Plasminogen activator inhibitors orchestrate the immunosuppressive tumor microenvironment in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a dense extracellular matrix (ECM) that sustains an immunosuppressive tumor microenvironment (TME). While this protective niche has been described, the molecular determinants orchestrating its formation and dictating its immune interactions are not well defined. Using Perturb-map, we determine how dozens of different gene perturbations shape the growth and cellular environments of PDAC clones through space and time.

The costimulatory molecule ICOS limits memory-like properties and function of exhausted PD-1CD8 T cells.

During persistent antigen stimulation, CD8 T cell responses are maintained by progenitor exhausted CD8 T (Tpex) cells. Tpex cells respond to blockade of the inhibitory receptor programmed cell death-1 (PD-1), and regulation of their differentiation is critical for immunotherapies. Tpex cells highly express inducible costimulator (ICOS), but how ICOS modulates PD-1CD8 T cells is not clear.

Cancer vaccines and the future of immunotherapy.

Vaccines have had a major impact on the control of infectious disease, most recently by helping to combat the COVID-19 pandemic. Prophylactic cancer vaccines have prevented several malignancies by protecting against cancer-causing pathogens. By contrast, therapeutic vaccines training the immune system to eliminate established tumours are now showing real promise in clinical settings.

Updates on radiotherapy-immunotherapy combinations: Proceedings of 8th Annual ImmunoRad Conference.

The annual ImmunoRad Conference has established itself as a recurrent occasion to explore the possibility of combining radiation therapy (RT) and immunotherapy (IT) for clinical cancer management. Bringing together a number of preclinical and clinical leaders in the fields of radiation oncology, immuno-oncology and IT, this annual event fosters indeed essential conversations and fruitful exchanges on how to address existing challenges to expand the therapeutic value of RT-IT combinations. The 8th edition of the ImmunoRad Conference, which has been held in October 2024 at the Weill Cornell Medical College of New York City, highlighted exciting preclinical and clinical advances at the interface between RT and IT, setting the stage for extra progress toward extended benefits for patients with an increasing variety of tumor types.

Enhancing antitumor immunity through chemotherapeutic-derived lipid nanoparticle-induced immunogenic cell death and CD40L/Flt3L mRNA-mediated dendritic cell activation.

Dendritic cells (DCs) are essential for inducing effective antitumor T cell responses. However, the immunosuppressive tumor microenvironment (TME) hinders DC recruitment and maturation, facilitating tumor progression and spread. This study investigates the synergistic potential of immunogenic cell death (ICD), triggered by chemotherapeutic-derived lipid nanoparticles (LNPs), in combination with Flt3L and CD40L mRNA delivery to enhance DC mobilization and activation, reprogram the TME, and ultimately promote robust antitumor T cell responses.

LNP-RNA-mediated antigen presentation leverages SARS-CoV-2-specific immunity for cancer treatment.

Lipid nanoparticle (LNP)-mRNA vaccines have demonstrated protective capability in combating SARS-CoV-2. Their extensive deployment across the global population leads to the broad presence of T-cell immunity against the SARS-CoV-2 spike protein, presenting an opportunity to harness this immunological response as a universal antigen target for cancer treatment. Herein, we design and synthesize a series of amino alcohol- or amino acid-derived ionizable lipids (AA lipids) and develop an LNP-RNA-based antigen presentation platform to redirect spike-specific T-cell immunity against cancer in mouse models.

Cholesterol mobilization regulates dendritic cell maturation and the immunogenic response to cancer.

Maturation of conventional dendritic cells (cDCs) is crucial for maintaining tolerogenic safeguards against auto-immunity and for promoting immunogenic responses to pathogens and cancer. The subcellular mechanism for cDC maturation remains poorly defined. We show that cDCs mature by leveraging an internal reservoir of cholesterol (harnessed from extracellular cell debris and generated by de novo synthesis) to assemble lipid nanodomains on cell surfaces of maturing cDCs, enhance expression of maturation markers and stabilize immune receptor signaling.

Bispecific antibody targeting of lipid nanoparticles.

Lipid nanoparticles (LNP) are the most clinically advanced non-viral gene delivery system. While progress has been made for enhancing delivery, cell specific targeting remains a challenge. Targeting moieties such as antibodies can be chemically-conjugated to LNPs however, this approach is complex and has challenges for scaling up.

Dendritic cells type 1 control the formation, maintenance, and function of tertiary lymphoid structures in cancer.

Tertiary lymphoid structures (TLS) are organized immune cell aggregates that arise in chronic inflammatory conditions. In cancer, TLS are associated with better prognosis and enhanced response to immunotherapy, making these structures attractive therapeutic targets. However, the mechanisms regulating TLS formation and maintenance in cancer are incompletely understood.

Unveiling the hidden network of STING's subcellular regulation.

A new study deconvolutes the systems-level control of the cGAS-STING pathway and identifies many novel regulators of STING biology. This was made possible by optical pooled screening (OPS), which enables high-dimensional imaging of millions of gene-edited cells, showcasing the future of CRISPR screening.

Ovarian cancer-derived IL-4 promotes immunotherapy resistance.

Ovarian cancer is resistant to immunotherapy, and this is influenced by the immunosuppressed tumor microenvironment (TME) dominated by macrophages. Resistance is also affected by intratumoral heterogeneity, whose development is poorly understood. To identify regulators of ovarian cancer immunity, we employed a spatial functional genomics screen (Perturb-map), focused on receptor/ligands hypothesized to be involved in tumor-macrophage communication.

