Hedgehog signaling regulates metabolism and polarization of mammary tumor-associated macrophages

MACC1 is a potential prognostic biomarker for cancer immunotherapy in lung adenocarcinoma

Our team previously reported that MACC1 levels are closely related to a variety of tumors and the efficacy of immune checkpoint blockade (ICB) therapy. However, the predictive value of MACC1 levels for lung adenocarcinoma (LUAD) immunotherapy has not been studied. This study aimed to investigate the predictive effect of the oncogene MACC1 on ICB reactivity in patients with LUAD. First, the expression patterns and clinical features of MACC1 in The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases were comprehensively evaluated using R packages. We subsequently assessed the correlations between MACC1 and immunological characteristics in the LUAD tumor microenvironment (TME) using the CIBERSORT algorithm. The results revealed that MACC1 overexpression was significantly correlated with 3 immune checkpoints, 14 tumor-infiltrating immune cells (TIICs), 9 immunomodulators, 5 anticancer immune process activities, and 3 effector genes of TIICs in LUAD. Additionally, on the basis of the prognostic genes from LASSO analysis, we developed the MACC1-related Risk Score (MRRS), which can accurately predict the prognosis and response to cancer immunotherapy in LUAD patients (HR = 3.50, AUC at 1, 2, and 3 years = 0.737, 0.744, and 0.724, respectively). Finally, in vivo experiments revealed that the combination of MACC1 silencing and PD-L1 inhibitors significantly inhibits tumor progression. These findings increase our understanding of MACC1 as a potential prognostic biomarker and potential therapeutic target for cancer immunotherapy. The MRRS may play a critical role in predicting the response of LUAD patients to ICB therapy.

Metabolic reprogramming shapes post-translational modification in macrophages

Polarized macrophages undergo metabolic reprogramming, as well as extensive epigenetic and post-translational modifications (PTMs) switch. Metabolic remodeling and dynamic changes of PTMs lead to timely macrophage response to infection or antigenic stimulation, as well as its transition from a pro-inflammatory to a reparative phenotype. The transformation of metabolites in the microenvironment also determines the PTMs of macrophages. Here we reviewed the current understanding of the altered metabolites of glucose, lipids and amino acids in macrophages shape signaling and metabolism pathway during macrophage polarization via PTMs, and how these metabolites in some macrophage-associated diseases affect disease progression by shaping macrophage PTMs.

Myeloid cells: key players in tumor microenvironments

Cancer is the result of evolving crosstalk between neoplastic cell and its immune microenvironment. In recent years, immune therapeutics targeting T lymphocytes, such as immune checkpoint blockade (ICB) and CAR-T, have made significant progress in cancer treatment and validated targeting immune cells as a promising approach to fight human cancers. However, responsiveness to the current immune therapeutic agents is limited to only a small proportion of solid cancer patients. As major components of most solid tumors, myeloid cells played critical roles in regulating the initiation and sustentation of adaptive immunity, thus determining tumor progression as well as therapeutic responses. In this review, we discuss emerging data on the diverse functions of myeloid cells in tumor progression through their direct effects or interactions with other immune cells. We explain how different metabolic reprogramming impacts the characteristics and functions of tumor myeloid cells, and discuss recent progress in revealing different mechanisms-chemotaxis, proliferation, survival, and alternative sources-involved in the infiltration and accumulation of myeloid cells within tumors. Further understanding of the function and regulation of myeloid cells is important for the development of novel strategies for therapeutic exploitation in cancer.

Myeloid cells are involved in tumor immunity, metastasis and metabolism in tumor microenvironment

Bone marrow-derived cells in the tumor microenvironment, including macrophages, neutrophils, dendritic cells, myeloid-derived suppressor cells, eosinophils and basophils, participate in the generation, development, invasion and metastasis of tumors by producing different cytokines and interacting with other cell types, and play a pro-tumor or anti-tumor role in regulating tumor immunity. Due to the complexity of cell types in the tumor microenvironment and the unknown process of tumor development and metastasis, cancer treatment to achieve better survival status remains challenging. In this article, we summarize the effects of myeloid cells in tumor microenvironment on tumor immunity, cancer migration, and crosstalk with metabolism (including glucose metabolism, lipid metabolism, and amino acid metabolism), which will help to further study the tumor microenvironment and seek targeted therapeutic strategies for patients.

O-GlcNAcylation in Gli1+ Mesenchymal Stem Cells Is Indispensable for Bone Formation and Fracture Healing

Adult mesenchymal stem cells (MSCs) play a crucial role in maintaining bone health and promoting regeneration. In our previous research, we identified Gli1+ MSCs as key contributors to the formation of most trabecular bone in adulthood and as essential for healing bicortical fractures. However, the mechanisms behind the maintenance and differentiation of Gli1+ MSCs are still not fully understood. O-linked N-acetylglucosamine modification (O-GlcNAcylation), mediated by O-GlcNAc glycosyltransferase (OGT), is involved in various biological processes and diseases. Our earlier work also demonstrated that O-GlcNAcylation is necessary for Wnt-stimulated bone formation. Nonetheless, the specific functions of O-GlcNAcylation in MSCs have not been completely elucidated. In this study, we found that the absence of OGT in Gli1+ MSCs led to a decrease in O-GlcNAcylation, which impaired both the bone formation and regeneration following fractures. Mechanistically, the Hedgehog signaling pathway induced O-GlcNAcylation through the insulin-like growth factor (Igf)-mTORC2 axis. This process stabilized the Gli2 protein at a specific site Ser355 and promoted osteogenesis in MSCs in vitro. Our findings reveal a significant mechanism by which O-GlcNAcylation regulates bone development and repair in mammals.

From silent partners to potential therapeutic targets: macrophages in colorectal cancer

Cancer cells grow and survive in the tumor microenvironment, which is a complicated process. As a key part of how colorectal cancer (CRC) progresses, tumor-associated macrophages (TAMs) exhibit a double role. Through angiogenesis, this TAM can promote the growth of cancers. Although being able to modify and adjust immune cells is a great advantage, these cells can also exhibit anti-cancer properties including direct killing of cancer cells, presenting antigens, and aiding T cell-mediated responses. The delicate regulatory mechanisms between the immune system and tumors are composed of a complex network of pathways regulated by several factors including hypoxia, metabolic reprogramming, cytokine/chemokine signaling, and cell interactions. Decoding and figuring out these complex systems become significant in building targeted treatment programs. Targeting TAMs in CRC involves disrupting chemokine signaling or adhesion molecules, reprogramming them to an anti-tumor phenotype using TLR agonists, CD40 agonists, or metabolic modulation, and selectively removing TAM subsets that promote tumor growth. Multi-drug resistance, the absence of an accurate biomarker, and drug non-specificity are also major problems. Combining macrophage-targeted therapies with chemotherapy and immunotherapy may revolutionize treatment. Macrophage studies will advance with new technology and multi-omics methodologies to help us understand CRC and build specific and efficient treatments.

Implications and mechanisms of O-GlcNAcylation in cancer therapy resistance

O-linked-N-acetylglucosaminylation (O-GlcNAcylation), one of the protein post-translational modifications, is the process of adding O-linked-β-D-N-acetylglucosaminylation (O-GlcNAc) to serine and threonine residues of proteins. O-GlcNAcylation regulates various fundamental cell biological processes, including gene transcription, signal transduction, and cellular metabolism. The role of dysregulated O-GlcNAcylation in tumorigenesis has been recognized, but its role in cancer therapy tolerance has not been elucidated. Therefore, this paper provides the latest evidence on the role of O-GlcNAcylation in cancer therapy responsiveness to understand the impact of O-GlcNAcylation on cancer therapy outcomes, as well as analyzing several possible mechanisms by which O-GlcNAcylation dysregulation affects cancer therapy efficacy, and discusses the possibility of O-GlcNAcylation as a cancer therapy sensitizer.

Targeting lipid metabolism of macrophages: A new strategy for tumor therapy

BACKGROUND

Lipid metabolism has been implicated in a variety of normal cellular processes and strongly related to the development of multiple diseases, including tumor. Tumor-associated macrophage (TAM) has emerged as a crucial regulator in tumorigenesis and promising target for tumor treatment.

