Potentiating the antitumour response of CD8(+) T cells by modulating cholesterol metabolism. Nature. 2016;531:651-655. [PMID: 26982734 DOI: 10.1038/nature17412]

Myeloid-derived suppressor cells deficient in cholesterol biosynthesis promote tumor immune evasion

Cancer immunotherapy targeting myeloid-derived suppressor cells (MDSCs) is one of the most promising anticancer strategies. Metabolic reprogramming is vital for MDSC activation, however, the regulatory mechanisms of cholesterol metabolic reprogramming in MDSCs remains largely unexplored. Using the receptor-interacting protein kinase 3 (RIPK3)-deficient MDSC model, a previously established tumor-infiltrating MDSC-like model, we found that the cholesterol accumulation was significantly decreased in these cells. Moreover, the phosphorylated AKT-mTORC1 signaling was reduced, and downstream SREBP2-HMGCR-mediated cholesterol synthesis was blunted. Interestingly, cholesterol deficiency profoundly elevated the immunosuppressive activity of MDSCs. Mechanistically, cholesterol elimination induced nuclear accumulation of LXRβ, thereby promoting LXRβ-RXRα heterodimer binding of a novel composite element in the promoter of Arg1. Furthermore, itraconazole enhanced the immunosuppressive activity of MDSCs to boost tumor growth by suppressing the RIPK3-AKT-mTORC1 pathway and impeding cholesterol synthesis. Our findings demonstrate that RIPK3 deficiency leads to cholesterol abrogation in MDSCs, which facilitates tumor-infiltrating MDSC activation, and highlight the therapeutic potential of targeting cholesterol synthesis to overcome tumor immune evasion.

A rising tide lifts all MBOATs: recent progress in structural and functional understanding of membrane bound O-acyltransferases

Acylation modifications play a central role in biological and physiological processes. Across a range of biomolecules from phospholipids to triglycerides to proteins, introduction of a hydrophobic acyl chain can dramatically alter the biological function and cellular localization of these substrates. Amongst the enzymes catalyzing these modifications, the membrane bound O-acyltransferase (MBOAT) family occupies an intriguing position as the combined substrate selectivities of the various family members span all three classes of these biomolecules. MBOAT-dependent substrates are linked to a wide range of health conditions including metabolic disease, cancer, and neurodegenerative disease. Like many integral membrane proteins, these enzymes have presented challenges to investigation due to their intractability to solubilization and purification. However, over the last several years new solubilization approaches coupled with computational modeling, crystallography, and cryoelectron microscopy have brought an explosion of structural information for multiple MBOAT family members. These studies enable comparison of MBOAT structure and function across members catalyzing modifications of all three substrate classes, revealing both conserved features amongst all MBOATs and distinct architectural features that correlate with different acylation substrates ranging from lipids to proteins. We discuss the methods that led to this renaissance of MBOAT structural investigations, our new understanding of MBOAT structure and implications for catalytic function, and the potential impact of these studies for development of new therapeutics targeting MBOAT-dependent physiological processes.

Predictive impact of prognostic nutritional index in patients with cancer treated with immune checkpoint inhibitors: a systematic review and meta-analysis

A few previous studies have investigated the prognostic value of the prognostic nutritional index (PNI) in patients treated with immune checkpoint inhibitors (ICIs); however, the results are inconsistent. Therefore, this study aimed to clarify the prognostic significance of PNI. The PubMed, Embase, and Cochrane Library databases were searched. A meta-analysis of the impact of PNI on overall survival (OS), progression-free survival (PFS), objective response rate (ORR), disease control rate (DCR), and rate of adverse events (AEs) in patients treated with ICIs was performed. Twenty-three studies involving 2,386 patients were included. Low PNI was associated with significantly poor OS (hazard ratio [HR] = 2.26, 95% confidence interval [CI]: 1.81-2.82, P < .001) and short PFS (HR = 1.75, 95% CI: 1.54-1.99, P < .001). Patients with low PNI tended to have a low ORR (odds ratio [OR] = 0.47, 95% CI: 0.34-0.65, P < .001) and DCR (OR = 0.43, 95% CI: 0.34-0.56, P < .001). However, the subgroup analysis demonstrated no significant association between PNI and survival time in patients receiving a programmed death ligand-1 inhibitor. PNI was significantly associated with survival time and treatment efficacy in patients treated with ICIs.

Role of T cells in the pathogenesis of systemic lupus erythematous: Focus on immunometabolism dysfunctions

Evidence demonstrates that T cells are implicated in developing SLE, and each of them dominantly uses distinct metabolic pathways. Indeed, intracellular enzymes and availability of specific nutrients orchestrate fate of T cells and lead to differentiation of regulatory T cells (Treg), memory T cells, helper T cells, and effector T cells. The function of T cells in inflammatory and autoimmune responses is determined by metabolic processes and activity of their enzymes. Several studies were conducted to determine metabolic abnormalities in SLE patients and clarify how these modifications could control the functions of the involved T cells. Metabolic pathways such as glycolysis, mitochondrial pathways, oxidative stress, mTOR pathway, fatty acid and amino acid metabolisms are dysregulated in SLE T cells. Moreover, immunosuppressive drugs used in treating autoimmune diseases, including SLE, could affect immunometabolism. Developing drugs to regulate autoreactive T cell metabolism could be a promising therapeutic approach for SLE treatment. Accordingly, increased knowledge about metabolic processes paves the way to understanding SLE pathogenesis better and introduces novel therapeutic options for SLE treatment. Although monotherapy with metabolic pathways modulators might not be sufficient to prevent autoimmune disease, they may be an ideal adjuvant to reduce administration doses of immunosuppressive drugs, thus reducing drug-associated adverse effects. This review summarized emerging data about T cells that are involved in SLE pathogenesis, focusing on immunometabolism dysregulation and how these modifications could affect the disease development.

Smart drug delivery systems to overcome drug resistance in cancer immunotherapy

Cancer immunotherapy, a therapeutic approach that inhibits tumors by activating or strengthening anti-tumor immunity, is currently an important clinical strategy for cancer treatment; however, tumors can develop drug resistance to immune surveillance, resulting in poor response rates and low therapeutic efficacy. In addition, changes in genes and signaling pathways in tumor cells prevent susceptibility to immunotherapeutic agents. Furthermore, tumors create an immunosuppressive microenvironment via immunosuppressive cells and secrete molecules that hinder immune cell and immune modulator infiltration or induce immune cell malfunction. To address these challenges, smart drug delivery systems (SDDSs) have been developed to overcome tumor cell resistance to immunomodulators, restore or boost immune cell activity, and magnify immune responses. To combat resistance to small molecules and monoclonal antibodies, SDDSs are used to co-deliver numerous therapeutic agents to tumor cells or immunosuppressive cells, thus increasing the drug concentration at the target site and improving efficacy. Herein, we discuss how SDDSs overcome drug resistance during cancer immunotherapy, with a focus on recent SDDS advances in thwarting drug resistance in immunotherapy by combining immunogenic cell death with immunotherapy and reversing the tumor immunosuppressive microenvironment. SDDSs that modulate the interferon signaling pathway and improve the efficacy of cell therapies are also presented. Finally, we discuss potential future SDDS perspectives in overcoming drug resistance in cancer immunotherapy. We believe that this review will contribute to the rational design of SDDSs and development of novel techniques to overcome immunotherapy resistance.

P53 deficiency affects cholesterol esterification to exacerbate hepatocarcinogenesis

BACKGROUND AND AIMS

Cholesterol ester (CE) biosynthesis and homeostasis play critical roles in many cancers, including HCC, but their exact mechanistic contributions to HCC disease development require further study.

APPROACH AND RESULTS

Here, we report on a proposed role of tumor suppressor P53 in its repressing ubiquitin-specific peptidase 19 (USP19) and sterol O-acyltransferase (SOAT) 1, which maintains CE homeostasis. USP19 enhances cholesterol esterification and contributes to hepatocarcinogenesis (HCG) by deubiquitinating and stabilizing SOAT1. Loss of either SOAT1 or USP19 dramatically attenuates cholesterol esterification and HCG in P53-deficient mice fed with either a normal chow diet or a high-cholesterol, high-fat diet (HCHFD). SOAT1 inhibitor avasimibe has more inhibitory effect on HCC progression in HCHFD-maintained P53-deficient mice when compared to the inhibitors of de novo cholesterol synthesis. Consistent with our findings in the mouse model, the P53-USP19-SOAT1 signaling axis is also dysregulated in human HCCs.

