Karen Olivia Dixon

Peripheral nerves are emerging regulators of the tumor microenvironment, but how sensory innervation shapes breast cancer immunity remains poorly defined. Here we show that triple-negative breast cancers (TNBCs) co-opt nociceptor neurons to suppress antitumor immunity and promote disease progression. Across orthotopic TNBC models, we found that primary tumors and tumor-draining lymph nodes were densely innervated by CGRP⁺ sensory fibers. Tumor-derived cues directly activated dorsal root ganglion neurons, increased calcium responsiveness, induced Ngfr and Atf3, and triggered release of CGRP and substance P. Mechanistically, a tumor-derived proNGF-NGFR axis reprogrammed nociceptors and promoted neuropeptide secretion. Soluble mediators from activated nociceptors suppressed CD8⁺ T cell-mediated tumor-cell killing, whereas sensory-neuron silencing or ablation curtailed tumor growth and remodeled the immune microenvironment toward dendritic-cell activation, myeloid reprogramming, and enhanced CD8⁺ T cell and NK-cell effector states. Subset-specific analysis revealed nonredundant sensory control of immune states, with MrgD⁺ neurons selectively shaping macrophage-centered programs. Finally, blockade of CGRP signaling through RAMP1 reduced tumor growth and markedly enhanced PD-1 blockade, nearly eliminating primary tumor burden and lung metastasis in vivo. T cell-specific Ramp1 deletion similarly restrained tumor growth, and RAMP1⁺ CD8⁺ T cells in human TNBC displayed an exhaustion-associated phenotype. Together, these findings define a tumor-promoting proNGF-nociceptor-CGRP-RAMP1 axis and identify neuroimmune signaling as a therapeutically actionable vulnerability in TNBC.

Oncolytic virotherapy represents a promising yet under-explored approach for precision cancer treatment, particularly when tailored to tumor-specific molecular profiles. Patients with high-grade isocitrate dehydrogenase (IDH) mutant astrocytomas have limited treatment options and poor prognoses. Here, we investigate the therapeutic efficacy of rQNestin34.5 v.2 (CAN-3110), an engineered oncolytic herpes simplex virus 1 (oHSV-1), in IDH1-R132H-mutant diffuse gliomas. We demonstrate that the IDH1-R132H mutation enhances glioma susceptibility to viral infection through upregulation of Nectin-1, the main HSV-1 entry receptor. Concurrently, IDH1-R132H-driven DNA hypermethylation suppresses interferon (IFN) signaling, creating a permissive microenvironment that facilitates viral replication and tumor cell apoptosis. In immunocompetent murine glioma models, intratumoral administration of rQNestin34.5 v.2 induces robust antitumor immune activation, including increased immune infiltration and systemic IFN-γ release. However, elevated expression of poliovirus receptor (PVR) and the immune checkpoint T-cell immunoreceptor with immunoglobulin and ITIM domain (TIGIT) on tumor-infiltrating leukocytes suggests a potential resistance mechanism to virotherapy. Combining rQNestin34.5 v.2 with TIGIT blockade enhances therapeutic efficacy compared to monotherapy, identifying IDH1-R132H as a potential predictive biomarker for oncolytic virotherapy response.

The nervous and immune systems have co-evolved to detect and respond to internal and external threats, working together to restore homeostasis after tissue injury or infection. Sharing several receptors and ligands, they engage in direct cross-talk that substantially influences disease development. The emerging field of cancer neuro-immunity focuses on the intricate interactions between the nervous system, immune responses and tumour growth. Additional findings have revealed that nerve fibres infiltrating peripheral tumours can release neuromodulatory factors that shape both immune cell behaviour and tumour progression. Conversely, tumour-infiltrating immune cells can modify the activity of local neurons, including pain-transmitting nociceptive sensory neurons. Beyond sensory fibres, sympathetic signalling can foster immunosuppression by recruiting myeloid-derived suppressor cells and promoting T cell exhaustion. This Review summarizes current evidence on how neuronal signalling regulates peripheral antitumour immune responses within the tumour microenvironment. We describe the complex, reciprocal interactions among neurons, immune cells and malignant cells, highlighting the key parts played by the peripheral nervous system in modulating immunity against cancer. By understanding this neuro-immune axis, novel therapeutic approaches may be uncovered to strengthen antitumour immunity and enhance responses to existing cancer treatments.

