Indoleamine 2,3-dioxygenase Research Articles

Design of a targeted dual drug delivery system for boosting the efficacy of photoimmunotherapy against melanoma proliferation and metastasis

IntroductionThe combination of a photosensitizer and indoleamine-2,3 dioxygenase (IDO) inhibitor provides a promising photoimmunotherapy (PIT) strategy for melanoma treatment. A dual drug delivery system offers a potential approach for optimizing the inhibitory effects of PIT on melanoma proliferation and metastasis. ObjectiveTo develop a dual drug delivery system based on PIT and to study its efficacy in inhibiting melanoma proliferation and metastasis. MethodsWe constructed a multifunctional nano-porphyrin material (P18-APBA-HA) using the photosensitizer-purpurin 18 (P18), hyaluronic acid (HA), and 4-(aminomethyl) phenylboronic acid (APBA). The resulting P18-APBA-HA was inserted into a phospholipid membrane and the IDO inhibitor epacadostat (EPA) was loaded into the internal phase to prepare a dual drug delivery system (Lip\\EPA\\P18-APBA-HA). Moreover, we also investigated its physicochemical properties, targeting, anti-tumor immunity, and anti-tumor proliferation and metastasis effects. ResultsThe designed system utilized the pH sensitivity of borate ester to realize an enhanced-targeting strategy to facilitate the drug distribution in tumor lesions and efficient receptor-mediated cellular endocytosis. The intracellular release of EPA from Lip\\EPA\\P18-APBA-HA was triggered by thermal radiation, thereby inhibiting IDO activity in the tumor microenvironment, and promoting activation of the immune response. Intravenous administration of Lip\\EPA\\P18-APBA-HA effectively induced anti-tumor immunity by promoting dendritic cell maturation, cytotoxic T cell activation, and regulatory T cell suppression, and regulating cytokine secretion, to inhibit the proliferation of melanoma and lung metastasis. ConclusionThe proposed nano-drug delivery system holds promise as offers a promising strategy to enhance the inhibitory effects of the combination of EPA and P18 on melanoma proliferation and metastasis.

Berberine alleviates diabetic retinopathy by regulating the Th17/Treg ratio

BackgroundDiabetic retinopathy (DR) stands as a prominent complication of diabetes. Berberine (BBR) has reported to be effective to ameliorate the retinal damage of DR. Studying the potential immunological mechanisms of BBR on the streptozotocin (STZ) induced DR mouse model will explain the therapeutic mechanisms of BBR and provide theoretical basis for the clinical application of this drug. MethodsC57BL/6 J mice were induced into a diabetic state using a 50 mg/(kg·d) dose of STZ over a 5-day period. Subsequently, they were subjected to a high-fat diet (HFD) for one month. Following a 5-week treatment with 100 mg/(kg·d) BBR, the concentrations of inflammatory factors in the mice's peripheral blood were determined using an enzyme-linked immunosorbent assay (ELISA). Hematoxylin-eosin staining was employed to scrutinize pathological changes in the mice's retinas, while flow cytometry assessed the proportions of T-lymphocyte subsets and the activation status of dendritic cells (DCs) in the spleen and lymph nodes. CD4+T cells and DC2.4 cell lines were utilized to investigate the direct and indirect effects of BBR on T cells under high glucose conditions in vitro. ResultsFollowing 5 weeks of BBR treatment in the streptozotocin (STZ) mouse model of DR, we observed alleviation of retinal lesions and a down-regulation in the secretion of inflammatory cytokines, namely TNF-α, IL-1β, and IL-6, in the serum of these mice. And in the spleen and lymph nodes of these mice, BBR inhibited the proportion of Th17 cells and promoted the proportion of Treg cells, thereby down-regulating the Th17/Treg ratio. Additionally, in vitro experiments, BBR directly inhibited the expression of the transcription factor RORγt and promoted the expression of the transcription factor Foxp3 in T cells, resulting in a down-regulation of the Th17/Treg ratio. Furthermore, BBR indirectly modulated the Th17/Treg ratio by suppressing the secretion of TNF-α, IL-1β, and IL-6 by DCs and enhancing the secretion of indoleamine 2,3-dioxygenase (IDO) and transforming growth factor-beta (TGF-β) by DCs. This dual action inhibited Th17 cell differentiation while promoting Treg cells. ConclusionOur findings indicate that BBR regulate T cell subpopulation differentiation, reducing the Th17/Treg ratio by directly or indirectly pathway. This represents a potential therapeutic avenue of BBR for improving diabetic retinopathy.

