Nardilysin-regulated scission mechanism activates polo-like kinase 3 to suppress the development of pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) develops through step-wise genetic and molecular alterations including Kras mutation and inactivation of various apoptotic pathways. Here, we find that development of apoptotic resistance and metastasis of KrasG12D-driven PDAC in mice is accelerated by deleting Plk3, explaining the often-reduced Plk3 expression in human PDAC. Importantly, a 41-kDa Plk3 (p41Plk3) that contains the entire kinase domain at the N-terminus (1-353 aa) is activated by scission of the precursor p72Plk3 at Arg354 by metalloendopeptidase nardilysin (NRDC), and the resulting p32Plk3 C-terminal Polo-box domain (PBD) is removed by proteasome degradation, preventing the inhibition of p41Plk3 by PBD. We find that p41Plk3 is the activated form of Plk3 that regulates a feed-forward mechanism to promote apoptosis and suppress PDAC and metastasis. p41Plk3 phosphorylates c-Fos on Thr164, which in turn induces expression of Plk3 and pro-apoptotic genes. These findings uncover an NRDC-regulated post-translational mechanism that activates Plk3, establishing a prototypic regulation by scission mechanism.

Progress in the Elimination of Organic Contaminants in Wastewater by Activation Persulfate over Iron-Based Metal-Organic Frameworks.

The release of organic contaminants has grown to be a major environmental concern and a threat to the ecology of water bodies. Persulfate-based Advanced Oxidation Technology (PAOT) is effective at eliminating hazardous pollutants and has an extensive spectrum of applications. Iron-based metal-organic frameworks (Fe-MOFs) and their derivatives have exhibited great advantages in activating persulfate for wastewater treatment. In this article, we provide a comprehensive review of recent research progress on the significant potential of Fe-MOFs for removing antibiotics, organic dyes, phenols, and other contaminants from aqueous environments. Firstly, multiple approaches for preparing Fe-MOFs, including the MIL and ZIF series were introduced. Subsequently, removal performance of pollutants such as antibiotics of sulfonamides and tetracyclines (TC), organic dyes of rhodamine B (RhB) and acid orange 7 (AO7), phenols of phenol and bisphenol A (BPA) by various Fe-MOFs was compared. Finally, different degradation mechanisms, encompassing free radical degradation pathways and non-free radical degradation pathways were elucidated. This review explores the synthesis methods of Fe-MOFs and their application in removing organic pollutants from water bodies, providing insights for further refining the preparation of Fe-MOFs.

Gasdermin C sensitizes tumor cells to PARP inhibitor therapy in cancer models.

Several poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi) are approved by FDA to treat cancer with BRCA mutations. BRCA mutations are considered to fuel a PARPi killing effect by inducing apoptosis. However, resistance to PARPi is frequently observed in the clinic due to an incomplete understanding on the molecular basis of PARPi function and a lack of good markers, beyond BRCA mutations, to predict response. Here, we show that gasdermin C (GSDMC) sensitized tumor cells to PARPi in vitro and in immunocompetent mice and caused durable tumor regression in an immune-dependent manner. A high expression level of GSDMC predicted better response to PARPi treatment in patients with triple-negative breast cancer (TNBC). PARPi treatment triggered GSDMC/caspase-8-mediated cancer cell pyroptosis (CCP) that enhanced PARPi killing of tumor cells. GSDMC-mediated CCP increased memory CD8+ T cell population in lymph node (LN), spleen, and tumor and, thus, promoted cytotoxic CD8+ T cell infiltration in the tumor microenvironment. T cell-derived granzyme B (GZMB) activated caspase-6, which subsequently cleaved GSDMC to induce pyroptosis. Interestingly, IFN-γ induced GSDMC expression, which, in turn, enhanced the cytotoxicity of PARPi and T cells. Importantly, GSDMC promoted tumor clearance independent of BRCA deficiency in multiple cancer types with PARPi treatment. This study identifies a general marker and target for PARPi therapy and offers insights into the mechanism of PARPi function.

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.

Novel SERS biosensor for rapid detection of breast cancer based on Ag2O-Ag-PSi nanochips.

Ag2O-Ag-PSi (porous silicon) surface-enhanced Raman scattering (SERS) chip was successfully synthesized by electrochemical corrosion, in situ reduction and heat treatment technology. The influence of different heat treatment temperature on SERS performance of the chip is studied. The results show that the chip treated at 300 °C has the best SERS performance. The chip was composed of Ag2O-Ag nano core shell with a diameter of 40-60 nm and porous silicon substrate. Then, the optimized chip was used to perform SERS test on serum samples from 30 healthy volunteers and 30 early breast cancer patients, and the baseline was corrected by LabSpec6 software. Finally, the data were analyzed by principal component analysis combined with t-distributed Stochastic Neighbor Embedding (PCA-t-SNE). The results showed that the accuracy of the improved substrate combined with multivariate statistical method was 98%. The shelf life of the chips exceeded six months due to the presence of the Ag2O shell. This study provides a basis for developing a low-cost rapid and sensitive early screening technology for breast cancer.

