COX2/mPGES1/PGE2 pathway regulates PD-L1 expression in tumor-associated macrophages and myeloid-derived suppressor cells

Platelets in cancer and immunotherapy: functional dynamics and therapeutic opportunities

Platelets play a critical role in tumor immunity, particularly in promoting cancer progression. Numerous studies suggest that platelets could serve as a novel target for cancer immunotherapy, however, no comprehensive reviews have yet summarized and discussed this potential. Our review provides an in-depth discussion of the roles and mechanisms of platelets within both the immunosuppressive tumor microenvironment and the anti-tumor immune microenvironment. Additionally, we summarize the key therapeutic targets and approaches for clinical translation. This work offers essential insights for reprogramming platelets to shift their function from tumor promotion to tumor suppression, providing a foundation for the development of novel immunotherapeutic strategies and related research.

The tumor microenvironment's role in the response to immune checkpoint blockade

Beyond cancer cells, the tumor microenvironment (TME) includes cells of the innate and adaptive immune systems but also non-immune cells, such as fibroblasts and endothelial cells. Depending on the cues they receive, infiltrating myeloid cells, such as monocytes, macrophages, dendritic cells and neutrophils, perform immune stimulatory or suppressive functions by educating adaptive immune cells, thereby guiding their responses to cancer cells and cancer treatment, such as immune checkpoint blockade (ICB). The increasing understanding that anti-tumor immunity goes beyond T cells with improved functionality, and the unraveling of resistance mechanisms beyond T cell exhaustion, have renewed interest in non-T cell components of the TME to identify novel therapeutic targets and improve ICB responses. Here, we review immune and non-immune cellular components of the TME that regulate adaptive cell responses and their role in ICB response and resistance.

BCG therapy in bladder cancer and its tumor microenvironment interactions

SUMMARYBacillus Calmette-Guérin (BCG) has been the standard treatment for non-muscle-invasive bladder cancer for over 30 years. Despite its proven efficacy, challenges persist, including unclear mechanisms of action, resistance in 30%-50% of patients, and significant side effects. This review presents an updated and balanced discussion of the antitumor mechanisms of BCG, focusing on its direct effects on bladder cancer and its interactions with various cell types within the bladder tumor microenvironment. Notably, recent research on the interactions between BCG and the bladder microbiome is also incorporated. We further summarize and analyze the latest preclinical and clinical studies regarding both intrinsic and adaptive resistance to BCG in bladder cancer. Based on the current understanding of BCG's therapeutic principles and resistance mechanisms, we systematically explore strategies to improve BCG-based tumor immunotherapy. These include the development of recombinant BCG, combination therapy with different drugs, optimization of therapeutic regimens and management, and the exploration of new approaches by targeting changes in the bladder microbiota and its metabolites. These measures aim to effectively address the BCG resistance in bladder cancer, reduce its toxicity, and ultimately enhance the clinical anti-tumor efficacy. Bacterial therapy, represented by genetically engineered oncolytic bacteria, has gradually emerged in the field of cancer treatment in recent years. As the only bacterial drug successfully approved for oncology use, BCG has provided decades of clinical experience. By consolidating lessons from BCG's successes and limitations, we hope to provide valuable insights for the development and application of bacterial therapies in cancer treatment.

CSF1R+ myeloid-monocytic cells drive CAR-T cell resistance in aggressive B cell lymphoma

Despite the improvement, approximately 60% of patients with relapsed or refractory (r/r) aggressive B cell lymphoma (B-NHL) do not achieve durable benefit from CAR-T cell therapy. To elucidate factors associated with CAR-T therapy resistance, we conducted high-dimensional analyses of pre- and post-CAR-T cell specimens. In patients with non-durable response, we identified a prognostically relevant lymphoma-associated myeloid-monocytic (LAMM) gene signature. In-depth profiling revealed a distinct CSF1R+CD14+CD68+ LAMM cell population in both human and murine B-NHL that inhibits CAR-T cell function and correlates with poor outcome. Cell-cell inference analysis uncovered that LAMM cells impair CAR-T cell function through a direct LAMM-T cell interaction via the PGE2-EP2/EP4 axis. In an autochthonous lymphoma mouse model, combined anti-CD19 CAR-T cell therapy with CSF1R blockade exhibited synergistic effects and improved survival. These findings provide strong rationale for combining anti-CD19 CAR-T cells with CSF1R inhibitors in treating r/r aggressive B-NHL patients.

Reversing hypoxia-induced immune evasion in tumors to enhance cancer immunotherapy

The strategy of inducing tumors to release damage-associated molecular patterns (DAMPs) to trigger immunogenic cell death has garnered significant attention in cancer therapy. However, the hypoxic tumor microenvironment, which is often programmed by cancer cells, results in the release of immunosuppressive DAMPs (iDAMPs), which substantially influence antitumor immune responses. In this study, we developed a redox-responsive carboxymethyl chitosan (CMC)-based nanoplatform for the sequential delivery of a hypoxia-inducible factor 1-α (HIF-1α) inhibitor, 3-(5'-hydroxymethyl-2-furyl)-1-benzylindazole (YC-1), and the chemotherapeutic agent doxorubicin (DOX), aimed to restore therapeutic sensitization and immunostimulation in tumors. The preferential release of YC-1 effectively targets the HIF-1α/cyclooxygenase-2 (COX-2) axis, significantly reducing the secretion of immunosuppressive factor prostaglandin E2 (PGE2), thereby resensitizing tumors to Tcell-mediated immunity. Additionally, YC-1 mitigates hypoxia-induced tumor chemoresistance by inhibiting the HIF-1α/P-glycoprotein (P-gp) axis, further improving the immunotherapeutic efficacy of DOX. Our work demonstrates that regulating hypoxia-induced immunosuppressive factors in tumors contributes to the inhibition of both primary and metastatic tumors, offering a promising approach to enhance immunotherapies.

Macrophages in the premetastatic and metastatic niche: key functions and therapeutic directions

Metastasis plays a significant role in the high mortality rates associated with cancer and is usually the endpoint of a series of sequential and dynamic events. A crucial step in metastasis development and progression is the formation of a premetastatic niche (PMN), which provides a conducive microenvironment for the settlement and colonization of disseminated tumor cells at distant metastatic sites. Extensive research has demonstrated the significance of macrophage populations within primary tumors in promoting metastatic progression. Nevertheless, the contribution of macrophages at secondary sites to the regulation of PMN formation is frequently overlooked. This review systematically explores the role of macrophages in priming the PMN to facilitate cancer metastasis. Additionally, we provide a compendium of existing strategies to target macrophages in cancer therapy.

Myelodysplastic Neoplasms (MDS): Pathogenesis and Therapeutic Prospects

Myelodysplastic neoplasms (MDS) are a group of hematological malignancies originating from hematopoietic stem cells (HSCs), characterized by distinct clinical and/or molecular heterogeneity across different MDS subtypes. This review elucidates the pathogenesis of MDS from two main perspectives: the bone marrow microenvironment and recurrent genetic abnormalities. Abnormal bone marrow microenvironment initiates aberrant innate immune response in HSCs, with quantitative and/or functional alterations of immune cells that collectively establish an immunosuppressive microenvironment, and abnormal bone marrow mesenchymal stromal cells that support and promote the progression of MDS. In addition, this review synthesizes current evidence on the biological functions and pathogenic mechanisms of frequently mutated genes in MDS. Furthermore, emerging therapies based on the pathogenesis of MDS are evaluated and summarized. In summary, aberrant innate immune responses promote pyroptosis of HSCs and acquisition of recurrent genetic abnormalities, resulting in the transformation of HSCs into MDS blasts; the immunosuppressive milieu (especially in higher-risk MDS) facilitates immune evasion of MDS blasts, ultimately leading to disease progression. Future research should focus on the interplay between different genetic abnormalities and immune dysregulation, coupled with the development of novel therapies targeting multiple nodes of the pathogenic network, to overcome current challenges in the treatment of MDS.

Immune Checkpoint Inhibitors and Immunosuppressive Tumor Microenvironment: Current Challenges and Strategies to Overcome Resistance

Immune checkpoint inhibitors (ICIs) are shown to improve cancer treatment effectiveness by boosting the immune system of the patient. Nevertheless, the unique and highly suppressive TME poses a significant challenge, causing heterogeneity of response or resistance in a considerable number of patients. This review focuses on the evasive attributes of the TME. Immune evasion mechanism in TME include immunosuppressive cells, cytokine and chemokine signaling, metabolic alterations and overexpression of immune checkpoint molecules such as PD-1, CTLA-4, LAG-3, TIM-3, TIGIT, BTLA and their interactions within the TME. In addition, this review focuses on the overcoming resistance by targeting immunosuppressive cells, normalizing tumor blood vessels, blocking two or three checkpoints simultaneously, combining vaccines, oncolytic viruses and metabolic inhibitors with ICIs or other therapies. This review also focuses on the necessity of finding predictive markers for the stratification of patients and to check response of ICIs treatment. It remains to be made certain by new research and intelligent innovations how these discoveries of the TME and its interplay facilitate ICI treatment and change the face of cancer treatment.

