TNF Receptor-2 Facilitates an Immunosuppressive Microenvironment in the Liver to Promote the Colonization and Growth of Hepatic Metastases

Role of T cells in liver metastasis

The liver is a major metastatic site (organ) for gastrointestinal cancers (such as colorectal, gastric, and pancreatic cancers) as well as non-gastrointestinal cancers (such as lung, breast, and melanoma cancers). Due to the innate anatomical position of the liver, the apoptosis of T cells in the liver, the unique metabolic regulation of hepatocytes and other potential mechanisms, the liver tends to form an immunosuppressive microenvironment and subsequently form a pre-metastatic niche (PMN), which can promote metastasis and colonization by various tumor cells(TCs). As a result, the critical role of immunoresponse in liver based metastasis has become increasingly appreciated. T cells, a centrally important member of adaptive immune response, play a significant role in liver based metastases and clarifying the different roles of the various T cells subsets is important to guide future clinical treatment. In this review, we first introduce the predisposing factors and related mechanisms of liver metastasis (LM) before introducing the PMN and its transition to LM. Finally, we detail the role of different subsets of T cells in LM and advances in the management of LM in order to identify potential therapeutic targets for patients with LM.

Concomitant NAFLD Facilitates Liver Metastases and PD-1-Refractory by Recruiting MDSCs via CXCL5/CXCR2 in Colorectal Cancer

BACKGROUND & AIMS

Both nonalcoholic fatty liver disease (NAFLD) and colorectal cancer (CRC) are prevalent worldwide. The effects of concomitant NAFLD on the risk of colorectal liver metastasis (CRLM) and its mechanisms have not been definitively elucidated.

METHODS

We observed the effect of concomitant NAFLD on CRLM in the mouse model and explored the underlying mechanisms of specific myeloid-derived suppressor cells (MDSCs) recruitment and then tested the therapeutic application based on the mechanisms. Finally we validated our findings in the clinical samples.

RESULTS

Here we prove that in different mouse models, NAFLD induces F4/80+ Kupffer cells to secret chemokine CXCL5 and then recruits CXCR2+ MDSCs to promote the growth of CRLM. CRLM with NAFLD background is refractory to the anti-PD-1 monoclonal antibody treatment, but when combined with Reparixin, an inhibitor of CXCR1/2, dual therapy cures the established CRLM in mice with NAFLD. Our clinical studies also indicate that fatty liver diseases increase the infiltration of CXCR2+ MDSCs, as well as the hazard of liver metastases in CRC patients.

CONCLUSIONS

Collectively, our findings highlight the significance of selective CXCR2+/CD11b+/Gr-1+ subset myeloid cells in favoring the development of CRLM with NAFLD background and identify a pharmaceutical medicine that is already available for the clinical trials and potential treatment.

Hallmarks of sex bias in immuno-oncology: mechanisms and therapeutic implications

Sex differences are present across multiple non-reproductive organ cancers, with male individuals generally experiencing higher incidence of cancer with poorer outcomes. Although some mechanisms underlying these differences are emerging, the immunological basis is not well understood. Observations from clinical trials also suggest a sex bias in conventional immunotherapies with male individuals experiencing a more favourable response and female individuals experiencing more severe adverse events to immune checkpoint blockade. In this Perspective article, we summarize the major biological hallmarks underlying sex bias in immuno-oncology. We focus on signalling from sex hormones and chromosome-encoded gene products, along with sex hormone-independent and chromosome-independent epigenetic mechanisms in tumour and immune cells such as myeloid cells and T cells. Finally, we highlight opportunities for future studies on sex differences that integrate sex hormones and chromosomes and other emerging cancer hallmarks such as ageing and the microbiome to provide a more comprehensive view of how sex differences underlie the response in cancer that can be leveraged for more effective immuno-oncology approaches.

From biology to the clinic - exploring liver metastasis in prostate cancer

Liver metastases from prostate cancer are associated with an aggressive disease course and poor prognosis. Results from autopsy studies indicate a liver metastasis prevalence of up to 25% in patients with advanced prostate cancer. Population data estimate that ~3-10% of patients with metastatic castration-resistant prostate cancer harbour liver metastases at the baseline, rising to 20-30% in post-treatment cohorts, suggesting that selective pressure imposed by novel therapies might promote metastatic spread to the liver. Liver metastases are associated with more aggressive tumour biology than lung metastases. Molecular profiling of liver lesions showed an enrichment of low androgen receptor, neuroendocrine phenotypes and high genomic instability. Despite advancements in molecular imaging modalities such as prostate-specific membrane antigen PET-CT, and liquid biopsy markers such as circulating tumour DNA, early detection of liver metastases from prostate cancer remains challenging, as both approaches are hampered by false positive and false negative results, impeding the accurate identification of early liver lesions. Current therapeutic strategies showed limited efficacy in this patient population. Emerging targeted radionuclide therapies, metastasis-directed therapy, and novel systemic agents have shown preliminary activity against liver metastases, but require further validation. Treatment with various novel prostate cancer therapies might lead to an increase in the prevalence of liver metastasis, underscoring the urgent need for coordinated efforts across preclinical and clinical researchers to improve characterization, monitoring, and management of liver metastases from prostate cancer. Elucidating molecular drivers of liver tropism and interactions with the liver microenvironment might ultimately help to identify actionable targets to enhance survival in this high-risk patient group.

Exosomes promote pre-metastatic niche formation in colorectal cancer

It is well known that colorectal cancer (CRC) has a high morbidity rate, a poor prognosis when metastasized, and a greatly shortened 5-year survival rate. Therefore, understanding the mechanism of tumor metastasis is still important. Based on the "seed and soil" theory, the concept of " premetastatic niche (PMN)" was introduced by Kaplan et al. The complex interaction between primary tumors and the metastatic organ provides a beneficial microenvironment for tumor cells to colonize at a distance. With further exploration of the PMN, exosomes have gradually attracted interest from researchers. Exosomes are extracellular vesicles secreted from cells that include various biological information and are involved in communication between cells. As a key molecule in the PMN, exosomes are closely related to tumor metastasis. In this article, we obtained information by conducting a comprehensive search across academic databases including PubMed and Web of Science using relevant keywords. Only recent, peer-reviewed articles published in the English language were considered for inclusion. This study aims to explore in depth how exosomes promote the formation of pre-metastatic microenvironment (PMN) in colorectal cancer and its related mechanisms.

Small extracellular vesicles promote the formation of the pre-metastatic niche through multiple mechanisms in colorectal cancer

Colorectal cancer (CRC) ranks among the most prevalent global malignancies, posing significant threats to human life and health due to its high recurrence and metastatic potential. Small extracellular vesicles (sEVs) released by CRC play a pivotal role in the formation of the pre-metastatic niche (PMN) through various mechanisms, preparing the groundwork for accelerated metastatic invasion. This review systematically describes how sEVs promote CRC metastasis by upregulating inflammatory factors, promoting immunosuppression, enhancing angiogenesis and vascular permeability, promoting lymphangiogenesis and lymphatic network remodeling, determining organophilicity, promoting stromal cell activation and remodeling and inducing the epithelial-to-mesenchymal transition (EMT). Furthermore, we explore potential mechanisms by which sEVs contribute to PMN formation in CRC and propose novel insights for CRC diagnosis, treatment, and prognosis.

Construction and validation of a novel prognostic nomogram for predicting overall survival in lung adenocarcinoma patients with different patterns of metastasis

OBJECTIVE

Metastasis of lung cancer is an important factor affecting survival. The present study proposed to establish and verify a nomogram for predicting overall survival (OS) in lung adenocarcinoma (LUAD) patients with different patterns of metastasis.