Nuclear export signal mutation of epidermal growth factor receptor enhances malignant phenotypes of cancer cells.

Nuclear epidermal growth factor receptor (EGFR) has been shown to be correlated with drug resistance and a poor prognosis in patients with cancer. Previously, we have identified a tripartite nuclear localization signal (NLS) within EGFR. To comprehensively determine the functions and underlying mechanism of nuclear EGFR and its clinical implications, we aimed to explore the nuclear export signal (NES) sequence of EGFR that is responsible for interacting with the exportins. We combined in silico prediction with site-directed mutagenesis approaches and identified a putative NES motif of EGFR, which is located in amino acid residues 736-749. Mutation at leucine 747 (L747) in the EGFR NES led to increased nuclear accumulation of the protein via a less efficient release of the exportin CRM1. Interestingly, L747 with serine (L747S) and with proline (L747P) mutations were found in both tyrosine kinase inhibitor (TKI)-treated and -naïve patients with lung cancer who had acquired or de novo TKI resistance and a poor outcome. Reconstituted expression of the single NES mutant EGFRL747P or EGFRL747S, but not the dual mutant along with the internalization-defective or NLS mutation, in lung cancer cells promoted malignant phenotypes, including cell migration, invasiveness, TKI resistance, and tumor initiation, supporting an oncogenic role of nuclear EGFR. Intriguingly, cells with germline expression of the NES L747 mutant developed into B cell lymphoma. Mechanistically, nuclear EGFR signaling is required for sustaining nuclear activated STAT3, but not for Erk. These findings suggest that EGFR functions are compartmentalized and that nuclear EGFR signaling plays a crucial role in tumor malignant phenotypes, leading to tumorigenesis in human cancer.

Detection of Gasdermin C-Mediated Cancer Cell Pyroptosis.

Gasdermin proteins except DFNB59 are the executioners of pyroptotic cell death. Cleavage of a gasdermin by an active protease causes lytic cell death. Gasdermin C (GSDMC) is cleaved by caspase-8 in response to macrophage-secreted TNF-α. Upon cleavage, the GSDMC-N domain is liberated and oligomerized, followed by pore formation in the plasma membrane. GSDMC cleavage, LDH release, and plasma membrane translocation of GSDMC-N domain are the reliable markers for GSDMC-mediated cancer cell pyroptosis (CCP). Here, we describe the methods for examining GSDMC-mediated CCP.

Study on Wastewater Demulsification Technology of Crude Oil in Xinjiang Oilfield.

The Second Oil Production Plant of Xinjiang Oilfield produces a large amount of highly emulsified crude oil, which has a serious impact on the subsequent oil-water separation. At present, the concentration of demulsifier has increased to 2000 mg/L, but the demulsification effect is still poor. In this paper, the source and physical properties of highly emulsified crude oil are investigated firstly. The results show that highly emulsified crude oil is composed of three kinds of liquid: (1) conventional water flooding (WF); (2) chemical flooding (CF); (3) fracturing backflow fluid (FB). Among them, high zeta potential, low density difference, high viscosity, and small emulsion particles are responsible for the difficulty in the demulsification of the WF emulsion, while the high pH value is the reason why the CF emulsion is difficult to demulsify. Therefore, systematic experiments were implemented to investigate the optimal demulsification approach towards the three liquids above. As for the WF emulsion, it was necessary to raise the temperature to 70 °C and the concentration of the demulsifier to 200 mg/L. Moreover, it was only necessary to add 200 mg/L of demulsifier to break the CF emulsion after adjusting the pH value to 7, while no extra treatments were needed to break the FB emulsion. We hope this study can provide a new insight for the treatment of emulsions in the later stage of oilfield development.

Molecular mechanisms and functions of pyroptosis in inflammation and antitumor immunity.

