Myeloma-derived IL-32γ induced PD-L1 expression in macrophages facilitates immune escape via the PFKFB3-JAK1 axis

New roles of tumor-derived exosomes in tumor microenvironment

Throughout tumorigenesis, the co-evolution of tumor cells and their surrounding microenvironment leads to the development of malignant phenotypes. Cellular communication within the tumor microenvironment (TME) plays a critical role in influencing various aspects of tumor progression, including invasion and metastasis. The release of exosomes, a type of extracellular vesicle, by most cell types in the body, is an essential mediator of intercellular communication. A growing body of research indicates that tumor-derived exosomes (TDEs) significantly expedite tumor progression through multiple mechanisms, inducing epithelial-mesenchymal transition and macrophage polarization, enhancing angiogenesis, and aiding in the immune evasion of tumor cells. Herein, we describe the formation and characteristics of the TME, and summarize the contents of TDEs and their diverse functions in modulating tumor development. Furthermore, we explore potential applications of TDEs in tumor diagnosis and treatment.

Pan-cancer analysis reveals IL32 is a potential prognostic and immunotherapeutic biomarker in cancer

Interleukin 32 (IL32) is a pro-inflammatory cytokine that plays a key role in promoting sterile inflammation by modulating immune responses. However, the role of IL32 in various cancers remains unclear. This research aimed to investigate the correlation between IL32 expression and immunity and visualize its prognostic landscape in pan-cancer. We investigated gene expression, genomic alterations, and survival analysis of IL32 in pan-cancer in numerous databases including TCGA, GTEx, cBioPortal, and GDC databases. Tumor immune cell infiltration was assessed using the CIBERSORT computational method as well as the ESTIMATE method to analyze the correlation of IL32 expression with stromal and immune components. Protein-protein interaction analysis was performed in the STRING and GeneMANIA databases, and gene function enrichment was performed by GO set enrichment analysis. Tumor tissues had higher IL32 expression levels than normal tissues. Elevated IL32 expression was associated with poor OS and prognosis. In addition, tumor stemness, TMB, MSI, and immune checkpoint genes were also associated with IL32 expression. Correlations were observed between IL32 expression and B cell, CD4T cell, CD8T cell, neutrophil, macrophage, and DC infiltration in multiple cancers. GO enrichment analysis showed that IL32 expression was associated with cancer pathways, cytokine-receptor interactions, and NOD-like receptor signaling pathways. These findings suggest that IL32 may serve as a biomarker of cancer immune infiltration and poor prognosis, providing new therapeutic targets for cancer treatment.

ADGRE5-centered Tsurv model in T cells recognizes responders to neoadjuvant cancer immunotherapy

Background

Neoadjuvant immunotherapy with anti-programmed death-1 (neo-antiPD1) has revolutionized perioperative methods for improvement of overall survival (OS), while approaches for major pathologic response patients' (MPR) recognition along with methods for overcoming non-MPR resistance are still in urgent need.

Methods

We utilized and integrated publicly-available immune checkpoint inhibitors regimens (ICIs) single-cell (sc) data as the discovery datasets, and innovatively developed a cell-communication analysis pipeline, along with a VIPER-based-SCENIC process, to thoroughly dissect MPR-responding subsets. Besides, we further employed our own non-small cell lung cancer (NSCLC) ICIs cohort's sc data for validation in-silico. Afterward, we resorted to ICIs-resistant murine models developed by us with multimodal investigation, including bulk-RNA-sequencing, Chip-sequencing and high-dimensional cytometry by time of flight (CYTOF) to consolidate our findings in-vivo. To comprehensively explore mechanisms, we adopted 3D ex-vivo hydrogel models for analysis. Furthermore, we constructed an ADGRE5-centered Tsurv model from our discovery dataset by machine learning (ML) algorithms for a wide range of tumor types (NSCLC, melanoma, urothelial cancer, etc.) and verified it in peripheral blood mononuclear cells (PBMCs) sc datasets.