M2 macrophages participate in ILC2 activation induced by Helicobacter pylori infection

ABSTRACT Helicobacter pylori (H. pylori) causes a diversity of gastric diseases. The host immune response evoked by H. pylori infection is complicated and can influence the development and progression of diseases. We have reported that the Group 2 innate lymphocytes (ILC2) were promoted and took part in building type-2 immunity in H. pylori infection-related gastric diseases. Therefore, in the present study, we aim to clarify how H. pylori infection induces the activation of ILC2. It was found that macrophages were necessary for activating ILC2 in H. pylori infection. Mechanistically, H. pylori infection up-regulated the expression of indoleamine 2,3-dioxygenase (IDO) in macrophages to induce M2 polarization, and the latter secreted the alarmin cytokine Thymic Stromal Lymphopoietin (TSLP) to arouse ILC2.

A formulation of combined Poria cocos and Cordyceps militaris rice ameliorates depressive-like effects by downregulating p38 MAPK signaling pathways

Background and aimPoria cocos (PC) is traditional Chinese medicine with sedative, diuretic, and tonic properties. Cordyceps militaris rice (CMR) is a matrix used for the solid-state culture of C. militaris, which has been used for anti-angiogenetic and anti-inflammation effects. To investigate a formulation of combined Poria cocos and Cordyceps militaris rice (PC-CMR) alleviates anxiety behaviours and depressive-like effects for the first time. Experimental procedureAfter five-week of stress, rats were induced by unpredictable chronic mild stress (UCMS) treated with PC-CMR formulation. Then, rats underwent various behavior tests, testing serum inflammatory mediators by enzyme-linked immunosorbent assays (ELISA), evaluated monoamines by high-performance liquid chromatography (HPLC) analysis, and protein expression by western blotting. ResultsTreatment with doses of formulated PC-CMR reversed sucrose preference and increased amount of time spent on the open arms in rat behavioral tests. The formulated PC-CMR significantly reduced glutamate content and turnover rates of serotonin and dopamine in the prefrontal cortex of rats. In the inflammation-related pathway, PC-CMR decreased interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) levels in serum and downregulated the expression of p38 mitogen-activated protein kinase (p38 MAPK), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) in the prefrontal cortex and signal transducer and activator of transcription 3 (STAT3), and indoleamine 2,3-dioxygenase (IDO) in the amygdala. ConclusionOur findings suggest that the formulated PC-CMR could have antidepressive and anxiolytic effects by modulating neurotransmitter levels and reducing inflammation.

IDO2 mediates inflammatory responses through both enzymatic and non-enzymatic mechanisms

Abstract The tryptophan catabolizing enzymes indoleamine-2,3-dioxygenase (IDO)1 and IDO2 play important immune modulatory roles in development of inflammation and tolerance. In contrast to the immune regulatory function described for IDO1, IDO2 is a proinflammatory modifier of disease in models of autoimmune arthritis and contact hypersensitivity. Using catalytically inactive IDO2 knock-in mice, we found that the enzymatic function of IDO2 was required to mediate inflammation in contact hypersensitivity but was not required for the development of autoimmunity, suggesting IDO2 acts through both enzymatic and non-enzymatic mechanisms depending on the immune context. Mechanistic studies identified the transcription factor Runx1 as a protein that directly binds to IDO2. The IDO2-Runx1 interaction is blocked by a therapeutic IDO2 monoclonal antibody, implicating Runx1 as a potential downstream mediator of IDO2 function. Runx1 has been shown to directly activate/repress genes involved in B cell activation and differentiation and indirectly affect transcription by inhibition of the NFκB pathway. Preliminary studies using luciferase reporter assays show that IDO2 does not affect Runx1’s direct transcriptional activity, suggesting that the downstream non-enzymatic IDO2 pathway is mediated by Runx1 indirect transcriptional regulation. Taken together, these data demonstrate IDO2 modulates inflammatory immune responses using both its enzymatic function and a non-enzymatic Runx1-mediated pathway.

