The duality of STAT2 mediated type I interferon signaling in the tumor microenvironment and chemoresistance

cGAS/STING-Independent Induction of Type I Interferon by Inhibitors of the Histone Methylase KDM5B

Studies support the role of hexamethylene bis-acetamide [HMBA] induced protein 1 (HEXIM1) as a tumor suppressor. We previously reported that the histone demethylase, KDM5B, inhibits the expression of HEXIM1, and KDM5B inhibitors (KDM5Bi) upregulate HEXIM1 expression. As a consequence, KDM5Bi inhibited cell proliferation, induced differentiation, potentiated sensitivity to cancer chemotherapy, and inhibited breast tumor metastasis. HEXIM1 is crucial for the regulation of triple-negative breast cancer (TNBC) phenotype by KDM5Bi. Type I Interferon (IFN-I) employs the immune system in the tumor microenvironment to restrict tumor growth. Moreover, therapeutic approaches (including mainstay chemotherapy) engage IFN-I signaling. We report herein that HEXIM1 and KDM5Bi induce IFN-I in TNBC. HEXIM1 and KDM5Bi downregulate the expression of polyribonucleotide nucleotidyltransferase 1 (PNPT1) resulting in the release of mitochondrial dsRNA (mt-dsRNA) into the cytoplasm. HEXIM1 also upregulates melanoma differentiation-associated protein 5 (MDA5), a cytoplasmic viral RNA receptor in the innate immune system. MDA5 is required for HEXIM1 and KDM5Bi to induce IFN-I and downstream signaling factors. We observed the augmentation of DNA damage response to Doxorubicin in the presence of KDM5Bi, and this action is a contributing factor in KDM5Bi-induced IFN-I. These actions of HEXIM1 and KDM5Bi occur independently of Cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (cGAS/STING), a major DNA sensing pathway and inducer of innate immunity. Via the upregulation of HEXIM1, KDM5Bi represent pharmacologically induced and tumor intrinsic IFN-I production that is cGAS/STING independent. This is critical because cGAS/STING induce an inflammatory response that promotes the survival of cancer cells, and STING is often impaired in malignant cancers.

USP5 motivates immunosuppressive microenvironment in multiple myeloma by activating STAT2-PFKFB4-mediated glycolysis

BACKGROUND

Glycolysis, a classic characteristic of cancer cells, can drive cancer progression by generating lactate, which play as a key immunosuppressive mediator. Currently, ubiquitin-specific proteases 5 (USP5) has been demonstrated to facilitate tumor cell survival in multiple myeloma (MM), whereas whether USP5 was involved in glycolysis-lactate production pathway and immunosuppressive microenvironment formation in MM remain unknown.

METHODS

The gene and protein expression characteristics were assessed via qRT-PCR and western blot. MM cell survival was determined by CCK-8 and flow cytometry analysis. Glycolysis was evaluated by examining glucose uptake, lactate production and ATP level via corresponding kits. Tumor-associated macrophages polarization was tested via measurement of M1/M2-like macrophage markers using qRT-PCR and flow cytometry methods. Dual-luciferase reporter, chromatin immunoprecipitation and co-immunoprecipitation assays were conducted to verified molecular relationship. Xenograft model was used for verified cellular findings.

RESULTS

USP5 was abnormally overexpressed in MM patients and cell lines. Knockdown of USP5 could restrain MM cell survival and glycolysis activity, thus reducing lactate-mediated immunosuppressive M2-like macrophage polarization in vitro and in vivo, whereas overexpression of USP5 play opposite impacts. Mechanistically, USP5 could downregulate the ubiquitination modification of STAT to stabilize STAT2 protein, thus activating PFKFB4 transcription. Moreover, STAT2 could overturn the regulatory role of USP5 on MM cell survival, glycolysis and lactate-mediated immunosuppressive M2-like macrophage polarization.

CONCLUSION

These findings elucidated that USP5 served as a regulator of glycolysis-lactate to stimulate M2-like macrophage formation by regulating STAT2-PFKFB4 signaling, which supported that USP5 could be a viable therapeutic target of MM treatment.

IL-4 mediated TAP2 downregulation is a dominant and reversible mechanism of immune evasion and immunotherapy resistance in non-small cell lung cancer

BACKGROUND

Resistance to both naturally occurring anti-cancer immunity and to immunotherapy is common in patients with aggressive non-small cell lung cancer (NSCLC). Recent studies indicate a role of loss of the HLA class-I antigen presentation machinery (APM) protein β-2-microglobulin in acquired resistance to immune checkpoint blockers. However, the mechanisms, functional consequences and therapeutic potential of APM defects in NSCLC remain poorly understood.

METHODS

Using multiplexed immunofluorescence, we spatially mapped CD8+ effector Tumor-Infiltrating Lymphocytes (TILs) and the APM components TAP1 and TAP2 in 819 baseline/pre-treatment NSCLCs from patients treated with and without PD-1 axis blockers in 4 independent cohorts. The impact of TAP1/2 silencing in lung cancer cells using siRNAs and CRISPR/Cas9 was studied using transcriptomic analysis, phosphoprotein arrays, ATAC-sequencing, measurement of surface HLA-peptide complexes and in vitro tumor-antigen specific T-cell killing. We established autologous co-cultures of tumor and immune cells from primary human NSCLCs to study the functional impact of IL4Rα and/or PD-1 blockade using monoclonal antibodies. A high-throughput drug screen supported the identification of compounds able to increase TAP2 expression in NSCLC cells.

