Targeting the CD47/thrombospondin-1 signaling axis regulates immune cell bioenergetics in the tumor microenvironment to potentiate antitumor immune response

Cancer energy reprogramming and the immune responses

Cancer as an uncontrolled growth of cells due to existing mutation in host cells that may proliferate, induce angiogenesis and sometimes metastasize due to the favorable tumor microenvironment (TME). Since it kills more than any disease, biomedical science does not relent in studying the exact pathogenesis. It was believed to be a problem that lies in the nucleus of the host cells; however, recent oncology findings are shifting attention to the mitochondria as an adjuvant to cancer pathogenesis. The changes in the gene are strongly related to cellular metabolism and metabolic reprogramming. It is now understood that reprogramming the TME will have a direct effect on the immune cells' metabolism. Although there are a number of studies on immune cells' response towards tumor energy reprogramming and cancer progression, there is still no existence with the updated collation of these immune cells' response to distinct energy reprogramming in cancer studies. To this end, this mini review shed some light on cancer energy reprogramming mechanisms and enzyme degradation pathways, the cancer pathogenicity activity series involved with reduced lactate production, the specific immune cell responses due to the energy reprogramming. This study highlighted some prospects and future experiments in harnessing the host immune response towards the altered energy metabolism due to cancer.

The molecular mechanism of thrombospondin family members in cardiovascular diseases

Cardiovascular diseases have been identified as vital factors in global morbidity and mortality in recent years. The available evidence suggests that various cytokines and pathological proteins participate in these complicated and changeable diseases. The thrombospondin (TSP) family is a series of conserved, multidomain calcium-binding glycoproteins that cause cell-matrix and cell-cell effects via interactions with other extracellular matrix components and cell surface receptors. The TSP family has five members that can be divided into two groups (Group A and Group B) based on their different structures. TSP-1, TSP-2, and TSP-4 are the most studied proteins. Among recent studies and findings, we investigated the functions of several family members, especially TSP-5. We review the basic concepts of TSPs and summarize the relevant molecular mechanisms and cell interactions in the cardiovascular system. Targeting TSPs in CVD and other diseases has a remarkable therapeutic benefit.

Emerging functions of thrombospondin-1 in immunity

Thrombospondin-1 is a secreted matricellular glycoprotein that modulates cell behavior by interacting with components of the extracellular matrix and with several cell surface receptors. Its presence in the extracellular matrix is induced by injuries that cause thrombospondin-1 release from platelets and conditions including hyperglycemia, ischemia, and aging that stimulate its expression by many cell types. Conversely, rapid receptor-mediated clearance of thrombospondin-1 from the extracellular space limits its sustained presence in the extracellular space and maintains sub-nanomolar physiological concentrations in blood plasma. Roles for thrombospondin-1 signaling, mediated by specific cellular receptors or by activation of latent TGFβ, have been defined in T and B lymphocytes, natural killer cells, macrophages, neutrophils, and dendritic cells. In addition to regulating physiological nitric oxide signaling and responses of cells to stress, studies in mice lacking thrombospondin-1 or its receptors have revealed important roles for thrombospondin-1 in regulating immune responses in infectious and autoimmune diseases and antitumor immunity.

Thrombospondin-1 in drug activity and tumor response to therapies

Thrombospondins (TSPs) have numerous different roles in cancer, regulating the behavior of cancer cells and non-neoplastic cells, and defining the responses of tumor cells to environmental changes, thorough their ability to orchestrate cellular and molecular interactions in the tumor microenvironment (TME). As a result of these activities, TSPs can also control drug delivery and activity, tumor response and resistance to therapies, with different outcomes depending on the nature of TSP-interacting cell types, receptors, and ligands, in a highly context-dependent manner. This review, focusing primarily on TSP-1, discusses the effects of TSPs on tumor response to chemotherapy, antiangiogenic, low-dose metronomic chemotherapy, immunotherapy, and radiotherapy, by analyzing TSP activity on different cell compartments - tumor cells, vascular endothelial cells and immune cells. We review evidence of the value of TSPs, specifically TSP-1 and TSP-2, as biomarkers of prognosis and tumor response to therapy. Finally, we examine possible approaches to develop TSP-based compounds as therapeutic tools to potentiate the efficacy of anticancer therapy.