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

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. 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. 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. 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.

SP94 engineered erythrocyte membrane enhanced the targeted delivery of biomimetic nanosuspension with IDO immunotherapy and chemotherapy in liver cancer

The efficient eradication of tumor cells remains a critical challenge in the realm of liver cancer therapies. The combination of chemotherapy and immunotherapy holds more significant potential for improving treatment efficacy. However, the effectiveness of immunotherapy is mainly impeded by the high activity of indoleamine 2,3-dioxygenase (IDO), which creates an immunosuppressive tumor microenvironment via robust proliferation of immunosuppressive T regulatory cells (Tregs) and inhibition of cytotoxic T lymphocytes (CTLs). Herein, we developed SR-ATO-ASIV@NS, a liver cancer-targeting peptide (SP94) modified RBCM-coated biomimetic nanosuspension. This innovative formulation incorporates the chemotherapeutic agent arsenic trioxide (ATO) and the immunomodulator astragaloside IV (AS-IV) as IDO inhibitor for the combined chemoimmunotherapy of liver cancer. The SR-ATO-ASIV@NS increased the solubility of both ATO and AS-IV and displayed excellent stability and exhibited high drug-loading efficiency, rendering it suitable for efficient dual drug delivery. Furthermore, this biomimetic nanosuspension efficiently evaded immune response and showed specific uptake in liver cancer cells via SP94 receptor-mediated endocytosis. The remarkable pharmacokinetic profile, characterized by prolonged blood circulation, enhanced the in vivo anti-tumor efficacy in H22 tumor bearing mice through the synergistic action of the dual drugs. On one hand, the released ATO resulted in excessive reactive oxygen species (ROS) generation, which stimulated the induction of apoptosis pathways via Bax/Bcl-2 and caspase mechanism. While on the other hand, AS-IV effectively blocked the IDO activity and hinders the production of Tregs within the tumor microenvironment. Consequently, the reduced Tregs population fosters the proliferation of CTLs, alleviating ITM and intensifying the immunotherapeutic response for the efficient killing of cancer cells. Additionally, the successful inhibition of liver cancer metastasis to the lungs and robust increase in T memory cells further boosted the anti-tumor therapeutic efficacy of SR-ATO-ASIV@NS. In summary, SR-ATO-ASIV@NS represents a novel and scientifically sophisticated strategy in targeted biomimetic nanotherapeutics. This approach not only enhances site-specific drug delivery but also showcases promising potential for advancing the field of combined chemoimmunotherapy for liver cancer.

Ultra-small Janus nanoparticle-induced activation of ferroptosis for synergistic tumor immunotherapy

Ferroptosis induced by lipid peroxide (LPO) accumulation is an effective cell death pathway for cancer therapy. However, how to effectively induce ferroptosis at tumor sites and improve its therapeutic effectiveness remains challenging. Here, MnFe2O4@NaGdF4@NLG919@HA (MGNH) nanocomplex with tumor-specific targeting and TME response is constructed to overcome immunosuppressive tumor microenvironment (TME) to potentiate the curative effect of ferroptosis by coupling the immune checkpoint indoleamine 2,3-dioxygenase (IDO) inhibitor, NLG919, and hyaluronic acid (HA) to novel ultra-small MnFe2O4@NaGdF4 (MG) nanoparticles with a Janus structure. Firstly, tumor site-precise delivery of MG and NLG919 is achieved with HA targeting. Secondly, MG acts as a magnetic resonance imaging contrast agent, which not only has a good photothermal effect to realize tumor photothermal therapy, but also depletes glutathione and catalyzes the production of reactive oxygen species from endogenous H2O2, which effectively promotes the accumulation of LPO and inhibits the expression of glutathione peroxidase 4, achieving enhanced ferroptosis. Thirdly, NLG919 inhibits the differentiation of Tregs by blocking the tryptophan/kynurenine immune escape pathway, thereby reversing immunosuppressive TME together with the Mn2+-activated cGAS-STING pathway. This work contributes new perspectives for the development of novel ultra-small Janus nanoparticles to reshape immunosuppressive TME and ferroptosis activation. Statement of significanceThe Janus structured MnFe2O4@NaGdF4@NLG919@HA (MGNH) nanocomplex was synthesized, which can realize the precise delivery of T1/T2 contrast agents MnFe2O4@NaGdF4 (MG) and NLG919 at the tumor site under the ultra-small Janus structural characteristics and targeted molecule HA. The production of ROS, consumption of GSH, and photothermal properties of MGNH make it possible for CDT/PTT activated ferroptosis, and synergistically disrupt and reprogram tumor growth and immunosuppressive tumor microenvironment with NLG919 and Mn2+-mediated activation of cGAS-STING pathway, achieving CDT/PTT/immunotherapy activated by ferroptosis. Meanwhile, ultra-small structural properties of MGNH facilitate subsequent metabolic clearance by the body, allowing for the minimization of potential biotoxicity associated with its prolonged retention.