Canonically, gasdermin D (GSDMD) cleavage by caspase-1 through inflammasome signaling triggers immune cell pyroptosis (ICP) as a host defense against pathogen infection. However, cancer cell pyroptosis (CCP) was recently discovered to be activated by distinct molecular mechanisms in which GSDMB, GSDMC, and GSDME, rather than GSDMD, are the executioners. Moreover, instead of inflammatory caspases, apoptotic caspases and granzymes are required for gasdermin protein cleavage to induce CCP. Sufficient accumulation of protease-cleaved gasdermin proteins is the prerequisite for CCP. Inflammation induced by ICP or CCP results in diametrically opposite effects on antitumor immunity because of the differential duration and released cellular contents, leading to contrary effects on therapeutic outcomes. Here, we focus on the distinct mechanisms of ICP and CCP and discuss the roles of ICP and CCP in inflammation and antitumor immunity, representing actionable targets.

PRMT1 enhances oncogenic arginine methylation of NONO in colorectal cancer.

Arginine methylation is an important posttranslational modification catalyzed by protein arginine methyltransferases (PRMTs). However, the role of PRMTs in colorectal cancer (CRC) progression is not well understood. Here we report that non-POU domain-containing octamer-binding protein (NONO) is overexpressed in CRC tissue and is a potential marker for poor prognosis in CRC patients. NONO silencing resulted in decreased proliferation, migration, and invasion of CRC cells, whereas overexpression had the opposite effect. In a xenograft model, tumors derived from NONO-deficient CRC cells were smaller than those derived from wild-type (WT) cells, and PRMT1 inhibition blocked CRC xenograft progression. A mass spectrometry analysis indicated that NONO is a substrate of PRMT1. R251 of NONO was asymmetrically dimethylated by PRMT1 in vitro and in vivo. Compared to NONO WT cells, NONO R251K mutant-expressing CRC cells showed reduced proliferation, migration, and invasion, and PRMT1 knockdown or pharmacological inhibition abrogated the malignant phenotype associated with NONO asymmetric dimethylation in both KRAS WT and mutant CRC cells. Compared to adjacent normal tissue, PRMT1 was highly expressed in the CRC zone in clinical specimens, which was correlated with poor overall survival in patients with locally advanced CRC. These results demonstrate that PRMT1-mediated methylation of NONO at R251 promotes CRC growth and metastasis, and suggest that PRMT1 inhibition may be an effective therapeutic strategy for CRC treatment regardless of KRAS mutation status.

Author Correction: PD-L1-mediated gasdermin C expression switches apoptosis to pyroptosis in cancer cells and facilitates tumour necrosis.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

PD-L1-mediated gasdermin C expression switches apoptosis to pyroptosis in cancer cells and facilitates tumour necrosis.

Although pyroptosis is critical for macrophages against pathogen infection, its role and mechanism in cancer cells remains unclear. PD-L1 has been detected in the nucleus, with unknown function. Here we show that PD-L1 switches TNFα-induced apoptosis to pyroptosis in cancer cells, resulting in tumour necrosis. Under hypoxia, p-Stat3 physically interacts with PD-L1 and facilitates its nuclear translocation, enhancing the transcription of the gasdermin C (GSDMC) gene. GSDMC is specifically cleaved by caspase-8 with TNFα treatment, generating a GSDMC N-terminal domain that forms pores on the cell membrane and induces pyroptosis. Nuclear PD-L1, caspase-8 and GSDMC are required for macrophage-derived TNFα-induced tumour necrosis in vivo. Moreover, high expression of GSDMC correlates with poor survival. Antibiotic chemotherapy drugs induce pyroptosis in breast cancer. These findings identify a non-immune checkpoint function of PD-L1 and provide an unexpected concept that GSDMC/caspase-8 mediates a non-canonical pyroptosis pathway in cancer cells, causing tumour necrosis.

Author Correction: CDK2-mediated site-specific phosphorylation of EZH2 drives and maintains triple-negative breast cancer.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

CDK2-mediated site-specific phosphorylation of EZH2 drives and maintains triple-negative breast cancer.

Triple-negative breast cancer (TNBC), which lacks estrogen receptor α (ERα), progesterone receptor, and human epidermal growth factor receptor 2 (HER2) expression, is closely related to basal-like breast cancer. Previously, we and others report that cyclin E/cyclin-dependent kinase 2 (CDK2) phosphorylates enhancer of zeste homolog 2 (EZH2) at T416 (pT416-EZH2). Here, we show that transgenic expression of phospho-mimicking EZH2 mutant EZH2T416D in mammary glands leads to tumors with TNBC phenotype. Coexpression of EZH2T416D in mammary epithelia of HER2/Neu transgenic mice reprograms HER2-driven luminal tumors into basal-like tumors. Pharmacological inhibition of CDK2 or EZH2 allows re-expression of ERα and converts TNBC to luminal ERα-positive, rendering TNBC cells targetable by tamoxifen. Furthermore, the combination of either CDK2 or EZH2 inhibitor with tamoxifen effectively suppresses tumor growth and markedly improves the survival of the mice bearing TNBC tumors, suggesting that the mechanism-based combination therapy may be an alternative approach to treat TNBC.