CONCLUSIONS

Collectively, our findings demonstrate that SOAT1 participates in HCG by increasing cholesterol esterification, thus indicating that SOAT1 is a potential biomarker and therapeutic target in P53-deficient HCC.

An ACAT inhibitor suppresses SARS-CoV-2 replication and boosts antiviral T cell activity

The severity of disease following infection with SARS-CoV-2 is determined by viral replication kinetics and host immunity, with early T cell responses and/or suppression of viraemia driving a favourable outcome. Recent studies uncovered a role for cholesterol metabolism in the SARS-CoV-2 life cycle and in T cell function. Here we show that blockade of the enzyme Acyl-CoA:cholesterol acyltransferase (ACAT) with Avasimibe inhibits SARS-CoV-2 pseudoparticle infection and disrupts the association of ACE2 and GM1 lipid rafts on the cell membrane, perturbing viral attachment. Imaging SARS-CoV-2 RNAs at the single cell level using a viral replicon model identifies the capacity of Avasimibe to limit the establishment of replication complexes required for RNA replication. Genetic studies to transiently silence or overexpress ACAT isoforms confirmed a role for ACAT in SARS-CoV-2 infection. Furthermore, Avasimibe boosts the expansion of functional SARS-CoV-2-specific T cells from the blood of patients sampled during the acute phase of infection. Thus, re-purposing of ACAT inhibitors provides a compelling therapeutic strategy for the treatment of COVID-19 to achieve both antiviral and immunomodulatory effects. Trial registration: NCT04318314.

Blocking Cholesterol Metabolism with Tumor-Penetrable Nanovesicles to Improve Photodynamic Cancer Immunotherapy

Photodynamic therapy (PDT)-mediated cancer immunotherapy is attenuated due to the dysfunction of T cells in immunosuppressive tumor microenvironment (TME). Cholesterol metabolism plays a vital role in T cell signaling and effector. While the metabolic fitness of tumor infiltrating CD8⁺ T cells is impaired by nutrition restriction in TME and accumulated metabolites by tumor cells. Here a matrix metalloproteinase-2-sensitive tumor-penetrable nanovesicle is designed to regulate cholesterol metabolism pathway for enhancing photodynamic cancer immunotherapy. The nanovesicles accumulate in tumor and release internalizing RGD to promote deep penetration. Released avasimibe from the nanovesicles simultaneously blocks cholesterol metabolism in CD8⁺ T and tumor cells, thus reinvigorating the functions of T cells and suppressing the migration of tumor cells. Immune responses induced by PDT-triggered immunogenic cell death are further improved with cholesterol metabolism blockage. Compared with PDT alone, the designed nanovesicles display enhanced tumor growth inhibition in B16-F10 mouse tumor model. The approach provides an alternative strategy to improve photodynamic cancer immunotherapy by cholesterol metabolism intervention.

[Latest Findings on the Function of Immune Metabolism in Tumor Immunity]

Metabolic reprogramming, an important hallmark of cancer, helps cancer achieve rapid proliferation. Metabolic changes in tumors regulate multiple metabolic pathways of immune cells, thereby suppressing antitumor immunity. Recent studies have been focused on in-depth investigation into the changes in the metabolism of glucose, amino acids, and lipids. Researchers have also conducted in-depth exploration of the interactive metabolic regulation of tumor cells and immune cells. Targeting various metabolic mechanisms while combining available anti-tumor therapies and enhancing the anti-tumor effects of immunotherapy by satisfying the metabolic demands of immune cells has offered new perspectives for therapies targeting the immune metabolism of tumors and enhancing anti-tumor immune responses. Studies on novel immune checkpoint molecules and cellular immunotherapies are also ongoing. Herein, we reviewed the latest findings on the mechanisms of immune metabolism underlying tumor immunosuppression and their application in immunotherapy. We also suggested some ideas for the future development of the regulation of immune metabolism.

The role of tumor metabolism in modulating T-Cell activity and in optimizing immunotherapy

Immunotherapy has revolutionized cancer treatment and revitalized efforts to harness the power of the immune system to combat a variety of cancer types more effectively. However, low clinical response rates and differences in outcomes due to variations in the immune landscape among patients with cancer continue to be major limitations to immunotherapy. Recent efforts to improve responses to immunotherapy have focused on targeting cellular metabolism, as the metabolic characteristics of cancer cells can directly influence the activity and metabolism of immune cells, particularly T cells. Although the metabolic pathways of various cancer cells and T cells have been extensively reviewed, the intersections among these pathways, and their potential use as targets for improving responses to immune-checkpoint blockade therapies, are not completely understood. This review focuses on the interplay between tumor metabolites and T-cell dysfunction as well as the relationship between several T-cell metabolic patterns and T-cell activity/function in tumor immunology. Understanding these relationships could offer new avenues for improving responses to immunotherapy on a metabolic basis.

The role of lipid metabolism in cancer radioresistance

Radiotherapy is one of the main therapies for cancer. The process leading to radioresistance is still not fully understood. Cancer radiosensitivity is related to the DNA reparation of cancer cells and the tumor microenvironment (TME), which supports cancer cell survival. Factors that affect DNA reparation and the TME can directly or indirectly affect the radiosensitivity of cancer. Recent studies have shown that lipid metabolism in cancer cells, which is involved in the stability of cell membrane structure, energy supply and signal transduction of cancer cells, can also affect the phenotype and function of immune cells and stromal cells in the TME. In this review, we discussed the effects of lipid metabolism on the radiobiological characteristics of cancer cells and the TME. We also summarized recent advances in targeted lipid metabolism as a radiosensitizer and discussed how these scientific findings could be translated into clinical practice to improve the radiosensitivity of cancer.

Lipid metabolism of hepatocellular carcinoma impacts targeted therapy and immunotherapy

Hepatocellular carcinoma (HCC) is a common malignant tumor that affecting many people's lives globally. The common risk factors for HCC include being overweight and obese. The liver is the center of lipid metabolism, synthesizing most cholesterol and fatty acids. Abnormal lipid metabolism is a significant feature of metabolic reprogramming in HCC and affects the prognosis of HCC patients by regulating inflammatory responses and changing the immune microenvironment. Targeted therapy and immunotherapy are being explored as the primary treatment strategies for HCC patients with unresectable tumors. Here, we detail the specific changes of lipid metabolism in HCC and its impact on both these therapies for HCC. HCC treatment strategies aimed at targeting lipid metabolism and how to integrate them with targeted therapy or immunotherapy rationally are also presented.

Metabolic challenges and interventions in CAR T cell therapy

Chimeric antigen receptor (CAR) T cells have achieved true clinical success in treating hematological malignancy patients, laying the foundation of CAR T cells as a new pillar of cancer therapy. Although these promising effects have generated strong interest in expanding the treatment of CAR T cells to solid tumors, reproducible demonstration of clinical efficacy in the setting of solid tumors has remained challenging to date. Here, we review how metabolic stress and signaling in the tumor microenvironment, including intrinsic determinants of response to CAR T cell therapy and extrinsic obstacles, restrict the efficacy of CAR T cell therapy in cancer treatment. In addition, we discuss the use of novel approaches to target and rewire metabolic programming for CAR T cell manufacturing. Last, we summarize strategies that aim to improve the metabolic adaptability of CAR T cells to enhance their potency in mounting antitumor responses and survival within the tumor microenvironment.

