Schwann cell-derived CXCL2 contributes to cancer pain by modulating macrophage infiltration in a mouse breast cancer model

Sympathetic nerve signaling rewires the tumor microenvironment: a shift in "microenvironmental-ity"

Nerve signaling within the tumor microenvironment (TME) plays a critical role in the initiation, progression, and metastasis of solid tumors. Due to their highly responsive behavior and activation upon injury and cancer onset, this review specifically focuses on how sympathetic nerves rewire the TME. Within tumors, sympathetic nerves closely interact with various TME components, and their combined signaling often shifts tumor-intrinsic physiology toward tumor-supportive phenotypes. In turn, the TME components, such as myeloid cells, lymphoid cells, extracellular matrix (ECM), endothelial cells, cancer associated fibroblasts (CAFs), and Schwann cells, secrete neurotrophic and axon guidance factors that influence both sympathetic outgrowth and tumor cell behavior, further exacerbating tumor progression and metastasis. Here, we review the current evidence on the multidirectional impacts of sympathetic nerves and both immune and non-immune TME components, the nature of these communication processes, and how exploring these interactions may inform future therapeutics to impair cancer progression and metastasis.

Unraveling the peripheral nervous System's role in tumor: A Double-edged Sword

The peripheral nervous system (PNS) includes all nerves outside the brain and spinal cord, comprising various cells like neurons and glial cells, such as schwann and satellite cells. The PNS is increasingly recognized for its bidirectional interactions with tumors, exhibiting both pro- and anti-tumor effects. Our review delves into the complex mechanisms underlying these interactions, highlighting recent findings that challenge the conventional understanding of PNS's role in tumorigenesis. We emphasize the contradictory results in the literature and propose novel perspectives on how these discrepancies can be resolved. By focusing on the PNS's influence on tumor initiation, progression, and microenvironment remodeling, we provide a comprehensive analysis that goes beyond the structural description of the PNS. Our review suggests that a deeper comprehension of the PNS-tumor crosstalk is pivotal for developing targeted anticancer strategies. We conclude by emphasizing the need for future research to unravel the intricate dynamics of the PNS in cancer, which may lead to innovative diagnostic tools and therapeutic approaches.

The role of macrophages in chronic pain

Chronic pain typically lasts or recurs for more than three months and is an unpleasant sensory and emotional experience, including neuropathic pain, long-term tissue damage, tumors, and viral or bacterial infections.The unpleasantness associated with pain affects the basic life of patients and has become a truly global problem. Macrophages, a powerful immune effector cell whose functional plasticity leads to polarization into different subtypes and opposite effects in different environments, are also indispensable in the development of pain.In recent years, there has been an increasing number of studies on the effects of macrophages on pain, and there are multiple pathways that regulate macrophage polarization, including lipopolysaccharide induction and IL-4/IL-13 stimulation.In addition, pathways involving macrophages and macrophage polarization have been found to have an exacerbating or mitigating role in the progression of chronic pain, with M1 macrophages generally exacerbating pain progression and M2 macrophages mitigating pain progression.Therefore, modulating macrophage polarization holds great promise as an intervention in chronic pain. In this paper, we synthesize multiple macrophage pathways as well as mechanisms affecting their pain processes in the context of different types of chronic pain, providing new avenues for chronic pain relief.

The Emerging Role of Schwann Cells in the Tumor Immune Microenvironment and Its Potential Clinical Application

As the primary glial cells in the peripheral nervous system (PNS), Schwann cells (SCs) have been proven to influence the behavior of cancer cells profoundly and are involved in cancer progression through extensive interactions with cancer cells and other stromal cells. Indeed, the tumor microenvironment (TME) is a critical factor that can significantly limit the efficacy of immunotherapeutic approaches. The TME promotes tumor progression in part by reshaping an immunosuppressive state. The immunosuppressive TME is the result of the crosstalk between the tumor cells and the different immune cell subsets, including macrophages, natural killer (NK) cells, dendritic cells (DCs), lymphocytes, myeloid-derived suppressor cells (MDSCs), etc. They are closely related to the anti-tumor immune status and the clinical prognosis of cancer patients. Increasing research demonstrates that SCs influence these immune cells and reshape the formation of the immunosuppressive TME via the secretion of various cytokines, chemokines, and other effector molecules, eventually facilitating immune evasion and tumor progression. In this review, we summarize the SC reprogramming in TME, the emerging role of SCs in tumor immune microenvironment, and the underlying mechanisms involved. We also discuss the possible therapeutic strategies to selectively target SCs, providing insights and perspectives for future research and clinical studies involving SC-targeted treatment.

