Indoleamine 2,3-dioxygenase 1 (IDO1) inhibitors in clinical trials for cancer immunotherapy

2D nanomaterials-based delivery systems and their potentials in anticancer synergistic photo-immunotherapy

As the field of cancer therapeutics evolves, integrating two-dimensional (2D) nanomaterials with photo-immunotherapy has emerged as a promising approach with significant potential to augment cancer treatment efficacy. These 2D nanomaterials include graphene-based 2D nanomaterials, 2D MXenes, 2D layered double hydroxides, black phosphorus nanosheets, 2D metal-organic frameworks, and 2D transition metal dichalcogenides. They exhibit high load capacities, multiple functionalization pathways, optimal biocompatibility, and physiological stability. Predominantly, they function as anti-tumor delivery systems, amalgamating diverse therapeutic modalities, most notably phototherapy and immunotherapy, and the former is a recognized non-invasive treatment modality, and the latter represents the most promising anti-cancer strategy presently accessible. Thus, integrating phototherapy and immunotherapy founded on 2D nanomaterials unveils a novel paradigm in the war against cancer. This review delineates the latest developments in 2D nanomaterials as delivery systems for synergistic photo-immunotherapy in cancer treatment. We elaborate on the burgeoning realm of photo-immunotherapy, exploring the interplay between phototherapy and enhanced immune cells, immune response modulation, or immunosuppressive tumor microenvironments. Notably, the strategies to augment photo-immunotherapy have also been discussed. Finally, we discuss the challenges and future perspectives of these 2D nanomaterials in photo-immunotherapy.

Achieving Immune Activation by Suppressing the IDO1 Checkpoint with Sono-Targeted Biobromination for Antitumor Combination Immunotherapy

Indoleamine-2,3-dioxygenase-1 (IDO1) pathogenically suppresses immune cell infiltration and promotes tumor cell immune escape by overmetabolizing tryptophan to N-formyl kynurenine in the tumor microenvironment (TME). However, it remains challenging for IDO1 immune checkpoint inhibitors to achieve a significant potency of progression-free survival. Here, we developed a breakthrough in IDO1 inhibition by sono-targeted biobromination reaction using immunostimulating hypobromic-P-phenylperoxydibenzoic acid-linked metallic organic framework nanomedicine (H-MOF NM) to remodel the TME from debrominated hypoxia into hypobromated normoxia and activate the IDO1 immune pathway with in vitro and in vivo remarkable antitumor efficacy. H-MOF NM contains Br+ and O- active ingredients with an enlarged band gap to deactivate IDO1 through an innovative biochemical mechanism, taking control over brominating IDO1 amino acid residues at the active sites in the remodeled TME and subsequently activating the immune response, including DC maturation, T-cell activation, and macrophage polarization. Importantly, the H-MOF NM achieves multiple immune responses with high tumor regression potency by combination sono-immunotherapy. This study describes an excellent IDO1 inhibition strategy through the development of immune biobrominative H-MOF nanomedicine and highlights efficient combination immunotherapy for tumor treatment.

Utility of PD-1, PD-L1, and IDO-1 Stains in Ocular Extranodal Marginal Zone Lymphoma (MZL) and Diffuse Large B-cell Lymphoma (DLBCL)

Extranodal marginal zone lymphoma (EMZL) is the most common subtype of ocular lymphomas. Diffuse large B-cell lymphoma (DLBCL) and EMZL with large-cell transformation present diagnostic challenges. Radiotherapy is the standard treatment for ocular lymphomas, but complications and relapse are common. Diagnostic utility in challenging cases, as well as treatment options using immune checkpoint inhibitors, are unclear in ocular lymphomas. We herein investigated the PD-1, PD-L1, and IDO1 staining patterns in 20 cases of ocular lymphomas, including EMZL (n=14), EMZL with increased large cells (n=2), and DLBCL (n=4). PD-1, PD-L1, and IDO1 staining was not detected in lymphoma cells in any cases but was observed within the tumor microenvironment in all cases. Positivity for PD-1, PD-L1, and IDO1 in inflammatory cells was seen either intratumorally or peritumorally. In all 6 cases with significantly more large B cells, the density of PD-1, PD-L1, and IDO1 expression in the tumor microenvironment was higher than that of the remaining 14 cases without large B cells ( P -value<0.0001), whereas other clinicopathologic features showed no statistical correlation. Increased expression of PD-1, PD-L1, and IDO1 in the inflammatory milieu in cases with large cells may provide diagnostic utility in small biopsies as well as therapeutic potential.

Heme-based dioxygenases: Structure, function and dynamics

Tryptophan dioxygenase (TDO) and indoleamine 2,3 dioxygenase (IDO) belong to a unique class of heme-based enzymes that insert dioxygen into the essential amino acid, L-tryptophan (Trp), to generate N-formylkynurenine (NFK), a critical metabolite in the kynurenine pathway. Recently, the two dioxygenases were recognized as pivotal cancer immunotherapeutic drug targets, which triggered a great deal of drug discovery targeting them. The advancement of the field is however hampered by the poor understanding of the structural properties of the two enzymes and the mechanisms by which the structures dictate their functions. In this review, we summarize recent findings centered on the structure, function, and dynamics of the human isoforms of the two enzymes.

Nanodelivery Optimization of IDO1 Inhibitors in Tumor Immunotherapy: Challenges and Strategies

Tryptophan (Trp) metabolism plays a vital role in cancer immunity. Indoleamine 2.3-dioxygenase 1 (IDO1), is a crucial enzyme in the metabolic pathway by which Trp is degraded to kynurenine (Kyn). IDO1-mediated Trp metabolites can inhibit tumor immunity and facilitate immune evasion by cancer cells; thus, targeting IDO1 is a potential tumor immunotherapy strategy. Recently, numerous IDO1 inhibitors have been introduced into clinical trials as immunotherapeutic agents for cancer treatment. However, drawbacks such as low oral bioavailability, slow onset of action, and high toxicity are associated with these drugs. With the continuous development of nanotechnology, medicine is gradually entering an era of precision healthcare. Nanodrugs carried by inorganic, lipid, and polymer nanoparticles (NPs) have shown great potential for tumor therapy, providing new ways to overcome tumor diversity and improve therapeutic efficacy. Compared to traditional drugs, nanomedicines offer numerous significant advantages, including a prolonged half-life, low toxicity, targeted delivery, and responsive release. Moreover, based on the physicochemical properties of these nanomaterials (eg, photothermal, ultrasonic response, and chemocatalytic properties), various combination therapeutic strategies have been developed to synergize the effects of IDO1 inhibitors and enhance their anticancer efficacy. This review is an overview of the mechanism by which the Trp-IDO1-Kyn pathway acts in tumor immune escape. The classification of IDO1 inhibitors, their clinical applications, and barriers for translational development are discussed, the use of IDO1 inhibitor-based nanodrug delivery systems as combination therapy strategies is summarized, and the issues faced in their clinical application are elucidated. We expect that this review will provide guidance for the development of IDO1 inhibitor-based nanoparticle nanomedicines that can overcome the limitations of current treatments, improve the efficacy of cancer immunotherapy, and lead to new breakthroughs in the field of cancer immunotherapy.

Targeted Protein Degradation (TPD) for Immunotherapy: Understanding Proteolysis Targeting Chimera-Driven Ubiquitin-Proteasome Interactions

Targeted protein degradation or TPD, is rapidly emerging as a treatment that utilizes small molecules to degrade proteins that cause diseases. TPD allows for the selective removal of disease-causing proteins, including proteasome-mediated degradation, lysosome-mediated degradation, and autophagy-mediated degradation. This approach has shown great promise in preclinical studies and is now being translated to treat numerous diseases, including neurodegenerative diseases, infectious diseases, and cancer. This review discusses the latest advances in TPD and its potential as a new chemical modality for immunotherapy, with a special focus on the innovative applications and cutting-edge research of PROTACs (Proteolysis TArgeting Chimeras) and their efficient translation from scientific discovery to technological achievements. Our review also addresses the significant obstacles and potential prospects in this domain, while also offering insights into the future of TPD for immunotherapeutic applications.

Chemo-immunotherapy by nanoliposomal epacadostat and docetaxel combination to IDO1 inhibition and tumor microenvironment suppression

The over-activation of tryptophan (Trp) metabolism to kynurenine (Kyn) catalyzed by Indoleamine 2,3-dioxygenase-1 (IDO1) enzyme, is one of the main metabolic pathways involved in tumor microenvironment (TME) immune escape and cancer treatment failure. The most efficient of IDO1 inhibitors is Epacadostat (EPA). Since monotherapy with single-agent IDO1 inhibitor regimen has led to an insufficient anti-tumor activity, we examined the efficacy of simultaneous treatment by Liposomal epacadostat (Lip-EPA) as a potent IDO inhibitor, in combination with docetaxel (DTX) as a complement immunogenic cell death (ICD) agent against B16F10 model. First, the in vitro combination index (CI) of epacadostat (EPA) and DTX was investigated by using the unified theory. Then, the in vivo efficacy of the combination therapy was assessed. Results indicated the synergestic cytotoxic effect of the combination on B16F10 compared to normal fibroblast cells (NIH). The immune profiling demonstrated a significant increase in the percentage of infiltrated T lymphocytes and IFN-γ release, a significant decrease in the percentage of regulatory T cells (Treg) population and the subsequent low levels of IL-10 generation in mice treated with Lip-EPA + DTX. Further, a significant tumor growth delay (TGD = 69.15 %) and an increased life span (ILS > 47.83 %) was observed with the combination strategy. Histopathology analysis revealed a remarkable increase in the Trp concentration following combination treatment, while Kyn levels significantly decreased. Results showed that the nano-liposomal form of IDO1 inhibitor in combination with chemotherapy could significantly improve the imunity response and dominate the tumor immuno-suppressive micro-environment, which merits further investigations.