Microglia are the resident immune cells in the brain and have pivotal roles in neurodevelopment and neuroinflammation^1,2. This study investigates the function of the immune-checkpoint molecule TIM-3 (encoded by HAVCR2) in microglia. TIM-3 was recently identified as a genetic risk factor for late-onset Alzheimer’s disease³, and it can induce T cell exhaustion⁴. However, its specific function in brain microglia remains unclear. We demonstrate in mouse models that TGFβ signalling induces TIM-3 expression in microglia. In turn, TIM-3 interacts with SMAD2 and TGFBR2 through its carboxy-terminal tail, which enhances TGFβ signalling by promoting TGFBR-mediated SMAD2 phosphorylation, and this process maintains microglial homeostasis. Genetic deletion of Havcr2 in microglia leads to increased phagocytic activity and a gene-expression profile consistent with the neurodegenerative microglial phenotype (MGnD), also referred to as disease-associated microglia (DAM). Furthermore, microglia-targeted deletion of Havcr2 ameliorates cognitive impairment and reduces amyloid-β pathology in 5×FAD mice (a transgenic model of Alzheimer’s disease). Single-nucleus RNA sequencing revealed a subpopulation of MGnD microglia in Havcr2-deficient 5×FAD mice characterized by increased pro-phagocytic and anti-inflammatory gene expression alongside reduced pro-inflammatory gene expression. These transcriptomic changes were corroborated by single-cell RNA sequencing data across most microglial clusters in Havcr2-deficient 5×FAD mice. Our findings reveal that TIM-3 mediates microglia homeostasis through TGFβ signalling and highlight the therapeutic potential of targeting microglial TIM-3 in Alzheimer’s disease.

Single-cell RNA sequencing (scRNA-seq) has revolutionized cell biology by enabling the profiling of transcriptomes at a single-cell resolution, leading to important discoveries that have advanced our understanding of cellular and tissue heterogeneity, developmental trajectories, and disease progression. Despite these important advances, scRNA-seq is limited to measuring the transcriptome providing a partial view of cellular function. To address this limitation, multimodal scRNA-seq assays have emerged, allowing for the simultaneous measurement of RNA expression and protein. Intracellular Transcriptomic and Protein Sequencing (InTraSeq), a novel multimodal scRNA-seq technology described here, enables the concurrent measurement of mRNA, surface markers, cytoplasmic proteins, and nuclear proteins within individual cells through oligo-barcoded antibodies. This method offers a comprehensive approach to studying cellular function by combining RNA and protein profiling from the same sample and utilizing a relatively simple protocol. The InTraSeq method enables researchers to expand their view of critical intracellular protein expression including post-translational modifications (PTMs) and transcription factors, allowing for the identification of novel cellular subtypes and states that may be obscured by RNA-based analyses alone. This is particularly valuable in understanding the heterogeneity of cell populations and identifying distinct functional states. In this report, we used InTraSeq to characterize the complex cellular states and regulatory mechanisms during Th17 cell differentiation. We simultaneously profiled RNA and protein expression in over 85,000 cells, capturing transcriptional changes, changes in protein expression and the dynamics of signaling pathways at a high resolution. Our results revealed novel insights into Th17 cell differentiation, including the identification of key regulatory factors and their target genes. By simultaneously measuring mRNA, extra and intra-cellular proteins, signaling proteins, and PTMs, InTraSeq offers a comprehensive understanding of cellular processes and enables the identification of novel regulatory mechanisms.

Summary: The field of cancer neuroscience has begun to define the contributions of nerves to cancer initiation and progression; here, we highlight the future directions of basic and translational cancer neuroscience for malignancies arising outside of the central nervous system.

T cell immunoglobulin and mucin domain-containing protein 3 (TIM-3) is an important immune checkpoint molecule initially identified as a marker of IFN-γ–producing CD4 ⁺ and CD8 ⁺ T cells. Since then, our understanding of its role in immune responses has significantly expanded. Here, we review emerging evidence demonstrating unexpected roles for TIM-3 as a key regulator of myeloid cell function, in addition to recent work establishing TIM-3 as a delineator of terminal T cell exhaustion, thereby positioning TIM-3 at the interface between fatigued immune responses and reinvigoration. We share our perspective on the antagonism between TIM-3 and T cell stemness, discussing both cell-intrinsic and cell-extrinsic mechanisms underlying this relationship. Looking forward, we discuss approaches to decipher the underlying mechanisms by which TIM-3 regulates stemness, which has remarkable potential for the treatment of cancer, autoimmunity, and autoinflammation.

The Arthur and Sandra Irving Cancer Immunology Symposium has been created as a platform for established cancer immunologists to mentor trainees and young investigators as they launch their research career in the field. By sharing their different paths to success, the senior faculty mentors provide an invaluable resource to support the development of the next generation of leaders in the cancer immunology community. This Commentary describes some of the key topics that were discussed during the 2022 symposium: scientific and career trajectory, leadership, mentoring, collaborations, and publishing. For each of these topics, established investigators discussed the elements that facilitate success in these areas as well as mistakes that can hinder progress. Herein, we outline the critical points raised in these discussions for establishing a successful independent research career. These points are highly relevant for the broader scientific community.