A novel TCGA-validated programmed cell-death-related signature of ovarian cancer

BackgroundOvarian cancer (OC) is a gynecological malignancy tumor with high recurrence and mortality rates. Programmed cell death (PCD) is an essential regulator in cancer metabolism, whose functions are still unknown in OC. Therefore, it is vital to determine the prognostic value and therapy response of PCD-related genes in OC.MethodsBy mining The Cancer Genome Atlas (TCGA), Genotype-Tissue Expression (GTEx) and Genecards databases, we constructed a prognostic PCD-related genes model and performed Kaplan-Meier (K-M) analysis and Receiver Operating Characteristic (ROC) curve for its predictive ability. A nomogram was created via Cox regression. We validated our model in train and test sets. Quantitative real-time PCR (qRT-PCR) was applied to identify the expression of our model genes. Finally, we analyzed functional analysis, immune infiltration, genomic mutation, tumor mutational burden (TMB) and drug sensitivity of patients in low- and high-risk group based on median scores.ResultsA ten-PCD-related gene signature including protein phosphatase 1 regulatory subunit 15 A (PPP1R15A), 8-oxoguanine-DNA glycosylase (OGG1), HECT and RLD domain containing E3 ubiquitin protein ligase family member 1 (HERC1), Caspase-2.(CASP2), Caspase activity and apoptosis inhibitor 1(CAAP1), RB transcriptional corepressor 1(RB1), Z-DNA binding protein 1 (ZBP1), CD3-epsilon (CD3E), Clathrin heavy chain like 1(CLTCL1), and CCAAT/enhancer-binding protein beta (CEBPB) was constructed. Risk score performed well with good area under curve (AUC) (AUC3 − year =0.728, AUC5 − year = 0.730). The nomogram based on risk score has good performance in predicting the prognosis of OC patients (AUC1 − year =0.781, AUC3 − year =0.759, AUC5 − year = 0.670). Kyoto encyclopedia of genes and genomes (KEGG) analysis showed that the erythroblastic leukemia viral oncogene homolog (ERBB) signaling pathway and focal adhesion were enriched in the high-risk group. Meanwhile, patients with high-risk scores had worse OS. In addition, patients with low-risk scores had higher immune-infiltrating cells and enhanced expression of checkpoints, programmed cell death 1 ligand 1 (PD-L1), indoleamine 2,3-dioxygenase 1 (IDO-1) and lymphocyte activation gene-3 (LAG3), and were more sensitive to A.443,654, GDC.0449, paclitaxel, gefitinib and cisplatin. Finally, qRT-PCR confirmed RB1, CAAP1, ZBP1, CEBPB and CLTCL1 over-expressed, while PPP1R15A, OGG1, CASP2, CD3E and HERC1 under-expressed in OC cell lines.ConclusionOur model could precisely predict the prognosis, immune status and drug sensitivity of OC patients.

Interfering tumor metabolism by bimetallic nanoagent for amplifying nanocatalytic-mediated glioblastoma immunotherapy