METHODS

A total of 9727 patients diagnosed with metastatic LUAD patients from 2010 to 2015 were enrolled based on surveillance, epidemiology and end results (SEER) Database and then randomly divided into training and validation cohorts, and 136 patients in our Cancer Center were enrolled as the external validation cohort. Univariate and multivariate analyses were performed to evaluate the prognostic impact on OS. A prognostic nomogram was constructed and evaluated by C-index, calibration curve, decision curve analysis (DCA), and risk stratification system.

RESULTS

Ultimately, 6809 and 2918 patients diagnosed with metastatic LUAD in the training and validation cohorts were enrolled in the study, respectively. A male sex, a later T and N stage, a larger tumor size, treatment including no surgery, no chemotherapy and no radiotherapy, metastasis sites were found to be independent risk factors in LUAD patients for worse OS, and then incorporated into the nomogram. The frequency of bone metastasis was the highest, and in single site metastasis, the prognosis of liver metastasis was the worst. Two-site metastasis is more common than three-site and four-site metastasis, and co-metastasis eventually leads to a worse survival outcome. The C-index value of nomogram for predicting OS were 0.798, 0.703 and 0.698 in the internal training, validation and external validation cohorts, separately. The calibration curves for the 6-months, 1-year and 2-year showed significant agreement between nomogram models and actual observations. The DCA curves indicated nomogram was more beneficial than the AJCC TNM stage. Patients were further divided into low-risk and high-risk groups according to nomogram predicted scores and developed a survival risk classification system.

CONCLUSIONS

Our prognostic nomogram is expected to be an accurate and individualized clinical predictive tool for predicting OS in LUAD patients with different patterns of metastasis.

Therapeutic potential of TNFR2 agonists: a mechanistic perspective

TNFR2 agonists have been investigated as potential therapies for inflammatory diseases due to their ability to activate and expand immunosuppressive CD4+Foxp3+ Treg cells and myeloid-derived suppressor cells (MDSCs). Despite TNFR2 being predominantly expressed in Treg cells at high levels, activated effector T cells also exhibit a certain degree of TNFR2 expression. Consequently, the role of TNFR2 signaling in coordinating immune or inflammatory responses under different pathological conditions is complex. In this review article, we analyze possible factors that may determine the therapeutic outcomes of TNFR2 agonism, including the levels of TNFR2 expression on different cell types, the biological properties of TNFR2 agonists, and disease status. Based on recent progress in the understanding of TNFR2 biology and the study of TNFR2 agonistic agents, we discuss the future direction of developing TNFR2 agonists as a therapeutic agents.

Anti-TNFR2 enhanced the antitumor activity of a new HMGN1/3M-052 stimulated dendritic cell vaccine in a mouse model of colon cancer

Immunotherapy is the new approach for cancer treatment that can be achieved through several strategies, one of which is dendritic cells (DCs) vaccine therapy. However, traditional DC vaccination lacks accurate targeting, so DC vaccine preparation needs to be optimized. Immunosuppressive CD4⁺Foxp3⁺ regulatory T cells (Tregs) in the tumor microenvironment can promote tumor immune escape. Therefore, targeting Tregs has become a strategy for tumor immunotherapy. In this study, we found that HMGN1 (N1, a dendritic cell-activating TLR4 agonist) and 3M-052 (a newly synthesized TLR7/8 agonist) synergistically stimulate DCs maturation and increase the production of proinflammatory cytokines TNFα and IL-12. In a colon cancer mice model, vaccination with N1 and 3M-052 stimulated and tumor antigen-loaded DCs combined with anti-TNFR2 inhibited tumor growth in mice, and the antitumor effect was mainly achieved through stimulation of cytotoxic CD8 T cell activation and depletion of Tregs. Overall, the combinating of DC activation by N1 and 3M-052 with inhibition of Tregs by antagonizing TNFR2 as a therapeutic strategy may represent a more effective strategy for cancer treatment.

The Immunosuppressive Effect of TNFR2 Expression in the Colorectal Cancer Microenvironment

Colorectal cancer (CRC) represents one of the most common causes of death among cancers worldwide. Its incidence has been increasing among the young population. Many risk factors contribute to the development and progression of CRC and about 70% of them are sporadic. The CRC microenvironment is highly heterogeneous and represents a very complex immunosuppressive platform. Many cytokines and their receptors are vital participants in this immunosuppressive microenvironment. Tumor necrosis factors (TNFs) and TNF receptor 2 (TNFR2) are critical players in the development of CRC. TNFR2 was observed to have increased the immunosuppressive activity of CRC cells via regulatory T cells (T regs) and myeloid-derived suppressor cells (MDSC) in the CRC microenvironment. However, the exact mechanism of TNFR2 in regulating the CRC prognosis remains elusive. Here, we discuss the role of TNFR2 in immune escape mechanism of CRC in the immunosuppressive cells, including Tregs and MDSCs, and the complex signaling pathways that facilitate the development of CRC. It is suggested that extensive studies on TNFR2 downstream signaling must be done, since TNFR2 has a high potential to be developed into a therapeutic agent and cancer biomarker in the future.

The Function and Therapeutic Implications of TNF Signaling in MDSCs

Myeloid-derived suppressor cells (MDSCs) are a group of immature and heterogeneous myeloid cells with immunosuppressive functions. MDSCs play important roles in the pathogenesis of cancer, chronic inflammatory diseases, and many autoimmune disorders. The accumulation and activation of MDSCs can be regulated by tumor necrosis factor α (TNF-α). In this review, we summarize the roles played by TNF-α in the recruitment, immunosuppressive functions, and chemotaxis of MDSCs, and discuss the potential therapeutic effects of TNF-α upon these cells in tumor growth and some inflammatory disorders.

TNFR2 antagonist and agonist: a potential therapeutics in cancer immunotherapy

Tumour necrosis factor receptor 2 or TNFR2 is considered an appealing target protein due to its limited frequency to TREGs, which are highly immunosuppressive and present on human malignancies. Numerous studies have revealed that TNFR2 is primarily found on MDSCs (myeloid-derived suppressor cells) and CD + Foxp3 + regulatory T cells (TREGs). Therefore, it has great importance in the proliferation and functional activity of TREGs and MDSCs. TNFR2 suppression must be downregulated or upregulated as required to treat malignancies and diseases like autoimmune disorders. Therefore, at the molecular level, advances in the comprehension of TNFR2's complex structure and its binding to TNF have opened the door to structure-guided drug development. Two critical obstacles to cancer treatment are the dearth of TREG-specific inhibitors and the lack of widely applicable ways to target tumours via frequently expressed surface oncogenes directly. Many researchers have discovered potential antagonists and agonists of TNFR2, which were successful in inhibiting TREGs proliferation, reducing soluble TNFR2 secretion from normal cells, and expanding T effector cells. The data represented in the following review article elucidates the clinically administrated TNFR2 antagonist and agonist in treating cancers.

IP6 reduces colorectal cancer metastasis by mediating the interaction of gut microbiota with host genes

Inositol hexaphosphate (IP6) is a phytochemical widely found in grains and legumes that plays an anti-cancer role. However, the mechanism underlying the inhibition of colorectal cancer metastasis by IP6 through host genes, gut microbiota, and their interactions remain elusive. In this study, 16S rRNA sequencing was used to study the effect of IP6 on gut microbiota in an orthotopic transplantation model of colorectal cancer mice. The transcriptome was used to study the changes of host genes in metastasis and the relationship with gut microbiota. The results showed that the gut microbiota composition of model mice was significantly different from that of normal mice. The beta diversity partly tended to return to the normal level after IP6 intervention. Especially, Lactobacillus helveticus and Lactococcus lactis were recovered after IP6-treated. Enrichment analysis showed that the enrichment score of the Cytokine-Cytokine receptor interaction signal pathway decreased after IP6 treatment compared to the model group. Further analysis of differentially expressed genes (DEGs) in this pathway showed that IP6 reduced the expression of the Tnfrsf1b gene related to the area of liver metastasis, and the Tnfrsf1b gene was negatively correlated with the relative abundance of Lactobacillus helveticus. Our results presented that host gene, microbiome and their interaction may serve as promising targets for the mechanism of IP6 intervention in colorectal cancer metastasis.

