The expression of PD-1 ligands and IDO1 by macrophage/microglia in primary central nervous system lymphoma

Updates of primary central nervous system lymphoma

Lymphoma occurring in the central nervous system is considered primary central nervous system lymphoma (PCNSL), usually without systematic lesions. Over the last few decades, a deep understanding of PCNSL has been lacking due to the low incidence rate, and the overall survival and progression-free survival of patients with PCNSL are lower than those with other types of non-Hodgkin lymphoma. Recently, there have been several advancements in research on PCNSL. Advances in diagnosis of the disease are primarily reflected in the promising diagnostic efficiency of novel biomarkers. Pathogenesis mainly involves abnormal activation of nuclear factor kappa-B signaling pathways, copy number variations, and DNA methylation. Novel therapies such as Bruton's tyrosine kinase inhibitors, immunomodulatory drugs, immune checkpoint inhibitors, and phosphoinositide 3-kinase/mammalian target of rapamycin inhibitors are being evaluated as possible treatment options for PCNSL, especially for relapsed/refractory (R/R) cases. Several clinical trials also indicated the promising feasibility and efficacy of chimeric antigen receptor T-cell therapy for selected R/R PCNSL patients. This review focuses on discussing recent updates, including the diagnosis, pathogenesis, and novel therapy of PCNSL.

Targeting the tumor microenvironment in primary central nervous system lymphoma: Implications for prognosis

Primary central nervous system lymphoma (PCNSL) is a rare extranodal non-Hodgkin lymphoma, and there is limited research on its tumor microenvironment (TME). Nevertheless, more and more studies have evidence that TME has essential effects on tumor cell proliferation, immune escape, and drug resistance. Thus, it is critical to elucidate the role of TME in PCNSL. The understanding of the PCNSL TME is gradually unfolding, including factors that distinguish it from systemic diffuse large B-cell lymphoma (DLBCL). The TME in PCNSL exhibits both transcriptional and spatial intratumor heterogeneity. Cellular interactions between tumor cells and stroma cells reveal immune evasion signaling. The comparative analysis between PCNSL and DLBCL suggests that PCNSL is more likely to be an immunologically deficient tumor. In PCNSL, T cell exhaustion and downregulation of macrophage immune function are accompanied by suppressive microenvironmental factors such as M2 polarized macrophages, endothelin B receptor, HLA depletion, PD-L1, and TIM-3. MMP-9, Integrin-β1, and ICAM-1/LFA-1 play crucial roles in transendothelial migration towards the CNS, while CXCL13/CXCR5, CD44, MAG, and IL-8 are essential for brain parenchymal invasion. Further, macrophages, YKL-40, CD31, CD105, PD-1/PD-L1 axis, osteopontin, galectin-3, aggregative perivascular tumor cells, and HLA deletion may contribute to poor outcomes in patients with PCNSL. This article reviews the effect of various components of TME on the progression and prognosis of PCNSL patients to identify novel therapeutic targets.

Inhibitor of PD-1/PD-L1: a new approach may be beneficial for the treatment of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a globally prevalent, progressive disease with limited treatment options and poor prognosis. Because of its irreversible disease progression, IPF affects the quality and length of life of patients and imposes a significant burden on their families and social healthcare services. The use of the antifibrotic drugs pirfenidone and nintedanib can slow the progression of the disease to some extent, but it does not have a reverse effect on the prognosis. The option of lung transplantion is also limited owing to contraindications to transplantation, possible complications after transplantation, and the risk of death. Therefore, the discovery of new, effective treatment methods is an urgent need. Over recent years, various studies have been undertaken to investigate the relationship between interstitial pneumonia and lung cancer, suggesting that some immune checkpoints in IPF are similar to those in tumors. Immune checkpoints are a class of immunosuppressive molecules that are essential for maintaining autoimmune tolerance and regulating the duration and magnitude of immune responses in peripheral tissues. They can prevent normal tissues from being damaged and destroyed by the immune response. While current studies have focused on PD-1/PD-L1 and CTLA-4, PD-1/PD-L1 may be the only effective immune checkpoint IPF treatment. This review discusses the application of PD-1/PD-L1 checkpoint in IPF, with the aim of finding a new direction for IPF treatment.

