Inhibition of Glutamate-to-Glutathione Flux Promotes Tumor Antigen Presentation in Colorectal Cancer Cells.

Colorectal cancer (CRC) cells display remarkable adaptability, orchestrating metabolic changes that confer growth advantages, pro-tumor microenvironment, and therapeutic resistance. One such metabolic change occurs in glutamine metabolism. Colorectal tumors with high glutaminase (GLS) expression exhibited reduced T cell infiltration and cytotoxicity, leading to poor clinical outcomes. However, depletion of GLS in CRC cells has minimal effect on tumor growth in immunocompromised mice. By contrast, remarkable inhibition of tumor growth is observed in immunocompetent mice when GLS is knocked down. It is found that GLS knockdown in CRC cells enhanced the cytotoxicity of tumor-specific T cells. Furthermore, the single-cell flux estimation analysis (scFEA) of glutamine metabolism revealed that glutamate-to-glutathione (Glu-GSH) flux, downstream of GLS, rather than Glu-to-2-oxoglutarate flux plays a key role in regulating the immune response of CRC cells in the tumor. Mechanistically, inhibition of the Glu-GSH flux activated reactive oxygen species (ROS)-related signaling pathways in tumor cells, thereby increasing the tumor immunogenicity by promoting the activity of the immunoproteasome. The combinatorial therapy of Glu-GSH flux inhibitor and anti-PD-1 antibody exhibited a superior tumor growth inhibitory effect compared to either monotherapy. Taken together, the study provides the first evidence pointing to Glu-GSH flux as a potential therapeutic target for CRC immunotherapy.

IRF2 loss is associated with reduced MHC I pathway transcripts in subsets of most human cancers and causes resistance to checkpoint immunotherapy in human and mouse melanomas.

BACKGROUND: In order for cancers to progress, they must evade elimination by CD8 T cells or other immune mechanisms. CD8 T cells recognize and kill tumor cells that display immunogenic tumor peptides bound to MHC I molecules. One of the ways that cancers can escape such killing is by reducing expression of MHC I molecules, and loss of MHC I is frequently observed in tumors. There are multiple different mechanisms that can underly the loss of MHC I complexes on tumor and it is currently unclear whether there are particular mechanisms that occur frequently and, if so, in what types of cancers. Also of importance to know is whether the loss of MHC I is reversible and how such loss and/or its restoration would impact responses to immunotherapy. Here, we investigate these issues for loss of IRF1 and IRF2, which are transcription factors that drive expression of MHC I pathway genes and some killing mechanisms. METHODS: Bioinformatics analyses of IRF2 and IRF2-dependent gene transcripts were performed for all human cancers in the TCGA RNAseq database. IRF2 protein-DNA-binding was analyzed in ChIPseq databases. CRISRPcas9 was used to knock out IRF1 and IRF2 genes in human and mouse melanoma cells and the resulting phenotypes were analyzed in vitro and in vivo. RESULTS: Transcriptomic analysis revealed that IRF2 expression was reduced in a substantial subset of cases in almost all types of human cancers. When this occurred there was a corresponding reduction in the expression of IRF2-regulated genes that were needed for CD8 T cell recognition. To test cause and effect for these IRF2 correlations and the consequences of IRF2 loss, we gene-edited IRF2 in a patient-derived melanoma and a mouse melanoma. The IRF2 gene-edited melanomas had reduced expression of transcripts for genes in the MHC I pathway and decreased levels of MHC I complexes on the cell surface. Levels of Caspase 7, an IRF2 target gene involved in CD8 T cell killing of tumors, were also reduced. This loss of IRF2 caused both human and mouse melanomas to become resistant to immunotherapy with a checkpoint inhibitor. Importantly, these effects were reversible. Stimulation of the IRF2-deficient melanomas with interferon induced the expression of a functionally homologous transcription factor, IRF1, which then restored the MHC I pathway and responsiveness to CPI. CONCLUSIONS: Our study shows that a subset of cases within most types of cancers downregulates IRF2 and that this can allow cancers to escape immune control. This can cause resistance to checkpoint blockade immunotherapy and is reversible with currently available biologics.

How underappreciated autoinflammatory (innate immunity) mechanisms dominate disparate autoimmune disorders.