Advances in siRNA Drug Delivery Strategies for Targeted TNBC Therapy

Among breast cancers, triple-negative breast cancer (TNBC) has been recognized as the most aggressive type with a poor prognosis and low survival rate. Targeted therapy for TNBC is challenging because it lacks estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). Chemotherapy, radiation therapy, and surgery are the common therapies for TNBC. Although TNBC is prone to chemotherapy, drug resistance and recurrence are commonly associated with treatment failure. Combination therapy approaches using chemotherapy, mAbs, ADC, and antibody-siRNA conjugates may be effective in TNBC. Recent advances with siRNA-based therapy approaches are promising for TNBC therapy with better prognosis and reduced mortality. This review discusses advances in nanomaterial- and nanobiomaterial-based siRNA delivery platforms for TNBC therapy exploring targeted therapy approaches for major genes, proteins, and TFs upregulated in TNBC tumors, which engage in molecular pathways associated with low TNBC prognosis. Bioengineered siRNA drugs targeting one or several genes simultaneously can downregulate desired genes, significantly reducing disease progression.

Targeting amino acid-metabolizing enzymes for cancer immunotherapy

Despite the immune system's role in the detection and eradication of abnormal cells, cancer cells often evade elimination by exploitation of various immune escape mechanisms. Among these mechanisms is the ability of cancer cells to upregulate amino acid-metabolizing enzymes, or to induce these enzymes in tumor-infiltrating immunosuppressive cells. Amino acids are fundamental cellular nutrients required for a variety of physiological processes, and their inadequacy can severely impact immune cell function. Amino acid-derived metabolites can additionally dampen the anti-tumor immune response by means of their immunosuppressive activities, whilst some can also promote tumor growth directly. Based on their evident role in tumor immune escape, the amino acid-metabolizing enzymes glutaminase 1 (GLS1), arginase 1 (ARG1), inducible nitric oxide synthase (iNOS), indoleamine 2,3-dioxygenase 1 (IDO1), tryptophan 2,3-dioxygenase (TDO) and interleukin 4 induced 1 (IL4I1) each serve as a promising target for immunotherapeutic intervention. This review summarizes and discusses the involvement of these enzymes in cancer, their effect on the anti-tumor immune response and the recent progress made in the preclinical and clinical evaluation of inhibitors targeting these enzymes.

Dual-targeted NAMPT inhibitors as a progressive strategy for cancer therapy

In mammals, nicotinamide phosphoribosyltransferase (NAMPT) is a crucial enzyme in the nicotinamide adenine dinucleotide (NAD+) synthesis pathway catalyzing the condensation of nicotinamide (NAM) with 5-phosphoribosyl-1-pyrophosphate (PRPP) to produce nicotinamide mononucleotide (NMN). Given the pivotal role of NAD+ in a range of cellular functions, including DNA synthesis, redox reactions, cytokine generation, metabolism, and aging, NAMPT has become a promising target for many diseases, notably cancer. Therefore, various NAMPT inhibitors have been reported and classified as first and second-generation based on their chemical structures and design strategies, dual-targeted being one. However, most NAMPT inhibitors suffer from several limitations, such as dose-dependent toxicity and poor pharmacokinetic properties. Consequently, there is no clinically approved NAMPT inhibitor. Hence, research on discovering more effective and less toxic dual-targeted NAMPT inhibitors with desirable pharmacokinetic properties has drawn attention recently. This review summarizes the previously reported dual-targeted NAMPT inhibitors, focusing on their design strategies and advantages over the single-targeted therapies.

Pathomic model based on histopathological features and machine learning to predict IDO1 status and its association with breast cancer prognosis

PURPOSE

To establish a pathomic model using histopathological image features for predicting indoleamine 2,3-dioxygenase 1 (IDO1) status and its relationship with overall survival (OS) in breast cancer.

METHODS

A pathomic model was constructed using machine learning and histopathological images obtained from The Cancer Genome Atlas database to predict IDO1 expression. The model performance was evaluated based on the area under the curve, calibration curve, and decision curve analysis (DCA). Prediction scores (PSes) were generated from the model and applied to divide the patients into two groups. Survival outcomes, gene set enrichment, immune microenvironment, and tumor mutations were assessed between the two groups.

RESULTS

Survival analysis followed by multivariate correction revealed that high IDO1 is a protective factor for OS. Further, the model was calibrated, and it exhibited good discrimination. Additionally, the DCA showed that the proposed model provided a good clinical net benefit. The Kaplan-Meier analysis revealed a positive correlation between high PS and improved OS. Univariate and multivariate Cox regression analyses demonstrated that PS is an independent protective factor for OS. Moreover, differentially expressed genes were enriched in various essential biological processes, including extracellular matrix receptor interaction, angiogenesis, transforming growth factor β signaling, epithelial mesenchymal transition, cell junction, tryptophan metabolism, and heme metabolic processes. PS was positively correlated with M1 macrophages, CD8 + T cells, T follicular helper cells, and tumor mutational burden.

CONCLUSION

These results indicate the potential ability of the proposed pathomic model to predict IDO1 status and the OS of breast cancer patients.

The Interplay between Metabolic Adaptations and Diet in Cancer Immunotherapy

Over the past decade, cancer immunotherapy has significantly advanced through the introduction of immune checkpoint inhibitors and the augmentation of adoptive cell transfer to enhance the innate cancer defense mechanisms. Despite these remarkable achievements, some cancers exhibit resistance to immunotherapy, with limited patient responsiveness and development of therapy resistance. Metabolic adaptations in both immune cells and cancer cells have emerged as central contributors to immunotherapy resistance. In the last few years, new insights emphasized the critical role of cancer and immune cell metabolism in animal models and patients. During therapy, immune cells undergo important metabolic shifts crucial for their acquired effector function against cancer cells. However, cancer cell metabolic rewiring and nutrient competition within tumor microenvironment (TME) alters many immune functions, affecting their fitness, polarization, recruitment, and survival. These interactions have initiated the development of novel therapies targeting tumor cell metabolism and favoring antitumor immunity within the TME. Furthermore, there has been increasing interest in comprehending how diet impacts the response to immunotherapy, given the demonstrated immunomodulatory and antitumor activity of various nutrients. In conclusion, recent advances in preclinical and clinical studies have highlighted the capacity of immune-based cancer therapies. Therefore, further exploration into the metabolic requirements of immune cells within the TME holds significant promise for the development of innovative therapeutic approaches that can effectively combat cancer in patients.

Targeting myeloid-derived suppressor cells promotes antiparasitic T-cell immunity and enhances the efficacy of PD-1 blockade (15 words)

Immune exhaustion corresponds to a loss of effector function of T cells that associates with cancer or chronic infection. Here, our objective was to decipher the mechanisms involved in the immune suppression of myeloid-derived suppressor cells (MDSCs) and to explore the potential to target these cells for immunotherapy to enhance checkpoint blockade efficacy in a chronic parasite infection. We demonstrated that programmed cell-death-1 (PD-1) expression was significantly upregulated and associated with T-cell dysfunction in advanced alveolar echinococcosis (AE) patients and in Echinococcus multilocularis-infected mice. PD-1 blockade ex vivo failed to reverse AE patients' peripheral blood T-cell dysfunction. PD-1/PD-L1 blockade or PD-1 deficiency had no significant effects on metacestode in mouse model. This was due to the inhibitory capacities of immunosuppressive granulocytic MDSCs (G-MDSCs), especially in the liver surrounding the parasite pseudotumor. MDSCs suppressed T-cell function in vitro in an indoleamine 2, 3 dioxygenase 1 (IDO1)-dependent manner. Although depleting MDSCs alone restored T-cell effector functions and led to some limitation of disease progression in E. multilocularis-infected mice, combination with PD-1 blockade was better to induce antiparasitic efficacy. Our findings provide preclinical evidence in support of targeting MDSC or combining such an approach with checkpoint blockade in patients with advanced AE. (200 words).