Glioblastoma is a malignant tumor with a high recurrence rate and a profound immunosuppressive microenvironment that makes immunotherapy ineffective. Herein, an iron-copper bimetallic nanoagent (NMCuA) grafted with blood–brain barrier (BBB) cells targeting peptide angiopep-2 and loaded indoleamine 2,3-dioxygenase 1 (IDO1) inhibitor (NLG919) for remodulating the immunosuppressive microenvironment to enhance the therapeutic efficiency of glioblastoma immunotherapy is demonstrated. Such NMCuA can synergistically amplify nanocatalytic-mediated glioblastoma immunotherapy by interfering with amino acid metabolism. Briefly, Cu/Fe released from the nanoagent undergoes a catalytic reaction to generate cytotoxic hydroxyl radicals (•OH) in the acidic tumor microenvironment (TME), leading to intracellular lipid peroxidation (LPO). Meanwhile, Cu2+ also chelates with excess cysteine (Cys), resulting in glutathione (GSH) depletion and glutathione peroxidase 4 (GPX4) inactivation, further promoting LPO accumulation. In addition, IDO1-mediated tryptophan metabolic pathway is inhibited by NLG919, thus contributing to the reduction of Treg cells (Tregs) accumulation and •OH clearance. Therefore, interfering tumor metabolism enhances metal-based catalytic therapy, which further strengthens •OH burst and intracellular LPO accumulation, thereby triggering an effective immunogenic cell death (ICD) process. This bimetallic nanoagent activates the body to generate a powerful immune response that can significantly inhibit in situ tumor growth and reversing the immunosuppressive TME. Furthermore, the nanoagent can generate effective immune memory effects by combining immune checkpoint inhibitor, thereby suppressing glioblastoma recurrence.

ASOptimizer: Optimizing antisense oligonucleotides through deep learning for IDO1 gene regulation

Recent studies have highlighted the effectiveness of using antisense oligonucleotides (ASOs) for cellular RNA regulation, including targets that are considered undruggable; however, manually designing optimal ASO sequences can be labor intensive and time consuming, which potentially limits their broader application. To address this challenge, we introduce a platform, the ASOptimizer, a deep-learning-based framework that efficiently designs ASOs at a low cost. This platform not only selects the most efficient mRNA target sites but also optimizes the chemical modifications for enhanced performance. Indoleamine 2,3-dioxygenase 1 (IDO1) promotes cancer survival by depleting tryptophan and producing kynurenine, leading to immunosuppression through the aryl-hydrocarbon receptor (Ahr) pathway within the tumor microenvironment. We used ASOptimizer to identify ASOs that target IDO1 mRNA as potential cancer therapeutics. Our methodology consists of two stages: sequence engineering and chemical engineering. During the sequence-engineering stage, we optimized and predicted ASO sequences that could target IDO1 mRNA efficiently. In the chemical-engineering stage, we further refined these ASOs to enhance their inhibitory activity while reducing their potential cytotoxicity. In conclusion, our research demonstrates the potential of ASOptimizer for identifying ASOs with improved efficacy and safety.

Abstract CT130: Epacadostat with preoperative chemoradiation in locally advanced rectal cancer (LARC): Results of a translational phase I clinical trial

Abstract BACKGROUND: In preclinical studies, we found that the immuno-oncology target and tryptophan metabolizing enzyme indoleamine 2, 3-dioxygenase 1 (IDO1) promotes resistance to radiation in rectal cancer regardless of MSI status. Furthermore, IDO1 inhibition with epacadostat improved tumor radiosensitivity, abrogated immunosuppression, limited distal recurrence, and was radioprotective of the normal intestine. This trial aimed to evaluate the safety of IDO1 inhibition when combined with neoadjuvant short-course radiation (SCRT) and chemotherapy with capecitabine and oxaliplatin (CAPOX) for LARC. METHODS: The primary objective was to determine the recommended phase II dose (RP2D) of epacadostat for combination with SCRT and CAPOX. Secondary objectives included determining antitumor activity as measured by neoadjuvant rectal (NAR) score and pathological or clinical complete responses. During the dose escalation phase, 3 doses of epacadostat (300mg, 400mg, & 600mg BID) were explored. Epacadostat was combined with SCRT (5Gy x 5 fractions) followed by 6 cycles of CAPOX chemotherapy, until the day of surgery (~24 wks). Tissues and blood were collected for correlative studies. A control cohort was generated from patients receiving the same treatment without epacadostat. NCT03516708 RESULTS: Seventeen patients were enrolled from 4/2019 to 8/2023. RP2D of epacadostat in combination with SCRT and CAPOX chemotherapy was determined to be 400mg BID. Two patients experienced dose-limiting toxicities (DLT) at 600mg dose level, one with G2 elevated ALT and another with G3 maculopapular rash. No DLT was reported at other dose levels. Of six patients who underwent surgery, the mean NAR score was 7.46 (SD 7.11; range 0 - 20.4), indicating potentially better response compared to the mean NAR of 17.8 in an institutional 2:1 matched control cohort (p=0.03). Tumor tissue revealed increased IDO1 expression and kynurenine levels in all patient tumors after radiation. After epacadostat, serum levels of kynurenine were reduced while TNFα, IFNγ, and MIP1a were all increased. Global metabolomics and RNAseq revealed a distinct pattern of serum biomarkers and immunophenotype respectively in patients after treatment. Tumoroids were evaluated as ex vivo models of treatment response. CONCLUSION: Epacadostat in combination with SCRT and CAPOX was well-tolerated. An NCI supported Phase 2 trial is ongoing to further evaluate the promising disease responses reported in dose escalation phase. Citation Format: Haeseong Park, Katrina Pedersen, Katherine Huang, Matthew Mutch, Hyun Kim, Nikolaos Trikalinos, Olivia Aranha, Benjamin Tan, Rama Suresh, Lee Ratner, Moh'd Khushman, John Visconti, Kian-Huat Lim, Lauren Henke, Maddie Swiecicki, Jingxia Liu, Parag Parikh, Matthew Ciorba. Epacadostat with preoperative chemoradiation in locally advanced rectal cancer (LARC): Results of a translational phase I clinical trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT130.