Historically inflammation against self was considered autoimmune which stems back to the seminal observations by Ehrlich who described serum factors, now known to be autoantibodies produced by B lineage cells that mediate "horror autotoxicus". The 20th century elucidation of B- and T-cell adaptive immune responses cemented the understanding of the key role of adaptive immune responses in mediating pathology against self. However, Mechnikov shared the Nobel Prize for the discovery of phagocytosis, the most rudimentary aspect of innate immunity. Fast forward some 100 years and an immunogenetic understanding of innate immunity led to the categorising of innate immunopathology under the umbrella term 'auto inflammation' and terminology such as "horror autoinflammaticus" to highlight the schism from the classical adaptive immune understanding of autoimmunity. These concepts lead to calls for a two-tiered classification of inflammation against self, but just as innate and adaptive immunity are functionally integrated, so is immunopathology in many settings and the concept of an autoimmune to autoinflammation continuum emerged with overlaps between both. Herein we describe several historically designated disorders of adaptive immunity where innate immunity is key, including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), systemic juvenile idiopathic arthritis (sJIA) and adult-onset Still's disease (AOSD) where the immunopathology phenotype is strongly linked to major histocompatibility complex (MHC) class II associations and responds to drugs that target T-cells. We also consider MHC-I-opathies including psoriasis and Behcet's disease(BD) that are increasingly viewed as archetype CD8 T-cell related disorders. We also briefly review the key role of barrier dysfunction in eczema and ulcerative colitis (UC) where innate tissue permeability barrier dysfunction and microbial dysbiosis contributes to prominent adaptive immune pathological mechanisms. We also highlight the emerging roles of intermediate populations of lymphocytes including gamma delta (γδ) and mucosal-associated invariant T (MAIT) cells that represent a blend of adaptive immune plasticity and innate immune rapid responders that may also determine site specific patterns of inflammation.

Corrigendum: Neuroprotection by upregulation of the major histocompatibility complex class I (MHC I) in SOD1G93A mice.

[This corrects the article DOI: 10.3389/fncel.2023.1211486.].

Ginsenoside Rh1 regulates the immune microenvironment of hepatocellular carcinoma via the glucocorticoid receptor.

OBJECTIVE: Ginsenoside Rh1 (G-Rh1) has been confirmed to inhibit the growth of breast cancer and colon cancer, but its therapeutic effect on hepatocellular carcinoma (HCC) is unclear. This study investigates the therapeutic effect of G-Rh1 on HCC as well as the underlying mechanism. METHODS: Bioinformatics methods were used to analyze glucocorticoid receptor (GR) expression and the tumor microenvironment in HCC tissues from HCC patients. The effect of G-Rh1 on HCC cells was investigated in vitro using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. The therapeutic effect of G-Rh1 was investigated in vivo using subcutaneous transplantation models in C57BL/6J and nude mice. Additionally, the proportion of infiltrating immune cells in tumors was analyzed using flow cytometry, the GR and major histocompatibility complex class-I (MHC-I) expression of HCC cells after G-Rh1 treatment was analyzed using Western blotting, and G-Rh1-treated Hepa1-6 cells were cocultured with bone marrow-derived dendritic cells and B3Z T cells to further analyze the ability of G-Rh1 to induce dendritic cell (DC) maturation and CD8+ T cell activation. RESULTS: GR expression was upregulated in HCC tissues, and high GR expression was associated with a worsened immune microenvironment. In vitro studies showed that G-Rh1 had no significant effect on the proliferation of HCC cells, while in vivo studies showed that G-Rh1 exerted antitumor effects in C57BL/6J mice but not in nude mice. Further research revealed that G-Rh1 ameliorated the immunosuppressive tumor microenvironment, thereby enhancing the antitumor effects of lenvatinib by increasing the infiltration of CD8+ T cells, mature DCs, and MHC-I-positive cells. MHC-I was upregulated by G-Rh1 via GR suppression. Moreover, overexpression of GR abolished the G-Rh1-mediated promotion of MHC-I expression in Huh7 cells, as well as the maturation of DCs and the activation of CD8+ T cells. CONCLUSION: G-Rh1 can regulate the immune microenvironment of HCC by targeting GR, thus increasing the antitumor effect of lenvatinib. Please cite this article as: Wang XH, Fu YL, Xu YN, Zhang PC, Zheng TX, Ling CQ, Feng YL. Ginsenoside Rh1 regulates the immune microenvironment of hepatocellular carcinoma via the glucocorticoid receptor. J Integr Med. 2024; Epub ahead of print.

