postbiotic components on high fat diet-induced gut microbiota and obesity

Cellular components, surface layer protein (SLP) and exopolysaccharides (EPS) of postbiotic lactic bacteria (PLAB) can rehabilitate high-fat diet-induced dysbiosis and obese characteristic gut microbiome. However, it is not clear whether and how PLAB components affect gut microbiota and specifically adipocyte gene expression. Furthermore, SLP and EPS of PLAB in combination with polyphenolics of prebiotic wine grape seed flour (GSF) may have greater benefit on high-fat diet (HFD)-induced obesity and gut microbiota imbalance. To investigate interactions, C57BL/6 mice were fed a HFD and orally administered saline (CON), 250 mg/Kg EPS, or 120 mg/Kg SLP or saline with fed 2% GSF (GSF) or combination (42 mg/Kg EPS + 20 mg/Kg SLP + 0.5% GSF; ALL). There were significant reductions of HFD-induced body weight gain, adipose weight, serum triglyceride, and insulin resistance by the SLP and ALL diets compared to CON, with the most profound effect by ALL. ALL significantly affected the distribution of intestinal bacterial genus and species particularly those involved in production of short chain fatty acid (SCFA) and anti-obesogenic action. Microarray analysis from adipose tissue showed that ALL significantly affected expression of genes related to fatty acid biosynthesis, autophagy, inflammatory response, immune response, brown adipose tissue development and response to lipoteichoic acid and peptidoglycan (p < 0.05). Interestingly, expression of Akp13 (A-kinase anchoring protein 13) gene, which is related to body mass index and immune response, was negatively associated with the abundance of obesogenic and SCFAs producing gut bacteria. These data suggest that a combination of postbiotic kefir LAB cellular components and prebiotic GSF establishes a healthy intestinal microbiota that in part was associated with the prevention of obesity and obesity-related diseases.

PP1A prevents ROS-induced pyroptosis by inhibiting MAPK/caspase-3 in mouse adipose tissue

Pyroptosis is a type of programmed cell death triggered by a variety of exogenous stimuli, playing important roles in the development of cells. Recent studies have shown that pyroptosis also occurs in human and mouse adipocytes. The serine/threonine protein phosphatase 1 catalytic subunit α (PP1A) is located in the nucleus and functions in the regulation of cell development, glucose metabolism and protein synthesis. PP1A can also target important proteins in the process of apoptosis. However, it is still unclear whether PP1A participates in the regulation of pyroptosis in mouse adipocytes. In the present study, we investigated the function of PP1A in reactive oxygen species-induced pyroptosis and the related mechanism in mouse adipose tissue. Our results demonstrated that PP1A suppressed pyroptosis in adipocytes by inhibiting the reactive oxygen species/mitogen-activated protein kinase/caspase-3 signaling pathway and promoting M2 macrophage polarization. This experiment provides a theoretical basis for understanding the regulatory function and mechanism of PP1A in pyroptosis caused by oxidative stress in adipocytes.

SLC7A11/GPX4 Inactivation-Mediated Ferroptosis Contributes to the Pathogenesis of Triptolide-Induced Cardiotoxicity

Triptolide exhibits promising efficacy in various cancers and immune diseases while its clinical application has been strongly restricted by its severe side effects, especially cardiotoxicity. However, the underlying mechanism of triptolide-induced cardiotoxicity (TIC) remains unclear. The RNA-seq analysis of triptolide-injured AC16 human cardiomyocyte cell line hinted that ferroptosis is involved in TIC. Further experimental validations proved that triptolide triggered ferroptosis, as evidenced by significant accumulation of lipid peroxidation (4-HNE and MDA levels) and ferrous iron, as well as depletion of intracellular GSH. Furthermore, triptolide-induced iron overload involved the upregulation of TF/TRFC/DMT1 signal axis and the degradation of ferritin, which contribute to ROS generation via Fenton reaction. In addition, inhibition of the antioxidant Nrf2/HO-1 pathway was observed in TIC, which may also lead to the overproduction of lethal lipid peroxides. Mechanistically, using streptavidin-biotin affinity pull-down assay and computational molecular docking, we unveiled that triptolide directly binds to SLC7A11 to inactivate SLC7A11/GPX4 signal axis. More importantly, employment of a ferroptosis inhibitor Ferrostatin-1 alleviated TIC by partially reversing the inhibitory effects of triptolide on SLC7A11/GPX4 signal. Altogether, our study demonstrated that SLC7A11/GPX4 inactivation-mediated ferroptosis contributed to the pathogenesis of TIC. Combating ferroptosis may be a promising therapeutic avenue to prevent TIC.