Novel strategies for cancer immunotherapy: counter-immunoediting therapy

The advent of immunotherapy has made an indelible mark on the field of cancer therapy, especially the application of immune checkpoint inhibitors in clinical practice. Although immunotherapy has proven its efficacy and safety in some tumors, many patients still have innate or acquired resistance to immunotherapy. The emergence of this phenomenon is closely related to the highly heterogeneous immune microenvironment formed by tumor cells after undergoing cancer immunoediting. The process of cancer immunoediting refers to the cooperative interaction between tumor cells and the immune system that involves three phases: elimination, equilibrium, and escape. During these phases, conflicting interactions between the immune system and tumor cells result in the formation of a complex immune microenvironment, which contributes to the acquisition of different levels of immunotherapy resistance in tumor cells. In this review, we summarize the characteristics of different phases of cancer immunoediting and the corresponding therapeutic tools, and we propose normalized therapeutic strategies based on immunophenotyping. The process of cancer immunoediting is retrograded through targeted interventions in different phases of cancer immunoediting, making immunotherapy in the context of precision therapy the most promising therapy to cure cancer.

Targeting inhibition of prognosis-related lipid metabolism genes including CYP19A1 enhances immunotherapeutic response in colon cancer

BACKGROUND

Lipid metabolic reprogramming in colon cancer shows a potential impact on tumor immune microenvironment and is associated with response to immunotherapy. Therefore, this study aimed to develop a lipid metabolism-related prognostic risk score (LMrisk) to provide new biomarkers and combination therapy strategies for colon cancer immunotherapy.

METHODS

Differentially expressed lipid metabolism-related genes (LMGs) including cytochrome P450 (CYP) 19A1 were screened to construct LMrisk in TCGA colon cancer cohort. The LMrisk was then validated in three GEO datasets. The differences of immune cell infiltration and immunotherapy response between LMrisk subgroups were investigated via bioinformatic analysis. These results were comfirmed by in vitro coculture of colon cancer cells with peripheral blood mononuclear cells, human colon cancer tissue microarray analysis, multiplex immunofluorescence staining and mouse xenograft models of colon cancer.

RESULTS

Six LMGs including CYP19A1, ALOXE3, FABP4, LRP2, SLCO1A2 and PPARGC1A were selected to establish the LMrisk. The LMrisk was positively correlated with the abundance of macrophages, carcinoma-associated fibroblasts (CAFs), endothelial cells and the levels of biomarkers for immunotherapeutic response including programmed cell death ligand 1 (PD-L1) expression, tumor mutation burden and microsatellite instability, but negatively correlated with CD8⁺ T cell infiltration levels. CYP19A1 protein expression was an independent prognostic factor, and positively correlated with PD-L1 expression in human colon cancer tissues. Multiplex immunofluorescence analyses revealed that CYP19A1 protein expression was negatively correlated with CD8⁺ T cell infiltration, but positively correlated with the levels of tumor-associated macrophages, CAFs and endothelial cells. Importantly, CYP19A1 inhibition downregulated PD-L1, IL-6 and TGF-β levels through GPR30-AKT signaling, thereby enhancing CD8⁺ T cell-mediated antitumor immune response in vitro co-culture studies. CYP19A1 inhibition by letrozole or siRNA strengthened the anti-tumor immune response of CD8⁺ T cells, induced normalization of tumor blood vessels, and enhanced the efficacy of anti-PD-1 therapy in orthotopic and subcutaneous mouse colon cancer models.

CONCLUSION

A risk model based on lipid metabolism-related genes may predict prognosis and immunotherapeutic response in colon cancer. CYP19A1-catalyzed estrogen biosynthesis promotes vascular abnormality and inhibits CD8⁺ T cell function through the upregulation of PD-L1, IL-6 and TGF-β via GPR30-AKT signaling. CYP19A1 inhibition combined with PD-1 blockade represents a promising therapeutic strategy for colon cancer immunotherapy.

Prognostic Value for Perioperative Serum Total Cholesterol Level on Postoperative Long-Term Prognosis of Pancreatic Cancer: A Retrospective Clinical Study

Cholesterol correlates with occurrence and progression of pancreatic cancer and has predictive value for postoperative prognosis in various cancers. Our study intended to reveal the relationship between perioperative serum total cholesterol (TC) level and postoperative prognosis of pancreatic cancer. We retrospectively analyzed the data of pancreatic cancer patients who underwent surgical treatment at our hospital from January 2015 to December 2021. ROC curves between serum TC level at each time point and 1-year survival rate were drawn, from which study object and optimal cutoff value was determined. Patients were divided into low and high-TC groups, and perioperative data and prognosis were compared. Risk factors for poor postoperative prognosis were identified by univariate and multivariate analysis. Overall survival rates at postoperative 1, 2 and 3 years in the low and high-TC groups were 52.9%, 29.4%, and 15.6% and 80.4%, 47.2%, and 33.8% (p = 0.005), respectively. Multivariate analysis confirmed tumor differentiation degree (RR = 2.054, 95% CI: 1.396-3.025), pTNM stage (RR = 1.595, 95% CI: 1.020-2.494), lymph node metastasis (RR = 1.693, 95% CI: 1.127-2.544), and postoperative 4-week serum TC level (RR = 0.663, 95% CI: 0.466-0.944) as independent risk factors for prognosis of pancreatic cancer. We conclude that postoperative 4-week serum TC level has certain predictive value for long-term postoperative prognosis of pancreatic cancer.

A pan-cancer analysis identifies SOAT1 as an immunological and prognostic biomarker

Sterol o-acyltransferase1 (SOAT1) is an enzyme that regulates lipid metabolism. Nevertheless, the predictive value of SOAT1 regarding immune responses in cancer is not fully understood. Herein, we aimed to expound the predictive value and the potential biological functions of SOAT1 in pan-cancer. Raw data related to SOAT1 expression in 33 different types of cancer were acquired from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) databases. SOAT1 expression was significantly increased in most cancers and showed a distinct correlation with prognosis. This enhanced expression of the SOAT1 gene was confirmed by evaluating SOAT1 protein expression using tissue microarrays. In addition, we found significant positive associations between SOAT1 expression levels and infiltrating immune cells, including T cells, neutrophils, and macrophages. Moreover, the co-expression analysis between SOAT1 and immune genes showed that many immune-related genes were increased with enhanced SOAT1 expression. A gene set enrichment analysis (GSEA) revealed that the expression of SOAT1 correlated with the tumor microenvironment, adaptive immune response, interferon signaling, and cytokine signaling. These findings indicate that SOAT1 is a potential candidate marker for predicting prognosis and a promising target for tumor immunotherapy in cancers.

Monomeric C-reactive protein evokes TCR Signaling-dependent bystander activation of CD4+ T cells

Bystander activation of T cells is defined as induction of effector responses by innate cytokines in the absence of cognate antigens and independent of T cell receptor (TCR) signaling. Here we show that C-reactive protein (CRP), a soluble pattern-recognition receptor assembled noncovalently by five identical subunits, can instead trigger bystander activation of CD4 + T cells by evoking allosteric activation and spontaneous signaling of TCR in the absence of cognate antigens. The actions of CRP depend on pattern ligand-binding induced conformational changes that result in the generation of monomeric CRP (mCRP). mCRP binds cholesterol in plasma membranes of CD4 + T cells, thereby shifting the conformational equilibrium of TCR to the cholesterol-unbound, primed state. The spontaneous signaling of primed TCR leads to productive effector responses manifested by upregulation of surface activation markers and release of IFN-γ. Our results thus identify a novel mode of bystander T cell activation triggered by allosteric TCR signaling, and reveal an interesting paradigm wherein innate immune recognition of CRP transforms it to a direct activator that evokes immediate adaptive immune responses.

Targeting Microglial Metabolic Rewiring Synergizes with Immune-Checkpoint Blockade Therapy for Glioblastoma

Glioblastoma (GBM) constitutes the most lethal primary brain tumor for which immunotherapy has provided limited benefit. The unique brain immune landscape is reflected in a complex tumor immune microenvironment (TIME) in GBM. Here, single-cell sequencing of the GBM TIME revealed that microglia were under severe oxidative stress, which induced nuclear receptor subfamily 4 group A member 2 (NR4A2)-dependent transcriptional activity in microglia. Heterozygous Nr4a2 (Nr4a2+/-) or CX3CR1+ myeloid cell-specific Nr4a2 (Nr4a2fl/flCx3cr1Cre) genetic targeting reshaped microglia plasticity in vivo by reducing alternatively activated microglia and enhancing antigen presentation capacity for CD8+ T cells in GBM. In microglia, NR4A2 activated squalene monooxygenase (SQLE) to dysregulate cholesterol homeostasis. Pharmacologic NR4A2 inhibition attenuated the protumorigenic TIME, and targeting the NR4A2 or SQLE enhanced the therapeutic efficacy of immune-checkpoint blockade in vivo. Collectively, oxidative stress promotes tumor growth through NR4A2-SQLE activity in microglia, informing novel immune therapy paradigms in brain cancer.