Bioinformatic-Experimental Screening Uncovers Multiple Targets for Increase of MHC-I Expression through Activating the Interferon Response in Breast Cancer.

Expression of major histocompatibility complex I (MHC-I) on tumor cells is extremely important for the antitumor immune response for its essential role in activating various immune cells, including tumor-specific CD8+ T cells. Cancers of lower MHC-I expression commonly exhibit less immune cell infiltration and worse prognosis in clinic. In this study, we conducted bioinformatic-experimental screening to identify potential gene targets to enhance MHC-I expression in breast cancer (BRCA). Through a combination of MHC-I scoring, gene expression correlation analysis, survival prognostication, and Cibersort tumor-infiltrated lymphocytes (TILs) scoring, we identify 144 genes negatively correlated with both MHC-I expression and TILs in breast cancer. Furthermore, we verified partially according to KEGG functional enrichment or gene-dependency analysis and figured out multiple genes, including PIP5K1A, NCKAP1, CYFIP1, DIS3, TBP, and EXOC1, as effective gene targets for increasing MHC-I expression in breast cancer. Mechanistically, knockout of each of these genes activated the intrinsic interferon response in breast cancer cells, which not only promoted MHC-I expression but also caused immunogenic cell death of breast cancer. Finally, the scRNA-seq confirmed the negative correlation of PIP5K1A et al. with TILs in breast cancer patients. Collectively, we identified multiple gene targets for an increase in MHC-I expression in breast cancer in this study.

PEDV evades MHC-I-related immunity through nsp1-mediated NLRC5 translation inhibition.

Major histocompatibility complex class I (MHC-I) plays crucial roles against viral infections not only by initiating CD8+ T cell immunity but also by modulating natural killer (NK) cell cytotoxicity. Understanding how viruses precisely regulate MHC-I to optimize their infection is important; however, the manipulation of MHC-I molecules by porcine epidemic diarrhea virus (PEDV) remains unclear. In this study, we demonstrate that PEDV infection promotes the transcription of NLRC5, a key transactivator of MHC-I, in several porcine cell lines and in vivo. Paradoxically, no increase in MHC-I expression is observed after PEDV infection both in vitro and in vivo. Mechanistic studies revealed that PEDV infection inhibits the translation of PEDV-elicited NLRC5 mRNA and the expression of downstream MHC-I proteins, without affecting the expression of physiological NLRC5 and MHC-I proteins. Through viral protein screening, we identified PEDV nonstructural protein 1 (nsp1) as the critical antagonist that inhibits NLRC5-mediated upregulation of MHC-I, and the nsp1's inhibitory effect on MHC-I requires the motif of 15 amino acids at its C-terminus. Notably, our results revealed that the cytotoxic ability of NK cells against PEDV-infected cells is similar to that against healthy cells. Collectively, our findings uncover an immune evasion mechanism by which PEDV-infected cells masquerade as healthy cells to evade NK and T cell immunity. This is achieved by targeting NLRC5, a key MHC-I transcriptional regulator, via nsp1.IMPORTANCEPorcine epidemic diarrhea virus (PEDV) is a highly contagious enteric coronavirus that inflicts substantial financial losses on the swine industry. Major histocompatibility complex class I (MHC-I) is a critical factor influencing both CD8+ T cell and natural killer (NK) cell immunity. However, how PEDV manipulates MHC-I expression to optimize its infection process remains largely unknown. In this study, we demonstrate that PEDV's nonstructural protein 1 (nsp1) inhibits virus-mediated induction of MHC-I expression by directly targeting NLRC5, a key MHC-I transactivator. Intriguingly, nsp1 does not reduce physiological NLRC5 and MHC-I expression. This selective inhibition of virus-elicited NLRC5 mRNA translation allows PEDV-infected cells to masquerade as healthy cells, thereby evading CD8+ T cell and NK cell cytotoxicity. Our findings provide unique insights into the mechanisms by which PEDV evades CD8+ T cell and NK cell immunity.

Computational identification of monkeypox virus epitopes to generate a novel vaccine antigen against Mpox.