Platelets and diseases: signal transduction and advances in targeted therapy

Platelets are essential anucleate blood cells that play pivotal roles in hemostasis, tissue repair, and immune modulation. Originating from megakaryocytes in the bone marrow, platelets are small in size but possess a highly specialized structure that enables them to execute a wide range of physiological functions. The platelet cytoplasm is enriched with functional proteins, organelles, and granules that facilitate their activation and participation in tissue repair processes. Platelet membranes are densely populated with a variety of receptors, which, upon activation, initiate complex intracellular signaling cascades. These signaling pathways govern platelet activation, aggregation, and the release of bioactive molecules, including growth factors, cytokines, and chemokines. Through these mechanisms, platelets are integral to critical physiological processes such as thrombosis, wound healing, and immune surveillance. However, dysregulated platelet function can contribute to pathological conditions, including cancer metastasis, atherosclerosis, and chronic inflammation. Due to their central involvement in both normal physiology and disease, platelets have become prominent targets for therapeutic intervention. Current treatments primarily aim to modulate platelet signaling to prevent thrombosis in cardiovascular diseases or to reduce excessive platelet aggregation in other pathological conditions. Antiplatelet therapies are widely employed in clinical practice to mitigate clot formation in high-risk patients. As platelet biology continues to evolve, emerging therapeutic strategies focus on refining platelet modulation to enhance clinical outcomes and prevent complications associated with platelet dysfunction. This review explores the structure, signaling pathways, biological functions, and therapeutic potential of platelets, highlighting their roles in both physiological and pathological contexts.

Glycosylation-driven programs coordinate immunoregulatory and pro-angiogenic functions of myeloid-derived suppressor cells

Myeloid-derived suppressor cells (MDSCs) promote tumor progression by suppressing antitumor immunity and inducing angiogenesis; however, the mechanisms linking these processes remain uncertain. Here, we identified a glycosylation-dependent program driven by galectin-1 (GAL1) that imparted both immunoregulatory and pro-angiogenic functions to MDSCs through shared receptor signaling pathways. GAL1 expression was associated with enhanced MDSC phenotypes and poor prognosis in diverse human cancers. Analysis of monocytic and polymorphonuclear MDSCs from tumor-bearing mice revealed niche-specific glycan signatures that selectively regulated GAL1 binding. Through glycosylation-dependent interactions with the CD18-CD11b-CD177 receptor complex and STAT3 signaling, GAL1 simultaneously orchestrated immunosuppressive and pro-angiogenic programs in MDSCs, driving tumor growth in vivo. Myeloid-specific deletion of β-galactoside α(2,6)-sialyltransferase 1, which prevented α(2,6)-linked sialic acid incorporation, enhanced GAL1-driven regulatory circuits and accelerated tumor progression, effects that were mitigated by GAL1-neutralizing antibodies. Thus, targeting GAL1-glycan interactions may offer opportunities to reprogram MDSCs and enhance the efficacy of immunotherapeutic and anti-angiogenic strategies.

Immunometabolism of tumor-associated macrophages: A therapeutic perspective

Tumor-associated macrophages (TAMs) play a pivotal role in the tumor microenvironment (TME), actively contributing to the formation of an immunosuppressive niche that fosters tumor progression. Consequently, there has been a growing interest in targeting TAMs as a promising avenue for cancer therapy. Recent advances in the field of immunometabolism have shed light on the influence of metabolic adaptations on macrophage physiology in the context of cancer. Here, we discuss the key metabolic pathways that shape the phenotypic diversity of macrophages. We place special emphasis on how metabolic reprogramming impacts the activation status of TAMs and their functions within the TME. Additionally, we explore alterations in TAM metabolism and their effects on phagocytosis, production of cytokines/chemokines and interaction with cytotoxic T and NK immune cells. Moreover, we examine the application of nanomedical approaches to target TAMs and assess the clinical significance of modulating the metabolism of TAMs as a strategy to develop new anti-cancer therapies. Taken together, in this comprehensive review article focusing on TAMs, we provide invaluable insights for the development of effective immunotherapeutic strategies and the enhancement of clinical outcomes for cancer patients.

Role of Extracellular Vesicles in the Pathogenesis of Brain Metastasis

Extracellular vesicles (EVs) are small particles released by various cells, including cancer cells. They play a significant role in the development of different cancers, including brain metastasis. These EVs transport biomolecular materials such as RNA, DNA, and proteins from tumour cells to other cells, facilitating the spread of primary tumours to the brain tissue. EVs interact with the endothelial cells of the blood-brain barrier (BBB), compromising its integrity and allowing metastatic cells to pass through easily. Additionally, EVs interact with various cells in the brain's microenvironment, creating a conducive environment for incoming metastatic cells. They also influence the immune system within this premetastatic environment, promoting the growth of metastatic cells. This review paper focuses on the research regarding the role of EVs in the development of brain metastasis, including their impact on disrupting the BBB, preparing the premetastatic environment, and modulating the immune system. Furthermore, the paper discusses the potential of EVs as diagnostic and prognostic biomarkers for brain metastasis.

Treatment of cancer-associated fibroblast-like cells with celecoxib enhances the anti-cancer T helper 1/Treg responses in breast cancer

Tumor inflammation, as one of the hallmarks of cancer, has been the target for anti-cancer treatments. Celecoxib is a selective inhibitor of the enzyme cycloxygenase-2 (COX-2) and inhibits the production of PGE2, which is an important mediator of tumor inflammation produced by cancer cells and cells of the tumor microenvironment. In this study, we aimed at inhibiting COX-2 using celecoxib, expressed in cancer-associated fibroblast (CAF)-like cells isolated from breast cancer and evaluated the alterations in their cytokine profile and gene expression. CAF-like cells were isolated by explant culture from 13 breast cancer tissues. Simultaneously, peripheral blood mononuclear cells (PBMCs) were isolated from patients' blood. CAF-like cells were treated with 10 µM of celecoxib and expression of genes COX-2, smooth muscle actin-alpha (α-SMA), and production of prostaglandin E2 (PGE2), Interleukin 10 (IL10), and transforming growth factor beta1 (TGF-β1) was evaluated. Next, PBMCs were co-cultured with celecoxib-treated CAF-like cells and the expression of genes T-bet, Foxp3, GATA-3; production of cytokines IFN-ɣ, IL-10, IL-4, TGF-β1, and the mediator PGE2 were assessed by real-time-PCR and ELISA, respectively. Isolated CAF-like cells showed expression of fibroblast activation protein (FAP). Treatment with celecoxib was able to efficiently reduce the production of PGE2 and the expression of α-SMA in isolated CAF-like cells. Furthermore, PBMCs in co-culture with these cells showed enhanced Th1 phenotype including T-bet and IFNγ expression and decreased the phenotypical markers of regulatory T cells such as FoxP3 and IL-10 and TGF-β1 production. Our study shows the important role of COX-2 in CAFs by promoting immune suppression. Our results suggested that high expression of COX-2 in CAFs may serve as a new therapeutic, targeting CAFs in enhancing immune responses in breast cancer treatment.

EGR2 promotes liver cancer metastasis by enhancing IL-8 expression through transcription regulation of PDK4 in M2 macrophages

Liver tumor is a common digestive system tumor, and its development is closely related to complex cytokines, tumor microenvironment and immunoregulatory mechanisms. Tumor-associated macrophages play a great role in a series of liver cancer development by secreting various cytokines and transmitting multiple signals, but how macrophages regulate the various biological behaviors of liver cancer cells at the microscopic level is a challenge we still need to overcome. In this research, we first identified the Early Growth Response 2 (EGR2) gene, which exhibited significant expression in M2 macrophages in comparison to M0 and M1 cell types, utilizing RNA sequencing. Subsequently, we validated this finding through a battery of methodologies, including WB, qRT-PCR, and immunofluorescence assays. We further employed a co-culture model involving MHCC97L and macrophages to investigate the impact of EGR2 downregulation within M2 cells on the in vivo and in vitro metastatic and invasive capabilities of MHCC97L cells. Subsequently, we directed our attention to investigating the impact of EGR2 on the levels of interleukin-8 (IL-8). Through comprehensive analyses including RNA sequencing, CUT-and-Tag, and ChIP techniques, we demonstrated that EGR2 can bind to the promoter region of the Pyruvate Dehydrogenase Kinase 4 (PDK4) gene. Finally, we introduced a virus overexpressing PDK4 and demonstrated that EGR2 could regulate the transcriptional level of PDK4 to affect the expression of IL-8, and ultimately alter the metastatic ability of hepatocellular carcinoma cells. Our study demonstrates that EGR2 may be a valuable target for future intervention in the disease process of hepatocellular carcinoma and refines the mechanism at the microscopic level of Tumor-associated macrophages.

