IFN-γ and tumor gangliosides: Implications for the tumor microenvironment

Dysfunction of dendritic cells in tumor microenvironment and immunotherapy

Dendritic cells (DCs) comprise diverse cell populations that play critical roles in antigen presentation and triggering immune responses in the body. However, several factors impair the immune function of DCs and may promote immune evasion in cancer. Understanding the mechanism of DC dysfunction and the diverse functions of heterogeneous DCs in the tumor microenvironment (TME) is critical for designing effective strategies for cancer immunotherapy. Clinical applications targeting DCs summarized in this report aim to improve immune infiltration and enhance the biological function of DCs to modulate the TME to prevent cancer cells from evading the immune system. Herein, factors in the TME that induce DC dysfunction, such as cytokines, hypoxic environment, tumor exosomes and metabolites, and co-inhibitory molecules, have been described. Furthermore, several key signaling pathways involved in DC dysfunction and signal-relevant drugs evaluated in clinical trials were identified. Finally, this review provides an overview of current clinical immunotherapies targeting DCs, especially therapies with proven clinical outcomes, and explores future developments in DC immunotherapies.

Bioactive sphingolipids as emerging targets for signal transduction in cancer development

Sphingolipids, crucial components of cellular membranes, play a vital role in maintaining cellular structure and signaling integrity. Disruptions in sphingolipid metabolism are increasingly implicated in cancer development. Key bioactive sphingolipids, such as ceramides, sphingosine-1-phosphate (S1P), ceramide-1-phosphate (C1P), and glycosphingolipids, profoundly impact tumor biology. They influence the behavior of tumor cells, stromal cells, and immune cells, affecting tumor aggressiveness, angiogenesis, immune modulation, and extracellular matrix remodeling. Furthermore, abnormal expression of sphingolipids and their metabolizing enzymes modulates the secretion of tumor-derived extracellular vesicles (TDEs), which are key players in creating an immunosuppressive tumor microenvironment, remodeling the extracellular matrix, and facilitating oncogenic signaling within in situ tumors and distant pre-metastatic niches (PMNs). Understanding the role of sphingolipids in the biogenesis of tumor-derived extracellular vesicles (TDEs) and their bioactive contents can pave the way for new biomarkers in cancer diagnosis and prognosis, ultimately enhancing comprehensive tumor treatment strategies.

Dendritic Cells: A Bridge between Tolerance Induction and Cancer Development in Transplantation Setting

Dendritic cells (DCs) are a heterogeneous group of antigen-presenting cells crucial for fostering allograft tolerance while simultaneously supporting host defense against infections and cancer. Within the tumor microenvironment, DCs can either mount an immune response against cancer cells or foster immunotolerance, presenting a dual role. In immunocompromised individuals, posttransplant malignancies pose a significant health concern, with DCs serving as vital players in immune responses against cancer cells. Both recipient- and donor-derived DCs play a critical role in the rejection process, infiltrating the transplanted organ and sustaining T-cell responses. The use of immunosuppressive drugs represents the predominant approach to control this immunological barrier in transplanted organs. Evidence has shed light on the immunopharmacology of these drugs and novel strategies for manipulating DCs to promote allograft survival. Therefore, comprehending the mechanisms underlying this intricate microenvironment and the effects of immunosuppressive therapy on DCs is crucial for developing targeted therapies to reduce graft failure rates. This review will delve into the fundamental immunobiology of DCs and provide a detailed exploration of their clinical significance concerning alloimmune responses and posttransplant malignancies.

Immune-Boosting Potentiating Properties of Brassica nigra Hydroalcoholic Extract in Cyclophosphamide-Induced Immunosuppression in Rats