Emerging strategies in targeting tumor-resident myeloid cells for cancer immunotherapy

Immune checkpoint inhibitors targeting programmed cell death protein 1, programmed death-ligand 1, and cytotoxic T-lymphocyte-associated protein 4 provide deep and durable treatment responses which have revolutionized oncology. However, despite over 40% of cancer patients being eligible to receive immunotherapy, only 12% of patients gain benefit. A key to understanding what differentiates treatment response from non-response is better defining the role of the innate immune system in anti-tumor immunity and immune tolerance. Teleologically, myeloid cells, including macrophages, dendritic cells, monocytes, and neutrophils, initiate a response to invading pathogens and tissue repair after pathogen clearance is successfully accomplished. However, in the tumor microenvironment (TME), these innate cells are hijacked by the tumor cells and are imprinted to furthering tumor propagation and dissemination. Major advancements have been made in the field, especially related to the heterogeneity of myeloid cells and their function in the TME at the single cell level, a topic that has been highlighted by several recent international meetings including the 2021 China Cancer Immunotherapy workshop in Beijing. Here, we provide an up-to-date summary of the mechanisms by which major myeloid cells in the TME facilitate immunosuppression, enable tumor growth, foster tumor plasticity, and confer therapeutic resistance. We discuss ongoing strategies targeting the myeloid compartment in the preclinical and clinical settings which include: (1) altering myeloid cell composition within the TME; (2) functional blockade of immune-suppressive myeloid cells; (3) reprogramming myeloid cells to acquire pro-inflammatory properties; (4) modulating myeloid cells via cytokines; (5) myeloid cell therapies; and (6) emerging targets such as Siglec-15, TREM2, MARCO, LILRB2, and CLEVER-1. There is a significant promise that myeloid cell-based immunotherapy will help advance immuno-oncology in years to come.

The Hepatic Pre-Metastatic Niche

Simple Summary

The pre-metastatic niche is a recently established concept that could lead to targeted therapies that prevent metastasis before ever occurring. Considering that 90% of cancer mortality results from metastasis, the PMN is thus a salient opportunity for intervention. The purpose of the current review is to cover what is known specifically about the hepatic pre-metastatic niche, a topic that has garnered increasing research focus within the last decade. We discuss the methods of communication between primary tumors and the liver, the involved cell populations, the key changes within liver tissue, and perspectives on the future of the field.

Abstract

Primary tumors can communicate with the liver to establish a microenvironment that favors metastatic colonization prior to dissemination, forming what is termed the “pre-metastatic niche” (PMN). Through diverse signaling mechanisms, distant malignancies can both influence hepatic cells directly as well as recruit immune cells into the PMN. The result is a set of changes within the hepatic tissue that increase susceptibility of tumor cell invasion and outgrowth upon dissemination. Thus, the PMN offers a novel step in the traditional metastatic cascade that could offer opportunities for clinical intervention. The involved signaling molecules also offer promise as biomarkers. Ultimately, while the existence of the hepatic PMN is well-established, continued research effort and use of innovative models are required to reach a functional knowledge of PMN mechanisms that can be further targeted.

The Roles of TNFR2 Signaling in Cancer Cells and the Tumor Microenvironment and the Potency of TNFR2 Targeted Therapy

The appreciation that cancer growth is promoted by a dynamic tumor microenvironment (TME) has spawned novel approaches to cancer treatment. New therapies include agents that activate quiescent T effector cells and agents that interfere with abnormal neovascularity. Although promising, many experimental therapies targeted at the TME have systemic toxicity. Another approach is to target the TME with greater specificity by taking aim at the tumor necrosis factor receptor 2 (TNFR2) signaling pathway. TNFR2 is an attractive molecular target because it is rarely expressed in normal tissues (thus, has low potential for systemic toxicity) and because it is overexpressed on many types of cancer cells as well as on associated TME components, such as T regulatory cells (Tregs), tumor-associated macrophages, and other cells that facilitate tumor progression and spread. Novel therapies that block TNFR2 signaling show promise in cell culture studies, animal models, and human studies. Novel antibodies have been developed that expressly kill only rapidly proliferating cells expressing newly synthesized TNFR2 protein. This review traces the origins of our understanding of TNFR2's multifaceted roles in the TME and discusses the therapeutic potential of agents designed to block TNFR2 as the cornerstone of a TME-specific strategy.

The Roles of TNFR2 Signaling in Cancer Cells and the Tumor Microenvironment and the Potency of TNFR2 Targeted Therapy

The appreciation that cancer growth is promoted by a dynamic tumor microenvironment (TME) has spawned novel approaches to cancer treatment. New therapies include agents that activate quiescent T effector cells and agents that interfere with abnormal neovascularity. Although promising, many experimental therapies targeted at the TME have systemic toxicity. Another approach is to target the TME with greater specificity by taking aim at the tumor necrosis factor receptor 2 (TNFR2) signaling pathway. TNFR2 is an attractive molecular target because it is rarely expressed in normal tissues (thus, has low potential for systemic toxicity) and because it is overexpressed on many types of cancer cells as well as on associated TME components, such as T regulatory cells (Tregs), tumor-associated macrophages, and other cells that facilitate tumor progression and spread. Novel therapies that block TNFR2 signaling show promise in cell culture studies, animal models, and human studies. Novel antibodies have been developed that expressly kill only rapidly proliferating cells expressing newly synthesized TNFR2 protein. This review traces the origins of our understanding of TNFR2’s multifaceted roles in the TME and discusses the therapeutic potential of agents designed to block TNFR2 as the cornerstone of a TME-specific strategy.

Tumor Necrosis Factor Receptor 2 (TNFR2): An Emerging Target in Cancer Therapy

Despite the great success of TNF blockers in the treatment of autoimmune diseases and the identification of TNF as a factor that influences the development of tumors in many ways, the role of TNFR2 in tumor biology and its potential suitability as a therapeutic target in cancer therapy have long been underestimated. This has been fundamentally changed with the identification of TNFR2 as a regulatory T-cell (Treg)-stimulating factor and the general clinical breakthrough of immunotherapeutic approaches. However, considering TNFR2 as a sole immunosuppressive factor in the tumor microenvironment does not go far enough. TNFR2 can also co-stimulate CD8⁺ T-cells, sensitize some immune and tumor cells to the cytotoxic effects of TNFR1 and/or acts as an oncogene. In view of the wide range of cancer-associated TNFR2 activities, it is not surprising that both antagonists and agonists of TNFR2 are considered for tumor therapy and have indeed shown overwhelming anti-tumor activity in preclinical studies. Based on a brief summary of TNFR2 signaling and the immunoregulatory functions of TNFR2, we discuss here the main preclinical findings and insights gained with TNFR2 agonists and antagonists. In particular, we address the question of which TNFR2-associated molecular and cellular mechanisms underlie the observed anti-tumoral activities of TNFR2 agonists and antagonists.