AIM OF REVIEW

A thorough understanding of TAM lipid metabolism and its value in tumorigenesis may provide new ideas for TAM-based anti-tumor therapy. Key scientific concepts of review: TAMs can be divided into two main types, M1-like TAMs and M2-like TAMs, which play anti-tumor and pro-tumor functions in tumor occurrence and development, respectively. Accumulating evidence has shown that lipid metabolic reprogramming, including fatty acid uptake and utilization, cholesterol expulsion, controls the polarization of TAMs and affects the tumorgenesis. These advances in uncovering the intricacies of lipid metabolism and TAMs have yielded new insights on tumor development and treatment. In this review, we aim to provide an update on the current understanding of the lipid metabolic reprogramming made by TAMs to adapt to the harsh tumor microenvironment (TME). In particular, we emphasize that there is complex lipid metabolism connections between TAMs and distinct tumors, which influences TAM to bias from M1 to M2 phenotype in tumor progression, and ultimately promotes tumor occurrence and development. Finally, we discuss the existing issues on therapeutic strategies by reprogramming TAMs based on lipid metabolism regulation (or increasing the ratio of M1/M2-like TAMs) that could be applied in the future to clinical tumor treatment.

The Role of mtDNA Mutations in Atherosclerosis: The Influence of Mitochondrial Dysfunction on Macrophage Polarization

Atherosclerosis is a complex inflammatory process associated with high-mortality cardiovascular diseases. Today, there is a growing body of evidence linking atherosclerosis to mutations of mitochondrial DNA (mtDNA). But the mechanism of this link is insufficiently studied. Atherosclerosis progression involves different cell types and macrophages are one of the most important. Due to their high plasticity, macrophages can demonstrate pro-inflammatory and pro-atherogenic (macrophage type M1) or anti-inflammatory and anti-atherogenic (macrophage type M2) effects. These two cell types, formed as a result of external stimuli, differ significantly in their metabolic profile, which suggests the central role of mitochondria in the implementation of the macrophage polarization route. According to this, we assume that mtDNA mutations causing mitochondrial disturbances can play the role of an internal trigger, leading to the formation of macrophage M1 or M2. This review provides a comparative analysis of the characteristics of mitochondrial function in different types of macrophages and their possible associations with mtDNA mutations linked with inflammation-based pathologies including atherosclerosis.

Acylglycerol kinase inhibits macrophage anti-tumor activity via limiting mtDNA release and cGAS-STING-type I IFN response

Background: Tumor associated macrophages (TAMs) are critical components in regulating the immune statuses of the tumor microenvironments. Although TAM has been intensively studied, it is unclear how mitochondrial proteins such as AGK regulate the TAMs' function. Methods: We investigated the AGK function in TAMs using macrophage-specific Agk deficient mice with B16 and LLC syngeneic tumor models. Flow cytometry was used to evaluate the stemness and activation of CD8+ T cells. The enhanced release of mtDNA into the cytosol in the Agk-deficient BMDMs was measured by RT-PCR and immunofluorescence; the cGAS-STING-type I IFN pathway was evaluated by immunoblotting. Mitochondria functions were evaluated by electron microscope and seahorse equipment. Results: We have noted an increased expression of AGK in TAMs of multiple tumor types, which was negatively correlates with the tumor tissue immune scores. In the B16 and LLC tumor models, macrophage Agk-deficient mice have reduced tumor growth and enhanced populations of CD8+ Tpex. AGK-deficient macrophages have increased mitochondrial damage and mtDNA release into the cytosol, which leads to enhanced cGAS-STING-type I IFN activation. Blockade of the type I IFN signaling pathway with anti-IFNAR reversed the phenotype in Agk-deficient mice. Conclusions: Our findings define a critical role of AGK in maintaining the macrophage mitochondrial homeostasis that is associated with mtDNA release and following cGAS-STING activation and type I IFN pathway. Targeting AGK in TAMs may represent a novel strategy to enhance anti-tumoral activity.

Systemic immune profiling analysis identifying M2-TAM related genes predicted colon cancer prognosis and chemotherapy responses

Colon cancer (COAD) poses great challenges to clinical treatment due to its heterogeneity and complex immune microenvironment. M2-like macrophages significantly influence COAD's onset, progression, and treatment. Yet, existing M2-like macrophage markers are limited in prognostic efficacy, prompting the exploration of new M2 signatures. Extensive data analysis aimed to unveil prognosis-associated M2-derived signatures. Bulk transcriptome, single-cell RNA sequencing, and clinical data from The Cancer Genome Atlas and Gene Expression Omnibus databases for patients with COAD were amassed. Cell-Type Identification by Estimating Relative Subsets of RNA Transcripts identified immune cell infiltration, and the Kaplan-Meier test identified crucial immune populations associated with prognosis. Genetic signatures linked to M2 tumor-associated macrophage were crafted utilizing weighted gene coexpression network analysis, least absolute shrinkage and selection operator, and Cox regression. The M2 tumor-associated macrophage gene signature was validated in GSE17536. The expression profile of the M2 gene signature was investigated in single-cell RNA sequencing dataset GSE166555. Systemic immune profile identified that M2-like macrophage has the most significant prognostic significance in The Cancer Genome Atlas-COAD. The core genes related to M2 macrophage infiltration were extracted by weighted gene coexpression network analysis. Least absolute shrinkage and selection operator-stepwise COX regression-derived M2-derived signatures (snail family zinc finger 1, gastrin-releasing peptide, gamma-aminobutyric acid type A receptor delta subunit, cluster of differentiation 1B, poly(A)-binding protein cytoplasmic 2, manic fringe, and death-associated protein kinase 1) as a risk model, which was confirmed as independent prognosis factors, validated by external dataset. This M2-based prognostic model reflected M2 macrophage infiltration. Mendelian randomization established cytotoxic T lymphocyte associate protein-4 and cluster of differentiation 274 immune checkpoints' causality with COAD. In conclusion, our study developed novel markers for discriminating M2-like macrophages and predicting the prognosis of patients with COAD, offering fresh perspectives for clinical interventions.

Mitochondria in tumor immune surveillance and tumor therapies targeting mitochondria

Mitochondria play a central role in cellular energy production and metabolic regulation, and their function has been identified as a key factor influencing tumor immune responses. This review provides a comprehensive overview of the latest advancements in understanding the role of mitochondria in tumor immune surveillance, covering both innate and adaptive immune responses. Specifically, it outlines how mitochondria influence the function of the tumor immune system, underscoring their crucial role in modulating immune cell behavior to either promote or inhibit tumor development and progression. Additionally, this review highlights emerging drug interventions targeting mitochondria, including novel small molecules with significant potential in cancer therapy. Through an in-depth analysis, it explores how these innovative strategies could improve the efficacy and outlook of tumor treatment.

Regulation of Oxygen in the Tumor Microenvironment Synergizes with Immunotherapy to Suppress Tumor Progression

Hypoxia represents a crucial characteristic of the tumor microenvironment, which is closely related to cell proliferation, angiogenesis, and metabolic responses. These factors will further promote tumor progression, increase tumor invasion, and enhance tumor metastasis potential. A hypoxic microenvironment will also inhibit the activity of infiltrated immune cells in the tumor microenvironment, leading to the failure of cancer immunotherapy. Additionally, the hypoxic tumor microenvironment contributes to resistance to conventional therapies and leads to unfavorable prognoses. This review discusses advancements in strategies aimed at ameliorating tumor hypoxia within the microenvironment and modulating immune cell responses against tumors.

rTM reprograms macrophages via the HIF-1α/METTL3/PFKM axis to protect mice against sepsis

The metabolic reprogramming of macrophages is a potential therapeutic strategy for sepsis treatment, but the mechanism underlying this reprogramming remains unclear. Since glycolysis can drive macrophage phenotype switching, the rate-limiting enzymes in glycolysis may be key to treating sepsis. Here, we found that, compared with other isoenzymes, the expression of 6-phosphofructokinase, muscle type (PFKM) was the most upregulated in monocytes from septic patients. Recombinant thrombomodulin (rTM) treatment downregulated the protein expression of PFKM in macrophages. Both rTM treatment and Pfkm knockout protected mice from sepsis and reduced the production of the proinflammatory cytokines IL-1β, IL-6, TNF-α, and IL-27, whereas PFKM overexpression increased the production of these cytokines. Mechanistically, rTM treatment inhibited glycolysis in macrophages by decreasing PFKM expression in a hypoxia-inducible factor-1α (HIF-1α)-dependent manner. HIF-1α overexpression increased methyltransferase-like 3 (METTL3) expression, elevated the m6A level on Pfkm, and upregulated the protein expression of PFKM. METTL3 silence attenuated HIF-1α-mediated PFKM expression. These findings provide insight into the underlying mechanism of macrophage reprogramming for the treatment of sepsis.