The role of pyroptosis in modulating the tumor immune microenvironment

The tumor immune microenvironment (TIME) plays a key role in immunosuppression in cancer, which results in tumorigenesis and tumor progression, and contributes to insensitivity to chemotherapy and immunotherapy. Understanding the mechanism of TIME formation is critical for overcoming cancer. Pyroptosis exerts a dual role in modulating the TIME. In this review, we summarize the regulatory mechanisms of pyroptosis in modulating the TIME and the potential application of targeted pyroptosis therapy in the clinic. Several treatments targeting pyroptosis have been developed; however, the majority of treatments are still in preclinical studies. Only a few agents have been used in clinic, but the outcomes are unsatisfactory. More studies are necessary to determine the role of pyroptosis in cancer, and more research is required to realize the application of treatments targeting pyroptosis in the clinic.

The Pyroptosis-Related Long Noncoding RNA Signature Predicts Prognosis and Indicates Immunotherapeutic Efficiency in Hepatocellular Carcinoma

Pyroptosis was recently demonstrated to be an inflammatory form of gasdermin-regulated programmed cell death characterized by cellular lysis and the release of several proinflammatory factors and participates in tumorigenesis. However, the effects of pyroptosis-related long noncoding RNAs (lncRNAs) on hepatocellular carcinoma (HCC) have not yet been completely elucidated. Based on the regression coefficients of ZFPM2-AS1, KDM4A-AS1, LUCAT1, NRAV, CRYZL2P-SEC16B, AL031985.3, SNHG4, AL049840.5, AC008549.1, MKLN1-AS, AC099850.3, and LINC01224, HCC patients were classified into a low- or high-risk group. The high-risk score according to pyroptosis-related lncRNA signature was significantly associated with poor overall survival even after adjusting for age and clinical stage. Receiver operating characteristic curves and principal component analysis further supported the accuracy of the model. Our study revealed that a higher pyroptosis-related lncRNA risk score was significantly associated with tumor staging, pathological grade, and tumor-node-metastasis stages. The nomogram incorporating the pyroptosis-related lncRNA risk score and clinicopathological factors demonstrated good accuracy. Furthermore, we observed distinct tumor microenvironment cell infiltration characteristics between high- and low-risk tumors. Notably, based on the risk model, we found that the risk score is closely related to the expression of immune checkpoint genes, immune subtypes of tumors, and the sensitivity of HCC to chemotherapy drugs and immunotherapy. In conclusion, our novel risk score of pyroptosis-related lncRNA can serve as a promising prognostic biomarker for HCC patients and provide help for HCC patients to guide precision drug treatment and immunotherapy.

Identification of pyroptosis-related gene prognostic signature in head and neck squamous cell carcinoma

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is a life-threatening disease with poor prognosis. Pyroptosis has been recently disclosed as a programmed cell death triggered by invasive infection, involved in cancer development. However, the prognosis role of pyroptosis-related genes in HNSCC has not been discussed.

METHODS

The RNA sequence data of pyroptosis-related genes were obtained from The Cancer Genome Atlas (TCGA) database. Cox regression and the least absolute shrinkage and selection operator (LASSO) analysis were performed to screen the HNSCC survival-related signature genes. We established a HNSCC risk model with the identified prognostic genes, then divided the HNSCC patients into low- and high-risk subgroups according to median risk score. Moreover, we utilized Gene Expression Omnibus (GEO) dataset to validate the risk model. Go and KEGG analyses were conducted to reveal the potential function of differential expression of genes that identified between low- and high-risk subgroups. ESTIMATE algorithm was performed to investigate the immune infiltration of tumors. Correlation between signature gene expression and drug-sensitivity was disclosed by Spearman's analysis.