Phase 2 trial of perioperative chemo-immunotherapy for gastro-esophageal adenocarcinoma: The role of M2 macrophage landscape in predicting response

We present the clinical results of a phase 2 trial combining neoadjuvant docetaxel, cisplatin, 5 Flourouracil, and the PD-L1 inhibitor avelumab in locally advanced gastro-esophageal adenocarcinoma (GEA). Fifty-one patients receive neoadjuvant therapy with 50 proceeding to surgery. Grade 3-4 adverse events occur in 40%; complete/major pathological response is found in 7/50 (14%) and 9/50 (18%), with 2-year disease-free survival of 67.5%. There is no correlation between tumor regression and PD-L1 or mismatch repair (MMR) status. Multiplex immunohistochemistry and longitudinal single-cell transcriptomic profiling reveal alterations in certain innate immune cell populations, particularly noting an M2-tumor-associated macrophage (M2-TAM) proliferation in non-responding tumors. These findings describe the effective nature of this treatment regimen for GEA and reveal associated features of the inflammatory milieux associated with response to chemo-immunotherapy. The specific character of the inflammatory environment in non-responders may, in the future, help personalize treatment. This study was registered at ClinicalTrials.gov (NCT03288350).

The potential role of PD-1/PD-L1 small molecule inhibitors in colorectal cancer with different mechanisms of action

Colorectal cancer (CRC) remains one of the leading causes of cancer-related death worldwide, with increasing incidence in younger ages highlighting the need for new or alternative therapy, of which is immune checkpoint inhibitors. Antibody-based immune checkpoint inhibitors targeting the interaction between programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) have revolutionized cancer treatment, including CRC. However, the low response rate in CRC highlights the need for additional research and innovative therapies. Small molecule inhibitors have risen as another strategy worth exploring, considering their potential to target a wide array of PD-1/PD-L1-related pathways. This review focuses on the potential of small molecule inhibitors targeting the PD-1/PD-L1 axis in CRC. Exploring various classes of small molecule inhibitors, including those that directly block the PD-1/PD-L1 interaction and others that target upstream regulators or downstream signaling pathways involved in PD-1/PD-L1-mediated immune suppression. Additionally, modulation of post-transcriptional and post-translational processes, thereby influencing the expression, stability, or localization of PD-1/PD-L1 proteins to enhance antitumor immunity, provides a multifaceted treatment approach. By disrupting these pathways, these inhibitors can restore immune system activity against tumor cells, offering new hope for overcoming resistance and improving outcomes in CRC patients who do not respond to conventional immune checkpoint inhibitors (ICIs). Integrating these small molecules into CRC treatment strategies could represent a promising advancement in the battle against the challenging disease.

MDSC checkpoint blockade therapy: a new breakthrough point overcoming immunosuppression in cancer immunotherapy

Despite the success of cancer immunotherapy in treating hematologic malignancies, their efficacy in solid tumors remains limited due to the immunosuppressive tumor microenvironment (TME), which is mainly formed by myeloid-derived suppressor cells (MDSCs). MDSCs not only exert potent immunosuppressive effects that hinder the success of immune checkpoint inhibitors (ICIs) and adaptive cellular therapies, but they also promote tumor advancement through non-immunological pathways, including promoting angiogenesis, driving epithelial-mesenchymal transition (EMT), and contributing to the establishment of pre-metastatic environments. While targeting MDSCs alone or in combination with conventional therapies has shown limited success, emerging evidence suggests that MDSC checkpoint blockade in combination with other immunotherapies holds great promise in overcoming both immunological and non-immunological barriers. In this review, we discussed the dual roles of MDSCs, with a particular emphasis on their underexplored checkpoints blockade strategies. We discussed the rationale behind combination strategies, their potential advantages in overcoming MDSC-mediated immunosuppression, and the challenges associated with their development. Additionally, we highlight future research directions aimed at optimizing combination immunotherapies to enhance cancer therapeutic effectiveness, particularly in solid tumor therapies where MDSCs are highly prevalent.

Immunoregulatory mechanisms of the arachidonic acid pathway in cancer

The arachidonic acid (AA) pathway promotes tumor progression by modulating the complex interactions between cancer and immune cells within the microenvironment. In this Review, we summarize the knowledge acquired thus far concerning the intricate mechanisms through which eicosanoids either promote or suppress the antitumor immune response. In addition, we will discuss the impact of eicosanoids on immune cells and how they affect responsiveness to immunotherapy, as well as potential strategies for manipulating the AA pathway to improve anticancer immunotherapy. Understanding the molecular pathways and mechanisms underlying the role played by AA and its metabolites in tumor progression may contribute to the development of more effective anticancer immunotherapies.

Cancer Biology and the Perioperative Period: Opportunities for Disease Evolution and Challenges for Perioperative Care

Efforts to deconvolve the complex interactions of cancer cells with other components of the tumor micro- and macro-environment have exposed a common tendency for cancers to subvert systems physiology and exploit endogenous programs involved in homeostatic control of metabolism, immunity, regeneration, and repair. Many such programs are engaged in the healing response to surgery which, together with other abrupt biochemical changes in the perioperative period, provide an opportunity for the macroevolution of residual disease. This review relates contemporary perspectives of cancer as a systemic disease with the overlapping biology of host responses to surgery and events within the perioperative period. With a particular focus on examples of cancer cell plasticity and changes within the host, we explore how perioperative inflammation and acute metabolic, neuroendocrine, and immune dyshomeostasis might contribute to cancer evolution within this contextually short, yet crucially influential timeframe, and highlight potential therapeutic opportunities within to further optimize surgical cancer care and its long-term oncological outcomes.

Novel immune drug combination induces tumour microenvironment remodelling and reduces the dosage of anti-PD-1 antibody

Immune checkpoint inhibitors (ICIs) are effective in clinical settings; however, they present immune-related adverse effects and financial burden. Although dose reduction of ICIs may mitigate these limitations, it could compromise therapeutic efficacy. Using two adjuvants (poly(I:C) and LAG-3-Ig) combined with three neoantigen peptides (Comb), we examined whether Comb could enhance the efficacy of reduced dose of αPD-1 monoclonal antibody (RD-αPD-1 mAb), which has limited efficacy. In a murine colorectal cancer model using an MC38 cell line, Comb addition to RD-αPD-1 mAb enhanced treatment efficacy. Analysis of the tumour microenvironment (TME) in mice treated with Comb using flow cytometry and single-cell RNA sequencing revealed decreased macrophages with highly expressing immunosuppressive genes and increased plasmacytoid dendritic cells with highly expressing antigen-presenting genes. A potent infiltration of CD8+ tumour-infiltrating lymphocytes (TILs) with an effector profile was only observed in RD-αPD-1 mAb with Comb. Additionally, single-cell T cell receptor repertoire analysis underscored an oligoclonal expansion of CD8+ TILs following treatment with RD-αPD-1 mAb with Comb. This novel immune drug combination may be a promising strategy for reducing αPD-1 mAb dosage while preserving antitumour efficacy through modulating the TME.

The Impact of Polyunsaturated Fatty Acids in Cancer and Therapeutic Strategies

PURPOSE OF REVIEW

Cancer is a disease influenced by both genetic and environmental factors, with dietary lipids being a significant contributing factor. This review summarizes the role of polyunsaturated fatty acids (PUFAs) in the mechanism of tumor occurrence and development, and elucidate the role of PUFAs in tumor treatment.

RECENT FINDINGS

PUFAs exert their impact on cancer through altering lipid composition in cell membranes, interacting with cell membrane lipid receptors, directly modulating gene expression in the cell nucleus, and participating in the metabolism of lipid mediators. Most omega-3 PUFAs are believed to inhibit cell proliferation, promote cancer cell death, suppress cancer metastasis, alter energy metabolism, inhibit tumor microenvironment inflammation, and regulate immune responses involving macrophages, T cells, NK cells, and others. However, certain omega-6 PUFAs exhibit weaker anti-tumor effects and may even promote tumor development, such as by fostering inflammatory tumor microenvironment and enhancing tumor cell proliferation. PUFAs play important roles in hallmarks of cancer including tumor cell proliferation, cell death, migration and invasion, energy metabolism remodeling, epigenetics, and immunity. These findings provide insights into the mechanisms of cancer development and offers options for dietary management of cancer.