Harnessing the tumor microenvironment to boost adoptive T cell therapy with engineered lymphocytes for solid tumors

Adoptive cell therapy (ACT) using Chimeric Antigen Receptor (CAR) and T Cell Receptor (TCR) engineered T cells represents an innovative therapeutic approach for the treatment of hematological malignancies, yet its application for solid tumors is still suboptimal. The tumor microenvironment (TME) places several challenges to overcome for a satisfactory therapeutic effect, such as physical barriers (fibrotic capsule and stroma), and inhibitory signals impeding T cell function. Some of these obstacles can be faced by combining ACT with other anti-tumor approaches, such as chemo/radiotherapy and checkpoint inhibitors. On the other hand, cutting edge technological tools offer the opportunity to overcome and, in some cases, take advantage of TME intrinsic characteristics to boost ACT efficacy. These include: the exploitation of chemokine gradients and integrin expression for preferential T-cell homing and extravasation; metabolic changes that have direct or indirect effects on TCR-T and CAR-T cells by increasing antigen presentation and reshaping T cell phenotype; introduction of additional synthetic receptors on TCR-T and CAR-T cells with the aim of increasing T cells survival and fitness.

Tumor microenvironment RNA test to predict immunotherapy outcomes in advanced gastric cancer: The TIMES001 trial

BACKGROUND

Clinical trials support the efficacy of immune checkpoint blockades (ICBs) plus chemotherapy in a subset of patients with metastatic gastric cancer (mGC). To identify the determinants of response, we developed a TMEscore model to assess tumor microenvironment (TME), which was previously proven to be a biomarker for ICBs.

METHODS

A reference database of TMEscore assays was established using PCR assay kits containing 30 TME genes. This multi-center prospective clinical trial (NCT#04850716) included patients with mGC who were administered ICB combined with chemotherapy as a first-line regimen. Eighty-six tumor samples extracted from five medical centers before treatment were used to estimate the TMEscore, PD-L1 (CPS), and mismatch repair deficiency.

FINDINGS

The objective response rate (ORR) and median PFS of the cohort were 31.4% and six months. Enhanced ORR was observed in TMEscore-high mGC patients (ORR = 59%). The survival analysis demonstrated that high TMEscore was significantly associated with a more favorable PFS and OS. Moreover, TMEscore was found to be a predictive biomarker that surpassed MSI and CPS (AUC = 0.873, 0.511, and 0.524, respectively). By integrating the TMEscore and clinical variables, the fused model further enhances the predictive efficiency and translational application in a clinical setting.

CONCLUSIONS

This prospective clinical study indicates that the TMEscore assay is a robust biomarker for screening patients with mGC who may derive survival benefits from ICB plus chemotherapy.

FUNDING

Guangdong Basic and Applied Basic Research Foundation (2023A1515011214), Science and Technology Program of Guangzhou (202206080011), and Guangzhou Science and Technology Project (2023A03J0722 and 2023A04J2357).

Appraising the effectiveness of immune cells on thyroid cancer: a Mendelian randomization study

BACKGROUND

The intricate interplay between the immune system and tumor plays a pivotal role in thyroid cancer (TC) pathogenesis, potentially influencing both the causation and therapeutic outcomes. Despite extensive research, existing literature offers ambiguous insights regarding the association between immune cell traits and thyroid cancer progression.

METHODS

To elucidate the potential causal relationships, we conducted an integrated two-sample Mendelian randomization (MR) analysis. This study utilized publicly genetic datasets to explore the causalities between 731 immune cell traits (categorized into four trait types across seven panels) and thyroid cancer. We ensured the robustness of our findings through comprehensive sensitivity analyses, meticulously assessing potential sources of bias such as pleiotropy.

RESULTS

After False Discovery Rate (FDR) correction, six immune cell traits were identified to be significantly associated with thyroid cancer risk (Inverse Variance Weighted, IVW): Absolute count of gamma delta T cells/ T-cell receptor gamma delta absolute count (TCRgd AC) 0.8464 (OR95% CI = 0.7477-0.9580, P = 0.0083, PFDR = 0.0103); CD8 on bright CD8 cells (CD8 on CD8br) 0.8867 (OR95% CI = 0.8159-0.9637, P = 0.0047, PFDR = 0.0093); CD127 on CD45RA negative CD4 T cells not regulatory T cells (CD127 on CD45RA- CD4 not Treg) 0.8969 (OR95% CI = 0.8192-0.9820, P = 0.0186, PFDR = 0.0186); CD80 on CD62L positive plasmacytoid dendritic cells (CD80 on CD62L+ plasmacytoid DC) 1.1091 (OR95% CI = 1.0267-1.1982, P = 0.0086, PFDR = 0.0103); CD80 on plasmacytoid DC 1.1283 (OR95% CI = 1.0462-1.2168, P = 0.0017, PFDR = 0.0093); Side scatter-area on bright CD8 cells (SSC - A on CD8br) 1.1622 (OR95% CI = 1.0507-1.2854, P = 0.0035, PFDR = 0.0093).

CONCLUSIONS

Our study demonstrated the causalities between immune cell traits and thyroid cancers by Mendelian randomization study, thus guiding future mechanism studies.

Interstitial Foci Expression of Indoleamine 2,3-Dioxygenase 1: A Potential Biomarker for Kidney Transplant Rejection

(1) Background: Kidney transplantation is the best therapy for patients with end-stage renal disease, but the risk of rejection complicates it. Indoleamine 2,3-dioxygenase 1 (IDO1), an enzyme involved in immune response modulation, has been suggested to play a role in transplant immunological injury. The aim of the study was to explore the expression of IDO1 in the interstitial foci of transplanted kidneys and its potential association with rejection episodes. (2) Methods: This retrospective study analysed kidney transplant biopsies from 121 patients, focusing on IDO1 expression in interstitial foci. Immunohistochemistry was used to detect IDO1, and patients were categorised based on IDO1 presence (IDO1-IF positive or negative). The incidence of rejection was compared between these groups. (3) Results: Patients with IDO1 expression in interstitial foci (IDO1-IF(+)) exhibited higher incidences of rejection 46/80 (57.5%) vs. 10/41 (24.34%) patients compared to IDO1-IF(-) patients, which was statistically significant with p = 0.0005. The analysis of antibody-mediated rejection showed that IDO1-IF(+) patients developed AMR at 12/80 (15%), while only 1 IDO1-IF(-) negative patient did (2,44%), with p = 0.035. T-cell-mediated rejection was also more common in IDO1-IF(+) patients 43/80 (53.75%) than in IDO1-IF(-) patients 7/41 (17.07%), with p = 0.0001. (4) Conclusions: IDO1 expression in interstitial foci of renal transplant biopsies is associated with a higher incidence of rejection, suggesting that IDO1 could serve as a potential biomarker for transplant rejection. These findings highlight the importance of IDO1 in immune regulation and its potential utility in improving the management of kidney transplant recipients.

Lipid-based nanosystems: the next generation of cancer immune therapy

Immunotherapy has become an important part of the oncotherapy arsenal. Its applicability in various cancer types is impressive, as well as its use of endogenous mechanisms to achieve desired ends. However, off-target or on-target-off-tumor toxicity, limited activity, lack of control in combination treatments and, especially for solid tumors, low local accumulation, have collectively limited clinical use thereof. These limitations are partially alleviated by delivery systems. Lipid-based nanoparticles (NPs) have emerged as revolutionary carriers due to favorable physicochemical characteristics, with specific applications and strengths particularly useful in immunotherapeutic agent delivery. The aim of this review is to highlight the challenges faced by immunotherapy and how lipid-based NPs have been, and may be further utilized to address such challenges. We discuss recent fundamental and clinical applications of NPs in a range of areas and provide a detailed discussion of the main obstacles in immune checkpoint inhibition therapies, adoptive cellular therapies, and cytokine therapies. We highlight how lipid-based nanosystems could address these through either delivery, direct modulation of the immune system, or targeting of the immunosuppressive tumor microenvironment. We explore advanced and emerging liposomal and lipid nanoparticle (LNP) systems for nucleic acid delivery, intrinsic and extrinsic stimulus-responsive formulations, and biomimetic lipid-based nanosystems in immunotherapy. Finally, we discuss the key challenges relating to the clinical use of lipid-based NP immunotherapies, suggesting future research directions for the near term to realize the potential of these innovative lipid-based nanosystems, as they become the crucial steppingstone towards the necessary enhancement of the efficacy of immunotherapy.

Hypoxia-Specific Metal-Organic Frameworks Augment Cancer Immunotherapy of High-Intensity Focused Ultrasound

As a noninvasive treatment modality, high-intensity focused ultrasound (HIFU)-induced antitumor immune responses play a vital role in surgery prognosis. However, limited response intensity largely hinders postoperative immunotherapy. Herein, a hypoxia-specific metal-organic framework (MOF) nanosystem, coordinated by Fe3+, hypoxic-activated prodrug AQ4N, and IDO-1 signaling pathway inhibitor NLG919, is developed for the potentiating immunotherapy of HIFU surgery. The loaded AQ4N enhances the photoacoustic imaging effects to achieve accurate intraoperative navigation. Within the HIFU-established severe hypoxic environment, AQ4N is activated sequentially, following which it cooperates with Fe3+ to effectively provoke immunogenic cell death. In addition, potent NLG919 suppresses IDO-1 activity and degrades the immunosuppressive tumor microenvironment aggravated by postoperative hypoxia. In vivo studies demonstrate that the MOF-mediated immunotherapy greatly inhibits the growth of primary/distant tumors and eliminates lung metastasis. This work establishes a robust delivery platform to improve immunotherapy and the overall prognosis of HIFU surgery with high specificity and potency.