Targeting tumor-associated macrophage: an adjuvant strategy for lung cancer therapy

The emergence of immunotherapy has revolutionized the treatment landscape for various types of cancer. Nevertheless, lung cancer remains one of the leading causes of cancer-related mortality worldwide due to the development of resistance in most patients. As one of the most abundant groups of immune cells in the tumor microenvironment (TME), tumor-associated macrophages (TAMs) play crucial and complex roles in the development of lung cancer, including the regulation of immunosuppressive TME remodeling, metabolic reprogramming, neoangiogenesis, metastasis, and promotion of tumoral neurogenesis. Hence, relevant strategies for lung cancer therapy, such as inhibition of macrophage recruitment, TAM reprograming, depletion of TAMs, and engineering of TAMs for drug delivery, have been developed. Based on the satisfactory treatment effect of TAM-targeted therapy, recent studies also investigated its synergistic effect with current therapies for lung cancer, including immunotherapy, radiotherapy, chemotherapy, anti-epidermal growth factor receptor (anti-EGFR) treatment, or photodynamic therapy. Thus, in this article, we summarized the key mechanisms of TAMs contributing to lung cancer progression and elaborated on the novel therapeutic strategies against TAMs. We also discussed the therapeutic potential of TAM targeting as adjuvant therapy in the current treatment of lung cancer, particularly highlighting the TAM-centered strategies for improving the efficacy of anti-programmed cell death-1/programmed cell death-ligand 1 (anti-PD-1/PD-L1) treatment.

Primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) is a diffuse large B cell lymphoma in which the brain, spinal cord, leptomeninges and/or eyes are exclusive sites of disease. Pathophysiology is incompletely understood, although a central role seems to comprise immunoglobulins binding to self-proteins expressed in the central nervous system (CNS) and alterations of genes involved in B cell receptor, Toll-like receptor and NF-κB signalling. Other factors such as T cells, macrophages or microglia, endothelial cells, chemokines, and interleukins, probably also have important roles. Clinical presentation varies depending on the involved regions of the CNS. Standard of care includes methotrexate-based polychemotherapy followed by age-tailored thiotepa-based conditioned autologous stem cell transplantation and, in patients unsuitable for such treatment, consolidation with whole-brain radiotherapy or single-drug maintenance. Personalized treatment, primary radiotherapy and only supportive care should be considered in unfit, frail patients. Despite available treatments, 15-25% of patients do not respond to chemotherapy and 25-50% relapse after initial response. Relapse rates are higher in older patients, although the prognosis of patients experiencing relapse is poor independent of age. Further research is needed to identify diagnostic biomarkers, treatments with higher efficacy and less neurotoxicity, strategies to improve the penetration of drugs into the CNS, and roles of other therapies such as immunotherapies and adoptive cell therapies.

Expression of Tryptophan Metabolism Enzymes in Patients with Diffuse Large B-cell Lymphoma and NK/T-cell Lymphoma

BACKGROUND

Metabolites of tryptophan (Trp) metabolism in the tumor microenvironment play crucial immunosuppressive roles in various cancers. However, the role of Trp metabolism in diffuse large B-cell lymphoma (DLBCL) or natural killer/T-cell lymphoma (NK/TCL) remains unelucidated.

METHODS

We investigated the potential role of Trp metabolism in a cohort of 43 patients with DLBCL and 23 with NK/TCL. We constructed tissue microarrays and performed in situ staining of Trp-catabolizing enzymes and PD-L1 using immunohistochemistry (IHC).

RESULTS

We observed 14.0% positive staining of IDO1 in DCBCL and 60.9% in NK/TCL; 55.8% of IDO2 in DCBCL and 95.7% in NK/TCL; 79.1% of TDO2 in DCBCL and 43.5% in NK/TCL; 29.7% of IL4I1 in DCBCL and 39.1% in NK/TCL. However, IDO1, IDO2, TDO2, and IL4I1 positivity did not significantly differ between PD-L1+ and PD-L1- biopsy tissue samples of NK/TCL; nonetheless, a positive correlation of IDO1 (r = 0.87, p < 0.001), IDO2 (r = 0.70, p < 0.001), TDO2 (r = 0.63, p < 0.001), and IL4I1 (r = 0.53, p < 0.05) with PD-L1 expression was observed in the TCGA-DLBCL dataset. Finally, immunohistochemical (IHC) analysis revealed the lack of superior prognostic effect with higher expression of Trp enzymes in DLBCL and NK/TCL. Furthermore, IDO1, IDO2, TDO2, and IL4I1 expression, as well as survival rates, did not significantly differ across all groups in the TCGA-DLBCL cohort.