Monkeypox virus (MPXV) belonging to poxviridae family causes chronic viral disease in various mammals including human and monkeys. Conventional vaccines developed against smallpox of poxviridae, are not specific against Mpox. Also, they can cause various side effects after vaccination. In this study, we aimed to analyze the A17L, A28L, A37R, A43R, E8L, H3L, B6R, and M1R structural proteins of MPXV and identify epitopes in them which can be used to generate vaccine antigens. Among the proteins analyzed, the M1R protein was predicted to be more appropriate for use in vaccine research due to its high antigenicity value and other physicochemical features. Also, A17L, B6R and E8L had high antigenicity values. E8L protein was more conserved while the A37R, A43R, and B6R proteins had signal peptides. Although a total of eight B cell epitopes were predicted in all proteins analyzed, CNGETK epitope belonging to B6R protein had the highest antigenicity value (1.7083), as well as was non-allergenic, non-toxic, and soluble. Based on T cell epitope analyses performed on all proteins, fourteen MHC-I/II epitopes were predicted that are antigenic, non-allergenic and non-toxic, as well as soluble. Among them, MHC-I related-HEIYDRNVGF epitope in A28L protein had the highest antigenicity value (1.6650) and MHC-II related-IGNIKIVQIDIRDIK epitope in A37R protein had the highest antigenicity value (2.0280). In conclusion, eight structural proteins of MPXV were successfully analyzed and 22 important epitopes were identified that could serve as vaccine antigens or in serological studies to develop diagnostic tools.

IRF2 loss is associated with reduced MHC I pathway transcripts in subsets of most human cancers and causes resistance to checkpoint immunotherapy in human and mouse melanomas.

Background: In order for cancers to progress, they must evade elimination by CD8 T cells or other immune mechanisms. CD8 T cells recognize and kill tumor cells that display immunogenic tumor peptides bound to MHC I molecules. One of the ways that cancers can escape such killing is by reducing expression of MHC I molecules, and loss of MHC I is frequently observed in tumors. There are multiple different mechanisms that can underly the loss of MHC I complexes on tumor and it is currently unclear whether there are particular mechanisms that occur frequently and, if so, in what types of cancers. Also of importance to know is whether the loss of MHC I is reversible and how such loss and/or its restoration would impact responses to immunotherapy. Here, we investigate these issues for loss of IRF1 and IRF2, which are transcription factors that drive expression of MHC I pathway genes and some killing mechanisms. Methods: Bioinformatics analyses of IRF2 and IRF2-dependent gene transcripts were performed for all human cancers in the TCGA RNAseq database. IRF2 protein-DNA-binding was analyzed in ChIPseq databases. CRISRPcas9 was used to knock out IRF1 and IRF2 genes in human and mouse melanoma cells and the resulting phenotypes were analyzed in vitro and in vivo. Results: Transcriptomic analysis revealed that IRF2 expression was reduced in a substantial subset of cases in almost all types of human cancers. When this occurred there was a corresponding reduction in the expression of IRF2-regulated genes that were needed for CD8 T cell recognition. To test cause and effect for these IRF2 correlations and the consequences of IRF2 loss, we gene-edited IRF2 in a patient-derived melanoma and a mouse melanoma. The IRF2 gene-edited melanomas had reduced expression of transcripts for genes in the MHC I pathway and decreased levels of MHC I complexes on the cell surface. Levels of Caspase 7, an IRF2 target gene involved in CD8 T cell killing of tumors, were also reduced. This loss of IRF2 caused both human and mouse melanomas to become resistant to immunotherapy with a checkpoint inhibitor. Importantly, these effects were reversible. Stimulation of the IRF2-deficient melanomas with interferon induced the expression of a functionally homologous transcription factor, IRF1, which then restored the MHC I pathway and responsiveness to CPI. Conclusions: Our study shows that a subset of cases within most types of cancers downregulates IRF2 and that this can allow cancers to escape immune control. This can cause resistance to checkpoint blockade immunotherapy and is reversible with currently available biologics.

The Proteolytic Activity of Neutrophil-Derived Serine Proteases Bound to the Cell Surface Arming Lung Epithelial Cells for Viral Defense.