Results

Through a meta-analysis of multimodal sequential sc sequencing data from pre-ICIs and post-ICIs, we identified an MPR-expanding T cells meta-cluster (MPR-E) in the tumor microenvironment (TME), characterized by a stem-like CD8+ T cluster (survT) with STAT5-ADGRE5 axis enhancement compared to non-MPR or pre-ICIs TME. Through multi-omics analysis of murine TME, we further confirmed the existence of survT with silenced function and immune checkpoints (ICs) in MPR-E. After verification of the STAT5-ADGRE5 axis of survT in independent ICIs cohorts, an ADGRE5-centered Tsurv model was then developed through ML for identification of MPR patients pre-ICIs and post-ICIs, both in TME and PBMCs, which was further verified in pan-cancer immunotherapy cohorts. Mechanistically, we unveiled ICIs stimulated ADGRE5 upregulation in a STAT5-IL32 dependent manner in a 3D ex-vivo system (3D-HYGTIC) developed by us previously, which marked Tsurv with better survival flexibility, enhanced stemness and potential cytotoxicity within TME.

Conclusion

Our research provides insights into mechanisms underlying MPR in neo-antiPD1 and a well-performed model for the identification of non-MPR.

Mutual regulation of PD-L1 immunosuppression between tumor-associated macrophages and tumor cells: a critical role for exosomes

Tumor cells primarily employ the PD-1/PD-L1 pathway to thwart the anti-tumor capabilities of T lymphocytes, inducing immunosuppression. This occurs through the direct interaction of PD-L1 with PD-1 on T lymphocyte surfaces. Recent research focusing on the tumor microenvironment has illuminated the pivotal role of immune cells, particularly tumor-associated macrophages (TAMs), in facilitating PD-L1-mediated immunosuppression. Exosomes, characterized by their ability to convey information and be engulfed by cells, significantly contribute to promoting TAM involvement in establishing PD-L1-mediated immunosuppression within the tumor microenvironment. Exosomes, characterized by their ability to convey information and be engulfed by cells, significantly contribute to promoting TAM involvement in establishing PD-L1-mediated immunosuppression within the tumor microenvironment. In addition to receiving signals from tumor-derived exosomes that promote PD-L1 expression, TAMs also exert control over PD-L1 expression in tumor cells through the release of exosomes. This paper aims to summarize the mechanisms by which exosomes participate in this process, identify crucial factors that influence these mechanisms, and explore innovative strategies for inhibiting or reversing the tumor-promoting effects of TAMs by targeting exosomes.

Good Cop, Bad Cop: Profiling the Immune Landscape in Multiple Myeloma

Multiple myeloma (MM) is a dyscrasia of plasma cells (PCs) characterized by abnormal immunoglobulin (Ig) production. The disease remains incurable due to a multitude of mutations and structural abnormalities in MM cells, coupled with a favorable microenvironment and immune suppression that eventually contribute to the development of drug resistance. The bone marrow microenvironment (BMME) is composed of a cellular component comprising stromal cells, endothelial cells, osteoclasts, osteoblasts, and immune cells, and a non-cellular component made of the extracellular matrix (ECM) and the liquid milieu, which contains cytokines, growth factors, and chemokines. The bone marrow stromal cells (BMSCs) are involved in the adhesion of MM cells, promote the growth, proliferation, invasion, and drug resistance of MM cells, and are also crucial in angiogenesis and the formation of lytic bone lesions. Classical immunophenotyping in combination with advanced immune profiling using single-cell sequencing technologies has enabled immune cell-specific gene expression analysis in MM to further elucidate the roles of specific immune cell fractions from peripheral blood and bone marrow (BM) in myelomagenesis and progression, immune evasion and exhaustion mechanisms, and development of drug resistance and relapse. The review describes the role of BMME components in MM development and ongoing clinical trials using immunotherapeutic approaches.

Programmed Death Ligand-1-Overexpressing Donor Exosomes Mediate Donor-Specific Immunosuppression by Delivering Co-Inhibitory Signals to Donor-Specific T Cells

Programmed death ligand-1 (PD-L1) and donor antigens are critical for donor immature dendritic cells (DCs) targeting donor-specific T cells to induce transplant tolerance. This study aims to clarify whether DC-derived exosomes (DEX) with donor antigens (H2b) and high levels of PD-L1 expression (DEXPDL1+ ) can help to suppress graft rejection. In this study, it is demonstrated that DEXPDL1+ presents donor antigens, as well as PD-L1 co-inhibitory signals, directly or semi-directly via DCs to H2b-reactive T cells. This dual signal presentation can prolong the survival of heart grafts from B6 (H2b) mice but not from C3H (H2k) mice by inhibiting T cell activation, inducing activated T cell apoptosis, and modulating the balance of T cell differentiation from inflammatory to regulatory. Additionally, even though DEXPDL1+ treatment cannot induce tolerance after short-term treatment, this study provides a new vehicle for presenting co-inhibitory signals to donor-specific T cells. This novel strategy may facilitate the realization of donor-specific tolerance via the further optimization of drug-loading combinations and therapeutic regimens to elevate their killing ability.