SIGNIFICANCE

Metabolic reprogramming of microglia in GBM informs synergistic vulnerabilities for immune-checkpoint blockade therapy in this immunologically cold brain tumor. This article is highlighted in the In This Issue feature, p. 799.

Nanomedicine sheds new light on cancer immunotherapy

Cancer immunotherapy comprising of immune checkpoint blockade (ICB) therapy, immune cell therapies, cancer vaccines and many others represents a profound arsenal in the fight against different types of cancers. However, their overall clinical objective response rates, particularly against most solid tumors, are still not sufficient owing to a variety of reasons including the heterogenous expression of tumor antigens, limited tumor infiltration of effector immune cells, acquired tumor immunosuppression and some other factors. In recent years, various nanomedicine strategies have been proposed to assist cancer immunotherapy via distinct mechanisms, presenting new promises in many published studies. This perspective will thus provide a brief overview regarding the development of nanomedicine platforms for improving cancer immunotherapy.

Cholesterol suppresses human iTreg differentiation and nTreg function through mitochondria-related mechanisms

BACKGROUND

Both the crystalline and soluble forms of cholesterol increase macrophage secretion of interleukin 1β (IL-1β), aggravating the inflammatory response in atherosclerosis (AS). However, the link between cholesterol and regulatory T cells (Tregs) remains unclear. This study aimed to investigate the effect of cholesterol treatment on Tregs.

METHODS

Differentiation of induced Tregs (iTregs) was analyzed using flow cytometry. The expression of hypoxia-inducible factor-1a (HIF-1a) and its target genes was measured by western blotting and/or RT-qPCR. Two reporter jurkat cell lines were constructed by lentiviral transfection. Mitochondrial function and the structure of natural Tregs (nTregs) were determined by tetramethylrhodamine (TMRM) and mitoSOX staining, Seahorse assay, and electron microscopy. The immunoregulatory function of nTregs was determined by nTreg-macrophage co-culture assay and ELISA.

RESULTS

Cholesterol treatment suppressed iTreg differentiation and impaired nTreg function. Mechanistically, cholesterol induced the production of mitochondrial reactive oxygen species (mtROS) in naïve T cells, inhibiting the degradation of HIF-1α and unleashing its inhibitory effects on iTreg differentiation. Furthermore, cholesterol-induced mitochondrial oxidative damage impaired the immunosuppressive function of nTregs. Mixed lymphocyte reaction and nTreg-macrophage co-culture assays revealed that cholesterol treatment compromised the ability of nTregs to inhibit pro-inflammatory conventional T cell proliferation and promote the anti-inflammatory functions of macrophages. Finally, mitoTEMPO (MT), a specific mtROS scavenger, restored iTreg differentiation and protected nTreg from further deterioration.

CONCLUSION

Our findings suggest that cholesterol may aggravate inflammation within AS plaques by acting on both iTregs and nTregs, and that MT may be a promising anti-atherogenic drug.

ACAT1/SOAT1 Blockade Suppresses LPS-Mediated Neuroinflammation by Modulating the Fate of Toll-like Receptor 4 in Microglia

Cholesterol is stored as cholesteryl esters by the enzymes acyl-CoA:cholesterol acyltransferases/sterol O:acyltransferases (ACATs/SOATs). ACAT1 blockade (A1B) ameliorates the pro-inflammatory responses of macrophages to lipopolysaccharides (LPS) and cholesterol loading. However, the mediators involved in transmitting the effects of A1B in immune cells is unknown. Microglial Acat1/Soat1 expression is elevated in many neurodegenerative diseases and in acute neuroinflammation. We evaluated LPS-induced neuroinflammation experiments in control vs. myeloid-specific Acat1/Soat1 knockout mice. We also evaluated LPS-induced neuroinflammation in microglial N9 cells with and without pre-treatment with K-604, a selective ACAT1 inhibitor. Biochemical and microscopy assays were used to monitor the fate of Toll-Like Receptor 4 (TLR4), the receptor at the plasma membrane and the endosomal membrane that mediates pro-inflammatory signaling cascades. In the hippocampus and cortex, results revealed that Acat1/Soat1 inactivation in myeloid cell lineage markedly attenuated LPS-induced activation of pro-inflammatory response genes. Studies in microglial N9 cells showed that pre-incubation with K-604 significantly reduced the LPS-induced pro-inflammatory responses. Further studies showed that K-604 decreased the total TLR4 protein content by increasing TLR4 endocytosis, thus enhancing the trafficking of TLR4 to the lysosomes for degradation. We concluded that A1B alters the intracellular fate of TLR4 and suppresses its pro-inflammatory signaling cascade in response to LPS.

Pretreatment Depressive Status Associated with Poor Nutrition and Prognosis in Breast Cancer Patients Receiving Neoadjuvant Chemotherapy

The prevalence of pretreatment depression in breast cancer patients and its impact on nutrition and prognosis during neoadjuvant chemotherapy remain unknown. One hundred twenty-one patients with previously untreated breast cancer undergoing neoadjuvant chemotherapy (NAC) were enrolled. Patients completed the Self-rating Depressive symptoms Scale (SDS) before treatment and were divided into two groups (non-depressive group and depressive group). The nutrition risk screening-2002 (NRS-2002), and nutritional and prognostic indicators, including neutrophil-to-lymphocyte ratio (NLR) and prognostic nutritional index (PNI), were collected at baseline (pretreatment) and post-treatment. One- and two-year progression-free survival (PFS) in both groups were also calculated. We found that 38.84% patients experienced pretreatment depressive symptoms. Patients in the depressive group had higher nutritional risk and lower body mass index, potassium, sodium, total cholesterol, total protein, and fasting blood glucose levels than those in pretreatment non-depressive group after NAC (all p < 0.05). And higher NLR (p = 0.039) and lower PNI level (p = 0.0021) after NAC were found in patients with pretreatment depressive status. Multivariable Cox analysis showed pretreatment depressive status (HR: 1.893; 95% CI: 1.047-3.426; p = 0.034) were a significant predictor of PFS. This study provides evidence for early identification of pretreatment depression in patients receiving NAC, which would certainly favor nutrition and survival outcome.

m6A methylation: a process reshaping the tumour immune microenvironment and regulating immune evasion

N6-methyladenosine (m⁶A) methylation is the most universal internal modification in eukaryotic mRNA. With elaborate functions executed by m⁶A writers, erasers, and readers, m⁶A modulation is involved in myriad physiological and pathological processes. Extensive studies have demonstrated m⁶A modulation in diverse tumours, with effects on tumorigenesis, metastasis, and resistance. Recent evidence has revealed an emerging role of m⁶A modulation in tumour immunoregulation, and divergent m⁶A methylation patterns have been revealed in the tumour microenvironment. To depict the regulatory role of m⁶A methylation in the tumour immune microenvironment (TIME) and its effect on immune evasion, this review focuses on the TIME, which is characterized by hypoxia, metabolic reprogramming, acidity, and immunosuppression, and outlines the m⁶A-regulated TIME and immune evasion under divergent stimuli. Furthermore, m⁶A modulation patterns in anti-tumour immune cells are summarized.

Metabolic classifications of renal cell carcinoma reveal intrinsic connections with clinical and immune characteristics

BACKGROUND

Kidney cancer undergoes a dramatic metabolic shift and has demonstrated responsiveness to immunotherapeutic intervention. However, metabolic classification and the associations between metabolic alterations and immune infiltration in Renal cell carcinoma still remain elucidative.