Metabolic heterogeneity in tumor microenvironment - A novel landmark for immunotherapy

The surrounding non-cancer cells and tumor cells that make up the tumor microenvironment (TME) have various metabolic rhythms. TME metabolic heterogeneity is influenced by the intricate network of metabolic control within and between cells. DNA, protein, transport, and microbial levels are important regulators of TME metabolic homeostasis. The effectiveness of immunotherapy is also closely correlated with alterations in TME metabolism. The response of a tumor patient to immunotherapy is influenced by a variety of variables, including intracellular metabolic reprogramming, metabolic interaction between cells, ecological changes within and between tumors, and general dietary preferences. Although immunotherapy and targeted therapy have made great strides, their use in the accurate identification and treatment of tumors still has several limitations. The function of TME metabolic heterogeneity in tumor immunotherapy is summarized in this article. It focuses on how metabolic heterogeneity develops and is regulated as a tumor progresses, the precise molecular mechanisms and potential clinical significance of imbalances in intracellular metabolic homeostasis and intercellular metabolic coupling and interaction, as well as the benefits and drawbacks of targeted metabolism used in conjunction with immunotherapy. This offers insightful knowledge and important implications for individualized tumor patient diagnosis and treatment plans in the future.

A metabolic dependency of EBV can be targeted to hinder B cell transformation

After infection of B cells, Epstein-Barr virus (EBV) engages host pathways that mediate cell proliferation and transformation, contributing to the propensity of the virus to drive immune dysregulation and lymphomagenesis. We found that the EBV protein EBNA2 initiates nicotinamide adenine dinucleotide (NAD) de novo biosynthesis by driving expression of the metabolic enzyme indoleamine 2,3-dioxygenase 1 (IDO1) in infected B cells. Virus-enforced NAD production sustained mitochondrial complex I activity, to match adenosine triphosphate (ATP) production with bioenergetic requirements of proliferation and transformation. In transplant patients, IDO1 expression in EBV-infected B cells, and a serum signature of increased IDO1 activity, preceded development of lymphoma. In humanized mice infected with EBV, IDO1 inhibition reduced both viremia and lymphomagenesis. Virus-orchestrated NAD biosynthesis is therefore a druggable metabolic vulnerability of EBV-driven B cell transformation, opening therapeutic possibilities for EBV-related diseases.

MR-Based Radiomics Predicts CDK6 Expression and Prognostic Value in High-grade Glioma

RATIONALE AND OBJECTIVES

This study aims to assess the prognostic value of Cyclin-dependent kinases 6 (CDK6) expression levels and establish a machine learning-based radiomics model for predicting the expression levels of CDK6 in high-grade gliomas (HGG).

MATERIALS AND METHODS

Clinical parameters and genomic data were extracted from 310 HGG patients in the Cancer Genome Atlas (TCGA) database and 27 patients in the Repository of Molecular Brain Neoplasia Data (REMBRANDT) database. Univariate and multivariate Cox regression, as well as Kaplan-Meier analysis, were performed for prognosis analysis. The correlation between immune cell Infiltration with CDK6 was assessed using spearman correlation analysis. Radiomic features were extracted from contrast-enhanced magnetic resonance imaging (CE-MRI) in the Cancer Imaging Archive (TCIA) database (n = 82) and REMBRANDT database (n = 27). Logistic regression (LR) and support vector machine (SVM) were employed to establish the radiomics model for predicting CDK6 expression. Receiver operating characteristic curve (ROC), calibration curve, and decision curve analysis (DCA) were utilized to assess the predictive performance of the radiomics model. Generate radiomic scores (RS) based on the LR model. An RS-based nomogram was constructed to predict the prognosis of HGG.

RESULTS

CDK6 was significantly overexpressed in HGG tissues and was related to lower overall survival. A significant elevation in infiltrating M0 macrophages was observed in the CDK6 high group (P < 0.001). The LR radiomics model for the prediction of CDK6 expression levels (AUC=0.810 in the training cohort, AUC = 0.784 after cross-validation, AUC=0.750 in the testing cohort) was established utilizing three radiomic features. The predictive efficiencies of the RS-based nomogram, as measured by AUC, were 0.769 for 1-year, 0.815 for 3-year, and 0.780 for 5-year, respectively.

CONCLUSION

The expression level of CDK6 can impact the prognosis of patients with HGG. The expression level of HGG can be noninvasively prognosticated utilizing a radiomics model.

Tumor Microenvironment-Specific Driven Nanoagents for Synergistic Mitochondria Damage-Related Immunogenic Cell Death and Alleviated Immunosuppression

Despite significant breakthroughs in immunotherapy, the limitations of inadequate immune stimulation and stubborn immune resistance continue to present opportunities and challenges. Therefore, a two-pronged approach, encompassing the activation of immunogenic cell death (ICD) and blocking the indoleamine 2,3-dioxygenase (IDO)-mediated pathway, is devised to elicit systemic anti-tumor immunity and alleviate immunosuppression. Herein, a tumor microenvironment (TME)-specific driven nanoagent is composed of a tetrasulfide bond-bridged mesoporous silica layer (MON) coated up-conversion nanoparticles as a nano-carrier, combines Fe2+, curcumin, and indoximod for operating chemodynamic therapy/chemotherapy/immunotherapy. The consumption of glutathione (GSH) caused by MON degradation, the Fenton reaction of Fe2+, and curcumin triggering mitochondrial damage collectively exacerbate the oxidative stress, leading to a violent immunoreaction and reversal of the immunosuppressive TME through a combination of IDO-inhibitors. Meanwhile, upconversion luminescence (UCL) imaging serves as a significant guiding tool for drug delivery and the treatment of nanoagents. In vivo and in vitro experiment results demonstrate that the nanosystem not only effectively inhibits the growth of primary tumors but also induces immune priming and memory effects to reject re-challenged tumors. The strategy as a complementary approach displays great potential for future immunotherapy along with other multimodal treatment modes.

Determinants of resistance and response to melanoma therapy

Metastatic melanoma is among the most enigmatic advanced cancers to clinically manage despite immense progress in the way of available therapeutic options and historic decreases in the melanoma mortality rate. Most patients with metastatic melanoma treated with modern targeted therapies (for example, BRAFV600E/K inhibitors) and/or immune checkpoint blockade (for example, anti-programmed death 1 therapy) will progress, owing to profound tumor cell plasticity fueled by genetic and nongenetic mechanisms and dichotomous host microenvironmental influences. Here we discuss the determinants of tumor heterogeneity, mechanisms of therapy resistance and effective therapy regimens that hold curative promise.

Harnessing CD8+ T cell dynamics in hepatitis B virus-associated liver diseases: Insights, therapies and future directions

Hepatitis B virus (HBV) infection playsa significant role in the etiology and progression of liver-relatedpathologies, encompassing chronic hepatitis, fibrosis, cirrhosis, and eventual hepatocellularcarcinoma (HCC). Notably, HBV infection stands as the primary etiologicalfactor driving the development of HCC. Given the significant contribution ofHBV infection to liver diseases, a comprehensive understanding of immunedynamics in the liver microenvironment, spanning chronic HBV infection,fibrosis, cirrhosis, and HCC, is essential. In this review, we focused on thefunctional alterations of CD8+ T cells within the pathogenic livermicroenvironment from HBV infection to HCC. We thoroughly reviewed the roles ofhypoxia, acidic pH, metabolic reprogramming, amino acid deficiency, inhibitory checkpointmolecules, immunosuppressive cytokines, and the gut-liver communication in shapingthe dysfunction of CD8+ T cells in the liver microenvironment. Thesefactors significantly impact the clinical prognosis. Furthermore, we comprehensivelyreviewed CD8+ T cell-based therapy strategies for liver diseases,encompassing HBV infection, fibrosis, cirrhosis, and HCC. Strategies includeimmune checkpoint blockades, metabolic T-cell targeting therapy, therapeuticT-cell vaccination, and adoptive transfer of genetically engineered CD8+ T cells, along with the combined usage of programmed cell death protein-1/programmeddeath ligand-1 (PD-1/PD-L1) inhibitors with mitochondria-targeted antioxidants.Given that targeting CD8+ T cells at various stages of hepatitis Bvirus-induced hepatocellular carcinoma (HBV + HCC) shows promise, we reviewedthe ongoing need for research to elucidate the complex interplay between CD8+ T cells and the liver microenvironment in the progression of HBV infection toHCC. We also discussed personalized treatment regimens, combining therapeuticstrategies and harnessing gut microbiota modulation, which holds potential forenhanced clinical benefits. In conclusion, this review delves into the immunedynamics of CD8+ T cells, microenvironment changes, and therapeuticstrategies within the liver during chronic HBV infection, HCC progression, andrelated liver diseases.