The antioxidative and immune-boosting properties of the hydroalcoholic extract of Brassica nigra sprouts in cyclophosphamide-induced immunosuppression in rats were investigated in this study. B. nigra sprouts were prepared in the lab to monitor the bio-changes in bioactive compounds during the sprouting period up to 7 days at 17 ± 1 °C and 90% relative humidity. The total phenolic content (TPC), antioxidant activity (AOA), total flavonoids (TFs), total flavonols (TFLs), and total carotenoids (TCs) were evaluated. Consequently, the identification and quantification of phenolic acids, their derivatives, and flavonoids were carried out using HPLC. Subsequently, the selected BN sprout (6-day-old sprout) was biologically examined, and oxidative stress biomarkers, hematological parameters, immunoglobulins (Igs), and pro-inflammatory and anti-inflammatory cytokines were investigated. An increase in TPC, AOA, TFs, TFLs, and TCs was observed by increasing the sprouting time. The HPLC analysis indicated that the B. nigra seeds contained 10 phenolic acids and 4 flavonoids, predominantly syringic acid and quercetin, respectively. After 3 days, the number of phenolic acids increased to 16, predominantly syringic acid, and the number of flavonoids increased to 7, predominantly quercetin. On the 6th day, 13 phenolic acids were estimated, with the highest being benzoic acid, and 6 flavonoids were estimated, with the highest being quercetin. The greatest rise in phenols was seen on the sixth day of sprouting. These included caffeic acid, chlorogenic acid, cinnamic acid, ferulic acid, coumaric acid, benzoic acid, and rosmarinic acid. Flavonoids such as kaempferol and myricetin increased. The sprouts on day 6 were recorded as having the highest bioactive compounds and AOA content. The selected B. nigra sprouts were examined for antioxidative and immunomodulatory properties in a rat model. Dosing 250 and 500 mg kg-1, the rats exhibited significant improvements in terms of antioxidative stress and the number of white blood cells (WBCs), lymphocytes, and neutrophils in the blood, indicating stimulation of the immune response in a dose-dependent manner. In addition, the production of immune proteins, such as IgG, IgM, and IgA, was enhanced in the blood. Moreover, the 500 mg kg-1 concentration of BN extract stimulated cytokine production in a stronger manner than the 250 mg kg-1 concentration, indicating that the extract significantly increased immune activity. In conclusion, the results indicate that mustard seed extracts have immunosuppressive properties against cyclophosphamide-induced immunosuppression in rats.

Current state-of-the-art on ganglioside-mediated immune modulation in the tumor microenvironment

Gangliosides are sialylated glycolipids, mainly present at the cell surface membrane, involved in a variety of cellular signaling events. During malignant transformation, the composition of these glycosphingolipids is altered, leading to structural and functional changes, which are often negatively correlated to patient survival. Cancer cells have the ability to shed gangliosides into the tumor microenvironment, where they have a strong impact on anti-tumor immunity and promote tumor progression. Since most ganglioside species show prominent immunosuppressive activities, they might be considered checkpoint molecules released to counteract ongoing immunosurveillance. In this review, we highlight the current state-of-the-art on the ganglioside-mediated immunomodulation, specified for the different immune cells and individual gangliosides. In addition, we address the dual role that certain gangliosides play in the tumor microenvironment. Even though some ganglioside species have been more extensively studied than others, they are proven to contribute to the defense mechanisms of the tumor and should be regarded as promising therapeutic targets for inclusion in future immunotherapy regimens.

Regulating tumor microenvironments by a lymph node-targeting adjuvant via tumor-specific CTL-derived IFNγ

Inducing tumor-specific T cell responses and regulating suppressive tumor microenvironments have been a challenge for effective tumor therapy. CpG (ODN), the Toll-like receptor 9 agonist, has been widely used as adjuvants of cancer vaccines to induce T cell responses. We developed a novel adjuvant to improve the targeting of lymph nodes. CpG were modified with lipid and glycopolymers by the combination of photo-induced RAFT polymerization and click chemistry, and the novel adjuvant was termed as lipid-glycoadjuvant@AuNPs (LCpG). OVA protein was used as model antigen and melanoma model was established to test the immunotherapy effect of the adjuvant. In tumor model, the antitumor effect and mechanism of LCpG on the response of CTLs were examined by flow cytometry and cell cytotoxicity assay. The effects of LCpG on macrophage polarization and Tregs differentiation in tumor microenvironment were also studied by cell depletion assay and cytokine neutralization assay. We also tested the therapeutic effect of the combination of the adjuvant and anti-PD-1 treatment. LCpG could be rapidly transported to and retained longer in the lymphoid nodes than unmodified CpG. In melanoma model, LCpG controlled both primary tumor and its metastasis, and established long-term memory. In spleen and tumor draining lymphoid nodes, LCpG activated tumor-specific Tc1 responses, with increased CD8+ T-cell proliferation, antigen-specific Tc1 cytokine production and specific-tumor killing capacity. In tumor microenvironments, antigen-specific Tc1 induced by the LCpG promoted CTL infiltration, skewed tumor associated macrophages to M1 phenotype, regulated Treg and induced proinflammatory cytokines production in a CTL-derived IFN-γ-dependent manner. In vivo cell depletion and adoptive transfer experiments confirmed that antitumor activity of LCpG included vaccine was mainly dependent on CTL-derived IFN-γ. The anti-tumor efficacy of LCpG was dramatically enhanced when combined with anti-PD1 immunotherapy. LCpG was a promising adjuvant for vaccine formulation which could augment tumor-specific Tc1 activity, and regulate tumor microenvironments.