Signaling pathway(s) of TNFR2 required for the immunoregulatory effect of CD4+Foxp3+ regulatory T cells

CD4⁺Foxp3⁺ regulatory T cells (Tregs), a subpopulation of CD4⁺ T cells, are engaged in maintaining the periphery tolerance and preventing autoimmunity. Recent studies showed that tumor necrosis factor receptor 2 (TNFR2) is preferentially expressed by Tregs and the expression of this receptor identifies the maximally suppressive Tregs. That is, TNFR2 is a liable phenotypic and functional surface marker of Tregs. Moreover, TNF activates and expands Tregs through TNFR2. However, it is very interesting which signaling pathway(s) of TNFR2 is required for the inhibitory effect of Tregs. Compelling evidence shows three TNFR2 signaling pathways in Tregs, including NF-κB, MAPK and PI3K-Akt pathways. Here, we summarize and discuss the latest progress in the studies on the downstream signaling pathways of TNF-TNFR2 for controlling Treg homeostasis, differentiation and proliferation.

Targeting TNFR2: A Novel Breakthrough in the Treatment of Cancer

Tumor necrosis factor (TNF) receptor type II (TNFR2) is expressed in various tumor cells and some immune cells, such as regulatory T cells and myeloid-derived suppressing cells. TNFR2 contributes a lot to the tumor microenvironment. For example, it directly promotes the occurrence and growth of some tumor cells, activates immunosuppressive cells, and supports immune escape. Existing studies have proved the importance of TNFR2 in cancer treatment. Here, we reviewed the activation mechanism of TNFR2 and its role in signal transduction in the tumor microenvironment. We summarized the expression and function of TNFR2 within different immune cells and the potential opportunities and challenges of targeting TNFR2 in immunotherapy. Finally, the advantages and limitations of TNFR2 to treat tumor-related diseases are discussed, and the problems that may be encountered in the clinical development and application of targeted anti-TNFR2 agonists and inhibitors are analyzed.

Antagonistic Antibody Targeting TNFR2 Inhibits Regulatory T Cell Function to Promote Anti-Tumor Activity

Infiltration of regulatory T cells (Tregs) in the tumor microenvironment suppresses anti-tumor immune response, and promotes tumor progression. Tumor necrosis factor receptor-2 (TNFR2), which is highly expressed on Tregs, activates Tregs through nuclear factor kappa B (NF-κB) pathway. Moreover, TNFR2⁺ Tregs have been shown to be most suppressive among all Tregs populations in tumor. Due to the unique expression pattern and function of TNFR2 on Tregs, a TNFR2 blocking antibody is expected to compromise Tregs function, relieve Tregs-mediated immunosuppression, and hence to enhance anti-tumor immune response. AN3025 is an antagonistic anti-human TNFR2 (hTNFR2) antibody that is currently under preclinical development. This study investigates the immunomodulatory and anti-tumor activity of AN3025. AN3025 was generated through rabbit immunization with extracellular domain of human TNFR2 and subsequent humanization by complementarity-determining regions (CDRs) grafting. AN3025 binds to the extracellular domain of both human and cynomolgus with sub-nanomolar affinity and specificity, but not mouse or rat TNFR2. AN3025 inhibited tumor necrosis factor alpha (TNFα) induced cell death of hTNFR2-overexpressing Jurkat cells by competing with TNFα for binding to hTNFR2. In the Tregs/T effector co-culture assay, AN3025 increased T effector proliferation and enhanced interferon gamma (IFNγ) production. As a monotherapy, AN3025 significantly inhibited MC38 tumor growth in TNFR2 humanized mouse model. Subsequent flow cytometry (FACS) and immunohistochemistry (IHC) analysis revealed that administration of AN3025 led to decreased Tregs population, increased CD4⁺ and CD8⁺ T cell numbers in the tumor. The anti-tumor activity of AN3025 was dependent on the existence of CD4⁺ and CD8⁺ T cells, as depletion of CD4⁺ and CD8⁺ T cells abolished the anti-tumor activity of AN3025. In addition, AN3025 in combination with anti-PD-1 antibody demonstrated stronger in-vivo anti-tumor activity. The potent anti-tumor efficacy of AN3025, either as a monotherapy or in combination with anti-PD-1 antibody, supports its further clinical development for the treatment of various human tumors.

The Role of Myeloid-Derived Suppressor Cells in Tumor Growth and Metastasis

Myeloid-derived suppressor cells (MDSCs) are immature bone marrow-derived suppressive cells that are an important component of the pathological immune response associated with cancer. Expansion of MDSCs has been linked to poor disease outcome and therapeutic resistance in patients with various malignancies, making these cells potential targets for next-generation treatment strategies. MDSCs are classified into monocytic (M-MDSC) and polymorphonuclear/granulocytic (PMN-MDSC) subtypes that undertake distinct and numerous roles in the tumor microenvironment or systemically to drive disease progression. In this chapter, we will discuss how MDSC subsets contribute to the growth of primary tumors and induce metastatic spread by suppressing the antitumor immune response, supporting cancer stem cell (CSC)/epithelial-to-mesenchymal transition (EMT) phenotypes and promoting angiogenesis. We will also summarize the signaling networks involved in the crosstalk between cancer cells and MDSCs that could represent putative immunotherapy targets.

Targeting the IGF-Axis Potentiates Immunotherapy for Pancreatic Ductal Adenocarcinoma Liver Metastases by Altering the Immunosuppressive Microenvironment

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy, resistant to chemotherapy and associated with high incidence of liver metastases and poor prognosis. Using murine models of aggressive PDAC, we show here that in mice bearing hepatic metastases, treatment with the IGF-Trap, an inhibitor of type I insulin-like growth factor receptor (IGF-IR) signaling, profoundly altered the local, immunosuppressive tumor microenvironment in the liver, curtailing the recruitment of myeloid-derived suppressor cells, reversing innate immune cell polarization and inhibiting metastatic expansion. Significantly, we found that immunotherapy with anti-PD-1 antibodies also reduced the growth of experimental PDAC liver metastases, and this effect was enhanced when combined with IGF-Trap treatment, resulting in further potentiation of a T-cell response. Our results show that a combinatorial immunotherapy based on dual targeting of the prometastatic immune microenvironment of the liver via IGF blockade, on one hand, and reversing T-cell exhaustion on the other, can provide a significant therapeutic benefit in the management of PDAC metastases.

The TNF-α/TNFR2 Pathway: Targeting a Brake to Release the Anti-tumor Immune Response

Newly discovered anti-cancer immunotherapies, such as immune checkpoint inhibitors and chimeric antigen receptor T cells, focus on spurring the anti-tumor effector T cell (Teff) response. Although such strategies have already demonstrated a sustained beneficial effect in certain malignancies, a substantial proportion of treated patients does not respond. CD4⁺FOXP3⁺ regulatory T cells (Tregs), a suppressive subset of T cells, can impair anti-tumor responses and reduce the efficacy of currently available immunotherapies. An alternative view that has emerged over the last decade proposes to tackle this immune brake by targeting the suppressive action of Tregs on the anti-tumoral response. It was recently demonstrated that the tumor necrosis factor alpha (TNF-α) tumor necrosis factor receptor 2 (TNFR2) is critical for the phenotypic stabilization and suppressive function of human and mouse Tregs. The broad non-specific effects of TNF-α infusion in patients initially led clinicians to abandon this signaling pathway as first-line therapy against neoplasms. Previously unrecognized, TNFR2 has emerged recently as a legitimate target for anti-cancer immune checkpoint therapy. Considering the accumulation of pre-clinical data on the role of TNFR2 and clinical reports of TNFR2⁺ Tregs and tumor cells in cancer patients, it is now clear that a TNFR2-centered approach could be a viable strategy, once again making the TNF-α pathway a promising anti-cancer target. Here, we review the role of the TNFR2 signaling pathway in tolerance and the equilibrium of T cell responses and its connections with oncogenesis. We analyze recent discoveries concerning the targeting of TNFR2 in cancer, as well as the advantages, limitations, and perspectives of such a strategy.