Targeting PKCδ as a Therapeutic Strategy against Heterogeneous Mechanisms of EGFR Inhibitor Resistance in EGFR-Mutant Lung Cancer.

Multiple mechanisms of resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have been identified in EGFR-mutant non-small cell lung cancer (NSCLC); however, recurrent resistance to EGFR TKIs due to the heterogeneous mechanisms underlying resistance within a single patient remains a major challenge in the clinic. Here, we report a role of nuclear protein kinase Cδ (PKCδ) as a common axis across multiple known TKI-resistance mechanisms. Specifically, we demonstrate that TKI-inactivated EGFR dimerizes with other membrane receptors implicated in TKI resistance to promote PKCδ nuclear translocation. Moreover, the level of nuclear PKCδ is associated with TKI response in patients. The combined inhibition of PKCδ and EGFR induces marked regression of resistant NSCLC tumors with EGFR mutations.

Deglycosylation of PD-L1 by 2-deoxyglucose reverses PARP inhibitor-induced immunosuppression in triple-negative breast cancer.

Triple-negative breast cancer (TNBC), the most difficult-to-treat breast cancer subtype, lacks well-defined molecular targets. TNBC has increased programmed death-ligand 1 (PD-L1) expression, and its immunosuppressive nature makes it suitable for immune checkpoint blockade therapy. However, the response rate of TNBC to anti-PD-L1 or anti-programmed cell death protein 1 (PD-1) therapy remains unsatisfactory, as only 10-20% of TNBC patients have a partial response. Glycosylated PD-L1, the functional form of PD-L1, is required for PD-L1-PD-1 interaction. TNBC cells have significantly higher levels of glycosylated PD-L1 than non-TNBC cells do. In a screening of glucose analogs to block PD-L1 glycosylation, we found that 2-deoxyglucose (2-DG) can act as a glucose analog to decrease PD-L1 glycosylation. Because PARP inhibition upregulates PD-L1, 2-DG reduced PARP inhibition-mediated expression of glycosylated PD-L1. The combination of PARP inhibition and 2-DG had potent anti-tumor activity. Together, our results provide a strong rationale for investigating the targeting of PD-L1 glycosylation in TNBC further.

Hepatitis B virus mRNAs functionally sequester let-7a and enhance hepatocellular carcinoma.

Hepatitis B virus (HBV) infection induces hepatocarcinogenesis and malignant progression, yet global effects of the redundant viral mRNAs produced during infection are unexplored. Here, microRNA (miRNA) target prediction and whole genome expression analysis revealed that HBV pre-C/C mRNA leads to upregulation of multiple let-7a targeted genes. A let-7a complementary region from nt 86 to 108 in the HBV genome was then identified in HBV pre-C/C, pre-S, and S mRNAs. The let-7a sequestration effect by HBV mRNAs was observed under transfection and virus infection, which is dependent on the let-7a response sequence. Moreover, we found reduced AGO2 binding, as well as functional mRNA and protein de-repression of let-7a targets (e.g., c-myc, K-RAS, and CCR7), upon viral mRNA expression. Let-7a levels in the liver were significantly decreased in hepatocellular carcinoma (HCC) patients with HBV infection and were negatively correlated with intrahepatic pre-S2 mRNA levels. Finally, both in vitro and in vivo studies demonstrated that let-7a inhibition by HBV mRNAs resulted in enhanced HCC cell colony formation and tumor growth, providing evidence of the oncogenic potential of HBV mRNAs.

Interaction of Toll-Like Receptors with the Molecular Chaperone Gp96 Is Essential for Its Activation of Cytotoxic T Lymphocyte Response.

The heat shock protein gp96 elicits specific T cell responses to its chaperoned peptides against cancer and infectious diseases in both rodent models and clinical trials. Although gp96-induced innate immunity, via a subset of Toll like receptors (TLRs), and adaptive immunity, through antigen presentation, are both believed to be important for priming potent T cell responses, direct evidence for the role of gp96-mediated TLR activation related to its functional T cell activation is lacking. Here, we report that gp96 containing mutations in its TLR-binding domain failed to activate macrophages, but peptide presentation was unaffected. Moreover, we found that peptide-specific T cell responses, as well as antitumor T cell immunity induced by gp96, are severely impaired when the TLR-binding domain is mutated. These data demonstrate the essential role of the gp96-TLR interaction in priming T cell immunity and provide further molecular basis for the coupling of gp96-mediated innate with adaptive immunity.