RESULTS

We constructed a HNSCC risk model with identified seven pyroptosis-related genes (CASP1, GSDME, IL6, NLRP1, NLRP2, NLRP6, and NOD2) as prognostic signature genes. High-risk subgroup of HNSCC patients in TCGA cohort correlated with lower survival probability than patients from low-risk subgroup (p < .001), and the result is verified with GEO dataset. In addition, 161 genes were identified differentially expressed between the low- and high-risk subgroups in the TCGA cohort, mainly related to immune response. Higher PD-L1 expression level was found in the high-risk subgroup that indicated the possible employment of immune checkpoint inhibitors. IL6 was positively correlated with WZ3105 and MPS-1-IN-1 in the cancer therapeutics response portal database.

CONCLUSION

We built and verified a risk model for HNSCC prognosis using seven pyroptosis-related signature genes, which could predict the overall survival of HNSCC patients and facilitate treatment.

Antitumor Effect of Simvastatin in Combination With DNA Methyltransferase Inhibitor on Gastric Cancer via GSDME-Mediated Pyroptosis

Gasdermin E (GSDME) is one of the executors of pyroptosis, a type of programmed lytic cell death, which can be triggered by caspase-3 activation upon stimulation. Silenced GSDME expression due to promoter hypermethylation is associated with gastric cancer (GC), which is confirmed in the present study by bioinformatics analysis and methylation-specific PCR (MSP) test of GC cell lines and clinical samples. GC cell lines and mouse xenograft models were used to investigate the pyroptosis-inducing effect of the common cholesterol-depleting, drug simvastatin (SIM), allied with upregulating GSDME expression by doxycycline (DOX)- inducible Tet-on system or DNA methyltransferase inhibitor 5-Aza-2′-deoxycytidine (5-Aza-CdR). Cell viability assessment and xenograft tumour growth demonstrated that the tumour inhibition effects of SIM can be enhanced by elevated GSDME expression. Morphological examinations and assays measuring lactate dehydrogenase (LDH) release and caspase-3/GSDME protein cleavage underlined the stimulation of pyroptosis as an important mechanism. Using short hairpin RNA (shRNA) knockdown of caspase-3 or GSDME, and caspase-3-specific inhibitors, we provided evidence of the requirement of caspase-3/GSDME in the pyroptosis process triggered by SIM. We conclude that reactivating GSDME expression and thereby inducing cancer cell-specific pyroptosis could be a potential therapeutic strategy against GC.

Prognosis and Characterization of Immune Microenvironment in Head and Neck Squamous Cell Carcinoma through a Pyroptosis-Related Signature

Pyroptosis, as a novel identified programmed cell death, is closely correlated with tumor immunity and shows potential roles in cancer treatment. Discerning a pyroptosis-related gene signature and its correlations with tumor immune microenvironment is critical in head and neck squamous cell carcinoma (HNSCC). Transcriptome data and corresponding clinical data were downloaded from TCGA and GEO databases. Tumor mutation burden (TMB) data were obtained from TCGA database. Firstly, univariate and least absolute shrinkage and selection operator (LASSO) regression analyses were used to construct a six pyroptosis-related gene signature. Kaplan-Meier analysis, receiver operating characteristic (ROC) curves, and principal component analysis (PCA) results verified that the risk model has good performance in predicting the survival. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that the pyroptosis-related gene signature was immune related. Finally, the immune landscape and immunotherapy sensitivity prediction capabilities of the risk model were further explored. There were close correlations between the overall survival (OS) and various immune cells and immune functions. Single-sample gene set enrichment analysis (ssGSEA) showed that high risk group had decreased expression of various immune cells and lower activities of immune functions. Meanwhile, tumor mutation burden (TMB) data combining risk score could well predict the OS of HNSCC patients. However, tumor immune dysfunction and exclusion (TIDE) analysis revealed that there was no significant difference in the sensitivity to immunotherapies between high and low risk groups. Finally, a nomogram based on risk score and clinicopathological parameters was constructed. And, the risk model demonstrated better sensitivity and specificity than TIDE scores and T-cell-inflamed signature (TIS). In conclusion, although the risk model could not well predict the immune escape and response to immunotherapies, the signature established by pyroptosis-related genes, with better sensitivity and specificity than TIDE scores and TIS signature, could be used for predicting prognosis and immune status of HNSCC patients.