Lung mesenchymal stromal cells influenced by Th2 cytokines mobilize neutrophils and facilitate metastasis by producing complement C3

Pre-metastatic niche formation is critical for the colonization of disseminated cancer cells in distant organs. Here we find that lung mesenchymal stromal cells (LMSCs) at pre-metastatic stage possess potent metastasis-promoting activity. RNA-seq reveals an upregulation of complement 3 (C3) in those LMSCs. C3 is found to promote neutrophil recruitment and the formation of neutrophil extracellular traps (NETs), which facilitate cancer cell metastasis to the lungs. C3 expression in LMSCs is induced and sustained by Th2 cytokines in a STAT6-dependent manner. LMSCs-driven lung metastasis is abolished in Th1-skewing Stat6-deficient mice. Blockade of IL-4 by antibody also attenuates LMSCs-driven cancer metastasis to the lungs. Consistently, metastasis is greatly enhanced in Th2-skewing T-bet-deficient mice or in nude mice adoptively transferred with T-bet-deficient T cells. Increased C3 levels are also detected in breast cancer patients. Our results suggest that targeting the Th2-STAT6-C3-NETs cascade may reduce breast cancer metastasis to the lungs.

The formation of the pre-metastatic niche enables the colonisation of disseminated cancer cells in distant organs. Here, the authors show that Th2 cytokines induce Complement 3 production in lung mesenchymal stromal cells, which recruits neutrophils and promotes the formation neutrophil extracellular traps, facilitating breast cancer cell metastasis to the lungs.

TNFα and Immune Checkpoint Inhibition: Friend or Foe for Lung Cancer?

Tumor necrosis factor-alpha (TNFα) can bind two distinct receptors (TNFR1/2). The transmembrane form (tmTNFα) preferentially binds to TNFR2. Upon tmTNFα cleavage by the TNF-alpha-converting enzyme (TACE), its soluble (sTNFα) form is released with higher affinity for TNFR1. This assortment empowers TNFα with a plethora of opposing roles in the processes of tumor cell survival (and apoptosis) and anti-tumor immune stimulation (and suppression), in addition to angiogenesis and metastases. Its functions and biomarker potential to predict cancer progression and response to immunotherapy are reviewed here, with a focus on lung cancer. By mining existing sequencing data, we further demonstrate that the expression levels of TNF and TACE are significantly decreased in lung adenocarcinoma patients, while the TNFR1/TNFR2 balance are increased. We conclude that the biomarker potential of TNFα alone will most likely not provide conclusive findings, but that TACE could have a key role along with the delicate balance of sTNFα/tmTNFα as well as TNFR1/TNFR2, hence stressing the importance of more research into the potential of rationalized treatments that combine TNFα pathway modulators with immunotherapy for lung cancer patients.

Sites of Synchronous Distant Metastases, Prognosis, and Nomogram for Small Cell Lung Cancer Patients with Bone Metastasis: A Large Cohort Retrospective Study

Background

Small cell lung cancer (SCLC) is often associated with metastases at the time of diagnosis, and the bone is one of the most common sites. The primary aim of this study was to investigate the site of synchronous distant metastasis to other organs in SCLC patients with bone metastasis (BM) and develop a robust predictive prognostic model.

Methods

We retrospectively analyzed the data from patients diagnosed with SCLC with BM in the Surveillance, Epidemiology, and End Results database. Univariate and multivariate Cox analyses were used to identify independent prognostic factors. A prognostic nomogram was constructed and evaluated by calibration curves, receiver operating characteristic (ROC) curves, and decision curve analysis (DCA). Then, according to the sites of metastasis and treatment modality, all patients were stratified into several subgroups. The relationship among sites of metastasis, treatment modality, and overall survival was then analyzed.

Results

A total of 6253 patients were included. Independent prognostic factors for SCLC with BM were age, sex, primary site, radiotherapy, chemotherapy, brain metastasis, liver metastasis, and marital status. Calibration, ROC curves, and DCA indicated the excellent performance of the prognostic nomogram. The liver is the most common organ for extraskeletal metastases, followed by the lung. Patients with only BM had the longest mean survival time (9.30 ± 0.31 months). In the subgroup analysis, chemotherapy was an independent prognostic factor for all subgroups. In contrast, radiotherapy showed a positive effect on the prognosis of patients in all subgroups except those with bone and brain metastases and those with bone, lung, and brain metastases.

Conclusions

The prognostic nomogram is expected to be an accurate and personalized tool for predicting the prognosis of SCLC patients with BM. Additionally, the determination of the sites of synchronous extraskeletal metastases and the associated prognosis helps in treatment selection.

Chemotherapy Shifts the Balance in Favor of CD8+ TNFR2+ TILs in Triple-Negative Breast Tumors

Triple-negative breast cancer (TNBC) is primarily treated via chemotherapy; in parallel, efforts are made to introduce immunotherapies into TNBC treatment. CD4+ TNFR2+ lymphocytes were reported as Tregs that contribute to tumor progression. However, our published study indicated that TNFR2+ tumor-infiltrating lymphocytes (TNFR2+ TILs) were associated with improved survival in TNBC patient tumors. Based on our analyses of the contents of CD4+ and CD8+ TILs in TNBC patient tumors, in the current study, we determined the impact of chemotherapy on CD4+ and CD8+ TIL subsets in TNBC mouse tumors. We found that chemotherapy led to (1) a reduction in CD4+ TNFR2+ FOXP3+ TILs, indicating that chemotherapy decreased the content of CD4+ TNFR2+ Tregs, and (2) an elevation in CD8+ TNFR2+ and CD8+ TNFR2+ PD-1+ TILs; high levels of these two subsets were significantly associated with reduced tumor growth. In spleens of tumor-bearing mice, chemotherapy down-regulated CD4+ TNFR2+ FOXP3+ cells but the subset of CD8+ TNFR2+ PD-1+ was not present prior to chemotherapy and was not increased by the treatment. Thus, our data suggest that chemotherapy promotes the proportion of protective CD8+ TNFR2+ TILs and that, unlike other cancer types, therapeutic strategies directed against TNFR2 may be detrimental in TNBC.

Liver Immune Microenvironment and Metastasis from Colorectal Cancer-Pathogenesis and Therapeutic Perspectives

A drastic difference exists between the 5-year survival rates of colorectal cancer patients with localized cancer and distal organ metastasis. The liver is the most favorable organ for cancer metastases from the colorectum. Beyond the liver-colon anatomic relationship, emerging evidence highlights the impact of liver immune microenvironment on colorectal liver metastasis. Prior to cancer cell dissemination, hepatocytes secrete multiple factors to recruit or activate immune cells and stromal cells in the liver to form a favorable premetastatic niche. The liver-resident cells including Kupffer cells, hepatic stellate cells, and liver-sinusoidal endothelial cells are co-opted by the recruited cells, such as myeloid-derived suppressor cells and tumor-associated macrophages, to establish an immunosuppressive liver microenvironment suitable for tumor cell colonization and outgrowth. Current treatments including radical surgery, systemic therapy, and localized therapy have only achieved good clinical outcomes in a minority of colorectal cancer patients with liver metastasis, which is further hampered by high recurrence rate. Better understanding of the mechanisms governing the metastasis-prone liver immune microenvironment should open new immuno-oncology avenues for liver metastasis intervention.