METHODS

Unsupervised consensus clustering was conducted on the TCGA cohorts for metabolic classification. GESA, mRNAsi, prognosis, clinical features, mutation load, immune infiltration and differentially expressed gene differences among different clusters were compared. The prognosis model and nomograms were constructed based on metabolic gene signatures and verified using external ICGC datasets. Immunohistochemical results from Human Protein Atlas database and Tongji hospital were used to validate gene expression levels in normal tissues and tumor samples. CCK8, apoptosis analysis, qPCR, subcutaneously implanted murine models and flowcytometry analysis were applied to investigate the roles of ACAA2 in tumor progression and anti-tumor immunity.

RESULTS

Renal cell carcinoma was classified into 3 metabolic subclusters and the subcluster with low metabolic profiles displayed the poorest prognosis, highest invasiveness and AJCC grade, enhanced immune infiltration but suppressive immunophenotypes. ACAA2, ACAT1, ASRGL1, AKR1B10, ABCC2, ANGPTL4 were identified to construct the 6 gene-signature prognosis model and verified both internally and externally with ICGC cohorts. ACAA2 was demonstrated as a tumor suppressor and was associated with higher immune infiltration and elevated PD-1 expression of CD8⁺ T cells.

CONCLUSIONS

Our research proposed a new metabolic classification method for RCC and revealed intrinsic associations between metabolic phenotypes and immune profiles. The identified gene signatures might serve as key factors bridging tumor metabolism and tumor immunity and warrant further in-depth investigations.

Mechanisms of drug resistance to immune checkpoint inhibitors in non-small cell lung cancer

Immune checkpoint inhibitors (ICIs) in the form of anti-CTLA-4 and anti-PD-1/PD-L1 have become the frontier of cancer treatment and successfully prolonged the survival of patients with advanced non-small cell lung cancer (NSCLC). But the efficacy varies among different patient population, and many patients succumb to disease progression after an initial response to ICIs. Current research highlights the heterogeneity of resistance mechanisms and the critical role of tumor microenvironment (TME) in ICIs resistance. In this review, we discussed the mechanisms of ICIs resistance in NSCLC, and proposed strategies to overcome resistance.

Real-time detection of T cell activation by visualizing TCR nanoclusters with a cholesterol derived aggregation-induced emission probe

Successful T-cell based immunotherapy usually depends on the activation of T cells. Most of commonly used methods for assessing T cell activity rely on the antibody-based technology, which focus on detecting protein-centered activation markers, including CD25, cytokines and so on. However, these methods always involve tedious sample-preparation process, labor-consuming and costly, which could not be utilized in real-time detection. The T cell receptor (TCR) clustering is another kind of essential T cell activation marker on the membrane, which increases during the activation state of T cells. We herein developed a cholesterol derived aggregation-induced emission (AIE) fluorescent probe (R-TPE-PEG-Chol) for detecting T cell activation in real-time. Five probes were first designed and synthesized and among them COOH-TPE-PEG-Chol displayed the best imaging effects, which had no significant impact on the key physiological functions of T cells. In addition, we have proved that COOH-TPE-PEG-Chol was introduced onto the naïve T cell membrane in its molecularly dissolved form without fluorescent emission. While during T cell activation, the formation of TCR nanoclusters would induce aggregation of membrane cholesterol, which could provoke the fluorescence signal of the COOH-TPE-PEG-Chol due to the AIE characteristic. Moreover, the enhancement of the fluorescence intensity was positively related to the activation state of T cells. Our study demonstrated the concept of cholesterol-derived AIE fluorescent probes for deciphering the spatiotemporal arrangements of TCR on the membrane during T cell activation, and consequently provided a novel and complementary strategy for detecting T cell activation in real-time.

Using temporal heatmaps to identify worthwhile articles on immune checkpoint blockade for melanoma (ICBM) in Mainland China, Hong Kong, and Taiwan since 2000: A bibliometric analysis

BACKGROUND

Melanoma is a life-threatening form of skin cancer. Due to its remarkable effectiveness, the immune checkpoint blockade is widely used to treat melanoma (ICBM). No research has been conducted on ICBM for identifying the most readable articles. A bibliometric analysis of 100 top-cited ICBM (T100ICBM) in recent decades is required to highlight articles worth reading.

METHODS

Based on the Web of Science Core Collection, we summarized the articles on ICBM published in each year from 2000 to 2022, with first authors from Mainland China, Hong Kong, and Taiwan (CHT). Using the CJAL score, data extraction and visualization of the distribution of ICBM publications were conducted on 2718, and 100 top-cited articles, respectively. We used the temporal heatmap to identify the most readable articles. Four descriptive, diagnostic, predictive, and prescriptive analytics (called DDPP model) were applied to describe the features of T100ICBM articles. The absolute advantage coefficient was used to determine the dominance extent of the most influential region, institute, department, and author.

RESULTS

A total of 2718 publications was included after removing first or corresponding authors who were not affiliated with CHT. Publications by year showed a sharp increase from 2014 onward and either peaked in 2022 or have not yet peaked. It was evident that there was a large difference between the number of publications in provinces/metropolitan cities/regions on CHT. Beijing, Sichuan University, Oncology, and Guo Jun from Beijing are the most prolific and influential region, institute, department, and author. When comparing research achievements to the next productive authors based on the CJAL score, only Dr Jun has a medium effect of dominance (=0.60). On the basis of their consecutive growth in citations over the past 4 years, 20 T100ICBM articles were recommended for readers.

CONCLUSION

The field of ICBM is growing rapidly, and Beijing and Sichuan University are taking the lead in CHT. Furthermore, the study provides references for worth-reading articles using the temporal heatmap. Future research hot spots may focus on these 4 themes of immunotherapy, melanoma, metastatic melanoma, regulatory T cells, cells, and activation, which may pave the way for additional study.

Cholesterol Transport to the Endoplasmic Reticulum

Most cholesterol in mammalian cells is stored in the plasma membrane (PM). Cholesterol transport from the PM to low-sterol regulatory regions of the endoplasmic reticulum (ER) controls cholesterol synthesis and uptake, and thereby influences the rates of cholesterol flux between tissues of complex organisms. Cholesterol transfer to the ER is also required for steroidogenesis, oxysterol and bile acid synthesis, and cholesterol esterification. The ER-resident Aster proteins (Aster-A, -B, and -C) form contacts with the PM to move cholesterol to the ER in mammals. Mice lacking Aster-B have low adrenal cholesteryl ester stores and impaired steroidogenesis because of a defect in cholesterol transport from high-density lipoprotein (HDL) to the ER. This work reviews the molecular characteristics of Asters, their role in HDL- and low-density lipoprotein (LDL)-cholesterol movement, and how cholesterol transferred to the ER is utilized by cells. The roles of other lipid transporters and of membrane lipid organization in maintaining aspects of cholesterol homeostasis are also highlighted.

CAR immune cells: design principles, resistance and the next generation

The remarkable clinical activity of chimeric antigen receptor (CAR) therapies in B cell and plasma cell malignancies has validated the use of this therapeutic class for liquid cancers, but resistance and limited access remain as barriers to broader application. Here we review the immunobiology and design principles of current prototype CARs and present emerging platforms that are anticipated to drive future clinical advances. The field is witnessing a rapid expansion of next-generation CAR immune cell technologies designed to enhance efficacy, safety and access. Substantial progress has been made in augmenting immune cell fitness, activating endogenous immunity, arming cells to resist suppression via the tumour microenvironment and developing approaches to modulate antigen density thresholds. Increasingly sophisticated multispecific, logic-gated and regulatable CARs display the potential to overcome resistance and increase safety. Early signs of progress with stealth, virus-free and in vivo gene delivery platforms provide potential paths for reduced costs and increased access of cell therapies in the future. The continuing clinical success of CAR T cells in liquid cancers is driving the development of increasingly sophisticated immune cell therapies that are poised to translate to treatments for solid cancers and non-malignant diseases in the coming years.