A One Stone Three Birds Paradigm of Photon-Driven Pyroptosis Dye for Amplifying Tumor Immunotherapy

Activating the pyroptosis pathway of tumor cells by photodynamic therapy (PDT) for immunogenic cell death (ICD) is considered a valid strategy in pursuit of antitumor immunotherapy, but it remains a huge challenge due to the lack of reliable design guidelines. Moreover, it is often overlooked that conventional PDT can exacerbate the development of tumor immunosuppressive microenvironment, which is apparently unfavorable to clinical immunotherapy. The endoplasmic reticulum's (ER) pivotal role in cellular homeostasis and its emerging link to pyroptosis have galvanized interest in ER-centric imaging and therapeutics. Herein, using the targeted group-assisted strategy (TAGS), an intriguing cyclooxygenase-2-targeted photodynamic conjugate, Indo-Cy, strategically created, which exploits the enzyme's overabundance in the tumoral ER, especially under proinflammatory hypoxic conditions. This conjugate, with its highly precise ER imaging, embodies a trifunctional strategy: i) innovating an electron transfer mechanism, converting the hemicyanine moiety into an oxygen-independent type I photosensitizer, thereby navigating around the hypoxia constraints of traditional PDT; ii) executing precise ER-targeted PDT, amplifying caspase-1/GSDMD-mediated pyroptosis for ICD; 3) attenuating immunosuppressive pathways by inhibiting cyclooxygenase-2 downstream factors, including HIF-1α, PGE2, and VEGF. Indo-Cy's multimodal approach potently induces in vivo tumor pyroptosis and bolsters antitumor immunity, underscoring cyclooxygenase-2-targeted dyes' potential as a versatile oncotherapeutics.

Bioactive lipid signaling and lipidomics in macrophage polarization: Impact on inflammation and immune regulation

Macrophages, crucial innate immune cells, defend against pathogens and resolve inflammation, maintaining tissue balance. They perform phagocytosis, present antigens to T cells, and bond innate and adaptive immunity through various activation states. Classical activation is associated with Th1 responses and interferon γ production, while alternative activation, induced by interleukin 4, is characterized by increased endocytosis, reduced secretion of pro-inflammatory cytokines, and roles in immunoregulation and tissue remodeling. Although these represent opposite extremes observed in vitro, the remarkable plasticity of macrophages allows for a wide spectrum of activation phenotypes that are complex to characterize experimentally. While the application of omics techniques has resulted in significant advances in the characterization of macrophage polarization, lipidomic studies have received lesser attention. Beyond their role as structural components and energy sources, lipids function as signaling molecules that regulate macrophage activation and polarization, thereby shaping immune responses. This work reviews the interaction between lipid signaling and macrophage polarization, exploring how lipid metabolism influences macrophage phenotype and function. These insights offer potential therapeutic strategies for immune-mediated diseases and inflammation-related disorders, including inflammaging.

Linking macrophage metabolism to function in the tumor microenvironment

Macrophages are present at high frequency in most solid tumor types, and their relative abundance negatively correlates with therapy responses and survival outcomes. Tissue-resident macrophages are highly tuned to integrate tissue niche signals, and multiple factors within the idiosyncratic tumor microenvironment (TME) drive macrophages to polarization states that favor immune suppression, tumor growth and metastasis. These diverse functional states are underpinned by extensive and complex rewiring of tumor-associated macrophage (TAM) metabolism. In this Review, we link distinct and specific macrophage functional states within the TME to major, phenotype-sustaining metabolic programs and discuss the metabolic impact of macrophage-modulating therapeutic interventions.

Theoretical framework and emerging challenges of lipid metabolism in cancer

Elevated lipid metabolism is one of hallmarks of malignant tumors. Lipids not only serve as essential structural components of biological membranes but also provide energy and substrates for the proliferation of cancer cells and tumor growth. Cancer cells meet their lipid needs by coordinating the processes of lipid absorption, synthesis, transport, storage, and catabolism. As research in this area continues to deepen, numerous new discoveries have emerged, making it crucial for scientists to stay informed about the developments of cancer lipid metabolism. In this review, we first discuss relevant concepts and theories or assumptions that help us understand the lipid metabolism and -based cancer therapies. We then systematically summarize the latest advancements in lipid metabolism including new mechanisms, novel targets, and up-to-date pre-clinical and clinical investigations of anti-cancer treatment with lipid metabolism targeted drugs. Finally, we emphasize emerging research directions and therapeutic strategies, and discuss future prospective and emerging challenges. This review aims to provide the latest insights and guidance for research in the field of cancer lipid metabolism.

Anti-Inflammatory and Antioxidant Effects of Gundelia tournefortii Aqueous Extract on the Liver and Kidney of PCOS Mice

BACKGROUND

Polycystic Ovarian Syndrome (PCOS) is an endocrine disorder associated with increased risk of kidney and liver damage. Current treatments have shown contradictory outcomes, and their long-term use causes unwanted side effects. G. tournefortii could serve as a complementary medicine to current PCOS treatments.

PURPOSE

This study evaluates the effect of G. tournefortii in alleviating liver and kidney damage induced by PCOS via the regulation of oxidative stress pathways.

STUDY DESIGN

PCOS was induced in female Balb/c mice using dehydroepiandrosterone over 21 days. They included a Sham group, a Vehicle group, a group treated with the extract only, and an untreated PCOS mice group. Positive Controls were treated with Metformin. The other PCOS groups were either co-treated while inducing PCOS or treated with the extract post-disease induction.

METHODS

Histological analysis was performed. Serum liver and kidney biochemical markers, levels of oxidative stress, and two pro-inflammatory markers were measured. NLRP3 and its associated genes (caspase-1 and ASC) gene expression was assessed.

RESULTS

The extract restored normal kidney and liver histology post-PCOS induction. It decreased ALT and AST levels by 50% and the oxidant marker malondialdehyde (MDA) by 65% (P < .05). Superoxide dismutase (SOD)/catalase (CAT) activities were normalized in PCOS treated group. IL-1β/TNF-α significantly decreased (80% and 68%, respectively, P < .05) in the post-treated group. NLRP3 genes decreased in kidney tissues post-treatment with G. tournefortii extract.

CONCLUSION

G. tournefortii reduced oxidative stress by modifying the ASC/caspase-1/IL-1β signaling pathway, thus protecting livers and kidneys highlighting the herb as a potential preventative and complementary agent in mitigating PCOS associated damage.

Anti-lung cancer synergy of low-dose doxorubicin and PD-L1 blocker co-delivered via mild photothermia-responsive black phosphorus

We have previously identified a latent interaction mechanism between non-small cell lung cancer cells (NSCLCC) and their associated macrophages (TAM) mediated by mutual paracrine activation of the HMGB1/RAGE/NF-κB signaling. Activation of this mechanism results in TAM stimulation and PD-L1 upregulation in the NSCLCC. In the present work, we found that free DOX at a low concentration that does not cause DNA damage could activate the HMGB1/RAGE/NF-κB/PD-L1 pathway byinducing oxidative stress. It was thus proposed that a combination of low-dose DOX and a PD-L1 blocker delivered in the NSCLC tumor would achieve synergistic TAM stimulation and thereby synergetic anti-tumor potency. To prove this idea, DOX and BMS-202 (a PD-L1 blocker) were loaded to black phosphorus (BP) nanoparticles after dosage titration to yield the BMS-202/DOX@BP composites that rapidly disintegrated and released drug cargo upon mild photothermal heating at 40 °C. In vitro experiments then demonstrated that low-dose DOX and BMS-202 delivered via BMS-202/DOX@BP under mild photothermia displayed enhanced tumor cell toxicity with a potent synergism only in the presence of TAM. This enhanced synergism was due to an anti-tumor M1-like TAM phenotype that was synergistically induced by low dose DOX plus BMS-202 only in the presence of the tumor cells, indicating the damaged tumor cells to be the cardinal contributor to the M1-like TAM stimulation. In vivo, BMS-202/DOX@BP under mild photothermia exhibited targeted delivery to NSCLC graft tumors in mice and synergistic anti-tumor efficacy of delivered DOX and BMS-202. In conclusion, low-dose DOX in combination with a PD-L1 blocker is an effective strategy to turn TAM against their host tumor cells exploiting the HMGB1/RAGE/NF-κB/PD-L1 pathway. The synergetic actions involved highlight the value of TAM and the significance of modulating tumor cell-TAM cross-talk in tumor therapy. Photothermia-responsive BP provides an efficient platform to translate this strategy into targeted, efficacious tumor therapy.