RESULTS

We identified cancer cell selective TAP2 protein downregulation in 42.4% of treatment naïve NSCLCs associated with reduced sensitivity to immune checkpoint blockers. TAP1 downregulation occurred in 24.4% of lung tumors without survival impact. Silencing of TAP2 in lung cancer cells altered key intracellular immunomodulatory pathways, limited sensitivity to proinflammatory cytokines, reduced the levels of surface peptide-HLA complexes and protected malignant cells from tumor antigen-specific T-cell killing via SOCS1 upregulation. TAP2 loss in human NSCLCs was associated with reduced TAP2 promoter chromatin accessibility and elevated IL-4 IL-4 expression. Treatment with IL-4 reduced TAP2 levels and the chromatin accessibility of the TAP2 gene promoter in NSCLC cells and reproduced all the functional consequences of TAP2 loss. In intact human NSCLC, IL-4 IL-4 transcripts were detected in intratumoral myeloid cells and IL-4Rα blockade increased human NSCLC cell killing by autologous TILs. Epigenetic modulators and other drugs with known anti-cancer activity increased TAP2 expression and its function in lung cancer cells.

CONCLUSIONS

Our study reveals previously unrecognized functions of TAP2 beyond antigen presentation and establishes a reversible multi-cellular axis mediating adaptive immune evasion and immunotherapy resistance with clinical potential.

Functional Involvement of Signal Transducers and Activators of Transcription in the Pathogenesis of Influenza A Virus

Signal transducers and activators of transcription (STATs) function both as signal transducers and transcription regulators. STAT proteins are involved in the signaling pathways of cytokines and growth factors; thus, they participate in various life activities and play especially critical roles in antiviral immunity. Convincing evidence suggests that STATs can establish innate immune status through multiple mechanisms, efficiently eliminating pathogens. STAT1 and STAT2 can activate the antiviral status by regulating the interferon (IFN) signal. In turn, suppressor of cytokine signaling-1 (SOCS1) and SOCS3 can modulate the activation of STATs and suppress the excessive antiviral immune response. STAT3 not only regulates the IFN signal, but also transduces Interleukin-6 (IL-6) to stimulate the host antiviral response. The function of STAT4 and STAT5 is related to CD4+ T helper (Th) cells, and the specific mechanism of STAT5 remains to be studied. STAT6 mainly exerts antiviral effects by mediating IL-4 and IL-13 signaling. Here, we reviewed the recent findings regarding the critical roles of STATs in the interactions between the host and viral infection, especially influenza A virus (IAV) infection. We also discuss the molecular mechanisms underlying their functions in antiviral responses.

Global and single-cell proteomics view of the co-evolution between neural progenitors and breast cancer cells in a co-culture model

BACKGROUND

Presence of nerves in tumours, by axonogenesis and neurogenesis, is gaining increased attention for its impact on cancer initiation and development, and the new field of cancer neuroscience is emerging. A recent study in prostate cancer suggested that the tumour microenvironment may influence cancer progression by recruitment of Doublecortin (DCX)-expressing neural progenitor cells (NPCs). However, the presence of such cells in human breast tumours has not been comprehensively explored.

METHODS

Here, we investigate the presence of DCX-expressing cells in breast cancer stromal tissue from patients using Imaging Mass Cytometry. Single-cell analysis of 372,468 cells across histopathological images of 107 breast cancers enabled spatial resolution of neural elements in the stromal compartment in correlation with clinicopathological features of these tumours. In parallel, we established a 3D in vitro model mimicking breast cancer neural progenitor-innervation and examined the two cell types as they co-evolved in co-culture by using mass spectrometry-based global proteomics.

FINDINGS

Stromal presence of DCX + cells is associated with tumours of higher histological grade, a basal-like phenotype, and shorter patient survival in tumour tissue from patients with breast cancer. Global proteomics analysis revealed significant changes in the proteomic landscape of both breast cancer cells and neural progenitors in co-culture.

INTERPRETATION

These results support that neural involvement plays an active role in breast cancer and warrants further studies on the relevance of nerve elements for tumour progression.

FUNDING

This work was supported by the Research Council of Norway through its Centre of Excellence funding scheme, project number 223250 (to L.A.A), the Norwegian Cancer Society (to L.A.A. and H.V.), the Regional Health Trust Western Norway (Helse Vest) (to L.A.A.), the Meltzer Research Fund (to H.V.) and the National Institutes of Health (NIH)/NIGMS grant R01 GM132129 (to J.A.P.).