MOF‐Coated Upconversion Nanoparticle Agents Enable Synergistic Photodynamic Therapy and Immunotherapy

AbstractAlthough conventional therapeutic approaches demonstrate significant success in treating primary tumors, their efficacy diminishes when addressing distant and metastatic tumors, calling for new technologies to transport and activate the therapeutic agents. Here, a core‐shell UCNP@MOF (upconversion nanoparticle — metal organic framework) nanoagents is constructed for Type I and Type II photodynamic therapy under biocompatible near‐infrared light irradiance (at 808 nm) and utilize their pore loading capacity to further realize synergistic immunotherapy in solid tumors. The Cu2+ to Cu+ reduction at the nodes in the MOFs shell is demonstrated to promote the generation of reactive oxygen species via depletion of overexpressed glutathione (GSH) compounds, while tumor microenvironment‐enriched hydrogen peroxide is found to substantially augment the PDT effects. Importantly, the MOFs pore‐loaded indoleamine 2,3‐dioxygenase (IDO) inhibitor, along with s‐nitroso‐n‐acetylpenicillamine (SNAP), upregulated tumor‐infiltrating lymphocytes and induced prominent immunotherapeutic effects in vivo. This core‐shell UCNP@MOF nanoagents have demonstrated effectiveness against both primary and distant tumors in xenografted tumor models, holding promise for treating solid tumors in metastasis.

Derangements of immunological proteins in HIV-associated diffuse large B-cell lymphoma: the frequency and prognostic impact.

Diffuse large B-cell lymphoma (DLBCL) is an aggressive malignancy of B-cells frequently encountered among people living with HIV. Immunological abnormalities are common in immunocompetent individuals with DLBCL, and are often associated with poorer outcomes. Currently, data on derangements of immunological proteins, such as cytokines and acute phase reactants, and their impact on outcomes in HIV-associated DLBCL (HIV-DLBCL) is lacking. This study assessed the levels and prognostic relevance of interleukin (IL)-6, IL-10 and Transforming Growth Factor Beta (TGFβ), the acute phase proteins C-reactive protein (CRP) and ferritin; serum free light chains (SFLC) (elevation of which reflects a prolonged pro-inflammatory state); and the activity of the immunosuppressive enzyme Indoleamine 2,3-dioxygenase (IDO)in South African patients with DLBCL. Seventy-six patients with incident DLBCL were enrolled, and peripheral blood IL-6, IL-10, TGFβ, SFLC and IDO-activity measured in selected patients. Additional clinical and laboratory findings (including ferritin and CRP) were recorded from the hospital records. Sixty-one (80.3%) of the included patients were people living with HIV (median CD4-count = 148 cells/ul), and survival rates were poor (12-month survival rate 30.0%). The majority of the immunological proteins, except for TGFβ and ferritin, were significantly higher among the people living with HIV. Elevation of IL-6, SFLC and IDO-activity were not associated with survival in HIV-DLBCL, while raised IL-10, CRP, ferritin and TGFβ were. On multivariate analysis, immunological proteins associated with survival independently from the International Prognostic Index (IPI) included TGFβ, ferritin and IL-10. Derangements of immunological proteins are common in HIV-DLBCL, and have a differential association with survival compared to that reported elsewhere. Elevation of TGFβ, IL-10 and ferritin were associated with survival independently from the IPI. In view of the poor survival rates in this cohort, investigation of the directed targeting of these cytokines would be of interest in our setting.