The Role of Innate Priming in Modifying Tumor-associated Macrophage Phenotype

Tumor-associated macrophages (TAMs) are innate immune cells that exert far reaching influence over the tumor microenvironment (TME). Depending on cues within the local environment, TAMs may promote tumor angiogenesis, cancer cell invasion and immunosuppression, or, alternatively, inhibit tumor progression via neoantigen presentation, tumoricidal reactive oxygen species generation and pro-inflammatory cytokine secretion. Therefore, TAMs have a pivotal role in determining tumor progression and response to therapy. TAM phenotypes are driven by cytokines and physical cues produced by tumor cells, adipocytes, fibroblasts, pericytes, immune cells, and other cells within the TME. Research has shown that TAMs can be primed by environmental stimuli, adding another layer of complexity to the environmental context that determines TAM phenotype. Innate priming is a functional consequence of metabolic and epigenetic reprogramming of innate cells by a primary stimulant, resulting in altered cellular response to future secondary stimulation. Innate priming offers a novel target for development of cancer immunotherapy and improved prognosis of disease, but also raises the risk of exacerbating existing inflammatory pathologies. This review will discuss the mechanisms underlying innate priming including metabolic and epigenetic modification, its relevance to TAMs and tumor progression, and possible clinical implications for cancer treatment.

Metabolism and macrophages in the tumor microenvironment

Tumor-associated macrophages (TAMs) constitute the primary subset of immune cells within the tumor microenvironment (TME). Exhibiting both phenotypic and functional heterogeneity, TAMs play distinct roles in tumor initiation, progression, and responses to therapy in patients with cancer. In response to various immune and metabolic cues within the TME, TAMs dynamically alter their metabolic profiles to adapt. Changes in glucose, amino acid, and lipid metabolism in TAMs, as well as their interaction with oncometabolites, not only sustain their energy demands but also influence their impact on tumor immune responses. Understanding the molecular mechanisms underlying the metabolic reprogramming of TAMs and their orchestration of metabolic processes can offer insights for the development of novel cancer immunotherapies targeting TAMs. Here, we discuss how metabolism reprograms macrophages in the TME and review clinical trials aiming to normalize metabolic alterations in TAMs and alleviate TAM-mediated immune suppression and protumor activity.

Egfl6 promotes ovarian cancer progression by enhancing the immunosuppressive functions of tumor-associated myeloid cells

Tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) play a critical role in resistance to immunotherapy. In this study, we identified epidermal growth factor-like 6 (Egfl6) as a regulator of myeloid cell functions. Our analyses indicated that Egfl6, via binding with β3 integrins and activation of p38 and SYK signaling, acts as a chemotactic factor for myeloid cell migration and promotes their differentiation toward an immunosuppressive state. In syngeneic mouse models of ovarian cancer (OvCa), tumor expression of Egfl6 increased the intratumoral accumulation of polymorphonuclear (PMN) MDSCs and TAMs and their expression of immunosuppressive factors, including CXCL2, IL-10, and PD-L1. Consistent with this, in an immune 'hot' tumor model, Egfl6 expression eliminated response to anti-PD-L1 therapy, while Egfl6 neutralizing antibody decreased the accumulation of tumor-infiltrating CD206+ TAMs and PMN-MDSCs and restored the efficacy of anti-PD-L1 therapy. Supporting a role in human tumors, in human OvCa tissue samples, areas of high EGFL6 expression colocalized with myeloid cell infiltration. scRNA-Seq analyses revealed a correlation between EGFL6 and immune cell expression of immunosuppressive factors. Our data provide mechanistic insights into the oncoimmunologic functions of EGFL6 in mediating tumor immune suppression and identified EGFL6 as a potential therapeutic target to enhance immunotherapy in patients with OvCa.

Myeloid-Derived Suppressor Cells in Bladder Cancer: An Emerging Target

Bladder cancer remains a prevalent and challenging malignancy. Myeloid-derived suppressor cells (MDSCs) have emerged as key contributors to the immunosuppressive tumor microenvironment, facilitating tumor progression, immune evasion, and resistance to therapies. This review explores the role of MDSC in bladder cancer, highlighting their involvement in immune regulation; tumor progression; and resistance to therapies such as bacillus Calmette-Guérin (BCG) therapy, chemotherapy, and immune checkpoint inhibitors (ICIs). We also discuss their potential as biomarkers and therapeutic targets, with current evidence suggesting that targeting MDSCs, either alone or in combination with existing treatments such as BCG and ICIs, may enhance anti-tumor immunity and improve clinical outcomes. However,, challenges remain, particularly regarding the identification and therapeutic modulation of MDSC subpopulations. Further research is warranted to fully elucidate their role in bladder cancer and to optimize MDSC-targeted therapies.

The DLEU2/miR-15a/miR-16-1 cluster shapes the immune microenvironment of chronic lymphocytic leukemia

The development and progression of chronic lymphocytic leukemia (CLL) depend on genetic abnormalities and on the immunosuppressive microenvironment. We have explored the possibility that genetic drivers might be responsible for the immune cell dysregulation that shapes the protumor microenvironment. We performed a transcriptome analysis of coding and non-coding RNAs (ncRNAs) during leukemia progression in the Rag2-/-γc-/- MEC1-based xenotransplantation model. The DLEU2/miR-16 locus was found downmodulated in monocytes/macrophages of leukemic mice. To validate the role of this cluster in the tumor immune microenvironment, we generated a mouse model that simultaneously mimics the overexpression of hTCL1 and the germline deletion of the minimal deleted region (MDR) encoding the DLEU2/miR-15a/miR-16-1 cluster. This model provides an innovative and faster CLL system where monocyte differentiation and macrophage polarization are exacerbated, and T-cells are dysfunctional. MDR deletion inversely correlates with the levels of predicted target proteins including BCL2 and PD1/PD-L1 on murine CLL cells and immune cells. The inverse correlation of miR-15a/miR-16-1 with target proteins has been confirmed on patient-derived immune cells. Forced expression of miR-16-1 interferes with monocyte differentiation into tumor-associated macrophages, indicating that selected ncRNAs drive the protumor phenotype of non-malignant immune cells.

NitraTh epitope-based neoantigen vaccines for effective tumor immunotherapy

Neoantigen vaccines represent an emerging and promising strategy in the field of tumor immunotherapy. Despite their potential, designing an effective neoantigen vaccine remains a challenge due to the current limitations in predicting CD4+ T cell epitopes with high accuracy. Here, we introduce a novel approach to neoantigen vaccine design that does not rely on computational prediction of CD4+ T cell epitopes. Utilizing nitrated helper T cell epitope containing p-nitrophenylalanine, termed "NitraTh epitope," we have successfully engineered a series of tumor neoantigen vaccines capable of eliciting robust neoantigen-specific immune responses. With the help of NitraTh epitope, even mutations with low predicted affinity for MHC class I molecules were successfully induced to elicit neoantigen-specific responses. In H22 cell allograft and patient-derived xenograft (PDX) liver cancer mouse models, the NitraTh epitope-based neoantigen vaccines significantly suppressed tumor progression. More strikingly, through single-cell sequencing we found that the NitraTh epitope-based neoantigen vaccines regulate macrophage reprogramming and modulate macrophages to decrease the levels of the immunosuppressive molecule prostaglandin E2 (PGE2), which in turn reshapes the tumor immunosuppressive microenvironment. In summary, NitraTh epitope-based neoantigen vaccines possess the dual effects of potently activating neoantigen-specific immunity and alleviating immunosuppression, potentially providing a new paradigm for the design of tumor neoantigen vaccines.