The Protective Effects of an Aged Black Garlic Water Extract on the Prostate

Chronic inflammation is a recognized risk factor for various cancers, including prostate cancer (PCa). We aim to explore the potential protective effects of aged black garlic extract (ABGE) against inflammation-induced prostate damage and its impact on prostate cancer cell lines. We used an ex vivo model of inflammation induced by Escherichia coli lipopolysaccharide (LPS) on C57BL/6 male mouse prostate specimens to investigate the anti-inflammatory properties of ABGE. The gene expression levels of pro-inflammatory biomarkers (COX-2, NF-κB, and TNF-α, IL-6) were measured. Additionally, we evaluated ABGE's therapeutic effects on the prostate cancer cell lines through in vitro functional assays, including colony formation, tumorsphere formation, migration assays, and phosphorylation arrays to assess the signaling pathways (MAPK, AKT, JAK/STAT, and TGF-β). ABGE demonstrated significant anti-inflammatory and antioxidant effects in preclinical models, partly attributed to its polyphenolic content, notably catechin and gallic acid. In the ex vivo model, ABGE reduced the gene expression levels of COX-2, NF-κB, TNF-α, and IL-6. The in vitro studies showed that ABGE inhibited cell proliferation, colony and tumorsphere formation, and cell migration in the prostate cancer cells, suggesting its potential as a therapeutic agent. ABGE exhibits promising anti-inflammatory and anti-cancer properties, supporting further investigation into ABGE as a potential agent for managing inflammation and prostate cancer.

Oncogenic STAT Transcription Factors as Targets for Cancer Therapy: Innovative Strategies and Clinical Translation

Despite advances in our understanding of molecular aspects of oncogenesis, cancer remains a leading cause of death. The malignant behavior of a cancer cell is driven by the inappropriate activation of transcription factors. In particular, signal transducers and activators of transcription (STATs), which regulate many critical cellular processes such as proliferation, apoptosis, and differentiation, are frequently activated inappropriately in a wide spectrum of human cancers. Multiple signaling pathways converge on the STATs, highlighting their importance in the development and progression of oncogenic diseases. STAT3 and STAT5 are two members of the STAT protein family that are the most frequently activated in cancers and can drive cancer pathogenesis directly. The development of inhibitors targeting STAT3 and STAT5 has been the subject of intense investigations in the last decade, although effective treatment options remain limited. In this review, we investigate the specific roles of STAT3 and STAT5 in normal physiology and cancer biology, discuss the opportunities and challenges in pharmacologically targeting STAT proteins and their upstream activators, and offer insights into novel therapeutic strategies to identify STAT inhibitors as cancer therapeutics.

STAT2 Controls Colorectal Tumorigenesis and Resistance to Anti-Cancer Drugs

Colorectal cancer (CRC) is a significant socioeconomic burden in modern society and is accountable for millions of premature deaths each year. The role of signal transducer and activator of transcription 2 (STAT2)-dependent signaling in this context is not yet fully understood, and no therapies targeting this pathway are currently being pursued. We investigated the role of STAT2 in CRC using experimental mouse models coupled with RNA-sequencing (RNA-Seq) data and functional assays with anti-cancer agents in three-dimensional tumoroids. Stat2-/- mice showed greater resistance to the development of CRC in both inflammation-driven and inflammation-independent experimental CRC models. In ex vivo studies, tumoroids derived from Stat2-/- mice with the multiple intestinal neoplasia (Min) mutant allele of the adenomatous polyposis coli (Apc) locus exhibited delayed growth, were overall smaller and more differentiated as compared with tumoroids from ApcMin/+ wildtype (WT) mice. Notably, tumoroids from ApcMin/+ Stat2-/- mice were more susceptible to anti-cancer agents inducing cell death by different mechanisms. Our findings clearly indicated that STAT2 promotes CRC and suggested that interventions targeting STAT2-dependent signals might become an attractive therapeutic option for patients with CRC.

The interactions of docetaxel with tumor microenvironment

There are several interactions within the tumor microenvironment (TME) that affect the response of cancer cells to therapy. There are also a large number of cells and secretions in TME that increase resistance to therapy. Following the release of immunosuppressive, pro-angiogenic, and metastatic molecules by certain cells such as tumor-associated macrophages (TAMs), cancer-associated fibroblasts (CAFs), and cancer cells, immune evasion, angiogenesis, and metastasis may be induced. However, natural killer (NK) cells and cytotoxic CD8 + T lymphocytes (CTLs) can responsively release anticancer molecules. In addition, anticancer drugs can modulate these cells and their interactions in favor of either cancer resistance or therapy. Docetaxel belongs to taxanes, a class of anti-tumor drugs, which acts through the polymerization of tubulin and the induction of cell cycle arrest. Also, it has been revealed that taxanes including docetaxel affect cancer cells and the other cells within TME through some other mechanisms such as modulation of immune system responses, angiogenesis, and metastasis. In this paper, we explain the basic mechanisms of docetaxel interactions with malignant cells. Besides, we review the diverse effects of docetaxel on TME and cancer cells in consequence. Lastly, the modulatory effects of docetaxel alone or in conjunction with other anticancer agents on anti-tumor immunity, cancer cell resistance, angiogenesis, and metastasis will be discussed.