The plasma kynurenine-to-tryptophan ratio as a biomarker of tuberculosis disease in people living with HIV on antiretroviral therapy: an exploratory nested case–control study

BackgroundNon-sputum-based tests are needed to predict or diagnose tuberculosis (TB) disease in people living with HIV (PWH). The enzyme indoleamine 2, 3-dioxygenase-1 (IDO1) is expressed in tuberculoid granuloma and catabolizes tryptophan (Trp) to kynurenine (Kyn). IDO1 activity compromises innate and adaptive immune responses, promoting mycobacterial survival. The plasma Kyn-to-Trp (K/T) ratio is a potential TB diagnostic and/or predictive biomarker in PWH on long-term antiretroviral therapy (ART).MethodsWe compared plasma K/T ratios in samples from PWH, who were followed up prospectively and developed TB disease after ART initiation. Controls were matched for age and duration of ART. Kyn and Trp were measured at 3 timepoints; at TB diagnosis, 6 months before TB diagnosis and 6 months after TB diagnosis, using ultra performance liquid chromatography combined with mass spectrometry.ResultsThe K/T ratios were higher for patients with TB disease at time of diagnosis (median, 0.086; IQR, 0.069–0.123) compared to controls (0.055; IQR 0.045–0.064; p = 0.006), but not before or after TB diagnosis. K/T ratios significantly declined after successful TB treatment, but increased upon treatment failure. The K/T ratios showed a parabolic correlation with CD4 cell counts in participants with TB (p = 0.005), but there was no correlation in controls.ConclusionsThe plasma K/T ratio helped identify TB disease and may serve as an adjunctive biomarker for for monitoring TB treatment in PWH. Validation studies to ascertain these findings and evaluate the optimum cut-off for diagnosis of TB disease in PWH should be undertaken in well-designed prospective cohorts.Trial registrationClinicalTrials.gov Identifier: NCT00411983.

New insight into arginine and tryptophan metabolism in macrophage activation during tuberculosis.

Arginine and tryptophan are pivotal in orchestrating cytokine-driven macrophage polarization and immune activation. Specifically, interferon-gamma (IFN-γ) stimulates inducible nitric oxide synthase (iNOS) expression), leading to the conversion of arginine into citrulline and nitric oxide (NO), while Interleukin-4 (IL4) promotes arginase activation, shifting arginine metabolism toward ornithine. Concomitantly, IFN-γ triggers indoleamine 2,3-dioxygenase 1 (IDO1) and Interleukin-4 induced 1 (IL4i1), resulting in the conversion of tryptophan into kynurenine and indole-3-pyruvic acid. These metabolic pathways are tightly regulated by NAD+-dependent sirtuin proteins, with Sirt2 and Sirt5 playing integral roles. In this review, we present novel insights that augment our understanding of the metabolic pathways of arginine and tryptophan following Mycobacterium tuberculosis infection, particularly their relevance in macrophage responses. Additionally, we discuss arginine methylation and demethylation and the role of Sirt2 and Sirt5 in regulating tryptophan metabolism and arginine metabolism, potentially driving macrophage polarization.