Molecular and immunological mechanisms of clonal evolution in multiple myeloma

Multiple myeloma (MM) is a hematologic malignancy characterized by the proliferation of clonal plasma cells in the bone marrow (BM). It is known that early genetic mutations in post-germinal center B/plasma cells are the cause of myelomagenesis. The acquisition of additional chromosomal abnormalities and distinct mutations further promote the outgrowth of malignant plasma cell populations that are resistant to conventional treatments, finally resulting in relapsed and therapy-refractory terminal stages of MM. In addition, myeloma cells are supported by autocrine signaling pathways and the tumor microenvironment (TME), which consists of diverse cell types such as stromal cells, immune cells, and components of the extracellular matrix. The TME provides essential signals and stimuli that induce proliferation and/or prevent apoptosis. In particular, the molecular pathways by which MM cells interact with the TME are crucial for the development of MM. To generate successful therapies and prevent MM recurrence, a thorough understanding of the molecular mechanisms that drive MM progression and therapy resistance is essential. In this review, we summarize key mechanisms that promote myelomagenesis and drive the clonal expansion in the course of MM progression such as autocrine signaling cascades, as well as direct and indirect interactions between the TME and malignant plasma cells. In addition, we highlight drug-resistance mechanisms and emerging therapies that are currently tested in clinical trials to overcome therapy-refractory MM stages.

Macrophage-Based Therapeutic Strategies in Hematologic Malignancies

Macrophages are types of immune cells, with ambivalent functions in tumor growth, which depend on the specific environment in which they reside. Tumor-associated macrophages (TAMs) are a diverse population of immunosuppressive myeloid cells that play significant roles in several malignancies. TAM infiltration in malignancies has been linked to a poor prognosis and limited response to treatments, including those using checkpoint inhibitors. Understanding the precise mechanisms through which macrophages contribute to tumor growth is an active area of research as targeting these cells may offer potential therapeutic approaches for cancer treatment. Numerous investigations have focused on anti-TAM-based methods that try to eliminate, rewire, or target the functional mediators released by these cells. Considering the importance of these strategies in the reversion of tumor resistance to conventional therapies and immune modulatory vaccination could be an appealing approach for the immunosuppressive targeting of myeloid cells in the tumor microenvironment (TME). The combination of reprogramming and TAM depletion is a special feature of this approach compared to other clinical strategies. Thus, the present review aims to comprehensively overview the pleiotropic activities of TAMs and their involvement in various stages of cancer development as a potent drug target, with a focus on hematologic tumors.

Targeting immune checkpoints on tumor-associated macrophages in tumor immunotherapy

Unprecedented breakthroughs have been made in cancer immunotherapy in recent years. Particularly immune checkpoint inhibitors have fostered hope for patients with cancer. However, immunotherapy still exhibits certain limitations, such as a low response rate, limited efficacy in certain populations, and adverse events in certain tumors. Therefore, exploring strategies that can improve clinical response rates in patients is crucial. Tumor-associated macrophages (TAMs) are the predominant immune cells that infiltrate the tumor microenvironment and express a variety of immune checkpoints that impact immune functions. Mounting evidence indicates that immune checkpoints in TAMs are closely associated with the prognosis of patients with tumors receiving immunotherapy. This review centers on the regulatory mechanisms governing immune checkpoint expression in macrophages and strategies aimed at improving immune checkpoint therapies. Our review provides insights into potential therapeutic targets to improve the efficacy of immune checkpoint blockade and key clues to developing novel tumor immunotherapies.