A novel ganglioside-related risk signature can reveal the distinct immune landscape of neuroblastoma and predict the immunotherapeutic response

Introduction

Gangliosides play an essential role in cancer development and progression. However, the involvement of gangliosides in the prognosis and tumor microenvironment (TME) of neuroblastoma is not entirely understood.

Methods

Consensus clustering analysis was performed to identify ganglioside-mediated molecular subtypes. LASSO-Cox analysis was conducted to identify independent prognostic genes, and a novel risk signature was constructed. The risk signature was validated internally and externally. We further explored the independent prognosis value, immune landscape, drug susceptibility, and tumor dedifferentiation of the risk signature. The role of the signature gene B3GALT4 in neuroblastoma was explored in vitro.

Results

Seventeen ganglioside-related genes were differentially expressed between INSS stage 4 and other stages, and two ganglioside-related clusters with distinct prognoses were identified. A novel risk signature integrating ten ganglioside-related prognostic genes was established. Across the train set and external validation sets, the risk signature presented high predictive accuracy and discrimination. The risk signature was an independent prognostic factor and constructed a nomogram combining multiple clinical characteristics. In the high-score group, the deficiency in antigen processing and presenting machinery, lack of immune cell infiltration, and escaping NK cells contributed substantially to immune escape. The low-score group was more responsive to immune checkpoint blockade therapy, while the high-score group showed substantial sensitivity to multiple chemotherapeutic drugs. Besides, the risk score was significantly positively correlated with the stemness index and reduced considerably in all-trans retinoic acid-treated neuroblastoma cell lines, indicating high dedifferentiation in the high-score group. Additionally, neuroblastoma cells with downregulation of B3GALT4 present with increased proliferation, invasion, and metastasis abilities in vitro.

Conclusion

The novel ganglioside-related risk signature highlights the role of ganglioside in neuroblastoma prognosis and immune landscape and helps optimize chemotherapy and immunotherapy for neuroblastoma.

Human repair-related Schwann cells adopt functions of antigen-presenting cells in vitro

The plastic potential of Schwann cells (SCs) is increasingly recognized to play a role after nerve injury and in diseases of the peripheral nervous system. Reports on the interaction between immune cells and SCs indicate their involvement in inflammatory processes. However, the immunocompetence of human SCs has been primarily deduced from neuropathies, but whether after nerve injury SCs directly regulate an adaptive immune response is unknown. Here, we performed comprehensive analysis of immunomodulatory capacities of human repair-related SCs (hrSCs), which recapitulate SC response to nerve injury in vitro. We used our well-established culture model of primary hrSCs from human peripheral nerves and analyzed the transcriptome, secretome, and cell surface proteins for pathways and markers relevant in innate and adaptive immunity, performed phagocytosis assays, and monitored T-cell subset activation in allogeneic co-cultures. Our findings show that hrSCs are phagocytic, which is in line with high MHCII expression. Furthermore, hrSCs express co-regulatory proteins, such as CD40, CD80, B7H3, CD58, CD86, and HVEM, release a plethora of chemoattractants, matrix remodeling proteins and pro- as well as anti-inflammatory cytokines, and upregulate the T-cell inhibiting PD-L1 molecule upon pro-inflammatory stimulation with IFNγ. In contrast to monocytes, hrSC alone are not sufficient to trigger allogenic CD4+ and CD8+ T-cells, but limit number and activation status of exogenously activated T-cells. This study demonstrates that hrSCs possess features and functions typical for professional antigen-presenting cells in vitro, and suggest a new role of these cells as negative regulators of T-cell immunity during nerve regeneration.