The collaboration between cellular proteases and host cells is pivotal in mounting an effective innate immune defense. Of particular interest is the synergistic interaction between cathepsin G (CatG) and neutrophil elastase (NE), which are proteases secreted by activated neutrophils, and the human alveolar basal epithelial cell line (A549) and the human lung epithelial-like cell line (H1299), because of the potential implications for viral infection. Our study aimed to investigate the binding capacity of CatG and NE on the surface of A549 and H1299 cells through preincubation with purified CatG and NE; thereby, the proteolytic activity could be detected using activity-based probes. Both CatG and NE were capable of binding to the cell surface and exhibited proteolytic activity, leading to increased cell surface levels of MHC I molecules, which is crucial for displaying the endogenous antigenic repertoire. In addition, CatG cleaved the S2' site of the SARS-CoV-2 spike protein at two specific sites (815RS816 and 817FI818) as well as NE (813SK814 and 818IE819), which potentially leads to the destruction of the fusion peptide. Additionally, furin required the presence of Ca2+ ions for the distinct cleavage site necessary to generate the fusion peptide. Overall, the findings suggest that CatG and NE can fortify target cells against viral entry, underscoring the potential significance of cell surface proteases in protecting against viral invasion.

Inhibition of Autophagy by Berbamine Hydrochloride Mitigates Tumor Immune Escape by Elevating MHC-I in Melanoma Cells.

Impaired tumor cell antigen presentation contributes significantly to immune evasion. This study identifies Berbamine hydrochloride (Ber), a compound derived from traditional Chinese medicine, as an effective inhibitor of autophagy that enhances antigen presentation in tumor cells. Ber increases MHC-I-mediated antigen presentation in melanoma cells, improving recognition and elimination by CD8+ T cells. Mutation of Atg4b, which blocks autophagy, also raises MHC-I levels on the cell surface, and further treatment with Ber under these conditions does not increase MHC-I, indicating Ber's role in blocking autophagy to enhance MHC-I expression. Additionally, Ber treatment leads to the accumulation of autophagosomes, with elevated levels of LC3-II and p62, suggesting a disrupted autophagic flux. Fluorescence staining and co-localization analyses reveal that Ber likely inhibits lysosomal acidification without hindering autophagosome-lysosome fusion. Importantly, Ber treatment suppresses melanoma growth in mice and enhances CD8+ T cell infiltration, supporting its therapeutic potential. Our findings demonstrate that Ber disturbs late-stage autophagic flux through abnormal lysosomal acidification, enhancing MHC-I-mediated antigen presentation and curtailing tumor immune escape.

Sex and disease regulate major histocompatibility complex class I expression in human lung epithelial cells.

Major histocompatibility complex class I (MHC I) molecules present peptides to CD8+ T-cells for immunosurveillance of infection and cancer. Recent studies indicate lineage-specific heterogeneity in MHC I expression. While respiratory diseases rank among the leading causes of mortality, studies in mice have shown that lung epithelial cells (LECs) express the lowest levels of MHC I in the lung. This study aims to answer three questions: (i) Do human LECs express low levels of MHC I? (ii) Is LEC MHC I expression modulated in chronic respiratory diseases? (iii) Which factors regulate MHC I levels in human LECs? We analyzed human LECs from parenchymal explants using single-cell RNA sequencing and immunostaining. We confirmed low constitutive MHC I expression in human LECs, with significant upregulation in chronic respiratory diseases. We observed a sexual dimorphism, with males having higher MHC I levels under steady-state conditions, likely due to differential redox balance. Our study unveils the complex interplay between MHC I expression, sex, and respiratory disease. Since MHC I upregulation contributes to the development of immunopathologies in other models, we propose that it may have a similar impact on chronic lung disease.

Low-dose SAHA enhances CD8+ T cell-mediated antitumor immunity by boosting MHC I expression in non-small cell lung cancer.