The CXCR2 chemokine receptor: A new target for gastric cancer therapy

Gastric cancer (GC) is one of the most common malignant tumors in the world, and current treatments are still based on surgery and drug therapy. However, due to the complexity of immunosuppression and drug resistance, the treatment of gastric cancer still faces great challenges. Chemokine receptor 2 (CXCR2) is one of the most common therapeutic targets in targeted therapy. As a G protein-coupled receptor, CXCR2 and its ligands play important roles in tumorigenesis and progression. The abnormal expression of these genes in cancer plays a decisive role in the recruitment and activation of white blood cells, angiogenesis, and cancer cell proliferation, and CXCR2 is involved in various stages of tumor development. Therefore, interfering with the interaction between CXCR2 and its ligands is considered a possible target for the treatment of various tumors, including gastric cancer.

The intersection of the nervous system and breast cancer

Breast cancer (BC) represents a paradigm of heterogeneity, manifesting as a spectrum of molecular subtypes with divergent clinical trajectories. It is fundamentally characterized by the aberrant proliferation of malignant cells within breast tissue, a process modulated by a myriad of factors that govern its progression. Recent endeavors outline the interplay between BC and the nervous system, illuminate the complex symbiosis between neural structures and neoplastic cells, and elucidate nerve dependence as a cornerstone of BC progression. This includes the neural modulations on immune response, neurovascular formation, and multisystem interactions. Such insights have unveiled the critical impact of neural elements on tumor dynamics and patient prognosis. This revelation beckons a deeper exploration into the neuro-oncological interface, potentially unlocking novel therapeutic vistas. This review endeavors to delineate the intricate mechanisms between the nervous system and BC, aiming to accentuate the implications and therapeutic strategies of this intersection for tumor evolution and the formulation of innovative therapeutic approaches.

Microcystin-LR Regulates Interaction between Tumor Cells and Macrophages via the IRE1α/XBP1 Signaling Pathway to Promote the Progression of Colorectal Cancer

Microcystin-LR (MC-LR), a cyanobacterial toxin, is a potent carcinogen implicated in colorectal cancer (CRC) progression. However, its impact on the tumor microenvironment (TME) during CRC development remains poorly understood. This study investigates the interaction between tumor cells and macrophages mediated by MC-LR within the TME and its influence on CRC progression. CRC mice exposed to MC-LR demonstrated a significant transformation from adenoma to adenocarcinoma. The infiltration of macrophages increased, and the IRE1α/XBP1 pathway was activated in CRC cells after MC-LR exposure, influencing macrophage M2 polarization under co-culture conditions. Additionally, hexokinase 2 (HK2), a downstream target of the IRE1α/XBP1 pathway, was identified, regulating glycolysis and lactate production. The MC-LR-induced IRE1α/XBP1/HK2 axis enhanced lactate production in CRC cells, promoting M2 macrophage polarization. Furthermore, co-culturing MC-LR-exposed CRC cells with macrophages, along with the IRE1α/XBP1 pathway inhibitor 4μ8C and the hexokinase inhibitor 2-DG, suppressed M2 macrophage-induced CRC cell migration, clonogenicity, and M2 macrophage polarization. This study elucidates the mechanism by which MC-LR-mediated interactions through the IRE1α/XBP1 pathway promote CRC progression, highlighting potential therapeutic targets.

Nerve-tumor crosstalk in tumor microenvironment: From tumor initiation and progression to clinical implications

The autonomic nerve system (ANS) innervates organs and tissues throughout the body and maintains functional balance among various systems. Further investigations have shown that excessive activation of ANS not only causes disruption of homeostasis, but also may promote tumor formation. In addition, the dynamic interaction between nerve and tumor cells in the tumor microenvironment also regulate tumor progression. On the one hand, nerves are passively invaded by tumor cells, that is, perineural invasion (PNI). On the other hand, compared with normal tissues, tumor tissues are subject to more abundant innervation, and nerves can influence tumor progression through regulating tumor proliferation, metastasis and drug resistance. A large number of studies have shown that nerve-tumor crosstalk, including PNI and innervation, is closely related to the prognosis of patients, and contributes to the formation of cancer pain, which significantly deteriorates the quality of life for patients. These findings suggest that nerve-tumor crosstalk represents a potential target for anti-tumor therapies and the management of cancer pain in the future. In this review, we systematically describe the mechanism by which nerve-tumor crosstalk regulates tumorigenesis and progression.