TNFR2: Role in Cancer Immunology and Immunotherapy

Immune checkpoint inhibitors (ICIs), including anti-CTLA-4 (cytotoxic T lymphocyte antigen-4) and anti-PD-1/PD-L1 (programmed death-1/programmed death-ligand 1), represent a turning point in the cancer immunotherapy. However, only a minor fraction of patients could derive benefit from such therapy. Therefore, new strategies targeting additional immune regulatory mechanisms are urgently needed. CD4⁺Foxp3⁺ regulatory T cells (Tregs) represent a major cellular mechanism in cancer immune evasion. There is compelling evidence that tumor necrosis factor (TNF) receptor type II (TNFR2) plays a decisive role in the activation and expansion of Tregs and other types of immunosuppressive cells such as myeloid-derived suppressor cells (MDSCs). Furthermore, TNFR2 is also expressed by some tumor cells. Emerging experimental evidence indicates that TNFR2 may be a therapeutic target to enhance naturally occurring or immunotherapeutic-triggered anti-tumor immune responses. In this article, we discuss recent advances in the understanding of the mechanistic basis underlying the Treg-boosting effect of TNFR2. The role of TNFR2-expressing highly suppressive Tregs in tumor immune evasion and their possible contribution to the non-responsiveness to checkpoint treatment are analyzed. Moreover, the role of TNFR2 expression on tumor cells and the impact of TNFR2 signaling on other types of cells that shape the immunological landscape in the tumor microenvironment, such as MDSCs, MSCs, ECs, EPCs, CD8⁺ CTLs, and NK cells, are also discussed. The reports revealing the effect of TNFR2-targeting pharmacological agents in the experimental cancer immunotherapy are summarized. We also discuss the potential opportunities and challenges for TNFR2-targeting immunotherapy.

A TNFR2-hnRNPK Axis Promotes Primary Liver Cancer Development via Activation of YAP Signaling in Hepatic Progenitor Cells

Most primary liver cancer (PLC) cases progress mainly due to underlying chronic liver inflammation, yet the underlying mechanisms of inflammation-mediated PLC remain unclear. Here we uncover a TNF receptor II (TNFR2)-hnRNPK-YAP signaling axis in hepatic progenitor cells (HPC) essential for PLC development. TNFR2, but not TNF receptor I (TNFR1), was required for TNFα-induced activation of YAP during malignant transformation of HPCs and liver tumorigenesis. Mechanistically, heterogeneous nuclear ribonuclear protein K (hnRNPK) acted downstream of TNFα-TNFR2 signaling to directly interact with and stabilize YAP on target gene promoters genome-wide, therefore coregulating the expression of YAP target genes. Single-cell RNA sequencing confirmed the association of TNFR2-hnRNPK with YAP expression and the pathologic importance of HPC. Accordingly, expressions of TNFR2, hnRNPK, and YAP were all upregulated in PLC tissues and were strongly associated with poor prognosis of PLC including patient survival. Collectively, this study clarifies the differential roles of TNFRs in HPC-mediated tumorigenesis, uncovering a TNFR2-hnRNPK-centered mechanistic link between the TNFα-mediated inflammatory milieu and YAP activation in HPCs during PLC development. SIGNIFICANCE: This work defines how hnRNPK links TNFα signaling and Hippo pathway transcription coactivator YAP in hepatic progenitor cells during primary liver tumorigenesis.

Harnessing Tumor Necrosis Factor Alpha to Achieve Effective Cancer Immunotherapy

Tumor necrosis factor alpha (TNFα) is a pleiotropic cytokine known to have contradictory roles in oncoimmunology. Indeed, TNFα has a central role in the onset of the immune response, inducing both activation and the effector function of macrophages, dendritic cells, natural killer (NK) cells, and B and T lymphocytes. Within the tumor microenvironment, however, TNFα is one of the main mediators of cancer-related inflammation. It is involved in the recruitment and differentiation of immune suppressor cells, leading to evasion of tumor immune surveillance. These characteristics turn TNFα into an attractive target to overcome therapy resistance and tackle cancer. This review focuses on the diverse molecular mechanisms that place TNFα as a source of resistance to immunotherapy such as monoclonal antibodies against cancer cells or immune checkpoints and adoptive cell therapy. We also expose the benefits of TNFα blocking strategies in combination with immunotherapy to improve the antitumor effect and prevent or treat adverse immune-related effects.

Myeloid tumor necrosis factor and heme oxygenase-1 regulate the progression of colorectal liver metastases during hepatic ischemia-reperfusion

The liver ischemia-reperfusion (IR) injury that occurs consequently to hepatic resection performed in patients with metastases can lead to tumor relapse for not fully understood reasons. We assessed the effects of liver IR on tumor growth and the innate immune response in a mouse model of colorectal (CR) liver metastasis. Mice subjected to liver ischemia 2 days after intrasplenic injection of CR carcinoma cells displayed a higher metastatic load in the liver, correlating with Kupffer cells (KC) death through the activation of receptor-interating protein 3 kinase (RIPK3) and caspase-1 and a recruitment of monocytes. Interestingly, the immunoregulatory mediators, tumor necrosis factor-α (TNF-α) and heme oxygenase-1 (HO-1) were strongly upregulated in recruited monocytes and were also expressed in the surviving KC following IR. Using TNF^flox/flox LysM^cre/wt mice, we showed that TNF deficiency in macrophages and monocytes favors tumor progression after IR. The antitumor effect of myeloid cell-derived TNF involved direct tumor cell apoptosis and a reduced expression of immunosuppressive molecules such as transforming growth factor-β, interleukin (IL)-10, inducible nitric oxyde synthase (iNOS), IL-33 and HO-1. Conversely, a monocyte/macrophage-specific deficiency in HO-1 (HO-1^flox/flox LysM^cre/wt ) or the blockade of HO-1 function led to the control of tumor progression post-liver IR. Importantly, host cell RIPK3 deficiency maintains the KC number upon IR, inhibits the IR-induced innate cell recruitment, increases the TNF level, decreases the HO-1 level and suppresses the tumor outgrowth. In conclusion, tumor recurrence in host undergoing liver IR is associated with the death of antitumoral KC and the recruitment of monocytes endowed with immunosuppressive properties. In both of which HO-1 inhibition would reinforce their antitumoral activity.

A profile of TNFR2+ regulatory T cells and CD103+ dendritic cells in the peripheral blood of patients with asthma

The interaction of tolerogenic CD103⁺ dendritic cells (DCs) with regulatory T (Tregs) cells modulates immune responses by inducing immune tolerance. Hence, we determined the proportion of these cells in the peripheral blood mononuclear cells (PBMC) of asthmatic patients. We observed lower trends of CD11b^-CD103⁺ DCs and CD86 within CD11b^-CD103⁺ DCs, while increased levels of Foxp3 expressing CD25^+/-TNFR2⁺ cells in asthmatics. There was a positive correlation in the expression of Foxp3 within CD3⁺CD4⁺CD25⁺TNFR2⁺ Tregs and CD11b^-CD103⁺ as well as the expression of CD86 within HLA-DR⁺CD11c⁺CD11b^-CD103⁺ DCs. In conclusion, we suggest that the increased levels of Tregs in blood could continuously suppress the T helper 2 (Th2) cells activation in the circulation which is also supported by the increase of anti-inflammatory cytokines IL-10 and TNF. Overall, functional immunoregulation of the regulatory cells, particularly Tregs, exhibit immune suppression and induce immune tolerance linked with the immune activation by the antigen presenting cells (APC).

The unique immune microenvironment of liver metastases: Challenges and opportunities

Liver metastases from gastrointestinal and non-gastrointestinal malignancies remain a major cause of cancer-related mortality and a major clinical challenge. The liver has unique properties that facilitate metastatic expansion, including a complex immune system that evolved to dampen immunity to neoantigens entering the liver from the gut, through the portal circulation. In this review, we describe the unique microenvironment encountered by cancer cells in the liver, focusing on elements of the innate and adaptive immune response that can act as a double-edge sword, contributing to the elimination of cancer cells on the one hand and promoting their survival and growth, on the other. We discuss this microenvironment in a clinical context, particularly for colorectal carcinoma, and highlight how a better understanding of the role of the microenvironment has spurred an intense effort to develop novel and innovative strategies for targeting liver metastatic disease, some of which are currently being tested in the clinic.