CONCLUSION

Collectively, our findings provide novel insights into the enzymes involved in Trp metabolism in DLBCL and NK/TCL and their association with PD-L1 expression, which offers potential strategies to combine Trp-metabolism enzyme inhibitors with anti-PD-L1 or other immunotherapeutic strategies in clinical DLBCL or NK/TCL treatment.

Spatial single cell analysis of tumor microenvironment remodeling pattern in primary central nervous system lymphoma

To determine the overall tumor microenvironment (TME), characteristics, and transition mechanisms in primary central nervous system lymphoma (PCNSL), we performed spatial transcriptomics and matched the corresponding single-cell sequencing data of PCNSL patients. We found that tumor cells may achieve a "TME remodeling pattern" through an "immune pressure-sensing model", in which they could choose to reshape the TME into a barrier environment or a cold environment according to the immune pressure. A key FKBP5⁺ tumor subgroup was found to be responsible for pushing tumors into the barrier environment, which provides a possible way to evaluate the stage of PCNSL. The specific mechanism of the TME remodeling pattern and the key molecules of the immune pressure-sensing model were identified through the spatial communication analysis. Finally, we discovered the spatial and temporal distributions and variation characteristics of immune checkpoint molecules and CAR-T target molecules in immunotherapy. These data clarified the TME remodeling pattern of PCNSL, provided a reference for its immunotherapy, and provided suggestions for the TME remodeling mechanism of other cancers.

The Current Landscape of Immune Checkpoint Inhibitor Immunotherapy for Primary and Metastatic Brain Tumors

Antibodies against immune checkpoint inhibitors (ICIs) have revolutionized the treatment of multiple aggressive malignancies, including melanoma and non-small cell lung cancer. ICIs for the treatment of primary and metastatic brain tumors have been used with varying degrees of success. Here, we discuss the available evidence for the use of ICIs in the treatment of primary and metastatic brain tumors, highlighting challenges and opportunities for furthering this type of cancer immunotherapy in neuro-oncology.

Novel long non-coding RNAs associated with inflammation and macrophage activation in human

Inflammation plays a central role in immune response and macrophage activation. Emerging studies demonstrate that along with proteins and genomic factors, noncoding RNA are potentially involved in regulation of immune response and inflammation. Our recent study demonstrated that lncRNA HOTAIR plays key roles in cytokine expression and inflammation in macrophages. The primary goal of this study is to discover novel lncRNAs that are crucial players in inflammation, macrophage activation, and immune response in humans. Towards this, we have stimulated THP1-derived macrophages (THP1-MΦ) with lipopolysaccharides (LPS) and performed the whole transcriptome RNA-seq analysis. Based on this analysis, we discovered that along with well-known marker for inflammation (such as cytokines), a series of long noncoding RNAs (lncRNAs) expression were highly induced upon LPS-stimulation of macrophages, suggesting their potential roles in inflammation and macrophage activation. We termed these family of lncRNAs as Long-noncoding Inflammation Associated RNA (LinfRNA). Dose and time dependent analysis demonstrated that many human LinfRNA (hLinfRNAs) expressions follow similar patterns as cytokine expressions. Inhibition of NF-κB suppressed the expression of most hLinfRNAs suggesting their potential regulation via NF-κB activation during inflammation and macrophage activation. Antisense-mediated knockdown of hLinfRNA1 suppressed the LPS-induced expression of cytokines and pro-inflammatory genes such as IL6, IL1β, and TNFα expression, suggesting potential functionality of the hLinfRNAs in cytokine regulation and inflammation. Overall, we discovered a series of novel hLinfRNAs that are potential regulators of inflammation and macrophage activation and may be linked to inflammatory and metabolic diseases.