Spatiotemporally Controlled T-Cell Combination Therapy for Solid Tumor

Due to multidimensional complexity of solid tumor, development of rational T-cell combinations and corresponding formulations is still challenging. Herein, a triple combination of T cells are developed with Indoleamine 2,3-dioxygenase inhibitors (IDOi) and Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i). To maximize synergism, a spatiotemporally controlled T-cell engineering technology to formulate triple drugs into one cell therapeutic, is established. Specifically, a sequentially responsive core-shell nanoparticle (SRN) encapsulating IDOi and CDK4/6i is anchored onto T cells. The yielded SRN-T cells migrated into solid tumor, and achieved a 1st release of IDOi in acidic tumor microenvironment (TME). Released IDOi restored tryptophan supply in TME, which activated effector T cells and inhibited Tregs. Meanwhile, 1st released core is internalized by tumor cells and degraded by glutathione (GSH), to realize a 2nd release of CDK4/6i, which induced up-regulated expression of C-X-C motif chemokine ligand 10 (CXCL10) and C-C motif chemokine ligand 5 (CCL5), and thus significantly increased tumor infiltration of T cells. Together, with an enhanced recruitment and activation, T cells significantly suppressed tumor growth, and prolonged survival of tumor-bearing mice. This study demonstrated rationality and superiority of a tri-drug combination mediated by spatiotemporally controlled cell-engineering technology, which provides a new treatment regimen for solid tumor.

Prognostic relevance of high expression of kynurenine pathway markers in glioblastoma

Glioblastoma (GBM) continues to exhibit a discouraging survival rate despite extensive research into new treatments. One factor contributing to its poor prognosis is the tumor's immunosuppressive microenvironment, in which the kynurenine pathway (KP) plays a significant role. This study aimed to explore how KP impacts the survival of newly diagnosed GBM patients. We examined tissue samples from 108 GBM patients to assess the expression levels of key KP markers-tryptophan 2,3-dioxygenase (TDO2), indoleamine 2,3-dioxygenase (IDO1/2), and the aryl hydrocarbon receptor (AhR). Using immunohistochemistry and QuPath software, three tumor cores were analyzed per patient to evaluate KP marker expression. Kaplan-Meier survival analysis and stepwise multivariate Cox regression were used to determine the effect of these markers on patient survival. Results showed that patients with high expression of TDO2, IDO1/2, and AhR had significantly shorter survival times. This finding held true even when controlling for other known prognostic variables, with a hazard ratio of 3.393 for IDO1, 2.775 for IDO2, 1.891 for TDO2, and 1.902 for AhR. We suggest that KP markers could serve as useful tools for patient stratification, potentially guiding future immunomodulating trials and personalized treatment approaches for GBM patients.

Quantification and Profiling of Early and Late Differentiation Stage T Cells in Mantle Cell Lymphoma Reveals Immunotherapeutic Targets in Subsets of Patients

With the aim to advance the understanding of immune regulation in MCL and to identify targetable T-cell subsets, we set out to combine image analysis and spatial omic technology focused on both early and late differentiation stages of T cells. MCL patient tissue (n = 102) was explored using image analysis and GeoMx spatial omics profiling of 69 proteins and 1812 mRNAs. Tumor cells, T helper (TH) cells and cytotoxic (TC) cells of early (CD57-) and late (CD57+) differentiation stage were analyzed. An image analysis workflow was developed based on fine-tuned Cellpose models for cell segmentation and classification. TC and CD57+ subsets of T cells were enriched in tumor-rich compared to tumor-sparse regions. Tumor-sparse regions had a higher expression of several key immune suppressive proteins, tentatively controlling T-cell expansion in regions close to the tumor. We revealed that T cells in late differentiation stages (CD57+) are enriched among MCL infiltrating T cells and are predictive of an increased expression of immune suppressive markers. CD47, IDO1 and CTLA-4 were identified as potential targets for patients with T-cell-rich MCL TIME, while GITR might be a feasible target for MCL patients with sparse T-cell infiltration. In subgroups of patients with a high degree of CD57+ TC-cell infiltration, several immune checkpoint inhibitors, including TIGIT, PD-L1 and LAG3 were increased, emphasizing the immune-suppressive features of this highly differentiated T-cell subset not previously described in MCL.

Qingfei mixture mitigates immunosuppression of tumor microenvironment in non-small cell lung cancer by blocking stat1/Ido1-mediated tryptophan-kynurenine pathway

Programmed death-1 (PD-1) acts as a T cell checkpoint and is important in controlling T cell exhaustion. Blocking the intercommunication across PD-1 and PD-L1 is promising for advanced lung cancer treatment. However, the response rate requires being strengthened. This study aimed to determine whether the combination treatment of Qingfei mixture (QFM) and PD-1 inhibitor could improve the sensitivity of monoclonal antibody by regulating STAT1/IDO1-mediated tryptophan (Trp)-kynurenine (Kyn) pathway. The in vivo imaging system, immunofluorescence, hematoxylin-eosin staining, TUNEL, flow cytometry, HPLC, and ELISA were used to estimate the anti-tumor effects in LLC-luc tumor-bearing C57BL/6 mice treated with QFM, PD-1 inhibitor, 2-NP (enhancer of STAT1 transcription), and FICZ (AhR agonist) alone or in combination. IFN-γ-mediated A549 and LLC cells were treated with QFM-containing serum and fludarabine (FLU, STAT1 inhibitor), and cell viability, apoptosis, and Kyn content were then evaluated using CCK-8 assays, flow cytometry, and HPLC assays, respectively. Additionally, the expressions of STAT1, IDO1, AhR, NFATc1, TRIP12, PD-1, and PD-L1 were measured in vivo and in vitro. We found QFM increased the anti-cancer actions of PD-1 inhibitors by increasing the CD8+IFNγ+ T cells infiltration and decreasing the ratio of Kyn/Trp. Besides, QFM-containing serum suppressed the proliferation and promoted apoptosis in A549 and LLC cells, meanwhile, FLU boosted the effects of QFM-containing serum. Moreover, the suppression of tumor growth in the combination therapy was attenuated in the mice receiving 2-NP or FICZ. The occurrence of the above results was accompanied by a decrease in STAT1, IDO1, AhR, PD-1, and PD-L1 expressions. Collectively, the findings suggested that QFM may increase the influences of PD-1 inhibitors at least partially by blocking the STAT1/IDO1-mediated tryptophan-kynurenine pathway in lung cancer.

The oral microbiome and oral and upper gastrointestinal diseases

Background

Microbiomes are essential components of the human body, and their populations are substantial. Under normal circumstances, microbiomes coexist harmoniously with the human body, but disturbances in this equilibrium can lead to various diseases. The oral microbiome is involved in the occurrence and development of many oral and gastrointestinal diseases. This review focuses on the relationship between oral microbiomes and oral and upper gastrointestinal diseases, and therapeutic strategies aiming to provide valuable insights for clinical prevention and treatment.

Methods

To identify relevant studies, we conducted searches in PubMed, Google Scholar, and Web of Science using keywords such as "oral microbiome," "oral flora, " "gastrointestinal disease, " without any date restrictions. Subsequently, the retrieved publications were subject to a narrative review.

Results

In this review, we found that oral microbiomes are closely related to oral and gastrointestinal diseases such as periodontitis, dental caries, reflux esophagitis, gastritis, and upper gastrointestinal tumors (mainly the malignant ones). Oral samples like saliva and buccal mucosa are not only easy to collect, but also display superior sample stability compared to gastrointestinal tissues. Consequently, analysis of the oral microbiome could potentially serve as an efficient preliminary screening method for high-risk groups before undergoing endoscopic examination. Besides, treatments based on the oral microbiomes could aid early diagnosis and treatment of these diseases.

Conclusions

Oral microbiomes are essential to oral and gastrointestinal diseases. Therapies centered on the oral microbiomes could facilitate the early detection and management of these conditions.

The tumor immune composition of mismatch repair deficient and Epstein-Barr virus-positive gastric cancer: A systematic review

BACKGROUND

Gastric cancer (GC), known for its unfavorable prognosis, has been classified in four distinct molecular subtypes. These subtypes not only exhibit differences in their genome and transcriptome but also in the composition of their tumor immune microenvironment. The microsatellite instable (MSI) and Epstein-Barr virus (EBV) positive GC subtypes show clear clinical benefits from immune checkpoint blockade, likely due to a neoantigen-driven and virus-driven antitumor immune response and high expression of immune checkpoint molecule PD-L1. However, even within these subtypes response to checkpoint inhibition is variable, which is potentially related to heterogeneity in the tumor immune microenvironment (TIME) and expression of co-inhibitory molecules. We conducted a systematic review to outline the current knowledge about the immunological features on the TIME of MSI and EBV + GCs.

METHODS

A systematic search was performed in PubMed, EMBASE and Cochrane Library. All articles from the year 1990 and onwards addressing immune features of gastric adenocarcinoma were reviewed and included based on predefined in- and exclusion criteria.

RESULTS

In total 5962 records were screened, of which 139 were included that reported immunological data on molecular GC subtypes. MSI and EBV + GCs were reported to have a more inflamed TIME compared to non-MSI and EBV- GC subtypes. Compared to microsatellite stable (MSS) tumors, MSI tumors were characterized by higher numbers of CD8 + and FoxP3 + T cells, and tumor infiltrating pro- and anti-inflammatory macrophages. HLA-deficiency was most common in MSI tumors compared to other molecular GC subtypes and associated with lower T and B cell infiltrates compared to HLA-proficient tumors. EBV + was associated with a high number of CD8 + T cells, Tregs, NK cells and macrophages. Expression of PD-L1, CTLA-4, Granzyme A and B, Perforin and interferon-gamma was enriched in EBV + tumors. Overall, MSI tumors harbored a more heterogeneous TIME in terms of immune cell composition and immune checkpoints compared to the EBV + tumors.