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.

Targeting lactate metabolism and glycolytic pathways in the tumor microenvironment by natural products: A promising strategy in combating cancer

Anticancer drugs are not purely effective because of their toxicity, side effects, high cost, inaccessibility, and associated resistance. On the other hand, cancer is a complex public health problem that could intelligently adopt different signaling pathways and alter the body's metabolism to escape from the immune system. One of the cancer strategies to metastasize is modifying pH in the tumor microenvironment, ranging between 6.5 and 6.9. As a powerful determiner, lactate is responsible for this acidosis. It is involved in immune stimulation, including innate and adaptive immunity, apoptotic-related factors (Bax/Bcl-2, caspase), and glycolysis pathways (e.g., GLUT-1, PKM2, PFK, HK2, MCT-1, and LDH). Lactate metabolism, in turn, is interconnected with several dysregulated signaling mediators, including PI3K/Akt/mTOR, AMPK, NF-κB, Nrf2, JAK/STAT, and HIF-1α. Because of lactate's emerging and critical role, targeting lactate production and its transporters is important for preventing and managing tumorigenesis. Hence, exploring and developing novel promising anticancer agents to minimize human cancers is urgent. Based on numerous studies, natural secondary metabolites as multi-target alternative compounds with health-promoting properties possess more high effectiveness and low side effects than conventional agents. Besides, the mechanism of multi-targeted natural sources is related to lactate production and cancer-associated cross-talked factors. This review focuses on targeting the lactate metabolism/transporters, and lactate-associated mediators, including glycolytic pathways. Besides, interconnected mediators to lactate metabolism are also targeted by natural products. Accordingly, plant-derived secondary metabolites are introduced as alternative therapies in combating cancer through modulating lactate metabolism and glycolytic pathways.

Detoxification strategies of triptolide based on drug combinations and targeted delivery methods

Tripterygium wilfordii Hook f. has a long history of use in Chinese medicine. Triptolide (TP), as its main pharmacological component, has been widely explored in various diseases, including systemic lupus erythematosus, rheumatoid arthritis and cancer. However, due to its poor water solubility, limited therapeutic range and multi-organ toxicity, TP's clinical application has been greatly hampered. To improve its clinical potential, many attenuated drug combinations have been developed based on its toxicity mechanism and targeted delivery systems aimed at its water-solubility and structure. This review, conducted a systematic review of TP detoxification strategies including drug combination detoxification strategies from metabolic and toxic mechanisms, as well as drug delivery detoxification strategies from the prodrug strategy and nanotechnology. Many detoxification strategies have demonstrated promising potential in vitro and in vivo due to previous extensive studies on TP. Therefore, summarizing and discussing TP detoxification strategies for clinical problems can serve as a reference for developing novel TP detoxification strategies, and provide opportunities for future clinical applications.

Pyroptosis patterns and immune infiltrates characterization in head and neck squamous cell carcinoma

Background

Pyroptosis plays an essential role in tumor immune responses and inflammation related to chemotherapy. Herein, we studied the characteristic patterns of pyroptosis in head and neck squamous cell carcinoma (HNSCC) to determine their prognostic and therapeutic effects.

Methods

Consensus clustering analysis was performed to classify patients into pyroptosis or gene clusters. A novel pyroptosis score was constructed by principal component analysis. Kaplan–Meier survival curves were used to show the prognostic value. We also assessed the functional enrichment, tumor mutation burden, immune cell infiltration, and the sensitivity to chemotherapy and immunotherapy between high and low pyroptosis score group.