Advances in reprogramming of energy metabolism in tumor T cells

Cancer is a leading cause of human death worldwide, and the modulation of the metabolic properties of T cells employed in cancer immunotherapy holds great promise for combating cancer. As a crucial factor, energy metabolism influences the activation, proliferation, and function of T cells, and thus metabolic reprogramming of T cells is a unique research perspective in cancer immunology. Special conditions within the tumor microenvironment and high-energy demands lead to alterations in the energy metabolism of T cells. In-depth research on the reprogramming of energy metabolism in T cells can reveal the mechanisms underlying tumor immune tolerance and provide important clues for the development of new tumor immunotherapy strategies as well. Therefore, the study of T cell energy metabolism has important clinical significance and potential applications. In the study, the current achievements in the reprogramming of T cell energy metabolism were reviewed. Then, the influencing factors associated with T cell energy metabolism were introduced. In addition, T cell energy metabolism in cancer immunotherapy was summarized, which highlighted its potential significance in enhancing T cell function and therapeutic outcomes. In summary, energy exhaustion of T cells leads to functional exhaustion, thus resulting in immune evasion by cancer cells. A better understanding of reprogramming of T cell energy metabolism may enable immunotherapy to combat cancer and holds promise for optimizing and enhancing existing therapeutic approaches.

Targeting tumor-associated macrophages: Novel insights into immunotherapy of skin cancer

BACKGROUND

The incidence of skin cancer is currently increasing, and conventional treatment options inadequately address the demands of disease management. Fortunately, the recent rapid advancement of immunotherapy, particularly immune checkpoint inhibitors (ICIs), has ushered in a new era for numerous cancer patients. However, the efficacy of immunotherapy remains suboptimal due to the impact of the tumor microenvironment (TME). Tumor-associated macrophages (TAMs), a major component of the TME, play crucial roles in tumor invasion, metastasis, angiogenesis, and immune evasion, significantly impacting tumor development. Consequently, TAMs have gained considerable attention in recent years, and their roles have been extensively studied in various tumors. However, the specific roles of TAMs and their regulatory mechanisms in skin cancer remain unclear.

AIM OF REVIEW

This paper aims to elucidate the origin and classification of TAMs, investigate the interactions between TAMs and various immune cells, comprehensively understand the precise mechanisms by which TAMs contribute to the pathogenesis of different types of skin cancer, and finally discuss current strategies for targeting TAMs in the treatment of skin cancer.

KEY SCIENTIFIC CONCEPTS OF OVERVIEW

With a specific emphasis on the interrelationship between TAMs and skin cancer, this paper posits that therapeutic modalities centered on TAMs hold promise in augmenting and harmonizing with prevailing clinical interventions for skin cancer, thereby charting a novel trajectory for advancing the landscape of immunotherapeutic approaches for skin cancer.

Opportunities and challenges of CD47-targeted therapy in cancer immunotherapy

Cancer immunotherapy has emerged as a promising strategy for the treatment of cancer, with the tumor microenvironment (TME) playing a pivotal role in modulating the immune response. CD47, a cell surface protein, has been identified as a crucial regulator of the TME and a potential therapeutic target for cancer therapy. However, the precise functions and implications of CD47 in the TME during immunotherapy for cancer patients remain incompletely understood. This comprehensive review aims to provide an overview of CD47's multifaced role in TME regulation and immune evasion, elucidating its impact on various types of immunotherapy outcomes, including checkpoint inhibitors and CAR T-cell therapy. Notably, CD47-targeted therapies offer a promising avenue for improving cancer treatment outcomes, especially when combined with other immunotherapeutic approaches. The review also discusses current and potential CD47-targeted therapies being explored for cancer treatment and delves into the associated challenges and opportunities inherent in targeting CD47. Despite the demonstrated effectiveness of CD47-targeted therapies, there are potential problems, including unintended effects on healthy cells, hematological toxicities, and the development if resistance. Consequently, further research efforts are warranted to fully understand the underlying mechanisms of resistance and to optimize CD47-targeted therapies through innovative combination approaches, ultimately improving cancer treatment outcomes. Overall, this comprehensive review highlights the significance of CD47 as a promising target for cancer immunotherapy and provides valuable insight into the challenges and opportunities in developing effective CD47-targeted therapies for cancer treatment.