Mechanisms and treatment of atherosclerosis: focus on macrophages

Macrophages are the basic mediators and coordinators of various types of chronic inflammation and play a crucial role in the formation and development of atherosclerosis (AS). In the complex microenvironment of atherosclerotic plaques, macrophages of different sources are exposed to different signal stimuli and thus polarized into various subpopulations. Various types of macrophages with predominantly M1 and M2 phenotypes also play different regulatory roles in the initiation and progression of AS. Lipid-lowering drugs, mainly statins, are widely used in clinical practice, but the adverse reactions are obvious and there is a lack of personalized treatment. Emerging targeted macrophage and Traditional Chinese medicine (TCM)-related therapies can regulate the cellular microenvironment, inhibit the polarization of M1 macrophages, and promote the activation of M2 macrophages, providing new ideas for the prevention and treatment of AS.

Downregulation of short-stature homeobox protein 2 suppresses gastric cancer cell growth and stemness in vitro and in vivo via inactivating wnt/β-catenin signaling

Gastric cancer (GC) a prevalent form of cancer globally. Previous research suggests that SHOX2 may have a role in promoting cancer progression. However, the role of SHOX2 in GC is not well understood. Based on data from TCGA_GC data set, SHXO2 levels were examined in normal and GC tissues. Patients in the TCGA_GC cohort were divided into high- and low-SHOX2 level groups for analysis of overall survival (OS), functional enrichment, and immune infiltration. Furthermore, experiments were conducted to investigate the impact of SHOX2 on GC cell function through gain- and loss-of-function experiments. Utilizing data from public databases, SHOX2 mRNA levels were found to be elevated in GC tissues compared to normal control, this finding was confirmed by RT-qPCR, western blot analysis, and immune-histochemical analyses. Elevated SHOX2 levels could serve as an independent indicator of poor prognosis in GC patients. Furthermore, SHOX2 levels had a negative correlation with CD8 T cells and CD4 memory activated T cells, and a positive correlation with of M0 macrophages in GC patients. Functional analyses revealed that SHOX2 deficiency notably suppressed GC cell proliferation, migration, and invasion. Additionally, SHOX2 deficiency was shown to suppress stemness in GC cells in vitro and in vivo via inactivating wnt/β-catenin signaling. Collectively, SHOX2 may serve as a prognostic marker for GC patients, and downregulation of SHOX2 could effectively impede GC cell growth and stemness by inactivating the wnt/β-catenin signaling pathway. These findings underscore the potential of SHOX2 as a promising therapeutic target for GC.

Research progress of tumor-associated macrophages in immune checkpoint inhibitor tolerance in colorectal cancer

The relevant mechanism of tumor-associated macrophages (TAMs) in the treatment of colorectal cancer patients with immune checkpoint inhibitors (ICIs) is discussed, and the application prospects of TAMs in reversing the treatment tolerance of ICIs are discussed to provide a reference for related studies. As a class of drugs widely used in clinical tumor immunotherapy, ICIs can act on regulatory molecules on cells that play an inhibitory role-immune checkpoints-and kill tumors in the form of an immune response by activating a variety of immune cells in the immune system. The sensitivity of patients with different types of colorectal cancer to ICI treatment varies greatly. The phenotype and function of TAMs in the colorectal cancer microenvironment are closely related to the efficacy of ICIs. ICIs can regulate the phenotypic function of TAMs, and TAMs can also affect the tolerance of colorectal cancer to ICI therapy. TAMs play an important role in ICI resistance, and making full use of this target as a therapeutic strategy is expected to improve the immunotherapy efficacy and prognosis of patients with colorectal cancer.

Metabolic regulation of the immune system in health and diseases: mechanisms and interventions

Metabolism, including glycolysis, oxidative phosphorylation, fatty acid oxidation, and other metabolic pathways, impacts the phenotypes and functions of immune cells. The metabolic regulation of the immune system is important in the pathogenesis and progression of numerous diseases, such as cancers, autoimmune diseases and metabolic diseases. The concept of immunometabolism was introduced over a decade ago to elucidate the intricate interplay between metabolism and immunity. The definition of immunometabolism has expanded from chronic low-grade inflammation in metabolic diseases to metabolic reprogramming of immune cells in various diseases. With immunometabolism being proposed and developed, the metabolic regulation of the immune system can be gradually summarized and becomes more and more clearer. In the context of many diseases including cancer, autoimmune diseases, metabolic diseases, and many other disease, metabolic reprogramming occurs in immune cells inducing proinflammatory or anti-inflammatory effects. The phenotypic and functional changes of immune cells caused by metabolic regulation further affect and development of diseases. Based on experimental results, targeting cellular metabolism of immune cells becomes a promising therapy. In this review, we focus on immune cells to introduce their metabolic pathways and metabolic reprogramming, and summarize how these metabolic pathways affect immune effects in the context of diseases. We thoroughly explore targets and treatments based on immunometabolism in existing studies. The challenges of translating experimental results into clinical applications in the field of immunometabolism are also summarized. We believe that a better understanding of immune regulation in health and diseases will improve the management of most diseases.

Hedgehog pathway and cancer: A new area (Review)

In years of research on classical pathways, the composition, information transmission mechanism, crosstalk with other pathways, and physiological and pathological effects of hedgehog (HH) pathway have been gradually clarified. HH also plays a critical role in tumor formation and development. According to the update of interpretation of tumor phenotypes, the latest relevant studies have been sorted out, to explore the specific mechanism of HH pathway in regulating different tumor phenotypes through gene mutation and signal regulation. The drugs and natural ingredients involved in regulating HH pathway were also reviewed; five approved drugs and drugs under research exert efficacy by blocking HH pathway, and at least 22 natural components have potential to treat tumors by HH pathway. Nevertheless, there is a deficiency of existing studies. The present review confirmed the great potential of HH pathway in future cancer treatment with factual basis.

Peri-Tumoural Lipid Composition and Hypoxia for Early Immune Response to Neoadjuvant Chemotherapy in Breast Cancer

The deregulation of monounsaturated, polyunsaturated, and saturated fatty acids (MUFAs, PUFAs, SFAs) from de novo synthesis and hypoxia are central metabolic features of breast tumour. Early response markers for neoadjuvant chemotherapy (NACT) are critical for stratified treatment for patients with breast cancer, and restoration of lipid metabolism and normoxia might precede observable structural change. In this study, we hypothesised that peri-tumoural lipid composition and hypoxia might be predictive and early response markers in patients with breast cancer undergoing NACT. Female patients with breast cancer were scanned on a 3T clinical MRI scanner at baseline and Cycle1, with acquisition of lipid composition maps of MUFAs, PUFAs, and SFAs, and hypoxia maps of effective transverse relaxation rate R2*. The percentage change in lipid composition and hypoxia at Cycle1 was calculated with reference to baseline. Tumour-associated macrophages were analysed based on immunostaining of CD163 from biopsy and resection, with the percentage change in the resected tumour calculated across the entire NACT. We found no significant difference in lipid composition and R2* between good and poor responders at baseline and Cycle1; however, the correlation between the percentage change in MUFAs and PUFAs against CD163 suggested the modulation in lipids with altered immune response might support the development of targeted therapies.

Tumor-derived GLI1 promotes remodeling of the immune tumor microenvironment in melanoma

BACKGROUND

Melanoma progression is based on a close interaction between cancer cells and immune cells in the tumor microenvironment (TME). Thus, a better understanding of the mechanisms controlling TME dynamics and composition will help improve the management of this dismal disease. Work from our and other groups has reported the requirement of an active Hedgehog-GLI (HH-GLI) signaling for melanoma growth and stemness. However, the role of the downstream GLI1 transcription factor in melanoma TME remains largely unexplored.