BACKGROUND: Non-small cell lung cancer (NSCLC) is a highly aggressive type of lung cancer with poor responses to traditional therapies such as surgery, radiotherapy, and chemotherapy. While immunotherapy has become an effective approach for treating multiple types of cancer, solid tumors frequently exhibit immune escape through various mechanisms, including downregulation of MHC I expression. However, whether the upregulation of MHC I expression can improve the immunotherapeutic effect on NSCLC remains unexplored. Suberoylanilide hydroxamic acid (SAHA) is a potent histone deacetylase (HDAC) inhibitor that has been applied clinically to treat lymphoma, but a high dose of SAHA kills tumor cells and normal cells without preference. Here, we report that low-dose SAHA enhances CD8+ T cell-mediated antitumor immunity by upregulating MHC I expression in NSCLC cells. METHODS: Flow cytometric analysis, quantitative real-time PCR and western blot were used to analyze the expression of MHC I, STAT1 and Smad2/3 in both human and mouse NSCLC cell lines after SAHA treatment. The nuclear translocation of phosphorylated STAT1 and Smad2/3 was investigated by western blot and immunofluorescence staining. The mechanisms underlying STAT1 and Smad2/3 upregulation were analyzed through database searches and chromatin immunoprecipitation-qPCR. Finally, we assessed the antitumor effect of specific CD8+ T cells with SAHA treatment in vivo and in vitro. RESULTS: We showed that low-dose SAHA upregulated the expression of MHC I in NSCLC cell lines without affecting cell viability. We also provided evidence that high levels of MHC I induced by SAHA promoted the activation, proliferation, and cytotoxicity of specific CD8+ T cells in mouse models. Mechanistically, low-dose SAHA increased the levels of H3K9ac and H3K27ac in the promoters of the STAT1, Smad2 and Smad3 genes in NSCLC cells by inhibiting HDAC activity, resulting in elevated expression levels of STAT1, Smad2 and Smad3. The nuclear translocation of phosphorylated STAT1 and Smad2/3 markedly upregulated the expression of MHC I in NSCLC cells. CONCLUSIONS: Low-dose SAHA enhances CD8+ T cell-mediated antitumor immunity by boosting MHC I expression in NSCLC cells. Thus, we revealed a key mechanism of SAHA-mediated enhanced antitumor immunity, providing insights into a novel immunotherapy strategy for NSCLC.

Targeted inhibition of glycogen synthase kinase-3 using 9-ING-41 (elraglusib) enhances CD8 T-cell-reactivity against neuroblastoma cells.

The prognosis of patients with high-risk neuroblastoma remains poor, partly due to inadequate immune recognition of the tumor. Neuroblastomas display extremely low surface MHC-I, preventing recognition by cytotoxic T lymphocytes (CTLs) and contributing to an immunosuppressive tumor microenvironment. Glycogen synthase kinase-3 beta (GSK-3ß) is involved in pathways that may affect the MHC-I antigen processing and presentation pathway. We proposed that therapeutic inhibition of GSK-3ß might improve the surface display of MHC-I molecules on neuroblastoma cells, and therefore tested if targeting of GSK-3ß using the inhibitor 9-ING-41 (Elraglusib) improves MHC-I-mediated CTL recognition. We analyzed mRNA expression data of neuroblastoma tumor datasets and found that non-MYCN-amplified neuroblastomas express higher GSK-3ß levels than MYCN-amplified tumors. In non-MYCN-amplified cells SH-SY5Y, SK-N-AS and SK-N-SH 9-ING-41 treatment enhanced MHC-I surface display and the expression levels of a subset of genes involved in MHC-I antigen processing and presentation. Further, 9-ING-41 treatment triggered increased STAT1 pathway activation, upstream of antigen presentation pathways in two of the three non-MYCN-amplified cell lines. Finally, in co-culture experiments with CD8 + T cells, 9-ING-41 improved immune recognition of the neuroblastoma cells, as evidenced by augmented T-cell activation marker levels and T-cell proliferation, which was further enhanced by PD-1 immune checkpoint inhibition. Our preclinical study provides experimental support to further explore the GSK-3ß inhibitor 9-ING-41 as an immunomodulatory agent to increase tumor immune recognition in neuroblastoma.

Monocyte/Macrophage-Mediated Transport of Dual-Drug ZIF Nanoplatforms Synergized with Programmed Cell Death Protein-1 Inhibitor Against Microsatellite-Stable Colorectal Cancer.