Metabolism along the life journey of T cells

T cells are one of few cell types in adult mammals that can proliferate extensively and differentiate diversely upon stimulation, which serves as an excellent example to dissect the metabolic basis of cell fate decisions. During the last decade, there has been an explosion of research into the metabolic control of T-cell responses. The roles of common metabolic pathways, including glycolysis, lipid metabolism, and mitochondrial oxidative phosphorylation, in T-cell responses have been well characterized, and their mechanisms of action are starting to emerge. In this review, we present several considerations for T-cell metabolism-focused research, while providing an overview of the metabolic control of T-cell fate decisions during their life journey. We try to synthesize principles that explain the causal relationship between cellular metabolism and T-cell fate decision. We also discuss key unresolved questions and challenges in targeting T-cell metabolism to treat disease.

Role of T Cells in the Pathogenesis of Rheumatoid Arthritis: Focus on Immunometabolism Dysfunctions

Evidence demonstrated that metabolic-associated T cell abnormalities could be detected in the early stage of RA development. In this context, molecular evaluations have revealed changes in metabolic pathways, leading to the aggressive phenotype of RA T cells. A growing list of genes is downregulated or upregulated in RA T cells, and most of these genes with abnormal expression fall into the category of metabolic pathways. It has been shown that RA T cells shunt glucose towards the pentose phosphate pathway (PPP), which is associated with a high level of nicotinamide adenine dinucleotide phosphate (NADPH) and intermediate molecules. An increased level of NADPH inhibits ATM activation and thereby increases the proliferation capabilities of the RA T cells. Defects in the DNA repair nuclease MRE11A cause failures in repairing mitochondrial DNA, resulting in inhibiting the fatty acid oxidation pathway and further elevated cytoplasmic lipid droplets. Accumulated lipid droplets employ to generate lipid membranes for the cell building program and are also used to form the front-end membrane ruffles that are accomplices with invasive phenotypes of RA T cells. Metabolic pathway involvement in RA pathogenesis expands the pathogenic concept of the disease beyond the common view of autoimmunity triggered by autoantigen recognition. Increased knowledge about metabolic pathways' implications in RA pathogenesis paves the way to understand better the environment/gene interactions and host/microbiota interactions and introduce potential therapeutic approaches. This review summarized emerging data about the roles of T cells in RA pathogenesis with a focus on immunometabolism dysfunctions and how these metabolic alterations can affect the disease process.

Low-density lipoprotein balances T cell metabolism and enhances response to anti-PD-1 blockade in a HCT116 spheroid model

Introduction

The discovery of immune checkpoints and the development of their specific inhibitors was acclaimed as a major breakthrough in cancer therapy. However, only a limited patient cohort shows sufficient response to therapy. Hence, there is a need for identifying new checkpoints and predictive biomarkers with the objective of overcoming immune escape and resistance to treatment. Having been associated with both, treatment response and failure, LDL seems to be a double-edged sword in anti-PD1 immunotherapy. Being embedded into complex metabolic conditions, the impact of LDL on distinct immune cells has not been sufficiently addressed. Revealing the effects of LDL on T cell performance in tumor immunity may enable individual treatment adjustments in order to enhance the response to routinely administered immunotherapies in different patient populations. The object of this work was to investigate the effect of LDL on T cell activation and tumor immunity in-vitro.

Methods

Experiments were performed with different LDL dosages (LDL^low = 50 μg/ml and LDL^high = 200 μg/ml) referring to medium control. T cell phenotype, cytokines and metabolism were analyzed. The functional relevance of our findings was studied in a HCT116 spheroid model in the context of anti-PD-1 blockade.

Results

The key points of our findings showed that LDL^high skewed the CD4⁺ T cell subset into a central memory-like phenotype, enhanced the expression of the co-stimulatory marker CD154 (CD40L) and significantly reduced secretion of IL-10. The exhaustion markers PD-1 and LAG-3 were downregulated on both T cell subsets and phenotypical changes were associated with a balanced T cell metabolism, in particular with a significant decrease of reactive oxygen species (ROS). T cell transfer into a HCT116 spheroid model resulted in a significant reduction of the spheroid viability in presence of an anti-PD-1 antibody combined with LDL^high.

Discussion

Further research needs to be conducted to fully understand the impact of LDL on T cells in tumor immunity and moreover, to also unravel LDL effects on other lymphocytes and myeloid cells for improving anti-PD-1 immunotherapy. The reason for improved response might be a resilient, less exhausted phenotype with balanced ROS levels.

Statin drugs enhance responses to immune checkpoint blockade in head and neck cancer models

BACKGROUND

Anti-PD-1 immune checkpoint blockade is approved for first-line treatment of recurrent/metastatic head and neck squamous cell carcinoma (HNSCC), but few patients respond. Statin drugs (HMG-CoA reductase inhibitors) are associated with superior survival in several cancer types, including HNSCC. Emerging data suggest that manipulation of cholesterol may enhance some aspects of antitumor immunity.

METHODS

We used syngeneic murine models (mouse oral cancer, MOC1 and TC-1) to investigate our hypothesis that a subset of statin drugs would enhance antitumor immunity and delay tumor growth.

RESULTS

Using an ex vivo coculture assay of murine cancer cells and tumor infiltrating lymphocytes, we discovered that all seven statin drugs inhibited tumor cell proliferation. Simvastatin and lovastatin also enhanced T-cell killing of tumor cells. In mice, daily oral simvastatin or lovastatin enhanced tumor control and extended survival when combined with PD-1 blockade, with rejection of MOC1 tumors in 30% of mice treated with lovastatin plus anti-PD-1. Results from flow cytometry of tumors and tumor-draining lymph nodes suggested T cell activation and shifts from M2 to M1 macrophage predominance as potential mechanisms of combination therapy.

CONCLUSIONS

These results suggest that statins deserve further study as well-tolerated, inexpensive drugs that may enhance responses to PD-1 checkpoint blockade and other immunotherapies for HNSCC.

Review to Understand the Crosstalk between Immunotherapy and Tumor Metabolism

Immune checkpoint inhibitors have ushered in a new era of cancer treatment by increasing the likelihood of long-term survival for patients with metastatic disease and by introducing fresh therapeutic indications in cases where the disease is still in its early stages. Immune checkpoint inhibitors that target the proteins cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) or programmed death-1/programmed death ligand-1 have significantly improved overall survival in patients with certain cancers and are expected to help patients achieve complete long-lasting remissions and cures. Some patients who receive immune checkpoint inhibitors, however, either experience therapeutic failure or eventually develop immunotherapy resistance. Such individuals are common, which necessitates a deeper understanding of how cancer progresses, particularly with regard to nutritional regulation in the tumor microenvironment (TME), which comprises metabolic cross-talk between metabolites and tumor cells as well as intracellular metabolism in immune and cancer cells. Combination of immunotherapy with targeted metabolic regulation might be a focus of future cancer research despite a lack of existing clinical evidence. Here, we reviewed the significance of the tumor microenvironment and discussed the most significant immunological checkpoints that have recently been identified. In addition, metabolic regulation of tumor immunity and immunological checkpoints in the TME, including glycolysis, amino acid metabolism, lipid metabolism, and other metabolic pathways were also incorporated to discuss the possible metabolism-based treatment methods being researched in preclinical and clinical settings. This review will contribute to the identification of a relationship or crosstalk between tumor metabolism and immunotherapy, which will shed significant light on cancer treatment and cancer research.

Metabolic Regulation of T cell Activity: Implications for Metabolic-Based T-cell Therapies for Cancer

Immunometabolism is an emerging field in tumor immunotherapy. Understanding the metabolic competition for access to the limited nutrients between tumor cells and immune cells can reveal the complexity of the tumor microenvironment and help develop new therapeutic approaches for cancer. Recent studies have focused on modifying the function of immune cells by manipulating their metabolic pathways. Besides, identifying metabolic events, which affect the function of immune cells leads to new therapeutic opportunities for treatment of inflammatory diseases and immune-related conditions. According to the literature, metabolic pathway such as glycolysis, tricarboxylic acid cycle, and fatty acid metabolism, significantly influence the survival, proliferation, activation, and function of immune cells and thus regulate immune responses. In this paper, we reviewed the role of metabolic processes and major signaling pathways involving in T-cell regulation and T-cell responses against tumor cells. Moreover, we summarized the new therapeutics suggested to enhance anti-tumor activity of T cells through manipulating metabolic pathways.