METHODS

The immune-modulatory activity of GLI1 was evaluated in a syngeneic B16F10 melanoma mouse model assessing immune populations by flow cytometry. Murine polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) were differentiated from bone marrow cells and their immunosuppressive ability was assessed by inhibition of T cells. Conditioned media (CM) from GLI1-overexpressing mouse melanoma cells was used to culture PMN-MDSCs, and the effects of CM were evaluated by Transwell invasion assay and T cell inhibition. Cytokine array analysis, qPCR and chromatin immunoprecipitation were performed to explore the regulation of CX3CL1 expression by GLI1. Human monocyte-derived dendritic cells (moDCs) were cultured in CM from GLI1-silenced patient-derived melanoma cells to assess their activation and recruitment. Blocking antibodies anti-CX3CL1, anti-CCL7 and anti-CXCL8 were used for in vitro functional assays.

RESULTS

Melanoma cell-intrinsic activation of GLI1 promotes changes in the infiltration of immune cells, leading to accumulation of immunosuppressive PMN-MDSCs and regulatory T cells, and to decreased infiltration of dendric cells (DCs), CD8 + and CD4 + T cells in the TME. In addition, we show that ectopic expression of GLI1 in melanoma cells enables PMN-MDSC expansion and recruitment, and increases their ability to inhibit T cells. The chemokine CX3CL1, a direct transcriptional target of GLI1, contributes to PMN-MDSC expansion and recruitment. Finally, silencing of GLI1 in patient-derived melanoma cells promotes the activation of human monocyte-derived dendritic cells (moDCs), increasing cytoskeleton remodeling and invasion ability. This phenotype is partially prevented by blocking the chemokine CCL7, but not CXCL8.

CONCLUSION

Our findings highlight the relevance of tumor-derived GLI1 in promoting an immune-suppressive TME, which allows melanoma cells to evade the immune system, and pave the way for the design of new combination treatments targeting GLI1.

From monocyte-derived macrophages to resident macrophages-how metabolism leads their way in cancer

Macrophages are innate immune cells that play key roles during both homeostasis and disease. Depending on the microenvironmental cues sensed in different tissues, macrophages are known to acquire specific phenotypes and exhibit unique features that, ultimately, orchestrate tissue homeostasis, defense, and repair. Within the tumor microenvironment, macrophages are referred to as tumor-associated macrophages (TAMs) and constitute a heterogeneous population. Like their tissue resident counterpart, TAMs are plastic and can switch function and phenotype according to the niche-derived stimuli sensed. While changes in TAM phenotype are known to be accompanied by adaptive alterations in their cell metabolism, it is reported that metabolic reprogramming of macrophages can dictate their activation state and function. In line with these observations, recent research efforts have been focused on defining the metabolic traits of TAM subsets in different tumor malignancies and understanding their role in cancer progression and metastasis formation. This knowledge will pave the way to novel therapeutic strategies tailored to cancer subtype-specific metabolic landscapes. This review outlines the metabolic characteristics of distinct TAM subsets and their implications in tumorigenesis across multiple cancer types.

The role of RNA methylation in tumor immunity and its potential in immunotherapy

RNA methylation, a prevalent post-transcriptional modification, has garnered considerable attention in research circles. It exerts regulatory control over diverse biological functions by modulating RNA splicing, translation, transport, and stability. Notably, studies have illuminated the substantial impact of RNA methylation on tumor immunity. The primary types of RNA methylation encompass N6-methyladenosine (m6A), 5-methylcytosine (m5C), N1-methyladenosine (m1A), and N7-methylguanosine (m7G), and 3-methylcytidine (m3C). Compelling evidence underscores the involvement of RNA methylation in regulating the tumor microenvironment (TME). By affecting RNA translation and stability through the "writers", "erasers" and "readers", RNA methylation exerts influence over the dysregulation of immune cells and immune factors. Consequently, RNA methylation plays a pivotal role in modulating tumor immunity and mediating various biological behaviors, encompassing proliferation, invasion, metastasis, etc. In this review, we discussed the mechanisms and functions of several RNA methylations, providing a comprehensive overview of their biological roles and underlying mechanisms within the tumor microenvironment and among immunocytes. By exploring how these RNA modifications mediate tumor immune evasion, we also examine their potential applications in immunotherapy. This review aims to provide novel insights and strategies for identifying novel targets in RNA methylation and advancing cancer immunotherapy efficacy.

A novel insight into cancer therapy: Lipid metabolism in tumor-associated macrophages

The tumor immune microenvironment (TIME) can limit the effectiveness and often leads to significant side effects of conventional cancer therapies. Consequently, there is a growing interest in identifying novel targets to enhance the efficacy of targeted cancer therapy. More research indicates that tumor-associated macrophages (TAMs), originating from peripheral blood monocytes generated from bone marrow myeloid progenitor cells, play a crucial role in the tumor microenvironment (TME) and are closely associated with resistance to traditional cancer therapies. Lipid metabolism alterations have been widely recognized as having a significant impact on tumors and their immune microenvironment. Lipids, lipid derivatives, and key substances in their metabolic pathways can influence the carcinogenesis and progression of cancer cells by modulating the phenotype, function, and activity of TAMs. Therefore, this review focuses on the reprogramming of lipid metabolism in cancer cells and their immune microenvironment, in which the TAMs are especially concentrated. Such changes impact TAMs activation and polarization, thereby affecting the tumor cell response to treatment. Furthermore, the article explores the potential of targeting the lipid metabolism of TAMs as a supplementary approach to conventional cancer therapies. It reviews and evaluates current strategies for enhancing efficacy through TAMs' lipid metabolism and proposes new lipid metabolism targets as potential synergistic options for chemo-radiotherapy and immunotherapy. These efforts aim to stimulate further research in this area.

Codonopsis pilosula-derived glycopeptide dCP1 promotes the polarization of tumor-associated macrophage from M2-like to M1 phenotype

The majority of the immune cell population in the tumor microenvironment (TME) consists of tumor-associated macrophages (TAM), which are the main players in coordinating tumor-associated inflammation. TAM has a high plasticity and is divided into two main phenotypes, pro-inflammatory M1 type and anti-inflammatory M2 type, with tumor-suppressive and tumor-promoting functions, respectively. Considering the beneficial effects of M1 macrophages for anti-tumor and the high plasticity of macrophages, the conversion of M2 TAM to M1 TAM is feasible and positive for tumor treatment. This study sought to evaluate whether the glycopeptide derived from simulated digested Codonopsis pilosula extracts could regulate the polarization of M2-like TAM toward the M1 phenotype and the potential regulatory mechanisms. The results showed that after glycopeptide dCP1 treatment, the mRNA relative expression levels of some M2 phenotype marker genes in M2-like TAM in simulated TME were reduced, and the relative expression levels of M1 phenotype marker genes and inflammatory factor genes were increased. Analysis of RNA-Seq of M2-like TAM after glycopeptide dCP1 intervention showed that the gene sets such as glycolysis, which is associated with macrophage polarization in the M1 phenotype, were significantly up-regulated, whereas those of gene sets such as IL-6-JAK-STAT3 pathway, which is associated with polarization in the M2 phenotype, were significantly down-regulated. Moreover, PCA analysis and Pearson's correlation also indicated that M2-like TAM polarized toward the M1 phenotype at the transcriptional level after treatment with the glycopeptide dCP1. Lipid metabolomics was used to further explore the efficacy of the glycopeptide dCP1 in regulating the polarization of M2-like TAM to the M1 phenotype. It was found that the lipid metabolite profiles in dCP1-treated M2-like TAM showed M1 phenotype macrophage lipid metabolism profiles compared with blank M2-like TAM. Analysis of the key differential lipid metabolites revealed that the interconversion between phosphatidylcholine (PC) and diacylglycerol (DG) metabolites may be the central reaction of the glycopeptide dCP1 in regulating the conversion of M2-like TAM to the M1 phenotype. The above results suggest that the glycopeptide dCP1 has the efficacy to regulate the polarization of M2-like TAM to M1 phenotype in simulated TME.

Roles of O-GlcNAcylation in Mitochondrial Homeostasis and Cardiovascular Diseases

Protein posttranslational modifications are important factors that mediate the fine regulation of signaling molecules. O-linked β-N-acetylglucosamine-modification (O-GlcNAcylation) is a monosaccharide modification on N-acetylglucosamine linked to the hydroxyl terminus of serine and threonine of proteins. O-GlcNAcylation is responsive to cellular stress as a reversible and posttranslational modification of nuclear, mitochondrial and cytoplasmic proteins. Mitochondrial proteins are the main targets of O-GlcNAcylation and O-GlcNAcylation is a key regulator of mitochondrial homeostasis by directly regulating the mitochondrial proteome or protein activity and function. Disruption of O-GlcNAcylation is closely related to mitochondrial dysfunction. More importantly, the O-GlcNAcylation of cardiac proteins has been proven to be protective or harmful to cardiac function. Mitochondrial homeostasis is crucial for cardiac contractile function and myocardial cell metabolism, and the imbalance of mitochondrial homeostasis plays a crucial role in the pathogenesis of cardiovascular diseases (CVDs). In this review, we will focus on the interactions between protein O-GlcNAcylation and mitochondrial homeostasis and provide insights on the role of mitochondrial protein O-GlcNAcylation in CVDs.