A new perspective on the therapeutic potential of tumor metastasis: targeting the metabolic interactions between TAMs and tumor cells

Tumor-associated macrophages (TAMs) undergo metabolic reprogramming, encompassing glucose, amino acid, fatty acid metabolism, tricarboxylic acid (TCA) cycle, purine metabolism, and autophagy, within the tumor microenvironment (TME). The metabolic interdependencies between TAMs and tumor cells critically influence macrophage recruitment, differentiation, M2 polarization, and secretion of epithelial-mesenchymal transition (EMT)-related factors, thereby activating intratumoral EMT pathways and enhancing tumor cell invasion and metastasis. Tumor cell metabolic alterations, including hypoxia, metabolite secretion, aerobic metabolism, and autophagy, affect the TME's metabolic landscape, driving macrophage recruitment, differentiation, M2 polarization, and metabolic reprogramming, ultimately facilitating EMT, invasion, and metastasis. Additionally, macrophages can induce tumor cell EMT by reprogramming their aerobic glycolysis. Recent experimental and clinical studies have focused on the metabolic interactions between macrophages and tumor cells to control metastasis and inhibit tumor progression. This review highlights the regulatory role of TAM-tumor cell metabolic codependencies in EMT, offering valuable insights for TAM-targeted therapies in highly metastatic tumors. Modulating the metabolic interplay between tumors and TAMs represents a promising therapeutic strategy for treating patients with metastatic cancers.

Tumor-associated macrophages within the immunological milieu: An emerging focal point for therapeutic intervention

Tumor-associated macrophages play an important role in the tumor immune microenvironment, and regulating the function of tumor-associated macrophages has important therapeutic potential in tumor therapy. Mature macrophages could migrate to the tumor microenvironment, influencing multiple factors such as tumor cell proliferation, invasion, metastasis, extracellular matrix remodeling, immune suppression, and drug resistance. As a major component of the tumor microenvironment, tumor-associated macrophages crosstalk with other immune cells. Currently, tumor-associated macrophages have garnered considerable attention in tumor therapy, broadening the spectrum of drug selection to some extent, thereby aiding in mitigating the prevailing clinical drug resistance dilemma. This article summarizes the recent advances in tumor-associated macrophages concerning immunology, drug targeting mechanisms for tumor-associated macrophages treatment, new developments, and existing challenges, offering insights for future therapeutic approaches. In addition, this paper summarized the impact of tumor-associated macrophages on current clinical therapies, discussed the advantages and disadvantages of targeted tumor-associated macrophages therapy compared with existing tumor therapies, and predicted and discussed the future role of targeted tumor-associated macrophages therapy and the issues that need to be focused on.

Disruption of the PGE2 synthesis / response pathway restrains atherogenesis in programmed cell death-1 (Pd-1) deficient hyperlipidemic mice

Immune checkpoint inhibitors (ICIs) that target programmed cell death 1 (PD-1) have revolutionized cancer treatment by enabling the restoration of suppressed T-cell cytotoxic responses. However, resistance to single-agent ICIs limits their clinical utility. Combinatorial strategies enhance their antitumor effects, but may also enhance the risk of immune related adverse effects of ICIs. Prostaglandin (PG) E2, formed by the sequential action of the cyclooxygenase (COX) and microsomal PGE synthase (mPGES-1) enzymes, acting via its E prostanoid (EP) receptors, EPr2 and EPr4, promotes lymphocyte exhaustion, revealing an additional target for ICIs. Thus, COX inhibitors and EPr4 antagonists are currently being combined with ICIs potentially to enhance antitumor efficacy in clinical trials. However, given the cardiovascular (CV) toxicity of COX inhibitors, such combinations may increase the risk particularly of CV AEs. Here, we compared the impact of distinct approaches to disruption of the PGE2 synthesis /response pathway - global or myeloid cell specific depletion of mPges-1 or global depletion of Epr4 - on the accelerated atherogenesis in Pd-1 deficient hyperlipidemic (Ldlr-/-) mice. All strategies restrained the atherogenesis. While depletion of mPGES-1 suppresses PGE2 biosynthesis, reflected by its major urinary metabolite, PGE2 biosynthesis was increased in mice lacking EPr4, consistent with enhanced expression of aortic Cox-1 and mPges-1. Deletions of mPges-1 and Epr4 differed in their effects on immune cell populations in atherosclerotic plaques; the former reduced neutrophil infiltration, while the latter restrained macrophages and increased the infiltration of T-cells. Consistent with these findings, chemotaxis by bone-marrow derived macrophages from Epr4-/- mice was impaired. Epr4 depletion also resulted in extramedullary lymphoid hematopoiesis and inhibition of lipoprotein lipase activity (LPL) with coincident spelenomegaly, leukocytosis and dyslipidemia. Targeting either mPGES-1 or EPr4 may restrain lymphocyte exhaustion while mitigating CV irAEs consequent to PD-1 blockade.

Immunomodulatory signalling networks in glioblastoma multiforme: a comprehensive review of therapeutic approaches

Glioblastoma multiforme is a very aggressive type of cancer with high mortality and poor prognosis worldwide. Advanced treatment options with an understanding of the molecules and signalling mechanisms involved in this type of cancer have the potential to increase targeted therapy and decrease off-target effects, resistance, and recurrence. Glioblastoma multiforme (GBM) presents a complex tumour microenvironment with numerous cellular components and an extracellular matrix comprising multiple components. A deeper understanding of these components and corresponding signalling pathways can increase the success of immune checkpoint inhibitors in the treatment of GBM. The discovery of specific molecular changes and biomarkers has led to the investigation of tailored treatments for individual patients. Combination therapies targeting multiple pathways or utilizing different modalities are emerging as a promising strategy albeit with challenges in drug delivery to the brain. The review presents a comprehensive update of the various immunomodulatory signalling networks in GBM and highlights the corresponding therapeutic approaches by targeting them.

The role of metabolic reprogramming in immune escape of triple-negative breast cancer

Triple-negative breast cancer (TNBC) has become a thorny problem in the treatment of breast cancer because of its high invasiveness, metastasis and recurrence. Although immunotherapy has made important progress in TNBC, immune escape caused by many factors, especially metabolic reprogramming, is still the bottleneck of TNBC immunotherapy. Regrettably, the mechanisms responsible for immune escape remain poorly understood. Exploring the mechanism of TNBC immune escape at the metabolic level provides a target and direction for follow-up targeting or immunotherapy. In this review, we focus on the mechanism that TNBC affects immune cells and interstitial cells through hypoxia, glucose metabolism, lipid metabolism and amino acid metabolism, and changes tumor metabolism and tumor microenvironment. This will help to find new targets and strategies for TNBC immunotherapy.

A Self-Delivery Nanodrug Simultaneously Inhibits COX-2/PGE2 Mediated Inflammation and Downregulates PD-L1 to Boost Photoimmunotherapy

Phototherapy promotes anti-tumor immunity by inducing immunogenic cell death (ICD), However, the accompanying inflammatory responses also trigger immunosuppression, attenuating the efficacy of photo-immunotherapy. Herein, they co-assembled a cell-membrane targeting chimeric peptide C16-Cypate-RRKK-PEG8-COOH (CCP) and anti-inflammatory diclofenac (DA) to develop a nanodrug (CCP@DA) that both enhances the immune effect of phototherapy and weakens the inflammation-mediated immunosuppression. CCP@DA achieves cell membrane-targeting photodynamic and photothermal synergistic therapies to damage programmed death ligand 1 (PD-L1) and induce a strong ICD to activate anti-tumor response. Simultaneously, the released DA inhibits the cycoperoxidase-2 (COX-2)/prostaglandin E2 (PGE2) pathway in tumor cells to inhibit pro-tumor inflammation and further down-regulate PD-L1 expression to relieve the immunosuppressive microenvironment. CCP@DA significantly inhibited tumor growth and inflammation both in vitro and in vivo, while maintaining a potent anti-tumor immune response. Additionally, it exhibits excellent anti-metastatic capabilities and prolongs mouse survival time with a single dose and low levels of near-infrared (NIR) light exposure. This work provides a valuable strategy to control the therapy-induced inflammation for high-efficiency photoimmunotherapy.

miR-122-3p targets UBE2I to regulate the immunosuppression of liver cancer and the intervention of Liujunzi formula

ETHNOPHARMACOLOGICAL RELEVANCE

Liujunzi formula has been used to treat liver cancer in China for many years, but its underlying mechanism remains unclear. We previously found that decreased expression of miR-122-3p was associated with liver cancer. In this study, we aimed to explore the target of miR-122-3p and the effect of the Liujunzi formula on miR-122-3p and its downstream events in liver cancer.

MATERIAL AND METHODS

Bioinformatics pinpointed potential targets of miR-122-3p. The actual target was confirmed by miRNA mimic/inhibitor transfections and a dual-luciferase reporter assay. RNA-seq looked at downstream genes impacted by this target. Flow cytometry checked for changes in T cell apoptosis levels after exposing them to liver cancer cells. Gene expression was measured by RT-qPCR, western blotting, and immunofluorescence staining.