Results

Two distinct pyroptosis clusters were defined based on the mRNA expression profiles of PRGs, which were related to immune activation in HNSCC. Notably, a pyroptosis score was constructed according to different expression gene signatures, and then, each HNSCC patient was classified into a low or high pyroptosis score group. Patients with low pyroptosis scores had better immunotherapeutic responses and higher sensitivities to chemotherapeutic agents (paclitaxel, docetaxel, and gemcitabine). Kaplan–Meier survival curves showed that the pyroptosis patterns were independent prognostic indicators regardless of the level of tumor mutation burden.

Conclusions

Pyroptosis plays an essential role in immune infiltration in HNSCC. Quantifying the pyroptosis score of individual patients might suggest prognostic, immunotherapeutic, and chemotherapeutic strategies for HNSCC.

Development of a prognostic pyroptosis-related gene signature for head and neck squamous cell carcinoma patient

Objective

Head and neck squamous cell carcinoma (HNSCC) is a major threat to public health. Pyroptosis is a form of inflammatory programmed cell death that is still incompletely understood. The role of pyroptotic cell death in HNSCC remains to be fully defined. As such, the present study was developed to explore the potential prognostic utility of a pyroptosis-related gene (PRG) signature in HNSCC.

Methods

PRG expression patterns and the associated mutational landscape in HNSCC were analyzed, after which a 6-gene prognostic model was constructed through least absolute shrinkage and selection operator (LASSO) and Cox regression analyses using the TCGA dataset, followed by validation with two GEO datasets (GSE41643 and GSE65858). The relative expression of the genes in the prognostic model was assessed via RT-qPCR in tumor and paired adjacent normal tissue samples from a 32-patient cohort. Potential predictors of patient outcomes associated with this 6-gene model were identified through topological degree analyses of a protein–protein interaction network. Moreover, the prognostic value of NLRP3 as a predictor of HNSCC patient prognosis was established through immunohistochemical (IHC) analyses of samples from 176 HNSCC patients. Lastly, in vitro studies were performed to further demonstrate the relevance of NLRP3 in the context of HNSCC development.

Results

Differentially expressed PRGs were able to readily differentiate between HNSCC tumors and normal tissues. Risk scores derived from the 6-gene PRG model were independent predictors of HNSCC patient prognosis, and genes that were differentially expressed between low- and high-risk groups were associated with tumor immunity. RT-qPCR assays also showed the potential protective role of NLRP3 in HNSCC patients. IHC analyses further supported the value of NLRP3 as a predictor of HNSCC patient outcomes. Invasion and migration assays demonstrated the potential role of NLRP3 in the inhibition of HNSCC development.

Conclusions

Overall, these results highlight a novel prognostic gene signature that offers value in the context of HNSCC patient evaluation, although additional research will be essential to elucidate the mechanisms linking these PRGs to HNSCC outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02476-3.

Signature Construction and Molecular Subtype Identification Based on Pyroptosis-Related Genes for Better Prediction of Prognosis in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide. However, there is a lack of adequate means of treatment prognostication for HCC. Pyroptosis is a newly discovered way of programmed cell death. However, the prognostic role of pyroptosis in HCC has not been thoroughly investigated. Here, we generated a novel prognostic signature to evaluate the prognostic value of pyroptosis-related genes (PRGs) using the data from The Cancer Genome Atlas (TCGA) database. The accuracy of the signature was validated using survival analysis through the International Cancer Genome Consortium cohort (n = 231) and the First Affiliated Hospital of Wenzhou Medical University cohort (n = 180). Compared with other clinical factors, the risk score of the signature was found to be associated with better patient outcomes. The enrichment analysis identified multiple pathways related with pyroptosis in HCC. Furthermore, drug sensitivity testing identified six potential chemotherapeutic agents to provide possible treatment avenues. Interestingly, patients with low risk were confirmed to be associated with lower tumor mutation burden (TMB). However, patients at high risk were found to have a higher count of immune cells. Consensus clustering was performed to identify two main molecular subtypes (named clusters A and B) based on the signature. It was found that compared with cluster B, better survival outcomes and lower TMB were observed in cluster A. In conclusion, signature construction and molecular subtype identification of PRGs could be used to predict the prognosis of HCC, which may provide a specific reference for the development of novel biomarkers for HCC treatment.