DISCUSSION AND CONCLUSION

MSI and EBV + GCs are highly Handbook for Conducting a Literature-Based Health Assessment Using OHAT Approach for Systematic Review and Evidence Integration.; 2019pro-inflammatory immune cell populations. Although studies on the direct comparison of EBV + and MSI tumors are limited, EBV + tumors show less intra-subgroup heterogeneity compared to MSI tumors. More studies are needed to identify how Intra-subgroup heterogeneity impacts response to immunotherapy efficacy.

FLI1 promotes IFN-γ-induced kynurenine production to impair anti-tumor immunity

Nasopharyngeal carcinoma (NPC)-mediated immunosuppression within the tumor microenvironment (TME) frequently culminates in the failure of otherwise promising immunotherapies. In this study, we identify tumor-intrinsic FLI1 as a critical mediator in impairing T cell anti-tumor immunity. A mechanistic inquiry reveals that FLI1 orchestrates the expression of CBP and STAT1, facilitating chromatin accessibility and transcriptional activation of IDO1 in response to T cell-released IFN-γ. This regulatory cascade ultimately leads to augmented IDO1 expression, resulting in heightened synthesis of kynurenine (Kyn) in tumor cells. This, in turn, fosters CD8+ T cell exhaustion and regulatory T cell (Treg) differentiation. Intriguingly, we find that pharmacological inhibition of FLI1 effectively obstructs the CBP/STAT1-IDO1-Kyn axis, thereby invigorating both spontaneous and checkpoint therapy-induced immune responses, culminating in enhanced tumor eradication. In conclusion, our findings delineate FLI1-mediated Kyn metabolism as an immune evasion mechanism in NPC, furnishing valuable insights into potential therapeutic interventions.

Immune profiling of dedifferentiated liposarcoma and identification of novel antigens for targeted immunotherapy

Dedifferentiated liposarcoma (DDLS) is an aggressive, recurring sarcoma with limited treatments. T-cell immunotherapies selectively target malignant cells, holding promise against DDLS. The development of successful immunotherapy for DDLS requires a thorough evaluation of the tumor immune microenvironment and the identification and characterization of targetable immunogenic tumor antigens. To assess the complexity of the human DDLS tumor immune microenvironment and to identify target antigens, we used the nCounter NanoString platform, analyzing gene expression profiles across 29 DDLS and 10 healthy adipose tissue samples. Hierarchical clustering of tumors based on expression of tumor inflammation signature genes revealed two distinct groups, consisting of 15 inflamed tumors and 14 non-inflamed tumors, demonstrating tumor heterogeneity within this sarcoma subtype. Among the identified antigens, PBK and TTK exhibited substantial upregulation in mRNA expression compared to healthy adipose tissue controls, further corroborated by positive protein expression by IHC. This data shows considerable inter-tumoral heterogeneity of inflammation, which should be taken into consideration when designing an immunotherapy for DDLS, and provides a novel targetable antigen in DDLS. The results of this study lay the groundwork for the development of a novel immunotherapy for this highly aggressive sarcoma.

Identification of hypoxic macrophages in glioblastoma with therapeutic potential for vasculature normalization

Monocyte-derived tumor-associated macrophages (Mo-TAMs) intensively infiltrate diffuse gliomas with remarkable heterogeneity. Using single-cell transcriptomics, we chart a spatially resolved transcriptional landscape of Mo-TAMs across 51 patients with isocitrate dehydrogenase (IDH)-wild-type glioblastomas or IDH-mutant gliomas. We characterize a Mo-TAM subset that is localized to the peri-necrotic niche and skewed by hypoxic niche cues to acquire a hypoxia response signature. Hypoxia-TAM destabilizes endothelial adherens junctions by activating adrenomedullin paracrine signaling, thereby stimulating a hyperpermeable neovasculature that hampers drug delivery in glioblastoma xenografts. Accordingly, genetic ablation or pharmacological blockade of adrenomedullin produced by Hypoxia-TAM restores vascular integrity, improves intratumoral concentration of the anti-tumor agent dabrafenib, and achieves combinatorial therapeutic benefits. Increased proportion of Hypoxia-TAM or adrenomedullin expression is predictive of tumor vessel hyperpermeability and a worse prognosis of glioblastoma. Our findings highlight Mo-TAM diversity and spatial niche-steered Mo-TAM reprogramming in diffuse gliomas and indicate potential therapeutics targeting Hypoxia-TAM to normalize tumor vasculature.

Metabolic adaptations determine whether natural killer cells fail or thrive within the tumor microenvironment

Natural Killer (NK) cells are a top contender in the development of adoptive cell therapies for cancer due to their diverse antitumor functions and ability to restrict their activation against nonmalignant cells. Despite their success in hematologic malignancies, NK cell-based therapies have been limited in the context of solid tumors. Tumor cells undergo various metabolic adaptations to sustain the immense energy demands that are needed to support their rapid and uncontrolled proliferation. As a result, the tumor microenvironment (TME) is depleted of nutrients needed to fuel immune cell activity and contains several immunosuppressive metabolites that hinder NK cell antitumor functions. Further, we now know that NK cell metabolic status is a main determining factor of their effector functions. Hence, the ability of NK cells to withstand and adapt to these metabolically hostile conditions is imperative for effective and sustained antitumor activity in the TME. With this in mind, we review the consequences of metabolic hostility in the TME on NK cell metabolism and function. We also discuss tumor-like metabolic programs in NK cell induced by STAT3-mediated expansion that adapt NK cells to thrive in the TME. Finally, we examine how other approaches can be applied to enhance NK cell metabolism in tumors.

Plasmid DNA ionisable lipid nanoparticles as non-inert carriers and potent immune activators for cancer immunotherapy

Immunotherapy is currently a standard of care in the treatment of many malignancies. However, predictable side effects caused by systemic administration of highly immunostimulatory molecules have been a serious concern within this field. Intratumoural expression or silencing of immunogenic and immunoinhibitory molecules using nucleic acid-based approaches such as plasmid DNA (pDNA) and small interfering RNA (siRNA), respectively, could represent a next generation of cancer immunotherapy. Here, we employed lipid nanoparticles (LNPs) to deliver either non-specific pDNA and siRNA, or constructs targeting two prominent immunotherapeutic targets OX40L and indoleamine 2,3-dioxygenase-1 (IDO), to tumours in vivo. In the B16F10 mouse model, intratumoural delivery of LNP-formulated non-specific pDNA and siRNA led to strong local immune activation and tumour growth inhibition even at low doses due to the pDNA immunogenic nature. Replacement of these non-specific constructs by pOX40L and siIDO resulted in more prominent immune activation as evidenced by increased immune cell infiltration in tumours and tumour-draining lymph nodes. Consistently, pOX40L alone or in combination with siIDO could prolong overall survival, resulting in complete tumour regression and the formation of immunological memory in tumour rechallenge models. Our results suggest that intratumoural administration of LNP-formulated pDNA and siRNA offers a promising approach for cancer immunotherapy.

CD8+ T cell-based cancer immunotherapy

The immune system in humans is a defense department against both exogenous and endogenous hazards, where CD8+ T cells play a crucial role in opposing pathological threats. Various immunotherapies based on CD8+ T cells have emerged in recent decades, showing their promising results in treating intractable diseases. However, in the fight against the constantly changing and evolving cancers, the formation and function of CD8+ T cells can be challenged by tumors that might train a group of accomplices to resist the T cell killing. As cancer therapy stepped into the era of immunotherapy, understanding the physiological role of CD8+ T cells, studying the machinery of tumor immune escape, and thereby formulating different therapeutic strategies become the imperative missions for clinical and translational researchers to fulfill. After brief basics of CD8+ T cell-based biology is covered, this review delineates the mechanisms of tumor immune escape and discusses different cancer immunotherapy regimens with their own advantages and setbacks, embracing challenges and perspectives in near future.

IDO1 correlates with the immune landscape of head and neck squamous cell carcinoma: a study based on bioinformatics analyses

Background

Head and neck squamous cell carcinoma (HNSCCs) is a common cancer type with a high mortality rate and poor prognosis. Recent studies have focused on the role of immune checkpoints in HNSCC progression and in their potential use as prognostic markers and immunotherapeutic candidates. Some immune checkpoints, such as PD-1 and PD-L1, have been studied thoroughly in HNSCC. Other molecules, such as indoleamine 2,3-dioxygenase 1 (IDO1), have been investigated minimally.

Methods

IDO1 expression, prognostic potential, and association with the immune profile of HNSCC were explored using online databases, including GEPIA, UALCAN, TIMER2.0, cBioPortal, and LinkedOmics, which utilize TCGA datasets and are freely available for use. For validation purposes, seven pairs of primary and metastatic HNSCC were immunostained for IDO1.