Dynamic polarization of tumor-associated macrophages and their interaction with intratumoral T cells in an inflamed tumor microenvironment: from mechanistic insights to therapeutic opportunities

Immunotherapy has brought a paradigm shift in the treatment of tumors in recent decades. However, a significant proportion of patients remain unresponsive, largely due to the immunosuppressive tumor microenvironment (TME). Tumor-associated macrophages (TAMs) play crucial roles in shaping the TME by exhibiting dual identities as both mediators and responders of inflammation. TAMs closely interact with intratumoral T cells, regulating their infiltration, activation, expansion, effector function, and exhaustion through multiple secretory and surface factors. Nevertheless, the heterogeneous and plastic nature of TAMs renders the targeting of any of these factors alone inadequate and poses significant challenges for mechanistic studies and clinical translation of corresponding therapies. In this review, we present a comprehensive summary of the mechanisms by which TAMs dynamically polarize to influence intratumoral T cells, with a focus on their interaction with other TME cells and metabolic competition. For each mechanism, we also discuss relevant therapeutic opportunities, including non-specific and targeted approaches in combination with checkpoint inhibitors and cellular therapies. Our ultimate goal is to develop macrophage-centered therapies that can fine-tune tumor inflammation and empower immunotherapy.

IL-32 and its Paradoxical Role in Neoplasia

Interleukin-32 (IL-32) is an interleukin cytokine usually linked to inflammation. In recent years, it has been found that IL-32 exhibits both pro- and anti-tumor effects. Although most of those effects from IL-32 appear to favor tumor growth, some isoforms have shown to favor tumor suppression. This suggests that the role of IL-32 in neoplasia is very complex. Thus, the role of IL-32 in these various cancers and protein pathways makes it a very crucial component to consider when looking at potential therapeutic options in tumor treatment. In this review, we will explore what is currently known about IL-32, including its relationship with tumorigenesis and the potential for IL-32 to enhance local and systemic anti-tumor immune responses. Such a study might be helpful to accelerate the development of IL-32-based immunotherapies.

Interleukin-32γ promotes macrophage-mediated chemoresistance by inducing CSF1-dependent M2 macrophage polarization in multiple myeloma

Macrophages (MΦs) are an abundant component in the multiple myeloma (MM) environment and contribute to MM drug resistance. We previously showed that interleukin-32 (IL-32) is highly expressed in MM patients and induces the immunosuppressive function of MΦs. The present study was designed to explore the role of IL-32 in MΦ-mediated MM drug resistance and the underlying mechanism. Our analysis revealed that IL-32 expression was upregulated in relapsed MM patients and associated with CD206⁺ M2 MΦ infiltration. Subsequently, we found that the most active isoform, IL-32γ, promoted MΦs to protect MM cells from drug-induced apoptosis both in vitro and in vivo. Furthermore, by evaluating many parameters, including surface markers, cytokines, metabolic enzymes and characteristic molecules, IL-32γ was verified to induce the polarization of M2 MΦs, a function that was partly dependent on increasing the expression of colony-stimulating factor 1 (CSF1). Taken together, the results of our study indicate that IL-32γ promotes MΦ-mediated MM drug resistance and modifies MΦs toward the M2 phenotype, providing a crucial theoretical basis for targeted MΦ immunotherapy.

Modulating Glycolysis to Improve Cancer Therapy

Cancer cells undergo metabolic reprogramming and switch to a 'glycolysis-dominant' metabolic profile to promote their survival and meet their requirements for energy and macromolecules. This phenomenon, also known as the 'Warburg effect,' provides a survival advantage to the cancer cells and make the tumor environment more pro-cancerous. Additionally, the increased glycolytic dependence also promotes chemo/radio resistance. A similar switch to a glycolytic metabolic profile is also shown by the immune cells in the tumor microenvironment, inducing a competition between the cancer cells and the tumor-infiltrating cells over nutrients. Several recent studies have shown that targeting the enhanced glycolysis in cancer cells is a promising strategy to make them more susceptible to treatment with other conventional treatment modalities, including chemotherapy, radiotherapy, hormonal therapy, immunotherapy, and photodynamic therapy. Although several targeting strategies have been developed and several of them are in different stages of pre-clinical and clinical evaluation, there is still a lack of effective strategies to specifically target cancer cell glycolysis to improve treatment efficacy. Herein, we have reviewed our current understanding of the role of metabolic reprogramming in cancer cells and how targeting this phenomenon could be a potential strategy to improve the efficacy of conventional cancer therapy.