Targeting O-GlcNAcylation in cancer therapeutic resistance: The sugar Saga continues

O-linked-N-acetylglucosaminylation (O-GlcNAcylation), a dynamic post-translational modification (PTM), holds profound implications in controlling various cellular processes such as cell signaling, metabolism, and epigenetic regulation that influence cancer progression and therapeutic resistance. From the therapeutic perspective, O-GlcNAc modulates drug efflux, targeting and metabolism. By integrating signals from glucose, lipid, amino acid, and nucleotide metabolic pathways, O-GlcNAc acts as a nutrient sensor and transmits signals to exerts its function on genome stability, epithelial-mesenchymal transition (EMT), cell stemness, cell apoptosis, autophagy, cell cycle. O-GlcNAc also attends to tumor microenvironment (TME) and the immune response. At present, several strategies aiming at targeting O-GlcNAcylation are under mostly preclinical evaluation, where the newly developed O-GlcNAcylation inhibitors markedly enhance therapeutic efficacy. Here we systematically outline the mechanisms through which O-GlcNAcylation influences therapy resistance and deliberate on the prospects and challenges associated with targeting O-GlcNAcylation in future cancer treatments.

Local thiamet-G delivery by a thermosensitive hydrogel confers ischemic cardiac repair via myeloid M2-like activation in a STAT6 O-GlcNAcylation-dependent manner

Infarct healing requires a dynamic and orchestrated inflammatory reaction following myocardial infarction (MI). While an uncontrolled excessive inflammatory response exaggerates ischemic injury post-MI, M2-like reparative macrophages may facilitate inflammation regression and promote myocardial healing. However, how protein post-translational modification regulates post-MI cardiac repair and dynamic myeloid activation remains unknown. Here we show that M2-like reparative, but not M1-like inflammatory activation, is enhanced by pharmacologically-induced hyper-O-GlcNAcylation. Mechanistically, myeloid knockdown of O-GlcNAc hydrolase O-GlcNAcase (Oga), which also results in hyper-O-GlcNAcylation, positively regulates M2-like activation in a STAT6-dependent fashion, which is controlled by O-GlcNAcylation of STAT6. Of note, both systemic and local supplementation of thiamet-G (TMG), an Oga inhibitor, effectively facilitates cardiac recovery in mice by elevating the accumulation of M2-like macrophages in infarcted hearts. Our study provides a novel clue for monocyte/macrophage modulating therapies aimed at reducing post-MI hyperinflammation in ischemic myocardium.

HucMSC-Exo Induced N2 Polarization of Neutrophils: Implications for Angiogenesis and Tissue Restoration in Wound Healing

Background

Neutrophils rapidly accumulate in large numbers at sites of tissue damage, exhibiting not only their well-known bactericidal capabilities but also playing crucial roles in angiogenesis and tissue repair. While exosomes derived from human umbilical cord mesenchymal stem cells (HucMSC-Exo) have emerged as a promising therapeutic tool, their exact mechanisms of action remain partly elusive. We hypothesize that HucMSC-Exo treatment may modulate neutrophil phenotypes, thereby significantly influencing wound healing outcomes.

Methods

HucMSC-Exo were isolated via ultracentrifugation and subsequently administered through subcutaneous injection into full-thickness cutaneous wounds in mice. To determine the impact of host neutrophils on the healing effects of HucMSC-Exo in skin injuries, strategies including neutrophil depletion and adoptive transfer were employed. Flow cytometry was used to evaluate the proportion of N2 subtype neutrophils in both normal and diabetic wounds, and the effect of HucMSC-Exo on this proportion was assessed. Furthermore, the mitochondrial metabolic reprogramming driven by HucMSC-Exo during N2 polarization was investigated through JC1 staining, ATP quantification, fatty acid uptake assays, and assessment of FAO-related genes (Cpt1b, Acadm, and Acadl).

Results

Depleting host neutrophils strikingly dampened prohealing effect of HucMSC-Exo on skin injury, while adoptive transfer of bone marrow neutrophils rescued this process. During normal healing process, some neutrophils expressed N2 markers, in contrast, diabetic wounds exhibited a reduced expression of N2 markers. After treatment with HucMSC-Exo, most neutrophils increased the phosphorylation of STAT6, leading to mitochondrial metabolic reprogramming and thus acquired an N2 phenotype. These N2 neutrophils, polarized by HucMSC-Exo, boosted the release of proangiogenic factors, particularly BV8, a myeloid cell-derived proangiogenic factor, and induced angiogenesis thereby favoring tissue restoration.

Conclusion

This research uniquely demonstrates the identification of N2 neutrophils in skin injury and shows that HucMSC-Exo could skew neutrophils toward N2 phenotype, enhancing our insight into how cells react to HucMSC-Exo.

A Metabolic Axis of Immune Intractability

Immune cells in the tumor niche robustly influence disease progression. Remarkably, in cancer, developmental pathways are reenacted. Many parallels between immune regulation of embryonic development and immune regulation of tumor progression can be drawn, with evidence clearly supporting an immune-suppressive microenvironment in both situations. In these ecosystems, metabolic and bioenergetic circuits guide and regulate immune cell differentiation, plasticity, and functional properties of suppressive and inflammatory immune subsets. As such, there is an emerging pattern of intersection across the dynamic process of ontogeny and the ever-evolving tumor neighborhood. In this article, we focus on the convergence of immune programming during ontogeny and in the tumor microenvironment. Exemplifying dysregulation of Hedgehog (Hh) activity, a key player during ontogeny, we highlight a critical convergence of these fields and the metabolic axis of the nutrient sensing hexosamine biosynthetic pathway (HBP) that integrates glucose, glutamine, amino acids, acetyl CoA, and uridine-5'-triphosphate (UTP), culminating in the synthesis of UDP-GlcNAc, a metabolite that functions as a metabolic and bioenergetic sensor. We discuss an emerging pattern of immune regulation, orchestrated by O-GlcNAcylation of key transcriptional regulators, spurring suppressive activity of dysfunctional immune cells in the tumor microenvironment.

The promising role of tumor-associated macrophages in the treatment of cancer

Macrophages are important components of the immune system. Mature macrophages can be recruited to tumor microenvironment that affect tumor cell proliferation, invasion and metastasis, extracellular matrix remodeling, immune suppression, as well as chemotherapy resistance. Classically activated type I macrophages (M1) exhibited marked tumor killing and phagocytosis. Therefore, using macrophages for adoptive cell therapy has attracted attention and become one of the most effective strategies for cancer treatment. Through cytokines and/or chemokines, macrophage can inhibit myeloid cells recruitment, and activate anti-tumor and immune killing functions. Applying macrophages for anti-tumor delivery is one of the most promising approaches for cancer therapy. This review article introduces the role of macrophages in tumor development and drug resistance, and the possible clinical application of targeting macrophages for overcoming drug resistance and enhancing cancer therapeutics, as well as its challenges.

Cinobufacini injection delays hepatocellular carcinoma progression by regulating lipid metabolism via SREBP1 signaling pathway and affecting macrophage polarization

ETHNOPHARMACOLOGICAL RELEVANCE

Cinobufacini injection, an aqueous extract of the toad, is a commonly used anti-tumor animal herbal medicine in clinical practice. It has the effects of detoxifying, reducing swelling, and relieving pain.

AIMS OF THE STUDY

To investigate the effects of Cinobufacini injection on hepatocellular carcinoma progression by regulating lipid metabolism and macrophage polarization in the tumor microenvironment and to identify the potential molecular mechanisms.