Importance of TNF-alpha and its alterations in the development of cancers

TNF-alpha is involved in many physiologic and pathologic cellular pathways, including cellular proliferation, differentiation, and death, regulation of immunologic reactions to different cells and molecules, local and vascular invasion of neoplasms, and destruction of tumor vasculature. It is obvious that because of integrated functions of TNF-alpha inside different physiologic systems, it cannot be used as a single-agent therapy for neoplasms; however, long-term investigation of its different cellular pathways has led to recognition of a variety of subsequent molecules with more specific interactions, and therefore, might be suitable as prognostic and therapeutic factors for neoplasms. Here, we will review different aspects of the TNF-alpha as a cytokine involved in both physiologic functions of cells and pathologic abnormalities, most importantly, cancers.

TNFR2+ TILs are significantly associated with improved survival in triple-negative breast cancer patients

In view of the relatively limited efficacy of immunotherapies targeting the PD-1-PD-L1 axis in triple-negative breast cancer (TNBC) and of published reports on tumor-promoting roles of TNFR2+ tumor-infiltrating lymphocytes (TNFR2+ TILs), we determined the incidence of TNFR2+ TILs in TNBC patient tumors, their association with disease outcome and relations with PD-1+ TILs. Using a cohort of treatment-naïve TNBC patients with long follow-up (n = 70), we determined the presence of TNFR2+ TILs and PD-1+ TILs by immunohistochemistry. TILs (≥ 1% of cellular mass) and TNFR2+ TILs (≥ 1% of total TILs) were detected in 96% and 74% of tumors, respectively. The presence of TILs at > 5% of tumor cell mass ("Positive TILs"), as well as of positive TNFR2+ TILs (> 5%), was independently associated with good prognosis, and combination of both parameters demonstrated superior outcome relative to their lower levels. PD1+ TILs (> 5/hot spot) were detected in 63% of patients. High levels of PD-1+ TILs (> 20/hot spot) showed an unfavorable disease outcome, and in their presence, the favorable outcome of positive TNFR2+ TILs was ablated. Thus, TNFR2+ TILs are strongly connected to improved prognosis in TNBC; these findings suggest that TNFR2+ TILs have favorable effects in TNBC patients, unlike the tumor-promoting roles attributed to them in other cancer systems. Overall, our observations propose that the TNFR2+ TIL subset should not be targeted in the course of TNBC therapy; rather, its beneficial impacts may become into power when anti-PD-1 regimens-that may potentiate immune activities-are administered to TNBC patients.

Liver Tropism in Cancer: The Hepatic Metastatic Niche

The liver is the largest organ in the human body and is prone for cancer metastasis. Although the metastatic pattern can differ depending on the cancer type, the liver is the organ to which cancer cells most frequently metastasize for the majority of prevalent malignancies. The liver is unique in several aspects: the vascular structure is highly permeable and has unparalleled dual blood connectivity, and the hepatic tissue microenvironment presents a natural soil for the seeding of disseminated tumor cells. Although 70% of the liver is composed of the parenchymal hepatocytes, the remaining 30% is composed of nonparenchymal cells including Kupffer cells, liver sinusoidal endothelial cells, and hepatic stellate cells. Recent discoveries show that both the parenchymal and the nonparenchymal cells can modulate each step of the hepatic metastatic cascade, including the initial seeding and colonization as well as the decision to undergo dormancy versus outgrowth. Thus, a better understanding of the molecular mechanisms orchestrating the formation of a hospitable hepatic metastatic niche and the identification of the drivers supporting this process is critical for the development of better therapies to stop or at least decrease liver metastasis. The focus of this perspective is on the bidirectional interactions between the disseminated cancer cells and the unique hepatic metastatic niche.

Neutrophils in the Tumor Microenvironment

Neutrophils are the first responders to inflammation, infection, and injury. As one of the most abundant leukocytes in the immune system, neutrophils play an essential role in cancer progression, through multiple mechanisms, including promoting angiogenesis, immunosuppression, and cancer metastasis. Recent studies demonstrating elevated neutrophil to lymphocyte ratios suggest neutrophil as a potential therapeutic target and biomarker for disease status in cancer. This chapter will discuss the phenotypic and functional changes in the neutrophil in the tumor microenvironment, the underlying mechanism(s) of neutrophil facilitated cancer metastasis, and clinical potential of neutrophils as a prognostic/diagnostic marker and therapeutic target.

Angiopoietin1 Deficiency in Hepatocytes Affects the Growth of Colorectal Cancer Liver Metastases (CRCLM)

Colorectal cancer liver metastases (CRCLM) that receive their blood supply via vessel co-option are associated with a poor response to anti-angiogenic therapy. Angiopoietins (Ang1 and Ang2) with their Tyrosine-protein kinase receptor (Tie2) have been shown to support vessel co-option. We demonstrate significantly higher expression of Ang1 in hepatocytes adjacent to the tumor region of human chemonaïve and treated co-opting (replacement histopathological growth patterns: RHGP) tumors. To investigate the role of the host Ang1 expression, Ang1 knockout (KO) mice were injected intra-splenically with metastatic MC-38 colon cancer cells that develop co-opting liver metastases. We observed a reduction in the number of liver metastases and interestingly, for the first time, the development of angiogenic driven desmoplastic (DHGP) liver metastases. In addition, in-vitro, knockout of Ang1 in primary hepatocytes inhibited viability, migration and invasion ability of MC-38 cells. We also demonstrate that Ang 1 alone promotes the migration and growth of both human and mouse colon cancer cell lines These results provide evidence that high expression of Ang1 in the host liver is important to support vessel co-option (RHGP lesions) and when inhibited, favours the formation of angiogenic driven liver metastases (DHGP lesions).

Sexual dimorphism and the role of estrogen in the immune microenvironment of liver metastases

Liver metastases (LM) remain a major cause of cancer-associated death and a clinical challenge. Here we explore a sexual dimorphism observed in the regulation of the tumor immune microenvironment (TIME) of LM, wherein the accumulation of myeloid-derived suppressor cells (MDSC) and regulatory T cells in colon and lung carcinoma LM is TNFR2-dependent in female, but not in male mice. In ovariectomized mice, a marked reduction is observed in colorectal, lung and pancreatic carcinoma LM that is reversible by estradiol reconstitution. This is associated with reduced liver MDSC accumulation, increased interferon-gamma (IFN-γ) and granzyme B production in CD8+ T cells and reduced TNFR2, IDO2, TDO and Serpin B9 expression levels. Treatment with tamoxifen increases liver cytotoxic T cell accumulation and reduces colon cancer LM. The results identify estrogen as a regulator of a pro-metastatic immune microenvironment in the liver and a potential target in the management of liver metastatic disease.

Neutrophils: Homing in on the myeloid mechanisms of metastasis

The metastasis cascade is complex and comprises several stages including local invasion into surrounding tissue, intravasation and survival of tumour cells in the circulation, and extravasation and colonisation of a distant site. It is increasingly clear that these processes are driven not only by signals within the tumour cells, but are also profoundly influenced by stromal cells and signals in the tumour microenvironment. Amongst the many cell types within the tumour microenvironment, immune cells such as lymphocytes, macrophages and neutrophils play a prominent role in tumour development and progression. Neutrophils, however, have only recently emerged as important players, particularly in metastasis. Here we review the current evidence suggesting a multi-faceted role for neutrophils in the metastatic cascade.