IL-32 is induced by activation of toll-like receptors in multiple myeloma cells

Multiple myeloma (MM) is a hematological cancer characterized by accumulation of malignant plasma cells in the bone marrow. The patients are immune suppressed and suffer from recurrent and chronic infections. Interleukin-32 is a non-conventional, pro-inflammatory cytokine expressed in a subgroup of MM patients with a poor prognosis. IL-32 has also been shown to promote proliferation and survival of the cancer cells. Here we show that activation of toll-like receptors (TLRs) promotes expression of IL-32 in MM cells through NFκB activation. In patient-derived primary MM cells, IL-32 expression is positively associated with expression of TLRs. Furthermore, we found that several TLR genes are upregulated from diagnosis to relapse in individual patients, predominantly TLRs sensing bacterial components. Interestingly, upregulation of these TLRs coincides with an increase in IL-32. Taken together, these results support a role for IL-32 in microbial sensing in MM cells and suggest that infections can induce expression of this pro-tumorigenic cytokine in MM patients.

Glycolysis in tumor microenvironment as a target to improve cancer immunotherapy

Cancer cells and immune cells all undergo remarkably metabolic reprogramming during the oncogenesis and tumor immunogenic killing processes. The increased dependency on glycolysis is the most typical trait, profoundly involved in the tumor immune microenvironment and cancer immunity regulation. However, how to best utilize glycolytic targets to boost anti-tumor immunity and improve immunotherapies are not fully illustrated. In this review, we describe the glycolytic remodeling of various immune cells within the tumor microenvironment (TME) and the deleterious effects of limited nutrients and acidification derived from enhanced tumor glycolysis on immunological anti-tumor capacity. Moreover, we elucidate the underlying regulatory mechanisms of glycolytic reprogramming, including the crosstalk between metabolic pathways and immune checkpoint signaling. Importantly, we summarize the potential glycolysis-related targets that are expected to improve immunotherapy benefits. Our understanding of metabolic effects on anti-tumor immunity will be instrumental for future therapeutic regimen development.

Extracellular vesicle-mediated immunoregulation in cancer

Extracellular vesicles (EVs) have emerged as immunomodulatory regulators during tumor progression. These small vesicles encapsulate a variety of molecules, including DNA, RNA, and proteins. When EVs come in contact with recipient cells, the EVs transmit various physiological characteristics; for example, proteins on the surface of EVs act as ligands. Immune checkpoint blockade targeting cytotoxic T-lymphocyte-associated antigen 4 (CTLA4), programmed cell death 1 (PD-1) and programmed cell death ligand 1 (PD-L1) has shown promise in a subset of cancer patients. PD-L1 on EVs acts as a key immunomodulator. Suppression of EV secretion enhances the efficacy of immunotherapy using immune checkpoint blockade antibodies. In addition to immune checkpoint blockade therapy, chimeric antigen receptor T (CAR-T) cell therapy has also been used to successfully eliminate cancer cells. Interestingly, CAR-T-cell-derived EVs express CAR on their surface. Compared with CAR-T cells, CAR-expressing EVs do not express PD1, so their antitumor effect cannot be weakened. In this review, we describe the current understanding of EVs in cancer immunity and summarize their crucial roles in immunomodulation.

The role of glycolysis and lactate in the induction of tumor-associated macrophages immunosuppressive phenotype

Growing evidence highlights that glycolysis and tumor-derived lactate could skew tumor-associated macrophages (TAMs) toward an immunosuppressive phenotype. However, the updated research has not been systematically summarized yet. TAMs are educated by the tumor microenvironment (TME) and exert immunosuppressive functions and tumorigenic effects via multiple biological processes. It is well known that lactate generated by aerobic glycolysis is significantly accumulated in TME and promotes tumor progression in solid tumors. Moreover, some recent research demonstrated that glycolysis is activated in TAMs to support M2-like polarization, which is absolutely in contrast with the metabolic profile of M2 macrophages in inflammation. Notably, lactate produced by high levels of glycolysis is not only a metabolic by-product but also an oncometabolite. TAMs could access the biological information delivered by lactate and further enhance protumor functions such as immunosuppression and angiogenesis. Here, we outline the connection between glycolysis and TAM phenotype to elucidate the metabolic characteristics of TAMs. Further, insights into the specific molecular mechanisms of lactate-induced TAM polarization and potential therapeutic targets are summarized. We sought to discuss the reciprocal interaction between tumor cells and TAMs mediated by lactate, which will lay a foundation for the research aiming to elucidate the complex functions of TAMs.