Molecular and clinical diversity in primary central nervous system lymphoma

BACKGROUND

Primary central nervous system lymphoma (PCNSL) is a rare and distinct entity within diffuse large B-cell lymphoma presenting with variable response rates probably to underlying molecular heterogeneity.

PATIENTS AND METHODS

To identify and characterize PCNSL heterogeneity and facilitate clinical translation, we carried out a comprehensive multi-omic analysis [whole-exome sequencing, RNA sequencing (RNA-seq), methylation sequencing, and clinical features] in a discovery cohort of 147 fresh-frozen (FF) immunocompetent PCNSLs and a validation cohort of formalin-fixed, paraffin-embedded (FFPE) 93 PCNSLs with RNA-seq and clinico-radiological data.

RESULTS

Consensus clustering of multi-omic data uncovered concordant classification of four robust, non-overlapping, prognostically significant clusters (CS). The CS1 and CS2 groups presented an immune-cold hypermethylated profile but a distinct clinical behavior. The 'immune-hot' CS4 group, enriched with mutations increasing the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) and nuclear factor-κB activity, had the most favorable clinical outcome, while the heterogeneous-immune CS3 group had the worse prognosis probably due to its association with meningeal infiltration and enriched HIST1H1E mutations. CS1 was characterized by high Polycomb repressive complex 2 activity and CDKN2A/B loss leading to higher proliferation activity. Integrated analysis on proposed targets suggests potential use of immune checkpoint inhibitors/JAK1 inhibitors for CS4, cyclin D-Cdk4,6 plus phosphoinositide 3-kinase (PI3K) inhibitors for CS1, lenalidomide/demethylating drugs for CS2, and enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2) inhibitors for CS3. We developed an algorithm to identify the PCNSL subtypes using RNA-seq data from either FFPE or FF tissue.

CONCLUSIONS

The integration of genome-wide data from multi-omic data revealed four molecular patterns in PCNSL with a distinctive prognostic impact that provides a basis for future clinical stratification and subtype-based targeted interventions.

Primary central nervous system lymphoma: advances in its pathogenesis, molecular markers and targeted therapies

PURPOSE OF REVIEW

Primary central nervous system lymphoma (PCNSL) is a rare subtype of diffuse large B-cell lymphoma (DLBCL) located in the CNS with a less favorable prognosis. Recent information addressing the disease molecular heterogeneity is paving the way for tailored treatment strategies. This article reviews current work on the pathogenesis of the disease, potential biomarkers, and treatments.

RECENT FINDINGS

Previous molecular classifications of PCNSL, built on DLBCL heterogeneity, did not properly address its intrinsic variability. Recent evidence has shown the existence of four different molecular PCNSL subtypes with associated multiomic characteristics, including prognostic relevance. Several studies have identified the tumor microenvironment (TME) as a driving prognostic factor in PCNSL. Therapy efforts continue mainly into targeting either the NF-κβ (nuclear factor kappa-light-chain enhancer of activated B cells) pathway or modulating the TME through immunomodulatory drugs (lenalidomide) or immunotherapy (antiprogrammed cell death 1/programmed cell death 1 ligand 1).

SUMMARY

Despite the increasing understanding of PCNSL pathogenesis with recent studies, future efforts are still needed to yield diagnostic biomarkers to detect either PCNSL or its molecular subtypes and hence ease routine clinical use.

Biomimetic nanoparticles directly remodel immunosuppressive microenvironment for boosting glioblastoma immunotherapy