MATERIALS AND METHODS

To establish the axillary transplantation tumor model of hepatocellular carcinoma Hepa1-6 in C57BL/6 mice, and to evaluate the inhibitory effect of Cinobufacini injection on hepatocellular carcinoma in vivo as well as drug delivery security. Combined metabolomics and transcriptomics analysis of the effect of Cinobufagin Injection on tumor microenvironment. An in vitro mouse co-culture model of peritoneal macrophages and Hepa1-6 cells was established to research the effects of Cinobufacini injection on macrophage polarization, hepatocellular carcinoma cell growth, migration, and changes in lipid metabolism. Cinobufacini injection inhibition of the AMPK/SREBP1/FASN signaling pathway regulating cholesterol metabolism and affecting macrophage polarization was examined using qRT-PCR, lentiviral transfection, immunofluorescence, and Western blot.

RESULT

In vivo experiments demonstrated that Cinobufacini injection treatment significantly inhibited the growth of Hepa1-6 hepatomas, along with a reduction in cholesterol content and a decrease in the percentage of M2 macrophages in tumor tissue. In vitro, we found that Cinobufacini injection inhibits IL-4-induced M2 macrophage polarization, reduces the cholesterol content of Hepa1-6 cells in a co-culture system, and inhibits the promotion of hepatocellular carcinoma cells by M2 macrophages. In addition, successful overexpression of SREBP1 in Hepa1-6 cells showed more pronounced cellular activity whereas Cinobufacini injection inhibited this change and reduced intracellular lipid levels.

CONCLUSION

Cinobufacini injection inhibits cholesterol synthesis within the tumor microenvironment via the AMPK/SERBP1/FASN signaling pathway, which in turn blocks the M2 polarization of macrophages, leading to the weakening of hepatocellular carcinoma growth and migration, and the promotion of its apoptosis. Our findings provide an important Introduction to understanding the molecular mechanism of Cinobufacini injection's anticancer activity and provide reliable theoretical and experimental support for its clinical application.

Characterizing hedgehog pathway features in senescence associated osteoarthritis through Integrative multi-omics and machine learning analysis

Purpose: Osteoarthritis (OA) is a disease of senescence and inflammation. Hedgehog's role in OA mechanisms is unclear. This study combines Bulk RNA-seq and scRNA-seq to identify Hedgehog-associated genes in OA, investigating their impact on the pathogenesis of OA. Materials and methods: Download and merge eight bulk-RNA seq datasets from GEO, also obtain a scRNA-seq dataset for validation and analysis. Analyze Hedgehog pathway activity in OA using bulk-RNA seq datasets. Use ten machine learning algorithms to identify important Hedgehog-associated genes, validate predictive models. Perform GSEA to investigate functional implications of identified Hedgehog-associated genes. Assess immune infiltration in OA using Cibersort and MCP-counter algorithms. Utilize ConsensusClusterPlus package to identify Hedgehog-related subgroups. Conduct WGCNA to identify key modules enriched based on Hedgehog-related subgroups. Characterization of genes by methylation and GWAS analysis. Evaluate Hedgehog pathway activity, expression of hub genes, pseudotime, and cell communication, in OA chondrocytes using scRNA-seq dataset. Validate Hedgehog-associated gene expression levels through Real-time PCR analysis. Results: The activity of the Hedgehog pathway is significantly enhanced in OA. Additionally, nine important Hedgehog-associated genes have been identified, and the predictive models built using these genes demonstrate strong predictive capabilities. GSEA analysis indicates a significant positive correlation between all seven important Hedgehog-associated genes and lysosomes. Consensus clustering reveals the presence of two hedgehog-related subgroups. In Cluster 1, Hedgehog pathway activity is significantly upregulated and associated with inflammatory pathways. WGCNA identifies that genes in the blue module are most significantly correlated with Cluster 1 and Cluster 2, as well as being involved in extracellular matrix and collagen-related pathways. Single-cell analysis confirms the significant upregulation of the Hedgehog pathway in OA, along with expression changes observed in 5 genes during putative temporal progression. Cell communication analysis suggests an association between low-scoring chondrocytes and macrophages. Conclusion: The Hedgehog pathway is significantly activated in OA and is associated with the extracellular matrix and collagen proteins. It plays a role in regulating immune cells and immune responses.

Blockade of C5aR1 resets M1 via gut microbiota-mediated PFKM stabilization in a TLR5-dependent manner

Targeting C5aR1 modulates the function of infiltrated immune cells including tumor-associated macrophages (TAMs). The gut microbiome plays a pivotal role in colorectal cancer (CRC) tumorigenesis and development through TAM education. However, whether and how the gut flora is involved in C5aR1 inhibition-mediated TAMs remains unclear. Therefore, in this study, genetic deletion of C5ar1 or pharmacological inhibition of C5aR1 with anti-C5aR1 Ab or PMX-53 in the presence or absence of deletion Abs were utilized to verify if and how C5aR1 inhibition regulated TAMs polarization via affecting gut microbiota composition. We found that the therapeutic effects of C5aR1 inhibition on CRC benefited from programming of TAMs toward M1 polarization via driving AKT2-mediated 6-phosphofructokinase muscle type (PFKM) stabilization in a TLR5-dependent manner. Of note, in the further study, we found that C5aR1 inhibition elevated the concentration of serum IL-22 and the mRNA levels of its downstream target genes encoded antimicrobial peptides (AMPs), leading to gut microbiota modulation and flagellin releasement, which contributed to M1 polarization. Our data revealed that high levels of C5aR1 in TAMs predicted poor prognosis. In summary, our study suggested that C5aR1 inhibition reduced CRC growth via resetting M1 by AKT2 activation-mediated PFKM stabilization in a TLR5-dependent manner, which relied on IL-22-regulated gut flora.

Glycolysis regulation in tumor-associated macrophages: Its role in tumor development and cancer treatment

Tumor-associated macrophages constitute the main cell population in the tumor microenvironment and play a crucial role in regulating the microenvironment composition. Emerging evidence has revealed that the metabolic profile determines the tumor-associated macrophage phenotype. Tumor-associated macrophage function is highly dependent on glucose metabolism, with glycolysis being the major metabolic pathway. Recent reports have demonstrated diversity in glucose flux of tumor-associated macrophages and complex substance communication with cancer cells. However, how the glucose flux in tumor-associated macrophages connects with glycolysis to influence tumor progression and the tumor microenvironment is still obscure. Moreover, while the development of single-cell sequencing technology allows a clearer and more accurate classification of tumor-associated macrophages, the metabolic profiles of tumor-associated macrophages from the perspective of single-cell omics has not been well summarized. Here, we review the current state of knowledge on glucose metabolism in tumor-associated macrophages and summarize the metabolic profiles of different tumor-associated macrophage subtypes from the perspective of single-cell omics. Additionally, we describe the current strategies targeting glycolysis in tumor-associated macrophages for cancer therapy.

An innovative gene expression modulating strategy by converting nucleic acids into HNC therapeutics using carrier-free nanoparticles

Background

Cell fate and microenvironmental changes resulting from aberrant expression of specific proteins in tumors are one of the major causes of inadequate anti-tumor immune response and poor prognosis in head and neck cancer (HNC). Eukaryotic initiation factor 3C (eIF3c) has emerged as a promising therapeutic target for HNC due to its ability to regulate protein expression levels in tumor cells, but its drug development is difficult to achieve by targeting traditional protein-protein interactions. siRNA has emerged as a highly promising modality for drug development targeting eIF3c, while its application is hindered by challenges pertaining to inadequate stability and insufficient concentration specifically within tumor sites.

Method

We employed a method to convert flexible siRNAs into stable and biologically active infinite Auric-sulfhydryl coordination supramolecular siRNAs (IacsRNAs). Through coordinated self-assembly, we successfully transformed eIF3C siRNAs into the carrier-free HNC nanotherapeutic agent Iacs-eif3c-RNA. The efficacy of this agent was evaluated in vivo using HNC xenograft models, demonstrating promising antitumor effects.

Results

Iacs-eif3c-RNA demonstrated the ability to overcome the pharmacological obstacle associated with targeting eIF3C, resulting in a significant reduction in eIF3C expression within tumor tissues, as well as effective tumor cell proliferating suppression and apoptosis promotion. In comparison to monotherapy utilizing the chemotherapeutic agent cisplatin, Iacs-eif3c-RNA exhibited superior anti-tumor efficacy and favorable biosafety.

Conclusion

The utilization of Iacs-eif3c-RNA as a carrier-free nanotherapeutic agent presents a promising and innovative approach for addressing HNC treating challenges. Moreover, this strategy demonstrates potential for the translation of therapeutic siRNAs into clinical drugs, extending its applicability to the treatment of other cancers and various diseases.