Gastric cancer derived exosomal THBS1 enhanced Vγ9Vδ2 T-cell function through activating RIG-I-like receptor signaling pathway in a N6-methyladenosine methylation dependent manner

Gamma delta (γδ) T-cell-based immunotherapy has shown favorable safety and clinical response in patients with multiple types of cancer. However, its efficiency in treating patients with solid tumors remains limited. In the current study, we investigated the function and molecular mechanism underlying gastric cancer (GC) cell-derived exosomal THBS1 in the regulation of Vγ9Vδ2 T cells. We found that GC cell-derived exosomal THBS1 markedly enhanced the cytotoxicity of Vγ9Vδ2 T cells against GC cells and the production of IFN-γ, TNF-α, perforin and granzyme B in vitro and elevated the killing effects of Vγ9Vδ2 T cells on GC cells in vivo. Mechanistically, exosomal THBS1 could regulate METTL3-or IGF2BP2-mediated m6A modification, further activating the RIG-I-like receptor signaling pathway in Vγ9Vδ2 T cells. Moreover, blocking the RIG-I-like receptor signaling pathway reversed the effects of exosomal THBS1 on the function of Vγ9Vδ2 T cells. In addition, THBS1 was expressed at low levels in GC tissues and was associated with an unfavorable prognosis in GC patients. In sum, our findings indicate that exosomal THBS1 derived from GC cells enhanced the function of Vγ9Vδ2 T cells by activating the RIG-I-like signaling pathway in a m6A methylation-dependent manner. Targeting the exosomal THBS1/m6A/RIG-I axis may have important implications for GC immunotherapy based on Vγ9Vδ2 T cells.

Anti-CD47 immunotherapy as a therapeutic strategy for the treatment of breast cancer brain metastasis

The presence of cell surface protein CD47 allows cancer cells to evade innate and adaptive immune surveillance resulting in metastatic spread. CD47 binds to and activates SIRPα on the surface of myeloid cells, inhibiting their phagocytic activity. On the other hand, CD47 binds the matricellular protein Thrombospondin-1, limiting T-cell activation. Thus, blocking CD47 is a potential therapeutic strategy for preventing brain metastasis. To test this hypothesis, breast cancer patient biopsies were stained with antibodies against CD47 to determine differences in protein expression. An anti-CD47 antibody was used in a syngeneic orthotopic triple-negative breast cancer model, and CD47 null mice were used in a breast cancer brain metastasis model by intracardiac injection of the E0771-Br-Luc cell line. Immunohistochemical staining of patient biopsies revealed an 89% increase in CD47 expression in metastatic brain tumors compared to normal adjacent tissue (p ≤ 0.05). Anti-CD47 treatment in mice bearing brain metastatic 4T1br3 orthotopic tumors reduced tumor volume and tumor weight by over 50% compared to control mice (p ≤ 0.05) and increased IBA1 macrophage/microglia marker 5-fold in tumors compared to control (p ≤ 0.05). Additionally, CD47 blockade increased the M1/M2 macrophage ratio in tumors 2.5-fold (p ≤ 0.05). CD47 null mice had an 89% decrease in metastatic brain burden (p ≤ 0.05) compared to control mice in a brain metastasis model. Additionally, RNA sequencing revealed several uniquely expressed genes and significantly enriched genes related to tissue development, cell death, and cell migration tumors treated with anti-CD47 antibodies. Thus, demonstrating that CD47 blockade affects cancer cell and tumor microenvironment signaling to limit metastatic spread and may be an effective therapeutic for triple-negative breast cancer brain metastasis.