Glioblastoma (GBM), as a very aggressive cancer of central nervous system, is very challenging to completely cure by the conventional combination of surgical resection with radiotherapy and chemotherapy. The success of emerging immunotherapy in hot tumors has attracted considerable interest for the treatment of GBM, but the unique tumor immunosuppressive microenvironment (TIME) of GBM leads to the failure of immunotherapy. Here, we show the significant improvement of the immunotherapy efficacy of GBM by modulating the TIME through novel all-in-one biomimetic nanoparticles (i.e. CS-I/J@CM NPs). The nanoparticles consist of utrasmall Cu_2-x Se nanoparticles (NPs) with outstanding intrinsic properties (e.g., photo-responsive Fenton-like catalytic property for inducing immunogenic cell death (ICD) and alleviating the hypoxia of tumor), indoximod (IND, an inhibitor of indoleamine-2,3-dioxygenease in tumor), JQ1 (an inhibitor for reducing the expression of PD-L1 by tumor cells), and tumor cell membrane for improving the targeting capability and accumulation of nanoparticles in tumor. We reveal that these smart CS-I/J@CM NPs could drastically activate the immune responses through remodeling TIME of GBM by multiple functions. They could (1) increase M1-phenotype macrophages at tumor site by promoting the polarization of tumor-associated macrophages through the reactive oxygen species (ROS) and oxygen generated from the Fenton-like reaction between nanoparticles and H₂O₂ within tumor under NIR II irradiation; (2) decrease the infiltration of Tregs cells at tumor site through the release of IND; (3) decrease the expression of PD-L1 on tumor cells through JQ1. The notable increments of anti-tumor CD8⁺T cells in the tumor and memory T cells (T_EM) in the spleen show excellent therapy efficacy and effectively prevent the recurrence of GBM after modulation of the TIME. This work demonstrates the modulation of TIME could be a significant strategy to improve the immunotherapy of GBM and other cold tumors.

Molecular characteristics of immunocytes infiltration in primary central nervous system lymphoma

Background: Primary central nervous system lymphoma (PCNSL) is a rare B-cell lymphoma of central nervous system, which is often found in immunocompromised patients. The common clinical treatment of PCNSL is methotrexate (MTX) and whole brain radiation therapy. With the development of tumour immunology research, the tumour microenvironment of PCNSL is characterised by abnormal expression of different immune signature molecules and patients with PCNSL may benefit from tumour immunotherapy.

Methods: In our research, RNA-seq data from 82 PCNSL patients were collated by mining the microarray data from the GEO database. All samples were classified into three types related to tumour immune response by the Cibersort algorithm and consistent clustering. Differential analysis of genes was used to uncover 2 sets of differential genes associated with tumour immunity. The ICI scores of each sample were obtained by PCA algorithm, and the relationship between ICI scores and immune checkpoint expression, immunotherapy and drug sensitivity was investigated. Genes associated with ICI scores and their functional characteristics were investigated by WGCNA analysis and PPI analysis, based on the ICI scores of each sample.

Results: The tumour microenvironment in PCNSL has a greater relationship with the tumour immune response. ICI scores obtained from 375 differential genes were associated with multiple immune responses in PCNSL. PCNSL patients with higher ICI scores had a better tumour microenvironment and were sensitive to immunotherapy and some small molecule drug. This study also identified 64 genes associated with ICI scores, which may serve as important therapeutic and prognostic targets for PCNSL.

Conclusion: The presence of multiple immunosuppressive responses in the tumour microenvironment of PCNSL which suggested that improving the immune function of PCNSL patients through immunotherapy and targeted therapies can be an effective treatment for PCNSL. And the ICI score and associated genes may also provide a better predictor of the clinical use of immunotherapy.

Correlation between PD-1/PD-L1 expression and polarization in tumor-associated macrophages: A key player in tumor immunotherapy

Tumor immunotherapy, such as PD-1/PD-L1 blockade, has shown promising clinical efficacy in patients with various types of tumors. However, the response to PD-1/PD-L1 blockade in a majority of malignancies is limited, indicating an urgent need for a deeper understanding of the mechanisms of PD-1/PD-L1 axis-mediated tumor tolerance. As the most abundant immune cells in the tumor stroma, macrophages display multiple phenotypes and functions in response to the stimuli of the tumor microenvironment. PD-1/PD-L1 has been demonstrated to be highly expressed in tumor-associated macrophages (TAMs), and TAM polarization has been shown to be important during tumor progression. In this review, we outline the relationship between TAM PD-1/PD-L1 expression and polarizations, summarize the involvement of M2 TAMs in PD-1/PD-L1-mediated T-cell exhaustion, and discuss improved approaches for overcoming PD-1/PD-L1 blockade resistance by inducing M2/M1 switching of TAMs.