O-GlcNAcylation at the center of antitumor immunity

The post-translational modification known as O-GlcNAcylation is a highly dysregulated process in tumors, and a key contributor to malignant transformation. In contrast, after three decades since its discovery, very little has been revealed about this process in the immune system. With the prospect of targeting O-GlcNAcylation as tumor therapy, greater understanding of how it regulates immune responses in the context of the tumor microenvironment will be needed. Here, we discuss recent discoveries from which a picture is emerging that O-GlcNAcylation, in either tumors or in immune cells, could negatively impact overall antitumor immune responses. We propose that interference with O-GlcNAcylation thus holds promise for cancer treatment from both perspectives.

The emerging role of the hedgehog signaling pathway in immunity response and autoimmune diseases

The Hedgehog (Hh) family is a prototypical morphogen involved in embryonic patterning, multi-lineage differentiation, self-renewal, morphogenesis, and regeneration. There are studies that have demonstrated that the Hh signaling pathway differentiates developing T cells into MHC-restricted self-antigen tolerant T cells in a concentration-dependent manner in the thymus. Whereas Hh signaling pathway is not required in the differentiation of B cells but is indispensable in maintaining the regeneration of hematopoietic stem cells (HSCs) and the viability of germinal centers (GCs) B cells. The Hh signaling pathway exerts both positive and negative effects on immune responses, which involves activating human peripheral CD4+ T cells, regulating the accumulation of natural killer T (NKT) cells, recruiting and activating macrophages, increasing CD4+Foxp3+ regulatory T cells in the inflammation sites to sustain homeostasis. Hedgehog signaling is involved in the patterning of the embryo, as well as homeostasis of adult tissues. Therefore, this review aims to highlight evidence for Hh signaling in the differentiation, function of immune cells and autoimmune disease. Targeting Hh signaling promises to be a novel, alternative or adjunct approach to treating tumors and autoimmune diseases.

Glucose metabolism of TAMs in tumor chemoresistance and metastasis

Tumor-associated macrophages (TAMs) are critical in promoting tumor progression and therapeutic resistance. In adapting to metabolic changes in the tumor microenvironment (TME), TAMs reprogram their metabolisms and acquire immunosuppressive and pro-tumor properties. Increased glucose metabolism in TAMs leads to the accumulation of a variety of oncometabolites that exhibit potent tumor-promoting capacity via regulating gene expression and signaling transduction. Glucose uptake also fuels O-GlcNAcylation and other post-translational modifications to promote pro-tumor polarization and function of TAMs. Glucose metabolism coordinates interactions between TAMs and various types of cells in the TME, creating a complex network that facilitates tumor progression. Targeting glucose metabolism represents a promising strategy to switch TAMs from pro-tumor toward anti-tumor function for cancer therapy.

Ubenimex suppresses glycolysis mediated by CD13/Hedgehog signaling to enhance the effect of cisplatin in liver cancer

Background

Liver cancer ranks third in fatalities among all cancer-related deaths. As a traditional chemotherapy drug, the application of cis-Diamminedichloroplatinum (II) (cisplatin, CDDP) for the treatment of liver cancer is greatly limited by its side effects and high drug resistance. Therefore, we are in urgent need of a more effective and less toxic CDDP therapeutic regimen. Our research aimed to clarify the possible mechanism of ubenimex in enhancing the effect of CDDP on liver cancer.

Methods

The underlying mechanism was determined using Cell Counting Kit-8 (CCK-8) assay, flow cytometry, immunofluorescence, enzyme-linked immunosorbent assay (ELISA), transwell assay, wound healing assay and western blot assay.

Results

The data indicated that ubenimex suppressed the expression levels of glycolysis-related proteins by decreasing the expression levels of cluster of differentiation 13 (CD13), while overexpression of CD13 could restore the activity of glycolysis. The glycolysis inhibitor 2-deoxy-D-glucose enhanced the antiproliferative effect of ubenimex and CDDP. In addition, the inhibition of the activity levels of the Hedgehog (Hh) pathway members was accompanied by a decrease in CD13 expression, which was reversed following CD13 overexpression. Moreover, ubenimex inhibited the production of lactic acid and adenosine triphosphate (ATP), as well as the expression of key proteins involved in glycolysis, which was similar to the effects caused by the Hh inhibitor cyclopamine. However, the effects of ubenimex were mediated by targeting CD13, while cyclopamine exhibited no effects on CD13, suggesting that Hh signaling occurred in the downstream of CD13. The inhibition of glycolysis by cyclopamine was reduced following CD13 overexpression, which further indicated that ubenimex targeted the CD13/Hh pathway to inhibit glycolysis. Finally, wound healing and transwell assays and cell proliferation and apoptosis analysis demonstrated that ubenimex inhibited glycolysis by alleviating the CD13/Hh pathway, which in turn enhanced the effects of CDDP on inhibiting the progression of liver cancer.

Conclusions

Ubenimex inhibits glycolysis by targeting the CD13/Hh pathway, thus playing an anti-tumor role together with CDDP. This study demonstrated the adjuvant effect of ubenimex from the perspective of Hh signal-dependent glycolysis regulation.

The emerging roles of metabolism in the crosstalk between breast cancer cells and tumor-associated macrophages

Breast cancer is the most common cancer affecting women worldwide. Investigating metabolism in breast cancer may accelerate the exploitation of new therapeutic options for immunotherapies. Metabolic reprogramming can confer breast cancer cells (BCCs) with a survival advantage in the tumor microenvironment (TME) and metabolic alterations in breast cancer, and the corresponding metabolic byproducts can affect the function of tumor-associated macrophages (TAMs). Additionally, TAMs undergo metabolic reprogramming in response to signals present in the TME, which can affect their function and breast cancer progression. Here, we review the metabolic crosstalk between BCCs and TAMs in terms of glucose, lipids, amino acids, iron, and adenosine metabolism. Summaries of inhibitors that target metabolism-related processes in BCCs or TAMs within breast cancer have also served as valuable inspiration for novel therapeutic approaches in the fight against this disease. This review provides new perspectives on targeted anticancer therapies for breast cancer that combine immunity with metabolism.

Long-term strategies for management of advanced basal cell carcinoma with hedgehog inhibitors

Basal cell carcinoma (BCC), the most common type of skin cancer, is characterized by aberrant activation of the hedgehog molecular pathway. Systemic therapy is indicated when local approaches, such as surgery and radiation, are inappropriate. In this article, a group of clinical experts recommends the long-term management strategy for advanced BCC patients treated with systemic therapy. The hedgehog inhibitors sonidegib and vismodegib are first-line treatments for advanced BCC with a long-lasting response, but long-term treatment with hedgehog inhibitors is often challenged by tolerability issues. However, several strategies for adverse effect management are available, such as dose interruptions, on-label alternate-day dosing and supportive medications. In conclusion, although BCC shows a high tumor mutational burden that favors a response to immunotherapy, experts recommend keeping patients on hedgehog inhibitors limiting immunotherapy to those who developed resistance during hedgehog inhibitor therapy or in case of persisting toxicity despite long-term management of adverse events.

Protein O-GlcNAcylation in multiple immune cells and its therapeutic potential

O-GlcNAcylation is a post-translational modification of proteins that involves the addition of O-GlcNAc to serine or threonine residues of nuclear or cytoplasmic proteins, catalyzed by O-GlcNAc transferase (OGT). This modification is highly dynamic and can be reversed by O-GlcNAcase (OGA). O-GlcNAcylation is widespread in the immune system, which engages in multiple physiologic and pathophysiologic processes. There is substantial evidence indicating that both the hexosamine biosynthesis pathway (HBP) and O-GlcNAcylation are critically involved in regulating immune cell function. However, the precise role of O-GlcNAcylation in the immune system needs to be adequately elucidated. This review offers a thorough synopsis of the present research on protein O-GlcNAcylation, accentuating the molecular mechanisms that control immune cells' growth, maturation, and performance via this PTM.