Evaluating the Nutritional and Immune Potentiating Characteristics of Unfermented and Fermented Turmeric Camel Milk in Cyclophosphamide-Induced Immunosuppression in Rats

Antioxidative, nutritional, and immune-boosting characteristics of turmeric-camel milk (TCM) and fermented turmeric-camel milk (FTCM) were investigated. A cyclophosphamide-induced immunosuppression rat model consisting of six experimental groups was carried out to study the effects of TCM and FTCM on weight gain, antioxidant status, immunoglobulin (Igs), pro-inflammatory and anti-inflammatory cytokines, and oxidative stress biomarkers. TCM or FTCM were orally administrated at 10 or 20 mL Kg^-1 rat weight to CYP-immunosuppressed rats for 2 weeks in the presence of negative (NR) and positive (CYP) control groups. The phytochemical analysis and antioxidant capacity results indicated that TCM and FTCM contained considerable phenolic content with super antioxidant activities. CYP injection affected the rats' weight directly during the first week and then, a low weight gain percentage was recorded in treated groups at the end of the experiment. The most efficient treatment for recovering rats' weight was administering TCM and FTCM at 20 mL kg^-1. Feed efficiency significantly increased with feeding TCM and FTCM in a dose-dependent manner. A significant improvement was found in WBCs, lymphocytes, and neutrophils count, suggesting that both TCM and FTCM alleviated the CYP-induced immunity suppression in a dose-dependent manner. IgG, IgA, and IgM concentrations in the CYP + TCM at 10 or 20 mL kg^-1 and CYP + FTCM at 10 or 20 mL kg^-1 groups were increased significantly. Concentrations of IL-1 beta, IL-6, IL-10, IL-13, and IL-TNF-α in the CYP group were significantly lower than in the NR group. Interestingly, both TCM and FTCM, especially with high doses, significantly enhanced cytokines production. Administrating FTCM was more potent than TCM, indicating that TCM with probiotics fermentation potentiated the immunological activity in immunosuppressed rats. Treated rats with TCM and FTCM can reverse CYP inhibition of antioxidant enzyme activities, significantly increase GSH, CAT, and SOD, and decrease MDA levels in a dose-dependent manner. In conclusion, these observations indicated that FTCM exhibits better improvements in weight gain, increased immune biomarkers in terms of WBCs, enhanced pro-inflammation and anti-inflammation responses, and accelerated antioxidant activity in immunosuppressed rats compared with TCM. It could be beneficial and profitable for boosting immunity and protecting against oxidative stress.

An ultrasound-driven immune-boosting molecular machine for systemic tumor suppression

Exploring facile and effective therapeutic modalities for synergistically controlling primary tumor and metastasis remains a pressing clinical need. Sonodynamic therapy (SDT) offers the possibility of noninvasively eradicating local solid tumors, but lacks antimetastatic activity because of its limited ability in generating systemic antitumor effect. Here, we exploited a previously unidentified ultrasound-driven “molecular machine,” DYSP-C34 (C34 for short), with multiple attractive features, emerging from preferential tumor accumulation, potent ultrasound-triggered cytotoxicity, and intrinsic immune-boosting capacity. Driven by the ultrasound, C34 functioned not only as a tumor cell killing reagent but also as an immune booster that could potentiate robust adaptive antitumor immunity by directly stimulating dendritic cells, resulting in the eradication of the primary solid tumor along with the inhibition of metastasis. This molecular machine, C34, rendered great promise to achieve systemic treatment against cancer via unimolecule-mediated SDT.

Plasmonic enhanced enzyme activity by catalytic cascade induced mutual benefit tumor starvation/immune/photothermal therapy

Single tumor starvation therapy can activate other signaling pathways in tumor cells and easily induce tumor cell metastasis. This research proposes an intelligent nanoparticle, which is effectively combined with plasmonic and immunotherapy to realize a new strategy of "upstream consumption and downstream blocking" of nutrients in tumor sites. The intelligent nanoparticle (Ag-G/C@M) was composed of Ag NCs loaded with glucose oxidase (GOx), catalase (CAT) and coated with the tumor cytomembrane (M). Homologous targeting of tumor cytomembrane facilitated more delivery of Ag-G/C@M to tumor sites and then the plasmonic excited from Ag-G/C@M can increase the catalytic efficiency of the enzymatic reaction. Hydrogen peroxide (H₂O₂) produced by Ag-G/C@M through the consumption of glucose is further catalyzed by CAT to produce oxygen (O₂). This self-reinforcing cascade reaction not only consumes the nutrients of tumor cells, but also the plasmonic-induced photothermal therapy can further stimulate the immune system to produce interferon-γ (IFN-γ), blocking angiogenesis and restricting the nutrient supply of tumor cells. This strategy takes the nutrition necessary for cell survival as the entry point, through endogenous continuous consumption of intracellular nutrients and containment of exogenous supplementation, combined with plasmonic thermal effect and immunotherapy to kill tumor cells, which provides a new way of treating cancer safely and effectively.