RESULTS

Cell experiments found the Liujunzi extract (LJZ) upregulated miR-122-3p and in a dose-dependent manner. Bioinformatics analysis found UBE2I was a potential target of miR-122-3p, which was validated through experiments using miRNA mimics/inhibitors and a dual-luciferase reporter assay. RNA-seq data implicated the NF-κB pathway as being downstream of the miR-122-3p/UBE2I axis, further confirmed by forcing overexpression of UBE2I. Bioinformatic evidence suggested a link between UBE2I and T cell infiltration in liver cancer. Given that the NF-κB pathway drives PD-L1 expression, which can inhibit T cell infiltration, we investigated whether PD-L1 is a downstream effector of miR-122-3p/UBE2I. This was corroborated through mining public databases, UBE2I overexpression studies, and tumor-T cell co-culture assays. In addition, we also confirmed that LJZ downregulates UBE2I and NF-κB/PD-L1 pathways through miR-122-3p. LJZ also suppressed SUMOylation in liver cancer cells and protected PD-1+ T cells from apoptosis induced by co-culture with tumor cells. Strikingly, a miR-122-3p inhibitor abrogated LJZ's effects on UBE2I and PD-L1, and UBE2I overexpression rescued the LJZ-mediated effects on NF-κB and PD-L1.

CONCLUSIONS

miR-122-3p targets UBE2I, thereby suppressing the NF-κB signaling cascade and downregulating PD-L1 expression, which potentiates anti-tumor immune responses. LJZ bolsters anti-tumor immunity by modulating the miR-122-3p/UBE2I/NF-κB/PD-L1 axis in liver cancer cells.

A review concerning the breast cancer-related tumour microenvironment

Breast cancer (BC) is currently the most common malignant tumour in women and one of the leading causes of their death around the world. New and increasingly personalised diagnostic and therapeutic tools have been introduced over the last few decades, along with significant advances regarding the study and knowledge related to BC. The tumour microenvironment (TME) refers to the tumour cell-associated cellular and molecular environment which can influence conditions affecting tumour development and progression. The TME is composed of immune cells, stromal cells, extracellular matrix (ECM) and signalling molecules secreted by these different cell types. Ever deeper understanding of TME composition changes during tumour development and progression will enable new and more innovative therapeutic strategies to become developed for targeting tumours during specific stages of its evolution. This review summarises the role of BC-related TME components and their influence on tumour progression and the development of resistance to therapy. In addition, an account on the modifications in BC-related TME components associated with therapy is given, and the completed or ongoing clinical trials related to this topic are presented.

Pexidartinib and Immune Checkpoint Inhibitors Combine to Activate Tumor Immunity in a Murine Colorectal Cancer Model by Depleting M2 Macrophages Differentiated by Cancer-Associated Fibroblasts

Tumor-associated macrophages (TAMs) and cancer-associated fibroblasts (CAFs) are known to play supportive roles in tumor development and progression, but their interactions in colorectal cancer (CRC) remain unclear. Here, we investigated the effects of colon-cancer-derived CAFs on TAM differentiation, migration, and tumor immunity, both in vitro and in vivo. When co-cultured with monocytes, CAFs attracted monocytes and induced their differentiation into M2 macrophages. Immunohistology of surgically resected human CRC specimens and orthotopically transplanted mouse tumors revealed a correlation between numbers of CAFs and numbers of M2 macrophages. In a mouse model of CRC orthotopic transplantation, treatment with an inhibitor of the colony-stimulating factor-1 receptor (PLX3397) depleted M2 macrophages and increased CD8-positive T cells infiltrating the tumor nest. While this treatment had a minor effect on tumor growth, combining PLX3397 with anti-PD-1 antibody significantly reduced tumor growth. RNA-seq following combination therapy showed activation of tumor immunity. In summary, CAFs are involved in the induction and mobilization of M2 macrophage differentiation in the CRC tumor immune microenvironment, and the combination of cancer immunotherapy and PLX3397 may represent a novel therapeutic option for CRC.

Programmed Cell Death Ligand 1 (PD-L1) Immunohistochemical Expression in Advanced Urothelial Bladder Carcinoma: An Updated Review with Clinical and Pathological Implications

The management of advanced bladder carcinoma involves a multidisciplinary approach, but the prognosis remains poor for many patients. The immune system plays a crucial role in this disease, influencing both tumor development and response to treatment, and exploiting the immune system against the tumor can be a valuable strategy to destroy neoplastic cells. This is the biological principle underlying Bacillus Calmette-Guérin (BCG) use and, more recently, immune checkpoint inhibitors (ICIs), like PD-1 (programmed death-1)/PD-L1 (programmed death-ligand 1) inhibitors. In fact, one of the best studied immune checkpoints is represented by the PD-1/PD-L1 axis, which is a well-known immune escape system adopted by neoplastic bladder cells. PD-L1 expression has been associated with a higher pathologic stage and has shown prognostic value in bladder carcinoma. Interestingly, high-grade bladder cancers tend to express higher levels of PD-1 and PD-L1, suggesting a potential role of such an axis in mediating disease progression. Immunotherapy with PD-1 and PD-L1 inhibitors has therefore emerged as a valuable treatment option and has shown efficacy in advanced bladder cancer patients, with high PD-L1 expression levels associated with better treatment responses. Our review aims to provide a comprehensive overview of the role of PD-L1 in advanced bladder cancer, focusing on its implications for treatment decisions and the prediction of treatment response. Overall, our work aims to contribute to the understanding of PD-L1 as a predictive biomarker and highlight its role in shaping therapeutic approaches for advanced bladder cancer.

Tumor-associated macrophages in anti-PD-1/PD-L1 immunotherapy for hepatocellular carcinoma: recent research progress

Hepatocellular carcinoma (HCC) is one of the cancers that seriously threaten human health. Immunotherapy serves as the mainstay of treatment for HCC patients by targeting the programmed cell death protein 1/programmed cell death 1 ligand 1 (PD-1/PD-L1) axis. However, the effectiveness of anti-PD-1/PD-L1 treatment is limited when HCC becomes drug-resistant. Tumor-associated macrophages (TAMs) are an important factor in the negative regulation of PD-1 antibody targeted therapy in the tumor microenvironment (TME). Therefore, as an emerging direction in cancer immunotherapy research for the treatment of HCC, it is crucial to elucidate the correlations and mechanisms between TAMs and PD-1/PD-L1-mediated immune tolerance. This paper summarizes the effects of TAMs on the pathogenesis and progression of HCC and their impact on HCC anti-PD-1/PD-L1 immunotherapy, and further explores current potential therapeutic strategies that target TAMs in HCC, including eliminating TAMs in the TME, inhibiting TAMs recruitment to tumors and functionally repolarizing M2-TAMs (tumor-supportive) to M1-TAMs (antitumor type).

Heterogeneity of myeloid cells in common cancers: Single cell insights and targeting strategies

Tumor microenvironment (TME), is characterized by a complex and heterogenous composition involving a substantial population of immune cells. Myeloid cells comprising over half of the solid tumor mass, are undoubtedly one of the most prominent cell populations associated with tumors. Studies have unambiguously established that myeloid cells play a key role in tumor development, including immune suppression, pro-inflammation, promote tumor metastasis and angiogenesis, for example, tumor-associated macrophages promote tumor progression in a variety of common tumors, including lung cancer, through direct or indirect interactions with the TME. However, due to previous technological constraints, research on myeloid cells often tended to be conducted as studies with low throughput and limited resolution. For example, the conventional categorization of macrophages into M1-like and M2-like subsets based solely on their anti-tumor and pro-tumor roles has disregarded their continuum of states, resulting in an inadequate analysis of the high heterogeneity characterizing myeloid cells. The widespread adoption of single-cell RNA sequencing (scRNA-seq) in tumor immunology has propelled researchers into a new realm of understanding, leading to the establishment of novel subsets and targets. In this review, the origin of myeloid cells in high-incidence cancers, the functions of myeloid cell subsets examined through traditional and single-cell perspectives, as well as specific targeting strategies, are comprehensively outlined. As a result of this endeavor, we will gain a better understanding of myeloid cell heterogeneity, as well as contribute to the development of new therapeutic approaches.