The role of lipid metabolic reprogramming in tumor microenvironment

Metabolic reprogramming is one of the most important hallmarks of malignant tumors. Specifically, lipid metabolic reprogramming has marked impacts on cancer progression and therapeutic response by remodeling the tumor microenvironment (TME). In the past few decades, immunotherapy has revolutionized the treatment landscape for advanced cancers. Lipid metabolic reprogramming plays pivotal role in regulating the immune microenvironment and response to cancer immunotherapy. Here, we systematically reviewed the characteristics, mechanism, and role of lipid metabolic reprogramming in tumor and immune cells in the TME, appraised the effects of various cell death modes (specifically ferroptosis) on lipid metabolism, and summarized the antitumor therapies targeting lipid metabolism. Overall, lipid metabolic reprogramming has profound effects on cancer immunotherapy by regulating the immune microenvironment; therefore, targeting lipid metabolic reprogramming may lead to the development of innovative clinical applications including sensitizing immunotherapy.

CD8+ T cell metabolic changes in breast cancer

Immunometabolism has advanced our understanding of how the cellular environment and nutrient availability regulates immune cell fate. Not only are metabolic pathways closely tied to cell signaling and differentiation, but can induce different subsets of immune cells to adopt unique metabolic programs, influencing disease progression. Dysregulation of immune cell metabolism plays an essential role in the progression of several diseases including breast cancer (BC). Metabolic reprogramming plays a critical role in regulating T cell functions. CD8⁺ T cells are an essential cell type within the tumor microenvironment (TME). To induce antitumor responses, CD8⁺ T cells need to adapt their metabolism to fulfill their energy requirement for effective function. However, different markers and immunologic techniques have made identifying specific CD8⁺ T cells subtypes in BC a challenge to the field. This review discusses the immunometabolic processes of CD8⁺ T cell in the TME in the context of BC and highlights the role of CD8⁺ T cell metabolic changes in tumor progression.

Comprehensive analysis of a glycolysis and cholesterol synthesis-related genes signature for predicting prognosis and immune landscape in osteosarcoma

Background

Glycolysis and cholesterol synthesis are crucial in cancer metabolic reprogramming. The aim of this study was to identify a glycolysis and cholesterol synthesis-related genes (GCSRGs) signature for effective prognostic assessments of osteosarcoma patients.

Methods

Gene expression data and clinical information were obtained from GSE21257 and TARGET-OS datasets. Consistent clustering method was used to identify the GCSRGs-related subtypes. Univariate Cox regression and LASSO Cox regression analyses were used to construct the GCSRGs signature. The ssGSEA method was used to analyze the differences in immune cells infiltration. The pRRophetic R package was utilized to assess the drug sensitivity of different groups. Western blotting, cell viability assay, scratch assay and Transwell assay were used to perform cytological validation.

Results

Through bioinformatics analysis, patients diagnosed with osteosarcoma were classified into one of 4 subtypes (quiescent, glycolysis, cholesterol, and mixed subtypes), which differed significantly in terms of prognosis and tumor microenvironment. Weighted gene co-expression network analysis revealed that the modules strongly correlated with glycolysis and cholesterol synthesis were the midnight blue and the yellow modules, respectively. Both univariate and LASSO Cox regression analyses were conducted on screened module genes to identify 5 GCSRGs (RPS28, MCAM, EN1, TRAM2, and VEGFA) constituting a prognostic signature for osteosarcoma patients. The signature was an effective prognostic predictor, independent of clinical characteristics, as verified further via Kaplan-Meier analysis, ROC curve analysis, univariate and multivariate Cox regression analysis. Additionally, GCSRGs signature had strong correlation with drug sensitivity, immune checkpoints and immune cells infiltration. In cytological experiments, we selected TRAM2 as a representative gene to validate the validity of GCSRGs signature, which found that TRAM2 promoted the progression of osteosarcoma cells. Finally, at the pan-cancer level, TRAM2 had been correlated with overall survival, progression free survival, disease specific survival, tumor mutational burden, microsatellite instability, immune checkpoints and immune cells infiltration.

Conclusion

Therefore, we constructed a GCSRGs signature that efficiently predicted osteosarcoma patient prognosis and guided therapy.

Manipulating T-cell metabolism to enhance immunotherapy in solid tumor

Cellular metabolism is not only essential for tumor cells to sustain their rapid growth and proliferation, but also crucial to maintain T cell fitness and robust immunity. Dysregulated metabolism has been recognized as a hallmark of cancer, which provides survival advantages for tumor cells under stress conditions. Also, emerging evidence suggests that metabolic reprogramming impacts the activation, differentiation, function, and exhaustion of T cells. Normal stimulation of resting T cells promotes the conversion of catabolic and oxidative metabolism to aerobic glycolysis in effector T cells, and subsequently back to oxidative metabolism in memory T cells. These metabolic transitions profoundly affect the trajectories of T-cell differentiation and fate. However, these metabolic events of T cells could be dysregulated by their interplays with tumor or the tumor microenvironment (TME). Importantly, metabolic competition in the tumor ecosystem is a new mechanism resulting in strong suppression of effector T cells. It is appreciated that targeting metabolic reprogramming is a promising way to disrupt the hypermetabolic state of tumor cells and enhance the capacity of immune cells to obtain nutrients. Furthermore, immunotherapies, such as immune checkpoint inhibitor (ICI), adoptive cell therapy (ACT), and oncolytic virus (OV) therapy, have significantly refashioned the clinical management of solid tumors, they are not sufficiently effective for all patients. Understanding how immunotherapy affects T cell metabolism provides a bright avenue to better modulate T cell anti-tumor response. In this review, we provide an overview of the cellular metabolism of tumor and T cells, provide evidence on their dynamic interaction, highlight how metabolic reprogramming of tumor and T cells regulate the anti-tumor responses, describe T cell metabolic patterns in the context of ICI, ACT, and OV, and propose hypothetical combination strategies to favor potent T cell functionality.

Atherosclerosis With Immune Checkpoint Inhibitor Therapy: Evidence, Diagnosis, and Management: JACC: CardioOncology State-of-the-Art Review

As the clinical applications of immune checkpoint inhibitors (ICIs) expand, our knowledge of the potential adverse effects of these drugs continues to broaden. Emerging evidence supports the association between ICI therapy with accelerated atherosclerosis and atherosclerotic cardiovascular (CV) events. We discuss the biological plausibility and the clinical evidence supporting an effect of inhibition of these immune checkpoints on atherosclerotic CV disease. Further, we provide a perspective on potential diagnostic and pharmacological strategies to reduce atherosclerotic risk in ICI-treated patients. Our understanding of the pathophysiology of ICI-related atherosclerosis is in its early stages. Further research is needed to identify the mechanisms linking ICI therapy to atherosclerosis, leverage the insight that ICI therapy provides into CV biology, and develop robust approaches to manage the expanding cohort of patients who may be at risk for atherosclerotic CV disease.

Progress of potential drugs targeted in lipid metabolism research

Lipids are a class of complex hydrophobic molecules derived from fatty acids that not only form the structural basis of biological membranes but also regulate metabolism and maintain energy balance. The role of lipids in obesity and other metabolic diseases has recently received much attention, making lipid metabolism one of the attractive research areas. Several metabolic diseases are linked to lipid metabolism, including diabetes, obesity, and atherosclerosis. Additionally, lipid metabolism contributes to the rapid growth of cancer cells as abnormal lipid synthesis or uptake enhances the growth of cancer cells. This review introduces the potential drug targets in lipid metabolism and summarizes the important potential drug targets with recent research progress on the corresponding small molecule inhibitor drugs. The significance of this review is to provide a reference for the clinical treatment of metabolic diseases related to lipid metabolism and the treatment of tumors, hoping to deepen the understanding of lipid metabolism and health.

Autophagy inhibition and reactive oxygen species elimination by acetyl-CoA acetyltransferase 1 through fused in sarcoma protein to promote prostate cancer

BACKGROUND

Prostate cancer is a major health issue affecting the male population worldwide, and its etiology remains relatively unknown. As presented on the Gene Expression Profiling Interactive Analysis database, acetyl-CoA acetyltransferase 1 (ACAT1) acts as a prostate cancer-promoting factor. ACAT1 expression in prostate cancer tissues is considerably higher than that in normal tissues, leading to a poor prognosis in patients with prostate cancer. Here, we aimed to study the role of the ACAT1-fused in sarcoma (FUS) complex in prostate cancer and identify new targets for the diagnosis and treatment of the disease.