Microsatellite-stable colorectal cancer (MSS-CRC) exhibits resistance to programmed cell death protein-1 (PD-1) therapy. Improving the infiltration and tumor recognition of cytotoxic T-lymphocytes (CTLs) is a promising strategy, but it encounters huge challenges from drug delivery and mechanisms aspects. Here, a zeolitic imidazolate framework (ZIF) coated with apoptotic body membranes derived from MSS-CRC cells is engineered for the co-delivery of ginsenoside Rg1 (Rg1) and atractylenolide-I (Att) to MSS-CRC, named as Ab@Rg1/Att-ZIF. This system is selectively engulfed by Ly-6C+ monocytes during blood circulation and utilizes a "hitchhiking" mechanism to migrate toward the core of MSS-CRC. Ab@Rg1/Att-ZIF undergoes rapid disassembly in the tumor, released Rg1 promotes the processing and transportation of tumor antigens in dendritic cells (DCs), enhancing their maturation. Meanwhile, Att enhances the activity of the 26S proteasome complex in tumor cells, leading to increased expression of major histocompatibility complex class-I (MHC-I). These coordinated actions enhance the infiltration and recognition of CTLs in the center of MSS-CRC, significantly improving the tumor inhibition of PD-1 treatment from ≈5% to ≈69%. This innovative design, involving inflammation-guided precise drug co-delivery and a rational combination, achieves synergistic engineering of the tumor microenvironment, providing a novel strategy for successful PD-1 treatment of MSS-CRC.

The Wdr5-H3K4me3 Epigenetic Axis Regulates Pancreatic Tumor Immunogenicity and Immune Suppression.

The WDR5/MLL1-H3K4me3 epigenetic axis is often activated in both tumor cells and tumor-infiltrating immune cells to drive various cellular responses in the tumor microenvironment and has been extensively studied in hematopoietic cancer, but its respective functions in tumor cells and immune cells in the context of tumor growth regulation of solid tumor is still incompletely understood. We report here that WDR5 exhibits a higher expression level in human pancreatic tumor tissues compared with adjacent normal pancreas. Moreover, WDR5 expression is negatively correlated with patients' response to chemotherapy or immunotherapy in human colon cancer and melanoma. However, WDR5 expression is positively correlated with the HLA level in human cancer cells, and H3K4me3 enrichment is observed at the promoter region of the HLA-A, HLA-B, and HLA-C genes in pancreatic cancer cells. Using mouse tumor cell lines and in vivo tumor models, we determined that WDR5 deficiency or inhibition significantly represses MHC I expression in vitro and in vivo in pancreatic tumor cells. Mechanistically, we determine that WDR5 deficiency inhibits H3K4me3 deposition at the MHC I (H2K) promoter region to repress MHC I (H2K) transcription. On the other hand, WDR5 depletion leads to the effective downregulation of immune checkpoints and immunosuppressive cytokines, including TGFß and IL6, in the pancreatic tumor microenvironments. Our data determine that WDR5 not only regulates tumor cell immunogenicity to suppress tumor growth but also activates immune suppressive pathways to promote tumor immune evasion. Selective activation of the WDR5-MHC I pathway and/or selective inhibition of the WDR5-immune checkpoint and WDR5-cytokine pathways should be considered in WDR5-based epigenetic cancer immunotherapy.

Tumor antigen presentation and the associated signal transduction during carcinogenesis.

Numerous developments have been achieved in the study and treatment of cancer throughout the decades that it has been common. After decades of research, about 100 different kinds of cancer have been found, each with unique subgroups within certain organs. This has significantly expanded our understanding of the illness. A mix of genetic, environmental, and behavioral variables contribute to the complicated and diverse process of cancer formation. Mutations, or changes in the DNA sequence, are crucial to the development of cancer. These mutations have the ability to downregulate the expression and function of Major Histocompatibility Complex class I (MHC I) and MHCII receptors, as well as activate oncogenes and inactivate tumor suppressor genes. Cancer cells use this tactic to avoid being recognized by cytotoxic CD8+T lymphocytes, which causes issues with antigen presentation and processing. This review goes into great length into the PI3K pathway, changes to MHC I, and positive impacts of tsMHC-II on disease-free survival and overall survival and the involvement of dendritic cells (DCs) in different tumor microenvironments. The vital functions that the PI3K pathway and its link to the mTOR pathway are highlighted and difficulties in developing effective cancer targeted therapies and feedback systems has also been mentioned, where resistance mechanisms include RAS-mediated oncogenic changes and active PI3K signalling.

Nilotinib boosts the efficacy of anti-PDL1 therapy in colorectal cancer by restoring the expression of MHC-I.