TNFR2-expressing CD4+Foxp3+ regulatory T cells in cancer immunology and immunotherapy

CD4⁺Foxp3⁺ regulatory T cells (Tregs) represent a major cellular mechanism in tumor immune evasion. Elimination of Treg activity has become a strategy to devise an effective tumor immunotherapy. We reported that TNF receptor type II (TNFR2), one of two receptors transducing TNF biological activity, is preferentially expressed by the most suppressive subset of Tregs. By interaction with TNFR2, TNF plays a decisive role in the activation, expansion and phenotype stability of Tregs. We also found that highly suppressive TNFR2-expressing Tregs appear to be tumor-associated Tregs. This finding has been supported by recent studies in mouse tumor models and in cancer patients. In this chapter, published data revealing the important role of TNFR2⁺ Tregs in tumor development and metastasis in different tumor types are reviewed and analyzed. The therapeutic potential of targeting TNF-TNFR2 interaction as means to eliminate Treg activity, and consequently to enhance anti-tumor immune responses, also is discussed.

Effects of exosomes on pre-metastatic niche formation in tumors

A pre-metastatic niche is a microenvironment prepared for the colonization of circulating tumor cells in specific organs. Exosomes are extracellular vesicles with a variety of biological functions. Exosomes play an irreplaceable role in the development of pre-metastatic niches, and mainly function as communication medium. In this review, we analyzed the effects of exosomes on pre-metastatic niches from various perspectives, including inflammation, immune response, angiogenesis, organotropism, matrix remodeling and biomarker expression. In particular, exosomes express programmed death ligand 1 (PD-L1) and cause the immune escape of tumor cells. The immunomodulatory effects of exosomes and their potential in liquid diagnosis have drawn our attention. The potential value of exosomes and pre-metastatic niches will be realized in the field of immunity therapy.

Myeloid Cells and Chronic Liver Disease: a Comprehensive Review

Myeloid cells play a major role in the sensitization to liver injury, particularly in chronic inflammatory liver diseases with a biliary or hepatocellular origin, and the interplay between myeloid cells and the liver may explain the increased incidence of hepatic osteodystrophy. The myeloid cell-liver axis involves several mature myeloid cells as well as immature or progenitor cells with the complexity of the liver immune microenvironment aggravating the mist of cell differentiation. The unique positioning of the liver at the junction of the peripheral and portal circulation systems underlines the interaction of myeloid cells and hepatic cells and leads to immune tolerance breakdown. We herein discuss the scenarios of different chronic liver diseases closely modulated by myeloid cells and illustrate the numerous potential targets, the understanding of which will ultimately steer the development of solid immunotherapeutic regimens. Ultimately, we are convinced that an adequate modulation of the liver microenvironment to modify the functional and quantitative characteristics of myeloid cells will be a successful approach to treating chronic liver diseases of different etiologies.

Advances in tumor-endothelial cells co-culture and interaction on microfluidics

The metastasis in which the cancer cells degrade the extracellular matrix (ECM) and invade to the surrounding and far tissues of the body is the leading cause of mortality in cancer patients. With a lot of advancement in the field, yet the biological cause of metastasis are poorly understood. The microfluidic system provides advanced technology to reconstruct a variety of in vivo-like environment for studying the interactions between tumor cells (TCs) and endothelial cells (ECs). This review gives a brief account of both two-dimensional models and three-dimensional microfluidic systems for the analysis of TCs-ECs co-culture as well as their applications to anti-cancer drug screening. Furthermore, the advanced methods for analyzing cell-to-cell interactions at single-cell level were also discussed.

TNF Receptor Type II as an Emerging Drug Target for the Treatment of Cancer, Autoimmune Diseases, and Graft-Versus-Host Disease: Current Perspectives and In Silico Search for Small Molecule Binders

There is now compelling evidence that TNF receptor type II (TNFR2) is predominantly expressed on CD4⁺Foxp3⁺ regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs), and plays a major role in the expansion and function of Tregs and MDSCs. Consequently, targeting of TNFR2 by either antagonists or agonists may represent a novel strategy in the treatment of cancer and autoimmune diseases, by downregulating or upregulating suppressor cell activity. The advance in the understanding of complex structure of TNFR2 and its binding with TNF at molecular levels offers opportunity for structure-guided drug discovery. This article reviews the current evidences regarding the decisive role of TNFR2 in immunosuppressive function of Tregs and MDSCs, and the current effort to develop novel TNFR2-targeting therapeutic agents in the treatment of cancer, autoimmune diseases, and graft-versus-host disease. To shed light on the potential TNFR2-targeting small molecules, we for the first time performed virtual screening of 400,000 natural compounds against the two TNF-binding sites, regions 3 and 4, of TNFR2. Our result showed that the top hits at region 4 had slightly higher docking energies than those at region 3. Nevertheless, free energy calculation from the TNF–TNFR2 molecular dynamics simulation revealed that the binding strength of TNF in region 3 is only one-tenth of that in region 4. This suggests that region 3 is a potentially more viable binding site to be targeted by small molecules than region 4. Therefore, the effectiveness in targeting region 3 of TNFR2 deserves further investigation.

The association between TNFR gene polymorphisms and the risk of Hepatitis B Virus-Related Liver Diseases in Chinese population

Tumor necrosis factor receptor superfamily 2 (TNFR2) plays an important role in controlling the progression of antiviral and antitumorr. Evidence suggests that TNFR2 is involved in the pathogenesis of HBV-induced liver injury. We therefore examined whether TNFR2 polymorphisms are associated with the risk of HBV-related liver disease in Chinese population. In this case-control study, 115 chronic hepatitis B (CHB) patients, 86 HBV-related liver cirrhosis patients (LC), 272 HBV-related hepatocellular carcinoma patients (HCC) and 269 healthy controls were recruited. TNFR2 rs1061622 and rs1061624 polymorphisms were examined using a polymerase chain reaction-restriction fragment length polymorphism analysis. Binary logistic regression analyses revealed that the A allele of rs1061624 was positively associated with the risk of CHB (AA vs. GG, P = 0.026; AA vs. GA+GG, P = 0.021), LC (AA vs. GG, P = 0.027; AA+GA vs. GG, P = 0.036), and HCC (GA vs. GG, P = 0.046; GA+AA vs. GG, P = 0.031). Moreover, subgroup analysis indicated that male subjects have increased risk in developing CHB and LC. Nevertheless, no association was found between rs1061622 polymorphism and HBV-related liver diseases in the overall or subgroup analyses. Our retrospective study suggests that the TNFR2 rs1061624 polymorphism is associated with HBV-related CHB, LC, and HCC in Chinese population, particularly in males.

TNF Receptor 2 Makes Tumor Necrosis Factor a Friend of Tumors

Tumor necrosis factor (TNF) is widely accepted as a tumor-suppressive cytokine via its ubiquitous receptor TNF receptor 1 (TNFR1). The other receptor, TNFR2, is not only expressed on some tumor cells but also on suppressive immune cells, including regulatory T cells and myeloid-derived suppressor cells. In contrast to TNFR1, TNFR2 diverts the tumor-inhibiting TNF into a tumor-advocating factor. TNFR2 directly promotes the proliferation of some kinds of tumor cells. Also activating immunosuppressive cells, it supports immune escape and tumor development. Hence, TNFR2 may represent a potential target of cancer therapy. Here, we focus on expression and role of TNFR2 in the tumor microenvironment. We summarize the recent progress in understanding how TNFR2-dependent mechanisms promote carcinogenesis and tumor growth and discuss the potential value of TNFR2 in cancer treatment.