Results

Our analysis revealed significantly higher expression of IDO1 in HNSCC, especially in HPV+ SCCs compared with healthy control tissue. However, IDO1 expression showed weak to no prognostic potential for overall and disease-free survival in HNSCC. IDO1 expression in HNSCC was positively correlated with several immune-related molecules, including most of the immune checkpoints. Additionally, GO enrichment analysis revealed that several immune-related pathways are positively correlated with IDO1 expression in HNSCC, such as response to type I interferon and lymphocyte-mediated immunity pathways. Finally, IDO1 expression positively correlated with infiltration of most of the immune cells in HNSCC, such as CD4+ T cells, CD8+ T cells, M1 and M2 macrophages, dendritic cells, and B cells.

Conclusion

IDO1 expression is closely correlated with the immune profile of the HNSCC. This observation should be explored further to elucidate the potential of targeting IDO1 as a novel immunotherapeutic approach for HNSCC.

Exploring a repurposed candidate with dual hIDO1/hTDO2 inhibitory potential for anticancer efficacy identified through pharmacophore-based virtual screening and in vitro evaluation

Discovering effective anti-cancer agents poses a formidable challenge given the limited efficacy of current therapeutic modalities against various cancer types due to intrinsic resistance mechanisms. Cancer immunochemotherapy is an alternative strategy for breast cancer treatment and overcoming cancer resistance. Human Indoleamine 2,3-dioxygenase (hIDO1) and human Tryptophan 2,3-dioxygenase 2 (hTDO2) play pivotal roles in tryptophan metabolism, leading to the generation of kynurenine and other bioactive metabolites. This process facilitates the de novo synthesis of Nicotinamide Dinucleotide (NAD), promoting cancer resistance. This study identified a new dual hIDO1/hTDO2 inhibitor using a drug repurposing strategy of FDA-approved drugs. Herein, we delineate the development of a ligand-based pharmacophore model based on a training set of 12 compounds with reported hIDO1/hTDO2 inhibitory activity. We conducted a pharmacophore search followed by high-throughput virtual screening of 2568 FDA-approved drugs against both enzymes, resulting in ten hits, four of them with high potential of dual inhibitory activity. For further in silico and in vitro biological investigation, the anti-hypercholesterolemic drug Pitavastatin deemed the drug of choice in this study. Molecular dynamics (MD) simulations demonstrated that Pitavastatin forms stable complexes with both hIDO1 and hTDO2 receptors, providing a structural basis for its potential therapeutic efficacy. At nanomolar (nM) concentration, it exhibited remarkable in vitro enzyme inhibitory activity against both examined enzymes. Additionally, Pitavastatin demonstrated potent cytotoxic activity against BT-549, MCF-7, and HepG2 cell lines (IC50 = 16.82, 9.52, and 1.84 µM, respectively). Its anticancer activity was primarily due to the induction of G1/S phase arrest as discovered through cell cycle analysis of HepG2 cancer cells. Ultimately, treating HepG2 cancer cells with Pitavastatin affected significant activation of caspase-3 accompanied by down-regulation of cellular apoptotic biomarkers such as IDO, TDO, STAT3, P21, P27, IL-6, and AhR.

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

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

High-parameter phenotypic characterization reveals a subset of human Th17 cells that preferentially produce IL-17 against M. tuberculosis antigen

Background

Interleukin-17-producing CD4 T cells contribute to the control of Mycobacterium tuberculosis (Mtb) infection in humans; whether infection with human immunodeficiency virus (HIV) disproportionately affects distinct Th17-cell subsets that respond to Mtb is incompletely defined.

Methods

We performed high-definition characterization of circulating Mtb-specific Th17 cells by spectral flow cytometry in people with latent TB and treated HIV (HIV-ART). We also measured kynurenine pathway activity by liquid chromatography-mass spectrometry (LC/MS) on plasma and tested the hypothesis that tryptophan catabolism influences Th17-cell frequencies in this context.

Results

We identified two subsets of Th17 cells: subset 1 defined as CD4+Vα7.2-CD161+CD26+and subset 2 defined as CD4+Vα7.2-CCR6+CXCR3-cells of which subset 1 was significantly reduced in latent tuberculosis infection (LTBI) with HIV-ART, yet Mtb-responsive IL-17-producing CD4 T cells were preserved; we found that IL-17-producing CD4 T cells dominate the response to Mtb antigen but not cytomegalovirus (CMV) antigen or staphylococcal enterotoxin B (SEB), and tryptophan catabolism negatively correlates with both subset 1 and subset 2 Th17-cell frequencies.

Conclusions

We found differential effects of ART-suppressed HIV on distinct subsets of Th17 cells, that IL-17-producing CD4 T cells dominate responses to Mtb but not CMV antigen or SEB, and that kynurenine pathway activity is associated with decreases of circulating Th17 cells that may contribute to tuberculosis immunity.

Potential of Targeting TDO2 as the Lung Adenocarcinoma Treatment

Tryptophan catabolism plays an important role in the metabolic reconnection in cancer cells to support special demands of tumor initiation and progression. The catabolic product of the tryptophan pathway, kynurenine, has the capability of suppressing the immune reactions of tumor cells. In this study, we conducted internal and external cohort studies to reveal the importance of tryptophan 2,3-dioxygenase (TDO) for lung adenocarcinoma (LUAD). Our study further demonstrated that the TDO2 expression was associated with the proliferation, survival, and invasion of LUAD cells, and targeting TDO2 for LUAD tumors could be a potential therapeutic strategy.

Dietary tryptophan improves growth and intestinal health by promoting the secretion of intestinal β-defensins against enterotoxigenic E. coli F4 in weaned piglets

Adequate dietary L-tryptophan (Trp) governs intestinal homeostasis in piglets. However, the defensive role of Trp in the diet against enterotoxigenic E. coli F4 (K88) in pigs is still poorly understood. Here, sixty (6.15 ± 1.52 kg, 24-day-old, Duroc × Landrace × Yorkshire) weaned piglets were used for an E. coli F4 attack test in a 2 × 2 factorial design. The growth (ADG, ADFI, GH), immune factors (IL-10, IgA, IgG, IgM), Trp metabolite 5-HT, intestinal morphology (jejunal and colonic VH), mRNA expression of β-defensins (jejunal BD-127, BD-119, ileal BD-1, BD-127), and abundance of beneficial microorganisms in the colon (Prevotella 9, Lactobacillus, Phascolarctobacterium, Faecalibacterium) were higher in the piglets in the HT (High Trp) and HTK (High Trp, K88) groups than in the LT (Low Trp) and LTK (Low Trp, K88) groups (P < 0.05), while FCR, diarrhea rate, diarrhea index, serum Trp, Kyn, IDO, D-LA, ET, and abundance of harmful microorganisms in the colon (Spirochaetes, Fusobacteria, Prevotella, Christensenellaceae R7) were lower in the HT and HTK groups than in the LT and LTK groups (P < 0.05). High Trp reduced the expression of virulence genes (K88 and LT) after E. coli F4 attack (P < 0.05). The IL-6, TNF-α was lower in the HTK group than in the LT, LTK group (P < 0.05). In short, a diet containing 0.35% Trp protected piglets from enterotoxigenic E. coli F4 (K88) via Trp metabolism promoting BD expression in the intestinal mucosa, which improved growth and intestinal health.

IDO1 Inhibition Promotes Activation of Tumor-intrinsic STAT3 Pathway and Induces Adverse Tumor-protective Effects

Pharmacological inhibition of IDO1 exhibits great promise as a strategy in cancer therapy. However, the failure of phase III clinical trials has raised the pressing need to understand the underlying reasons for this outcome. To gain comprehensive insights into the reasons behind the clinical failure of IDO1 inhibitors, it is essential to investigate the entire tumor microenvironment rather than focusing solely on individual cells or relying on knockout techniques. In this study, we conducted single-cell RNA sequencing to determine the overall response to apo-IDO1 inhibitor administration. Interestingly, although apo-IDO1 inhibitors were found to significantly activate intratumoral immune cells (mouse colon cancer cell CT26 transplanted in BALB/C mice), such as T cells, macrophages, and NK cells, they also stimulated the infiltration of M2 macrophages. Moreover, these inhibitors prompted monocytes and macrophages to secrete elevated levels of IL-6, which in turn activated the JAK2/STAT3 signaling pathway in tumor cells. Consequently, this activation enables tumor cells to survive even in the face of heightened immune activity. These findings underscore the unforeseen adverse effects of apo-IDO1 inhibitors on tumor cells and highlight the potential of combining IL-6/JAK2/STAT3 inhibitors with apo-IDO1 inhibitors to improve their clinical efficacy.

Multi-functional nanomedicines for combinational cancer immunotherapy that transform cold tumors to hot tumors

INTRODUCTION

Currently, cancer immunotherapy is widely used as a groundbreaking method that can completely cure advanced cancers. However, this new immunotherapy has the challenge of low patient response, which is often due to many patients' tumors having an immunosuppressive environment, known as cold tumors.

AREAS COVERED

This review aims to introduce various nanomedicine-derived combinational cancer immunotherapy that can transform cold tumor into hot tumors. Initially, we discuss new technologies for combinational immunotherapy based on multifunctional nanomedicines that can deliver combinational immunogenic cell death (ICD) inducers, immune checkpoint blockades (ICBs) and immune modulators (IMs) to targeted tumor tissues at the same time. Ultimately, we highlight how multifunctional nanomedicines for combinational cancer immunotherapy can be used to transform cold tumor into hot tumors against advanced cancers.