Lipid Metabolic Regulatory Crosstalk Between Cancer Cells and Tumor-Associated Macrophages

In the tumor microenvironment, tumor-associated macrophages (TAMs) are one of the most abundant cell populations, playing key roles in tumorigenesis, chemoresistance, immune evasion, and metastasis. There is an important interaction between TAMs and cancer cells: on the one hand, tumors control the function of infiltrating macrophages, contributing to reprogramming of TAMs, and on the other hand, TAMs affect the growth of cancer cells. This review focuses on lipid metabolism changes in the complex relationship between cancer cells and TAMs. We discuss how lipid metabolism in cancer cells affects macrophage phenotypic and metabolic changes and, subsequently, how altered lipid metabolism of TAMs influences tumor progression. Identifying the metabolic changes that influence the complex interaction between tumor cells and TAMs is also an important step in exploring new therapeutic approaches that target metabolic reprogramming of immune cells to enhance their tumoricidal potential and bypass therapy resistance. Our work may provide new targets for antitumor therapies.

Impact of Lipid Metabolism on Macrophage Polarization: Implications for Inflammation and Tumor Immunity

Macrophage polarization is influenced by lipids, which also exert significant control over macrophage functions. Lipids and their metabolites are players in intricate signaling pathways that modulate macrophages' responses to pathogens, phagocytosis, ferroptosis, and inflammation. This review focuses on lipid metabolism and macrophage functions and addresses potential molecular targets for the treatment of macrophage-related diseases. While lipogenesis is crucial for lipid accumulation and phagocytosis in M1 macrophages, M2 macrophages likely rely on fatty acid β-oxidation to utilize fatty acids as their primary energy source. Cholesterol metabolism, regulated by factors such as SREBPs, PPARs, and LXRs, is associated with the cholesterol efflux capacity and the formation of foam cells (M2-like macrophages). Foam cells, which are targets for atherosclerosis, are associated with an increase in inflammatory cytokines. Lipolysis and fatty acid uptake markers, such as CD36, also contribute to the production of cytokines. Enhancing the immune system through the inhibition of lipid-metabolism-related factors can potentially serve as a targeted approach against tumor cells. Cyclooxygenase inhibitors, which block the conversion of arachidonic acid into various inflammatory mediators, influence macrophage polarization and have generated attention in cancer research.

Bioinformatics Screen Reveals Gli-Mediated Hedgehog Signaling as an Associated Pathway to Poor Immune Infiltration of Dedifferentiated Liposarcoma

Liposarcomas are the most diagnosed soft tissue sarcoma, with most cases consisting of well-differentiated (WDLPS) or dedifferentiated (DDLPS) histological subtypes. While both tumor subtypes can have clinical recurrence due to incomplete resections, DDLPS often has worse prognosis due to a higher likelihood of metastasis compared to its well-differentiated counterpart. Unfortunately, targeted therapeutic interventions have lagged in sarcoma oncology, making the need for molecular targeted therapies a promising future area of research for this family of malignancies. In this work, previously published data were analyzed to identify differential pathways that may contribute to the dedifferentiation process in liposarcoma. Interestingly, Gli-mediated Hedgehog signaling appeared to be enriched in dedifferentiated adipose progenitor cells and DDLPS tumors, and coincidentally Gli1 is often co-amplified with MDM2 and CDK4, given its genomic proximity along chromosome 12q13-12q15. However, we find that Gli2, but not Gli1, is differentially expressed between WDLPS and DDLPS, with a noticeable co-expression signature between Gli2 and genes involved in ECM remodeling. Additionally, Gli2 co-expression had a noticeable transcriptional signature that could suggest Gli-mediated Hedgehog signaling as an associated pathway contributing to poor immune infiltration in these tumors.

Role of UPRmt and mitochondrial dynamics in host immunity: it takes two to tango

The immune system of a host contains a group of heterogeneous cells with the prime aim of restraining pathogenic infection and maintaining homeostasis. Recent reports have proved that the various subtypes of immune cells exploit distinct metabolic programs for their functioning. Mitochondria are central signaling organelles regulating a range of cellular activities including metabolic reprogramming and immune homeostasis which eventually decree the immunological fate of the host under pathogenic stress. Emerging evidence suggests that following bacterial infection, innate immune cells undergo profound metabolic switching to restrain and countervail the bacterial pathogens, promote inflammation and restore tissue homeostasis. On the other hand, bacterial pathogens affect mitochondrial structure and functions to evade host immunity and influence their intracellular survival. Mitochondria employ several mechanisms to overcome bacterial stress of which mitochondrial UPR (UPR^mt) and mitochondrial dynamics are critical. This review discusses the latest advances in our understanding of the immune functions of mitochondria against bacterial infection, particularly the mechanisms of mitochondrial UPR^mt and mitochondrial dynamics and their involvement in host immunity.

GNPNAT1 is a potential biomarker correlated with immune infiltration and immunotherapy outcome in breast cancer

Background

Glucosamine 6-phosphate N-acetyltransferase (GNPNAT1) is a crucial enzyme involving hexosamine biosynthesis pathway and is upregulated in breast cancer (BRCA). However, its biological function and mechanism on patients in BRCA have not been investigated.

Methods

In this study, the differential expression of GNPNAT1 was analyzed between BRCA tissues and normal breast tissues using the Cancer Genome Atlas (TCGA) database and Gene Expression Omnibus (GEO) database, which was validated by quantitative real-time polymerase chain reaction, Western blot and immunohistochemistry. Then, the potential clinical value of GNPNAT1 in BRCA was investigated based on TCGA database. Functional enrichment analyses, including Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, Gene Set Variation Analysis, were performed to explore the potential signaling pathways and biological functions involved in GNPNAT1 in BRCA. Tumor immune infiltration was analyzed using ESTIMATE, CIBERSORT and TISIDB database; and immune therapy response scores were assessed using TIDE. Finally, Western blot, Cell counting kit-8 and Transwell assay were used to determine the proliferation and invasion abilities of breast cancer cells with GNPNAT1 knockdown.

Results

GNPNAT1 was up-regulated in BRCA tissues compared with normal tissues which was subsequently verified in different cell lines and clinical tissue samples. Based on TCGA and GEO, the overexpression of GNPNAT1 in BRCA contributed to a significant decline in overall survive and disease specific survive. Functional enrichment analyses indicated that the enriched pathways in high GNPNAT1 expression group included citrate cycle, N-glycan biosynthesis, DNA repair, and basal transcription factors. Moreover, the overexpression of GNPNAT1 was negatively correlated with immunotherapy response and the levels of immune cell infiltration of CD8+ T cells, B cells, natural killer cells, dendritic cells and macrophages. Knockdown of GNPNAT1 impairs the proliferation and invasion abilities of breast cancer cells.

Conclusion

GNPNAT1 is a potential diagnostic, prognostic biomarker and novel target for intervention in BRCA.

Hedgehog Signaling Regulates Treg to Th17 Conversion Through Metabolic Rewiring in Breast Cancer

The tumor immune microenvironment dynamically evolves to support tumor growth and progression. Immunosuppressive regulatory T cells (Treg) promote tumor growth and metastatic seeding in patients with breast cancer. Deregulation of plasticity between Treg and Th17 cells creates an immune regulatory framework that enables tumor progression. Here, we discovered a functional role for Hedgehog (Hh) signaling in promoting Treg differentiation and immunosuppressive activity, and when Hh activity was inhibited, Tregs adopted a Th17-like phenotype complemented by an enhanced inflammatory profile. Mechanistically, Hh signaling promoted O-GlcNAc modifications of critical Treg and Th17 transcription factors, Foxp3 and STAT3, respectively, that orchestrated this transition. Blocking Hh reprogramed Tregs metabolically, dampened their immunosuppressive activity, and supported their transdifferentiation into inflammatory Th17 cells that enhanced the recruitment of cytotoxic CD8+ T cells into tumors. Our results demonstrate a previously unknown role for Hh signaling in the regulation of Treg differentiation and activity and the switch between Tregs and Th17 cells in the tumor microenvironment.

Metabolism in type 2 immune responses

The immune response is tailored to the environment in which it takes place. Immune cells sense and adapt to changes in their surroundings, and it is now appreciated that in addition to cytokines made by stromal and epithelial cells, metabolic cues provide key adaptation signals. Changes in immune cell activation states are linked to changes in cellular metabolism that support function. Furthermore, metabolites themselves can signal between as well as within cells. Here, we discuss recent progress in our understanding of how metabolic regulation relates to type 2 immunity firstly by considering specifics of metabolism within type 2 immune cells and secondly by stressing how type 2 immune cells are integrated more broadly into the metabolism of the organism as a whole.