Nanomaterials modulate tumor-associated macrophages for the treatment of digestive system tumors

The treatment of digestive system tumors presents challenges, particularly in immunotherapy, owing to the advanced immune tolerance of the digestive system. Nanomaterials have emerged as a promising approach for addressing these challenges. They provide targeted drug delivery, enhanced permeability, high bioavailability, and low toxicity. Additionally, nanomaterials target immunosuppressive cells and reshape the tumor immune microenvironment (TIME). Among the various cells in the TIME, tumor-associated macrophages (TAMs) are the most abundant and play a crucial role in tumor progression. Therefore, investigating the modulation of TAMs by nanomaterials for the treatment of digestive system tumors is of great significance. Here, we present a comprehensive review of the utilization of nanomaterials to modulate TAMs for the treatment of gastric cancer, colorectal cancer, hepatocellular carcinoma, and pancreatic cancer. We also investigated the underlying mechanisms by which nanomaterials modulate TAMs to treat tumors in the digestive system. Furthermore, this review summarizes the role of macrophage-derived nanomaterials in the treatment of digestive system tumors. Overall, this research offers valuable insights into the development of nanomaterials tailored for the treatment of digestive system tumors.

Glial cell alterations in diabetes-induced neurodegeneration

Type 2 diabetes mellitus is a global epidemic that due to its increasing prevalence worldwide will likely become the most common debilitating health condition. Even if diabetes is primarily a metabolic disorder, it is now well established that key aspects of the pathogenesis of diabetes are associated with nervous system alterations, including deleterious chronic inflammation of neural tissues, referred here as neuroinflammation, along with different detrimental glial cell responses to stress conditions and neurodegenerative features. Moreover, diabetes resembles accelerated aging, further increasing the risk of developing age-linked neurodegenerative disorders. As such, the most common and disabling diabetic comorbidities, namely diabetic retinopathy, peripheral neuropathy, and cognitive decline, are intimately associated with neurodegeneration. As described in aging and other neurological disorders, glial cell alterations such as microglial, astrocyte, and Müller cell increased reactivity and dysfunctionality, myelin loss and Schwann cell alterations have been broadly described in diabetes in both human and animal models, where they are key contributors to chronic noxious inflammation of neural tissues within the PNS and CNS. In this review, we aim to describe in-depth the common and unique aspects underlying glial cell changes observed across the three main diabetic complications, with the goal of uncovering shared glial cells alterations and common pathological mechanisms that will enable the discovery of potential targets to limit neuroinflammation and prevent neurodegeneration in all three diabetic complications. Diabetes and its complications are already a public health concern due to its rapidly increasing incidence, and thus its health and economic impact. Hence, understanding the key role that glial cells play in the pathogenesis underlying peripheral neuropathy, retinopathy, and cognitive decline in diabetes will provide us with novel therapeutic approaches to tackle diabetic-associated neurodegeneration.

Peripheral nervous system glia in support of metabolic tissue functions

The peripheral nervous system (PNS) relays information between organs and tissues and the brain and spine to maintain homeostasis, regulate tissue functions, and respond to interoceptive and exteroceptive signals. Glial cells perform support roles to maintain nerve function, plasticity, and survival. The glia of the central nervous system (CNS) are well characterized, but PNS glia (PNSG) populations, particularly tissue-specific subtypes, are underexplored. PNSG are found in large nerves (such as the sciatic), the ganglia, and the tissues themselves, and can crosstalk with a range of cell types in addition to neurons. PNSG are also subject to phenotypic changes in response to signals from their local tissue environment, including metabolic changes. These topics and the importance of PNSG in metabolically active tissues, such as adipose, muscle, heart, and lymphatic tissues, are outlined in this review.

Schwann cells regulate tumor cells and cancer-associated fibroblasts in the pancreatic ductal adenocarcinoma microenvironment

Neuropathy is a feature more frequently observed in pancreatic ductal adenocarcinoma (PDAC) than other tumors. Schwann cells, the most prevalent cell type in peripheral nerves, migrate toward tumor cells and associate with poor prognosis in PDAC. To unveil the effects of Schwann cells on the neuro-stroma niche, here we perform single-cell RNA-sequencing and microarray-based spatial transcriptome analysis of PDAC tissues. Results suggest that Schwann cells may drive tumor cells and cancer-associated fibroblasts (CAFs) to more malignant subtypes: basal-like and inflammatory CAFs (iCAFs), respectively. Moreover, in vitro and in vivo assays demonstrate that Schwann cells enhance the proliferation and migration of PDAC cells via Midkine signaling and promote the switch of CAFs to iCAFs via interleukin-1α. Culture of tumor cells and CAFs with Schwann cells conditioned medium accelerates PDAC progression. Thus, we reveal that Schwann cells induce malignant subtypes of tumor cells and CAFs in the PDAC milieu.