EXPERT OPINION

Nanomedicine-derived combinational cancer immunotherapy for delivering multiple ICD inducers, ICBs, and IMs at the same time is recognized as a new potential technology that can activate tumor immunity and simultaneously increase the therapeutic efficacy of immune cells that can transform effectively the cold tumors into hot tumors. Finally, nanomedicine-derived combinational cancer immunotherapy can solve the serious problems of low therapeutic efficacy that occurs when treating single drug or simple combinational drugs in cancer immunotherapy.

Targeting NAD+ Metabolism to Modulate Autoimmunity and Inflammation

NAD+ biology is involved in controlling redox balance, functioning as a coenzyme in numerous enzymatic reactions, and is a cofactor for Sirtuin enzymes and a substrate for multiple regulatory enzyme reactions within and outside the cell. At the same time, NAD+ levels are diminished with aging and are consumed during the development of inflammatory and autoimmune diseases linked to aberrant immune activation. Direct NAD+ augmentation via the NAD+ salvage and Priess-Handler pathways is being investigated as a putative therapeutic intervention to improve the healthspan in inflammation-linked diseases. In this review, we survey NAD+ biology and its pivotal roles in the regulation of immunity and inflammation. Furthermore, we discuss emerging studies evaluate NAD+ boosting in murine models and in human diseases, and we highlight areas of research that remain unresolved in understanding the mechanisms of action of these nutritional supplementation strategies.

A lipid/PLGA nanocomplex to reshape tumor immune microenvironment for colon cancer therapy

Immune checkpoint blockade therapy provides a new strategy for tumor treatment; however, the insufficient infiltration of cytotoxic T cells and immunosuppression in tumor microenvironment lead to unsatisfied effects. Herein, we reported a lipid/PLGA nanocomplex (RDCM) co-loaded with the photosensitizer Ce6 and the indoleamine 2,3-dioxygenase (IDO) inhibitor 1MT to improve immunotherapy of colon cancer. Arginine-glycine-aspartic acid (RGD) as the targeting moiety was conjugated on 1,2-distearoyl-snglycero-3-phosphoethanolamine lipid via polyethylene glycol (PEG), and programmed cell death-ligand 1 (PD-L1) peptide inhibitor DPPA (sequence: CPLGVRGK-GGG-d(NYSKPTDRQYHF)) was immobilized on the terminal group of PEG via matrix metalloproteinase 2 sensitive peptide linker. The Ce6 and 1MT were encapsulated in PLGA nanoparticles. The drug loaded nanoparticles were composited with RGD and DPPA modified lipid and lecithin to form lipid/PLGA nanocomplexes. When the nanocomplexes were delivered to tumor, DPPA was released by the cleavage of a matrix metalloproteinase 2-sensitive peptide linker for PD-L1 binding. RGD facilitated the cellular internalization of nanocomplexes via avβ3 integrin. Strong immunogenic cell death was induced by 1O2 generated from Ce6 irradiation under 660 nm laser. 1MT inhibited the activity of IDO and reduced the inhibition of cytotoxic T cells caused by kynurenine accumulation in the tumor microenvironment. The RDCM facilitated the maturation of dendritic cells, inhibited the activity of IDO, and markedly recruited the proportion of tumor-infiltrating cytotoxic T cells in CT26 tumor-bearing mice, triggering a robust immunological memory effect, thus effectively preventing tumor metastasis. The results indicated that the RDCM with dual IDO and PD-L1 inhibition effects is a promising platform for targeted photoimmunotherapy of colon cancer.

Discovery of the sEH Inhibitor Epoxykynin as a Potent Kynurenine Pathway Modulator

Disease-related phenotypic assays enable unbiased discovery of novel bioactive small molecules and may provide novel insights into physiological systems and unprecedented molecular modes of action (MMOA). Herein, we report the identification and characterization of epoxykynin, a potent inhibitor of the soluble epoxide hydrolase (sEH). Epoxykynin was discovered by means of a cellular assay monitoring modulation of kynurenine (Kyn) levels in BxPC-3 cells upon stimulation with the cytokine interferon-γ (IFN-γ) and subsequent target identification employing affinity-based chemical proteomics. Increased Kyn levels are associated with immune suppression in the tumor microenvironment and, thus, the Kyn pathway and its key player indoleamine 2,3-dioxygenase 1 (IDO1) are appealing targets in immuno-oncology. However, targeting IDO1 directly has led to limited success in clinical investigations, demonstrating that alternative approaches to reduce Kyn levels are in high demand. We uncover a cross-talk between sEH and the Kyn pathway that may provide new opportunities to revert cancer-induced immune tolerance.

Targeting Tryptophan Catabolism in Ovarian Cancer to Attenuate Macrophage Infiltration and PD-L1 Expression

High-grade serous carcinoma (HGSC) of the fallopian tube, ovary, and peritoneum is the most common type of ovarian cancer and is predicted to be immunogenic because the presence of tumor-infiltrating lymphocytes conveys a better prognosis. However, the efficacy of immunotherapies has been limited because of the immune-suppressed tumor microenvironment (TME). Tumor metabolism and immune-suppressive metabolites directly affect immune cell function through the depletion of nutrients and activation of immune-suppressive transcriptional programs. Tryptophan (TRP) catabolism is a contributor to HGSC disease progression. Two structurally distinct rate-limiting TRP catabolizing enzymes, indoleamine 2,3-dioxygenase 1 (IDO1) and tryptophan 2,3-dioxygenase 2 (TDO2), evolved separately to catabolize TRP. IDO1/TDO2 are aberrantly expressed in carcinomas and metabolize TRP into the immune-suppressive metabolite kynurenine (KYN), which can engage the aryl hydrocarbon receptor to drive immunosuppressive transcriptional programs. To date, IDO inhibitors tested in clinical trials have had limited efficacy, but those inhibitors did not target TDO2, and we find that HGSC cell lines and clinical outcomes are more dependent on TDO2 than IDO1. To identify inflammatory HGSC cancers with poor prognosis, we stratified patient ascites samples by IL6 status, which correlates with poor prognosis. Metabolomics revealed that IL6-high patient samples had enriched KYN. TDO2 knockdown significantly inhibited HGSC growth and TRP catabolism. The orally available dual IDO1/TDO2 inhibitor, AT-0174, significantly inhibited tumor progression, reduced tumor-associated macrophages, and reduced expression of immune-suppressive proteins on immune and tumor cells. These studies demonstrate the importance of TDO2 and the therapeutic potential of AT-0174 to overcome an immune-suppressed TME.

SIGNIFICANCE

Developing strategies to improve response to chemotherapy is essential to extending disease-free intervals for patients with HGSC of the fallopian tube, ovary, and peritoneum. In this article, we demonstrate that targeting TRP catabolism, particularly with dual inhibition of TDO2 and IDO1, attenuates the immune-suppressive microenvironment and, when combined with chemotherapy, extends survival compared with chemotherapy alone.

Discovery of novel IDO1/TDO2 dual inhibitors: a consensus Virtual screening approach with molecular dynamics simulations, and binding free energy analysis

The pursuit of effective cancer immunotherapy drugs remains challenging, with overexpression of indoleamine 2,3-dioxygenase 1 (IDO1) and tryptophan 2,3-dioxygenase 2 (TDO2) allowing cancer cells to evade immune attacks. While several IDO1 inhibitors have undergone clinical testing, only three dual IDO1/TDO2 inhibitors have reached human trials. Hence, this study focuses on identifying novel IDO1/TDO2 dual inhibitors through consensus structure-based virtual screening (SBVS). ZINC15 natural products library was refined based on molecular descriptors, and the selected compounds were docked to the holo form IDO1 and TDO2 using two different software programs and ranked according to their consensus docking scores. The top-scoring compounds underwent in silico evaluations for pharmacokinetics, toxicity, CYP3A4 affinity, molecular dynamics (MD) simulations, and MM-GBSA binding free energy calculations. Five compounds (ZINC00000079405/10, ZINC00004028612/11, ZINC00013380497/12, ZINC00014613023/13, and ZINC00103579819/14) were identified as potential IDO1/TDO2 dual inhibitors due to their high consensus docking scores, key residue interactions with the enzymes, favorable pharmacokinetics, and avoidance of CYP3A4 binding. MD simulations of the top three hits with IDO1 indicated conformational changes and compactness, while MM-GBSA analysis revealed strong binding free energy for compounds 10 (ΔG: -20.13 kcal/mol) and 11 (ΔG: -16.22 kcal/mol). These virtual hits signify a promising initial step in identifying candidates as supplementary therapeutics to immune checkpoint inhibitors in cancer treatment. Their potential to deliver potent dual inhibition of IDO1/TDO2, along with safety and favorable pharmacokinetics, makes them compelling. Validation through in vitro and in vivo assays should be conducted to confirm their activity, selectivity, and preclinical potential as holo IDO1/TDO2 dual inhibitors.Communicated by Ramaswamy H. Sarma.