ICOS limits memory-like properties and function of exhausted PD-1 CD8 T cells.

During persistent antigen stimulation, PD-1 CD8 T cells are maintained by progenitor exhausted PD-1 TCF-1 CD8 T cells (Tpex). Tpex respond to PD-1 blockade, and regulation of Tpex differentiation into more functional Tex is of major interest for cancer immunotherapies. Tpex express high levels of Inducible Costimulator (ICOS), but the role of ICOS for PD-1 CD8 T cell responses has not been addressed.

Direct presentation of inflammation-associated self-antigens by thymic innate-like T cells induces elimination of autoreactive CD8 thymocytes.

Upregulation of diverse self-antigens that constitute components of the inflammatory response overlaps spatially and temporally with the emergence of pathogen-derived foreign antigens. Therefore, discrimination between these inflammation-associated self-antigens and pathogen-derived molecules represents a unique challenge for the adaptive immune system. Here, we demonstrate that CD8 T cell tolerance to T cell-derived inflammation-associated self-antigens is efficiently induced in the thymus and supported by redundancy in cell types expressing these molecules.

Myeloid progenitor dysregulation fuels immunosuppressive macrophages in tumors.

Monocyte-derived macrophages (mo-macs) drive immunosuppression in the tumor microenvironment (TME) and tumor-enhanced myelopoiesis in the bone marrow (BM) fuels these populations. Here, we performed paired transcriptome and chromatin analysis over the continuum of BM myeloid progenitors, circulating monocytes, and tumor-infiltrating mo-macs in mice and in patients with lung cancer to identify myeloid progenitor programs that fuel pro-tumorigenic mo-macs. Analyzing chromatin accessibility and histone mark changes, we show that lung tumors prime accessibility for Nfe2l2 (NRF2) in BM myeloid progenitors as a cytoprotective response to oxidative stress.

The tissue-resident regulatory T cell pool is shaped by transient multi-tissue migration and a conserved residency program.

The tissues are the site of many important immunological reactions, yet how the immune system is controlled at these sites remains opaque. Recent studies have identified Foxp3 regulatory T (Treg) cells in non-lymphoid tissues with unique characteristics compared with lymphoid Treg cells. However, tissue Treg cells have not been considered holistically across tissues.

Accelerating diabetic wound healing by ROS-scavenging lipid nanoparticle-mRNA formulation.

Current treatment options for diabetic wounds face challenges due to low efficacy, as well as potential side effects and the necessity for repetitive treatments. To address these issues, we report a formulation utilizing trisulfide-derived lipid nanoparticle (TS LNP)-mRNA therapy to accelerate diabetic wound healing by repairing and reprogramming the microenvironment of the wounds. A library of reactive oxygen species (ROS)-responsive TS LNPs was designed and developed to encapsulate interleukin-4 (IL4) mRNA.

An IL-4 signalling axis in bone marrow drives pro-tumorigenic myelopoiesis.

Myeloid cells are known to suppress antitumour immunity. However, the molecular drivers of immunosuppressive myeloid cell states are not well defined. Here we used single-cell RNA sequencing of human and mouse non-small cell lung cancer (NSCLC) lesions, and found that in both species the type 2 cytokine interleukin-4 (IL-4) was predicted to be the primary driver of the tumour-infiltrating monocyte-derived macrophage phenotype.

Pattern recognition receptor agonists in pathogen vaccines mediate antitumor T-cell cross-priming.

Background: Cancer immunotherapies are generally effective in patients whose tumors contain a priori primed T-cells reactive to tumor antigens (TA). One approach to prime TA-reactive T-cells is to administer immunostimulatory molecules, cells, or pathogens directly to the tumor site, that is, in situ vaccination (ISV). We recently described an ISV using Flt3L to expand and recruit dendritic cells (DC), radiotherapy to load DC with TA, and pattern recognition receptor agonists (PRRa) to activate TA-loaded DC.

Hepatic stellate cells maintain liver homeostasis through paracrine neurotrophin-3 signaling that induces hepatocyte proliferation.

Organ size is maintained by the controlled proliferation of distinct cell populations. In the mouse liver, hepatocytes in the midlobular zone that are positive for cyclin D1 (CCND1) repopulate the parenchyma at a constant rate to preserve liver mass. Here, we investigated how hepatocyte proliferation is supported by hepatic stellate cells (HSCs), pericytes that are in close proximity to hepatocytes.

TREM2 macrophages drive NK cell paucity and dysfunction in lung cancer.

Natural killer (NK) cells are commonly reduced in human tumors, enabling many to evade surveillance. Here, we sought to identify cues that alter NK cell activity in tumors. We found that, in human lung cancer, the presence of NK cells inversely correlated with that of monocyte-derived macrophages (mo-macs).

Expanding cross-presenting dendritic cells enhances oncolytic virotherapy and is critical for long-term anti-tumor immunity.

Immunotherapies directly enhancing anti-tumor CD8 T cell responses have yielded measurable but limited success, highlighting the need for alternatives. Anti-tumor T cell responses critically depend on antigen presenting dendritic cells (DC), and enhancing mobilization, antigen loading and activation of these cells represent an attractive possibility to potentiate T cell based therapies. Here we show that expansion of DCs by Flt3L administration impacts in situ vaccination with oncolytic Newcastle Disease Virus (NDV).