A pyroptosis-related lncRNA signature predicts prognosis and immune microenvironment in head and neck squamous cell carcinoma

BACKGROUND

Pyroptosis, a type of regulated cell death controlled by the gasdermin family of proteins to form plasma membrane pores is known. Nonetheless, the function of pyroptosis-related long non-coding RNAs (lncRNAs) in this process still lacks exhaustive elucidation in head and neck squamous cell carcinoma (HNSCC). Other attributes encompassing the function of such lncRNAs in the immune microenvironment and potential prognosis for HNSCC are yet to see the light of the day. This work was designed to probe the possible prognostic worth of pyroptosis-related lncRNAs along with their impact on the immune microenvironment in the case of HNSCC.

METHODS

The Cancer Genome Atlas (TCGA) database was the source of RNA-sequencing data of HNSCC patients. Pearson correlation analysis was employed to scour for lncRNAs linked to pyroptosis based on 40 genes related to the process. Following the construction of a pyroptosis-related lncRNA signature employing univariate, Least absolute shrinkage and selection operator (LASSO) and multivariate Cox regression analyses, survival and nomogram analyses ensued to scrutinize the predictive value of the prognostic signature.

RESULTS

The segregation of patients into two risk groups was done by the constructed pyroptosis-related-lncRNA signature (encompassing 14 lncRNAs). The prognosis was poorer for individuals of the high-risk group versus (vs.) the low-risk group with the risk score emerging as an independent prognostic factor by regression analyses. The accuracy of this signature was corroborated by Receiver operating characteristic curve (ROC) analysis with the three-years area under time-dependent ROC curve (AUC) reaching 0.767. Further analyses unveiled a conspicuous enrichment of immune-related pathways in the low-risk group. The high-risk group demonstrated an immunologically "cold" profile based on the immune cell infiltration landscape.

CONCLUSIONS

The lncRNA signature encompassing 14 pyroptosis-related lncRNAs could be a prognostic marker for HNSCC, suggesting pyroptosis might be a promising therapeutic target in HNSCC.

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.

Long non‑coding RNA nuclear paraspeckle assembly transcript 1 regulates ionizing radiation‑induced pyroptosis via microRNA‑448/gasdermin E in colorectal cancer cells

Pyroptosis is mediated by gasdermins and serves a critical role in ionizing radiation (IR)-induced damage in normal tissues, but its role in cancer radiotherapy and underlying mechanisms remains unclear. Long non-coding (lnc) RNAs serve important roles in regulating the radiosensitivity of cancer cells. The present study aimed to investigate the mechanistic involvement of lncRNAs in IR-induced pyroptosis in human colorectal cancer HCT116 cells. LncRNA, microRNA (miR)-448 and gasdermin E (GSDME) levels were evaluated using reverse transcription-quantitative polymerase chain reaction. Protein expression and activation of gasdermins were measured using western blotting. The binding association between miR-448 and GSDME was assessed using the dual-luciferase reporter assay. Pyroptosis was examined using phase-contrast microscopy, flow cytometry, Cell Counting Kit-8 assay and lactate dehydrogenase release assay. IR dose-dependently induced GSDME-mediated pyroptosis in HCT116 cells. GSDME was identified as a downstream target of miR-448. LncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) was upregulated in response to IR and enhanced GSDME expression by negatively regulating miR-448 expression. Notably, NEAT1 knockdown suppressed IR-induced pyroptosis, full-length GSDME expression and GSDME cleavage compared with that in irradiated cells. In addition, NEAT1 knockdown rescued the IR-induced decrease in cell viability in HCT116 cells. The findings of the present study indicated that lncRNA NEAT1 modulates IR-induced pyroptosis and viability in HCT116 cells via miR-448 by regulating the expression, but not activation of GSDME. The present study provides crucial mechanistic insight into the potential role of lncRNA NEAT1 in IR-induced pyroptosis.