BACKGROUND: Although immune checkpoint inhibitors (ICIs) have revolutionized the landscape of cancer treatment, only a minority of colorectal cancer (CRC) patients respond to them. Enhancing tumor immunogenicity by increasing major histocompatibility complex I (MHC-I) surface expression is a promising strategy to boost the antitumor efficacy of ICIs. METHODS: Dual luciferase reporter assays were performed to find drug candidates that can increase MHC-I expression. The effect of nilotinib on MHC-I expression was verified by dual luciferase reporter assays, qRT-PCR, flow cytometry and western blotting. The biological functions of nilotinib were evaluated through a series of in vitro and in vivo experiments. Using RNA-seq analysis, immunofluorescence assays, western blotting, flow cytometry, rescue experiments and microarray chip assays, the underlying molecular mechanisms were investigated. RESULTS: Nilotinib induces MHC-I expression in CRC cells, enhances CD8+ T-cell cytotoxicity and subsequently enhances the antitumor effects of anti-PDL1 in both microsatellite instability and microsatellite stable models. Mechanistically, nilotinib promotes MHC-I mRNA expression via the cGAS-STING-NF-κB pathway and reduces MHC-I degradation by suppressing PCSK9 expression in CRC cells. PCSK9 may serve as a potential therapeutic target for CRC, with nilotinib potentially targeting PCSK9 to exert anti-CRC effects. CONCLUSION: This study reveals a previously unknown role of nilotinib in antitumor immunity by inducing MHC-I expression in CRC cells. Our findings suggest that combining nilotinib with anti-PDL1 therapy may be an effective strategy for the treatment of CRC.

Clinico-sero-pathological profiles and risk prediction model of idiopathic inflammatory myopathy (IIM) patients with different perifascicular changes.

AIMS: To explore the clinico-sero-pathological characteristics and risk prediction model of idiopathic inflammatory myopathy (IIM) patients with different muscular perifascicular (PF) changes. METHODS: IIM patients in our center were enrolled and the clinico-sero-pathological data were retrospectively analyzed. A decision tree model was established through machine learning. RESULTS: There were 231 IIM patients enrolled, including 53 with perifascicular atrophy (PFA), 39 with perifascicular necrosis (PFN), and 26 with isolated perifascicular enhancement of MHC-I/MHC-II (PF-MHCn). Clinically, PFA patients exhibited skin rashes and dermatomyositis-specific antibodies (DM-MSAs, 74.5%) except for anti-Mi2. PFN patients showed the most severe muscle weakness, highest creatine kinase (CK), anti-Mi2 (56.8%), and anti-Jo-1 (24.3%) antibodies. PF-MHCn patients demonstrated negative MSAs (48.0%) and elevated CK. Histopathologically, MAC predominantly deposited on PF capillaries in PFA but on non-necrotic myofiber in PFN (43.4% and 36.8%, p < 0.001). MxA expression was least in PF-MHCn (36.0% vs. 83.0% vs. 63.2%, p < 0.001). The decision tree model could effectively predict different subgroups, especially PFA and PFN. CONCLUSIONS: Three types of PF change of IIMs representing distinct clinico-serological characteristics and pathomechanism. Undiscovered MSAs should be explored especially in PF-MHCn patients. The three pathological features could be accurately predicted through the decision tree model.

Extracellular vesicle-packaged lncRNA from cancer-associated fibroblasts promotes immune evasion by downregulating HLA-A in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is characterised by immune evasion that contribute to poor prognosis. Cancer-associated fibroblasts (CAFs) play a pivotal role in orchestrating the PDAC tumour microenvironment. We investigated the role of CAF-derived extracellular vesicle (EV)-packaged long non-coding RNAs (lncRNAs) in immune evasion and explored gene therapy using engineered EVs loading small interfering RNAs (siRNAs) as a potential therapeutic strategy. Our findings highlight the significance of EV-packaged lncRNA RP11-161H23.5 from CAF in promoting PDAC immune evasion by downregulating HLA-A expression, a key component of antigen presentation. Mechanistically, RP11-161H23.5 forms a complex with CNOT4, a subunit of the mRNA deadenylase CCR4-NOT complex, enhancing the degradation of HLA-A mRNA by shortening its poly(A) tail. This immune evasion mechanism compromises the anti-tumour immune response. To combat this, we propose an innovative approach utilising engineered EVs as natural and biocompatible nanocarriers for siRNA-based gene therapy and this strategy holds promise for enhancing the effectiveness of immunotherapy in PDAC. Overall, our study sheds light on the critical role of CAF-derived EV-packaged lncRNA RP11-161H23.5/CNOT4/HLA-A axis in PDAC immune evasion and presents a novel avenue for therapeutic intervention.