The role of the immunosuppressive PD-1/PD-L1 checkpoint pathway in the aging process and age-related diseases

The accumulation of senescent cells within tissues is a hallmark of the aging process. Senescent cells are also commonly present in many age-related diseases and in the cancer microenvironment. The escape of abnormal cells from immune surveillance indicates that there is some defect in the function of cytotoxic immune cells, e.g., CD8+ T cells and natural killer (NK) cells. Recent studies have revealed that the expression of programmed death-ligand 1 (PD-L1) protein is abundantly increased in senescent cells. An increase in the amount of PD-L1 protein protects senescent cells from clearance by the PD-1 checkpoint receptor in cytotoxic immune cells. In fact, the activation of the PD-1 receptor suppresses the cytotoxic properties of CD8+ T and NK cells, promoting a state of immunosenescence. The inhibitory PD-1/PD-L1 checkpoint pathway acts in cooperation with immunosuppressive cells; for example, activation of PD-1 receptor can enhance the differentiation of regulatory T cells (Treg), myeloid-derived suppressor cells (MDSC), and M2 macrophages, whereas the cytokines secreted by immunosuppressive cells stimulate the expression of the immunosuppressive PD-L1 protein. Interestingly, many signaling pathways known to promote cellular senescence and the aging process are crucial stimulators of the expression of PD-L1 protein, e.g., epigenetic regulation, inflammatory mediators, mTOR-related signaling, cGAS-STING pathway, and AhR signaling. It seems that the inhibitory PD-1/PD-L1 immune checkpoint axis has a crucial role in the accumulation of senescent cells and thus it promotes the aging process in tissues. Thus, the blockade of the PD-1/PD-L1 checkpoint signaling might be a potential anti-aging senolytic therapy. KEY MESSAGES: Senescent cells accumulate within tissues during aging and age-related diseases. Senescent cells are able to escape immune surveillance by cytotoxic immune cells. Expression of programmed death-ligand 1 (PD-L1) markedly increases in senescent cells. Age-related signaling stimulates the expression of PD-L1 protein in senescent cells. Inhibitory PD-1/PD-L1 checkpoint pathway suppresses clearance of senescent cells.

PD-L1 regulates tumor proliferation and T-cell function in NF2-associated meningiomas

INTRODUCTION

Programmed death-ligand 1 (PD-L1) expression is an immune evasion mechanism that has been demonstrated in many tumors and is commonly associated with a poor prognosis. Over the years, anti-PD-L1 agents have gained attention as novel anticancer therapeutics that induce durable tumor regression in numerous malignancies. They may be a new treatment choice for neurofibromatosis type 2 (NF2) patients.

AIMS

The aims of this study were to detect the expression of PD-L1 in NF2-associated meningiomas, explore the effect of PD-L1 downregulation on tumor cell characteristics and T-cell functions, and investigate the possible pathways that regulate PD-L1 expression to further dissect the possible mechanism of immune suppression in NF2 tumors and to provide new treatment options for NF2 patients.

RESULTS

PD-L1 is heterogeneously expressed in NF2-associated meningiomas. After PD-L1 knockdown in NF2-associated meningioma cells, tumor cell proliferation was significantly inhibited, and the apoptosis rate was elevated. When T cells were cocultured with siPD-L1-transfected NF2-associated meningioma cells, the expression of CD69 on both CD4+ and CD8+ T cells was partly reversed, and the capacity of CD8+ T cells to kill siPD-L1-transfected tumor cells was partly restored. Results also showed that the PI3K-AKT-mTOR pathway regulates PD-L1 expression, and the mTOR inhibitor rapamycin rapidly and persistently suppresses PD-L1 expression. In vivo experimental results suggested that anti-PD-L1 antibody may have a synergetic effect with the mTOR inhibitor in reducing tumor cell proliferation and that reduced PD-L1 expression could contribute to antitumor efficacy.

CONCLUSIONS

Targeting PD-L1 could be helpful for restoring the function of tumor-infiltrating lymphocytes and inducing apoptosis to inhibit tumor proliferation in NF2-associated meningiomas. Dissecting the mechanisms of the PD-L1-driven tumorigenesis of NF2-associated meningioma will help to improve our understanding of the mechanisms underlying tumor progression and could facilitate further refinement of current therapies to improve the treatment of NF2 patients.

Multi-omics analysis of macrophage-associated receptor and ligand reveals a strong prognostic signature and subtypes in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a significant contributor to morbidity and mortality worldwide. The interaction between receptors and ligands is the primary mode of intercellular signaling and plays a vital role in the progression of HCC. This study aimed to identify the macrophage-related receptor ligand marker genes associated with HCC and further explored the molecular immune mechanisms attributed to altered biomarkers. Single-cell RNA sequencing data containing primary and recurrent samples were downloaded from the China National GeneBank. Cell types were first identified to explore differences between immune cells from different sample sources. CellChat analysis was used to infer and analyze intercellular communication networks quantitatively. Three molecular subtypes were constructed based on the screened twenty macrophage-associated receptor ligand genes. Bulk RNA-Seq data were downloaded from The Cancer Genome Atlas and Gene Expression Omnibus databases. After the screening, the minor absolute shrinkage and selection operator (LASSO) regression model was employed to identify key markers. After collecting peripheral blood and clinical information from patients, an enzyme-linked immunosorbent assay (ELISA) was used to detect the correlation between key markers and IL-10, one of the macrophage markers. After developing a new HCC risk adjustment model and conducting analysis, it was found that there were significant differences in immune status and gene mutations between the high-risk and low-risk groups of patients based on macrophage-associated receptor and ligand genes. This study identified SPP1, ANGPT2, and NCL as key biological targets for HCC. The drug-gene interaction network analysis identified wortmannin, ribavirin, and tarnafloxin as potential therapeutic drugs for the three key markers. In a clinical cohort study, patients with immune checkpoint inhibitor (ICI) resistance had significantly higher expression levels of OPN, ANGPT2, NCL, and IL-10 than patients with ICI-responsiveness. These three key markers were positively correlated with the expression level of IL-10. The signature based on macrophage-associated receptor and ligand genes can accurately predict the prognosis of patients with HCC and the sensitivity to immunotherapy. These results may help guide the development of targeted prevention and personalized treatment of HCC.

Understanding the immunosuppressive microenvironment of glioma: mechanistic insights and clinical perspectives

Glioblastoma (GBM), the predominant and primary malignant intracranial tumor, poses a formidable challenge due to its immunosuppressive microenvironment, thereby confounding conventional therapeutic interventions. Despite the established treatment regimen comprising surgical intervention, radiotherapy, temozolomide administration, and the exploration of emerging modalities such as immunotherapy and integration of medicine and engineering technology therapy, the efficacy of these approaches remains constrained, resulting in suboptimal prognostic outcomes. In recent years, intensive scrutiny of the inhibitory and immunosuppressive milieu within GBM has underscored the significance of cellular constituents of the GBM microenvironment and their interactions with malignant cells and neurons. Novel immune and targeted therapy strategies have emerged, offering promising avenues for advancing GBM treatment. One pivotal mechanism orchestrating immunosuppression in GBM involves the aggregation of myeloid-derived suppressor cells (MDSCs), glioma-associated macrophage/microglia (GAM), and regulatory T cells (Tregs). Among these, MDSCs, though constituting a minority (4-8%) of CD45+ cells in GBM, play a central component in fostering immune evasion and propelling tumor progression, angiogenesis, invasion, and metastasis. MDSCs deploy intricate immunosuppressive mechanisms that adapt to the dynamic tumor microenvironment (TME). Understanding the interplay between GBM and MDSCs provides a compelling basis for therapeutic interventions. This review seeks to elucidate the immune regulatory mechanisms inherent in the GBM microenvironment, explore existing therapeutic targets, and consolidate recent insights into MDSC induction and their contribution to GBM immunosuppression. Additionally, the review comprehensively surveys ongoing clinical trials and potential treatment strategies, envisioning a future where targeting MDSCs could reshape the immune landscape of GBM. Through the synergistic integration of immunotherapy with other therapeutic modalities, this approach can establish a multidisciplinary, multi-target paradigm, ultimately improving the prognosis and quality of life in patients with GBM.

Breaking Barriers: Modulation of Tumor Microenvironment to Enhance Bacillus Calmette-Guérin Immunotherapy of Bladder Cancer

The clinical management of bladder cancer continues to present significant challenges. Bacillus Calmette-Guérin (BCG) immunotherapy remains the gold standard of treatment for non-muscle invasive bladder cancer (NMIBC), but many patients develop recurrence and progression to muscle-invasive disease (MIBC), which is resistant to BCG. This review focuses on the immune mechanisms mobilized by BCG in bladder cancer tumor microenvironments (TME), mechanisms of BCG resistance, the dual role of the BCG-triggered NFkB/TNFα/PGE2 axis in the regulation of anti-tumor and tumor-promoting aspects of inflammation, and emerging strategies to modulate their balance. A better understanding of BCG resistance will help develop new treatments and predictive biomarkers, paving the way for improved clinical outcomes in bladder cancer patients.