HX009, a novel BsAb dual targeting PD1 x CD47, demonstrates potent anti-lymphoma activity in preclinical models

Both PD1/PD-L1 and CD47 blockades have demonstrated limited activity in most subtypes of NHL save NK/T-cell lymphoma. The hemotoxicity with anti-CD47 agents in the clinic has been speculated to account for their limitations. Herein we describe a first-in-class and rationally designed bispecific antibody (BsAb), HX009, targeting PD1 and CD47 but with weakened CD47 binding, which selectively hones the BsAb for tumor microenvironment through PD1 interaction, potentially reducing toxicity. In vitro characterization confirmed: (1) Both receptor binding/ligand blockade, with lowered CD47 affinity; (2) functional PD1/CD47 blockades by reporter assays; (3) T-cell activation in Staphylococcal-enterotoxin-B-pretreated PBMC and mixed-lymphocyte-reaction. In vivo modeling demonstrated antitumor activity in Raji-B and Karpass-229-T xenograft lymphomas. In the humanized mouse syngeneic A20 B-lymphoma (huCD47-A20) HuGEMM model, which has quadruple knocked-in hPD1xhPD-L1xhCD47xhSIRPα genes and an intact autologous immune-system, a contribution of effect is demonstrated for each targeted biologic (HX008 targeting PD1 and SIRPα-Fc targeting CD47), which is clearly augmented by the dual targeting with HX009. Lastly, the expression of the immune-checkpoints PD-L1/L2 and CD47 seemed co-regulated among a panel of lymphoma-derived-xenografts, where HX009 maybe more effective in those with upregulated CD47. Our data warrants HX009's further clinical development for treating NHLs.

CD47-Dependent Regulation of Immune Checkpoint Gene Expression and MYCN mRNA Splicing in Murine CD8 and Jurkat T Cells

Elevated expression of CD47 in some cancers is associated with poor survival related to its function as an innate immune checkpoint when expressed on tumor cells. In contrast, elevated CD47 expression in cutaneous melanomas is associated with improved survival. Previous studies implicated protective functions of CD47 expressed by immune cells in the melanoma tumor microenvironment. RNA sequencing analysis of responses induced by CD3 and CD28 engagement on wild type and CD47-deficient Jurkat T lymphoblast cells identified additional regulators of T cell function that were also CD47-dependent in mouse CD8 T cells. MYCN mRNA expression was upregulated in CD47-deficient cells but downregulated in CD47-deficient cells following activation. CD47 also regulated alternative splicing that produces two N-MYC isoforms. The CD47 ligand thrombospondin-1 inhibited expression of these MYCN mRNA isoforms, as well as induction of the oncogenic decoy MYCN opposite strand (MYCNOS) RNA during T cell activation. Analysis of mRNA expression data for melanomas in The Cancer Genome Atlas identified a significant coexpression of MYCN with CD47 and known regulators of CD8 T cell function. Thrombospondin-1 inhibited the induction of TIGIT, CD40LG, and MCL1 mRNAs following T cell activation in vitro. Increased mRNA expression of these T cell transcripts and MYCN in melanomas was associated with improved overall survival.

A narrative review for platelets and their RNAs in cancers: New concepts and clinical perspectives

Recent years have witnessed a growing body of evidence suggesting that platelets are involved in several stages of the metastatic process via direct or indirect interactions with cancer cells, contributing to the progression of neoplastic malignancies. Cancer cells can dynamically exchange components with platelets in and out of blood vessels, and directly phagocytose platelets to hijack their proteome, transcriptome, and secretome, or be remotely regulated by metabolites or microparticles released by platelets, resulting in phenotypic, genetic, and functional modifications. Moreover, platelet interactions with stromal and immune cells in the tumor microenvironment lead to alterations in their components, including the ribonucleic acid (RNA) profile, and complicate the impact of platelets on cancers. A deeper understanding of the roles of platelets and their RNAs in cancer will contribute to the development of anticancer strategies and the optimization of clinical management. Encouragingly, advances in high-throughput sequencing, bioinformatics data analysis, and machine learning have allowed scientists to explore the potential of platelet RNAs for cancer diagnosis, prognosis, and guiding treatment. However, the clinical application of this technique remains controversial and requires larger, multicenter studies with standardized protocols. Here, we integrate the latest evidence to provide a broader insight into the role of platelets in cancer progression and management, and propose standardized recommendations for the clinical utility of platelet RNAs to facilitate translation and benefit patients.