Multiplicity of Glycosphingolipid-Enriched Microdomain-Driven Immune Signaling

Glycosphingolipids (GSLs), together with cholesterol, sphingomyelin (SM), and glycosylphosphatidylinositol (GPI)-anchored and membrane-associated signal transduction molecules, form GSL-enriched microdomains. These specialized microdomains interact in a cis manner with various immune receptors, affecting immune receptor-mediated signaling. This, in turn, results in the regulation of a broad range of immunological functions, including phagocytosis, cytokine production, antigen presentation and apoptosis. In addition, GSLs alone can regulate immunological functions by acting as ligands for immune receptors, and exogenous GSLs can alter the organization of microdomains and microdomain-associated signaling. Many pathogens, including viruses, bacteria and fungi, enter host cells by binding to GSL-enriched microdomains. Intracellular pathogens survive inside phagocytes by manipulating intracellular microdomain-driven signaling and/or sphingolipid metabolism pathways. This review describes the mechanisms by which GSL-enriched microdomains regulate immune signaling.

Tumor microenvironment: Challenges and opportunities in targeting metastasis of triple negative breast cancer

Triple negative breast cancer (TNBC) is most aggressive subtype of breast cancers with high probability of metastasis as well as lack of specific targets and targeted therapeutics. TNBC is characterized with unique tumor microenvironment (TME), which differs from other subtypes. TME is associated with induction of proliferation, angiogenesis, inhibition of apoptosis and immune system suppression, and drug resistance. Exosomes are promising nanovesicles, which orchestrate the TME by communicating with different cells within TME. The components of TME including transformed ECM, soluble factors, immune suppressive cells, epigenetic modifications and re-programmed fibroblasts together hamper antitumor response and helps progression and metastasis of TNBCs. Therefore, TME could be a therapeutic target of TNBC. The current review presents latest updates on the role of exosomes in modulation of TME, approaches for targeting TME and combination of immune checkpoint inhibitors and target chemotherapeutics. Finally, we also discussed various phytochemicals that alter genetic, transcriptomic and proteomic profiles of TME along with current challenges and future implications. Thus, as TME is associated with the hallmarks of TNBC, the understanding of the impact of different components can improve the clinical benefits of TNBC patients.

Immunomodulatory Effects of Phosphorylated Radix Cyathulae officinalis Polysaccharides in Immunosuppressed Mice

This research aimed to investigate the immunomodulatory effects of phosphorylated Radix Cyathulae officinalis Kuan polysaccharides (pRCPS) in immunosuppressed mice, improving their cellular and humoral immune function. Our results showed that pRCPS increased serum immunoglobulin (IgG, IgA, IgM) concentrations significantly, enhanced splenocyte proliferation, and the thymus and spleen indices. pRCPS also promoted phagocytosis in peritoneal macrophages and enhanced cytokine (IFN-γ, IL-2, -4, -5, -6, and -10) serum levels. Importantly, pRCPS increased the proportions of selected T cell subpopulations (CD3+, CD4+, and the CD4+ to CD8+ ratio). Our results revealed that phosphorylation of the polysaccharides promoted their immune-enhancing effects. Thus, pRCPS can enhance cellular and humoral immunity and could be used as an immune-enhancing agent to overcome cyclophosphamide (CY)-induced immunosuppression.

The Interferon-Gamma Paradox in Cancer

Interferon-gamma (IFNG) has long been implicated as a central orchestrator of antitumor immune responses in the elimination stage of the immunoediting paradigm. However, mounting evidence suggests that IFNG may also have important and significant protumor roles to play in the equilibrium and escape phases through its regulatory effects on immunoevasive functions that promote tumorigenesis. These seemingly contradictory effects of IFNG undoubtedly play profound roles in not only the activation of inflammatory response to cancer but also in the determination of its outcome. In the face of the recent explosion of anticancer immunotherapeutic strategies in the clinic, it is critical that a complete understanding is achieved of the underpinnings of the mechanisms that determine the two faces of IFNG signaling in cancer. Here, the current state of this dichotomy is reviewed.