METHODS

We conducted immunohistochemical analysis of 57 clinical samples and in vitro and in vivo experiments using a mouse model and plasmid constructs to determine the expression of ACAT1 in prostate cancer.

RESULTS

The relationship between the expression of ACAT1 and the Gleason score was significant. The expression of ACAT1 was higher in tissues with a Gleason score of > 7 than in tissues with a Gleason score of ≤7 (P = 0.0011). In addition, we revealed that ACAT1 can interact with the FUS protein.

CONCLUSIONS

In prostate cancer, ACAT1 promotes the expression of P62 and Nrf2 through FUS and affects reactive oxygen species scavenging. These effects are due to the inhibition of autophagy by ACAT1. That is, ACAT1 promotes prostate cancer by inhibiting autophagy and eliminating active oxygen species. The expression of ACAT1 is related to prostate cancer. Studying the underlying mechanism may provide a new perspective on the treatment of prostate cancer.

Association between ACAT1 rs1044925 and increased hypertension risk in Tongdao Dong

Hypertension is a multifactorial disease that partially caused by genetic factors, including variation in genes related to lipid metabolism. ACAT1 gene is implicated in lipid metabolism for its encoding product, the enzyme acetyl-CoA acetyltransferase 1, catalyzing the synthesis of cholesteryl ester from cholesterol and playing an important role in the metabolism of cholesterol. Until now, there's little study on the relationship between ACAT1 variants and hypertension. Here, we report a link between ACAT1 rs1044925 and hypertension in Tongdao Dong population. Polymerase chain reaction-restriction fragment length polymorphism was used to detect the genotypes of the ACAT1 SNP rs1044925 in a total of 637 subjects, including 406 hypertensive patients and 231 normotensive controls. The genotypic and allelic frequencies of rs1044925 were significantly different between the normotensive and hypertensive subjects (P = .001). AC/CC genotypes of rs1044925 were associated with an increased risk of hypertension (AC/CC vs AA: adjusted odds ratio = 1.723, 95% confidence interval = 1.160-2.559, P = .007). However, the AC/CC genotypes showed no relationship with serum lipid levels. The results suggest that the C carriers of ACAT1 rs1044925 might increase the risk of hypertension in Tongdao Dong population, and the underlying mechanism needs to be further studied.

Targeting T-cell metabolism to boost immune checkpoint inhibitor therapy

Immune checkpoint inhibitors (ICIs) have shown promising therapeutic effects in the treatment of advanced solid cancers, but their overall response rate is still very low for certain tumor subtypes, limiting their clinical scope. Moreover, the high incidence of drug resistance (including primary and acquired) and adverse effects pose significant challenges to the utilization of these therapies in the clinic. ICIs enhance T cell activation and reverse T cell exhaustion, which is a complex and multifactorial process suggesting that the regulatory mechanisms of ICI therapy are highly heterogeneous. Recently, metabolic reprogramming has emerged as a novel means of reversing T-cell exhaustion in the tumor microenvironment; there is increasing evidence that T cell metabolic disruption limits the therapeutic effect of ICIs. This review focuses on the crosstalk between T-cell metabolic reprogramming and ICI therapeutic efficacy, and summarizes recent strategies to improve drug tolerance and enhance anti-tumor effects by targeting T-cell metabolism alongside ICI therapy. The identification of potential targets for altering T-cell metabolism can significantly contribute to the development of methods to predict therapeutic responsiveness in patients receiving ICI therapy, which are currently unknown but would be of great clinical significance.

Cancer cell-intrinsic XBP1 drives immunosuppressive reprogramming of intratumoral myeloid cells by promoting cholesterol production

A hostile microenvironment in tumor tissues disrupts endoplasmic reticulum homeostasis and induces the unfolded protein response (UPR). A chronic UPR in both cancer cells and tumor-infiltrating leukocytes could facilitate the evasion of immune surveillance. However, how the UPR in cancer cells cripples the anti-tumor immune response is unclear. Here, we demonstrate that, in cancer cells, the UPR component X-box binding protein 1 (XBP1) favors the synthesis and secretion of cholesterol, which activates myeloid-derived suppressor cells (MDSCs) and causes immunosuppression. Cholesterol is delivered in the form of small extracellular vesicles and internalized by MDSCs through macropinocytosis. Genetic or pharmacological depletion of XBP1 or reducing the tumor cholesterol content remarkably decreases MDSC abundance and triggers robust anti-tumor responses. Thus, our data unravel the cell-non-autonomous role of XBP1/cholesterol signaling in the regulation of tumor growth and suggest its inhibition as a useful strategy for improving the efficacy of cancer immunotherapy.

Recent advances in developing active targeting and multi-functional drug delivery systems via bioorthogonal chemistry

Bioorthogonal chemistry reactions occur in physiological conditions without interfering with normal physiological processes. Through metabolic engineering, bioorthogonal groups can be tagged onto cell membranes, which selectively attach to cargos with paired groups via bioorthogonal reactions. Due to its simplicity, high efficiency, and specificity, bioorthogonal chemistry has demonstrated great application potential in drug delivery. On the one hand, bioorthogonal reactions improve therapeutic agent delivery to target sites, overcoming off-target distribution. On the other hand, nanoparticles and biomolecules can be linked to cell membranes by bioorthogonal reactions, providing approaches to developing multi-functional drug delivery systems (DDSs). In this review, we first describe the principle of labeling cells or pathogenic microorganisms with bioorthogonal groups. We then highlight recent breakthroughs in developing active targeting DDSs to tumors, immune systems, or bacteria by bioorthogonal chemistry, as well as applications of bioorthogonal chemistry in developing functional bio-inspired DDSs (biomimetic DDSs, cell-based DDSs, bacteria-based and phage-based DDSs) and hydrogels. Finally, we discuss the difficulties and prospective direction of bioorthogonal chemistry in drug delivery. We expect this review will help us understand the latest advances in the development of active targeting and multi-functional DDSs using bioorthogonal chemistry and inspire innovative applications of bioorthogonal chemistry in developing smart DDSs for disease treatment.

Cholesterol accumulation on dendritic cells reverses chronic hepatitis B virus infection-induced dysfunction

Chronic hepatitis B (CHB) infection remains a serious public health problem worldwide; however, the relationship between cholesterol levels and CHB remains unclear. We isolated peripheral blood mononuclear cells from healthy blood donors and CHB patients to analyze free cholesterol levels, lipid raft formation, and cholesterol metabolism-related pathways. Hepatitis B virus (HBV)-carrier mice were generated and used to confirm changes in cholesterol metabolism and cell-surface lipid raft formation in dendritic cells (DCs) in the context of CHB. Additionally, HBV-carrier mice were immunized with a recombinant HBV vaccine (rHBVvac) combined with lipophilic statins and evaluated for vaccine efficacy against HBV. Serum samples were analyzed for HBsAg, anti-HBs, and alanine aminotransferase levels, and liver samples were evaluated for HBV DNA and RNA and HBcAg. CHB reduced free cholesterol levels and suppressed lipid raft formation on DCs in patients with CHB and HBV-carrier mice, whereas administration of lipophilic statins promoted free cholesterol accumulation and restored lipid rafts on DCs accompanied by an enhanced antigen-presentation ability in vitro and in vivo. Cholesterol accumulation on DCs improved the rHBVvac-mediated elimination of serum HBV DNA and intrahepatic HBV DNA, HBV RNA, and HBcAg and promoted the rHBVvac-mediated generation and polyfunctionality of HBV-specific CD11ahi CD8αlo cells, induction of the development of memory responses against HBV reinfection, and seroconversion from HBsAg to anti-HBs. The results demonstrated the important role of cholesterol levels in DC dysfunction during CHB, suggesting that strategies to increase cholesterol accumulation on DCs might enhance therapeutic vaccine efficacy against HBV and support development toward clinical CHB treatment.