Improved automated one-pot two-step radiosynthesis of (S)-[18F]FETrp, a radiotracer for PET imaging of indoleamine 2,3-dioxygenase 1 (IDO1)

Background(S)-[18F]FETrp is a promising PET radiotracer for imaging IDO1 activity, one of the main enzymes involved in the tryptophan metabolism that plays a key role in several diseases including cancers. To date, the radiosynthesis of this tryptophan analogue remains highly challenging due to partial racemization occurring during the nucleophilic radiofluorination step. This work aims to develop a short, epimerization-free and efficient automated procedure of (S)-[18F]FETrp from a corresponding enantiopure tosylate precursor.ResultsEnantiomerically pure (S)- and (R)-FETrp references as well as tosylate precursors (S)- and (R)-3 were obtained from corresponding Na-Boc-(L and D)-tryptophan in 2 and 4 steps, respectively. Manual optimisation of the radiolabelling conditions resulted in > 90% radiochemical conversion with more than 99% enantiomeric purity. Based on these results, the (S)-[18F]FETrp radiosynthesis was fully automated on a SynChrom R&D EVOI module to produce the radiotracer in 55.2 ± 7.5% radiochemical yield, 99.9% radiochemical purity, 99.1 ± 0.5% enantiomeric excess, and molar activity of 53.2 ± 9.3 GBq/µmol (n = 3).ConclusionsTo avoid racemisation and complicated purification processes, currently encountered for the radiosynthesis of (S)-[18F]FETrp, we report herein significant improvements, including a versatile synthesis of enantiomerically pure tosylate precursor and reference compound and a convenient one-pot two-step automated procedure for the radiosynthesis of (S)-[18F]FETrp. This optimised and robust production method could facilitate further investigations of this relevant PET radiotracer for imaging IDO1 activity.

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.

HSA-nanobinders crafted from bioresponsive prodrugs for combined cancer chemoimmunotherapy-an in vitro exploration.

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer still lacking effective treatment options. Chemotherapy in combination with immunotherapy can restrict tumor progression and repolarize the tumor microenvironment towards an anti-tumor milieu, improving clinical outcome in TNBC patients. The chemotherapeutic drug paclitaxel has been shown to induce immunogenic cell death (ICD), whereas inhibitors of the indoleamine 2,3- dioxygenase 1 (IDO1) enzyme, whose expression is shared in immune regulatory and tumor cells, have been revealed to enhance the anti-tumor immune response. However, poor bioavailability and pharmacokinetics, off-target effects and hurdles in achieving therapeutic drug concentrations at the target tissue often limit the effectiveness of combination therapies. This work describes the development of novel biomimetic and carrier-free nanobinders (NBs) loaded with both paclitaxel and the IDO1 inhibitor NLG919 in the form of bioresponsive and biomimetic prodrugs. A fine tuning of the preparation conditions allowed to identify NB@5 as the most suitable nanoformulation in terms of reproducibility, stability and in vitro effectiveness. Our data show that NB@5 effectively binds to HSA in cell-free experiments, demonstrating its protective role in the controlled release of drugs and suggesting the potential to exploit the protein as the endogenous vehicle for targeted delivery to the tumor site. Our study successfully proves that the drugs encapsulated within the NBs are preferentially released under the altered redox conditions commonly found in the tumor microenvironment, thereby inducing cell death, promoting ICD, and inhibiting IDO1.

Comprehensive analysis of the prognostic value and immunological role of IDO1 gene in pan-cancer

ObjectiveIt has been demonstrated that IDO1, a target of immune checkpoint inhibition, functions as an oncogene in the majority of human malignancies. IDO1’s function in human pan-cancers hasn’t been thoroughly studied, though.Materials and methodsThe Kaplan–Meier (K-M) and COX analyses were applied to the survival analysis. Furthermore, we used Spearman’s correlation analysis to examine the associations between IDO1 and microsatellite instability (MSI), DNA methyltransferases (DNMTs), tumor mutational burden (TMB), the associated genes of mismatch repair (MMR), and immune checkpoint biomarkers. Moreover, immunohistochemical analysis and qRT-PCR were used to evaluate IDO1’s expression in pan-cancer cells.ResultsThe findings of this study reveal that IDO1 has abnormal expression in a number of malignancies and is related to the prognosis for UVM, LGG, KIRP, GBM, LAML, OV, READ, MESO, SARC, SKCM, and HNSC. Furthermore, the aberrant IDO1 expression was connected to the TMB, MSI, MMR, drug sensitivity, immune cells infiltrating, and tumor immune microenvironment across a variety of cancer types. The PCR results showed that in contrast to normal cells, IDO1 was found to be significantly highly expressed in breast cancer cells and hepatocellular carcinoma cells, and significantly lowly expressed in gastric cancer cells.ConclusionThe clinical treatment of IDO1 is now better supported by a theoretical basis and guidelines provided by our study.