PD-1/PD-L Axis in Neuroinflammation: New Insights

The approval of immune checkpoint inhibitors (ICIs) by the Food and Drug Administration (FDA) led to an improvement in the treatment of several types of cancer. The main targets of these drugs are cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed cell death protein-1/programmed death-ligand 1 pathway (PD-1/PD-L1), which are important inhibitory molecules for the immune system. Besides being generally safer than common chemotherapy, the use of ICIs has been associated with several immune-related adverse effects (irAEs). Although rare, neurological adverse effects are reported within the irAEs in clinical trials, particularly in patients treated with anti-PD-1 antibodies or a combination of both anti-CTLA-4 and PD-1 drugs. The observations obtained from clinical trials suggest that the PD-1 axis may play a remarkable role in the regulation of neuroinflammation. Moreover, numerous studies in preclinical models have demonstrated the involvement of PD-1 in several neurological disorders. However, a comprehensive understanding of these cellular mechanisms remains elusive. Our review aims to summarize the most recent evidence concerning the regulation of neuroinflammation through PD-1/PD-L signaling, focusing on cell populations that are involved in this pathway.

The Role of Indoleamine 2, 3-Dioxygenase 1 in Regulating Tumor Microenvironment

Indoleamine 2, 3-dioxygenase 1 (IDO1) is a rate-limiting enzyme that metabolizes an essential amino acid tryptophan (Trp) into kynurenine (Kyn), and it promotes the occurrence of immunosuppressive effects by regulating the consumption of Trp and the accumulation of Kyn in the tumor microenvironment (TME). Recent studies have shown that the main cellular components of TME interact with each other through this pathway to promote the formation of tumor immunosuppressive microenvironment. Here, we review the role of the immunosuppression mechanisms mediated by the IDO1 pathway in tumor growth. We discuss obstacles encountered in using IDO1 as a new tumor immunotherapy target, as well as the current clinical research progress.

Aqueous extract of Passiflora alata leaves modulates in vitro the indoleamine 2,3-dioxygenase (IDO) and CD86 expression in bone marrow-derived professional antigen-presenting cells polarizing NOD mice T cells to a Treg profile

Dendritic cells (DCs) and macrophages are professional antigen-presenting cells (pAPCs), numerous in the pancreas of nonobese diabetic (NOD) mice and playing an essential role in the autoimmune response of type 1 diabetes. The expression of the enzyme indoleamine 2,3-dioxygenase (IDO) is a critical factor for the tolerogenic activity of pAPCs, acting in the catabolism of tryptophan, providing metabolites that suppress the T cell effectors and induce T regulatory cells differentiation. Here we investigated the in vitro mechanisms of lyophilized aqueous extract from Passiflora alata leaves (LAEPAL) that modulates bone marrow-derived professional antigen-presenting cells (BM-pAPCs), affecting their ability to polarize T cells. A cell culture model was defined using mixed cultures of BM-pAPCs and T lymphocytes NOD mice with stressed MIN-6 cells as a source of pancreatic β cells antigens. We showed that the treatment with 300 µg/mL of LAEPAL induces a significant decrease in the CD4 and CD8 T effector lymphocytes proliferation from diabetic but not in non-diabetic mice, followed by a reduction of the IL-6 and IFN-γ cytokines release in the cell cultures supernatants. Moreover, we observed an increase of CD4⁺CD25⁺FoxP3⁺ Tregs in the cell cultures from diabetic mice. These results could be partially explained by the LAEPAL modulatory effects in BM-pAPCs, downregulating the CD86 co-stimulatory molecule expression, and increasing IDO-1 expression in F4/80+ BM-pAPCs. These results contribute to a better understanding of the polyphenols' immunomodulatory properties, meaning they could induce tolerogenic antigen-presenting cells, which could polarize T cells to a Treg profile and decrease the activity of CD4+ and CD8+ T effector cells.

Superinduction of immunosuppressive glioblastoma extracellular vesicles by IFN-γ through PD-L1 and IDO1

Background

Glioblastoma (GBM), the most common primary brain tumor, has a median survival of 15-16 months. Immunotherapy is promising but GBM-mediated immunosuppression remains a barrier. GBMs express the interferon-gamma (IFN-γ)-responsive immunosuppressive molecules PD-L1 and IDO1. Extracellular vesicles (EVs) have also been implicated in GBM-mediated immunosuppression, in part through PD-L1. We therefore sought to determine if GBM IFN-γ exposure increased GBM EV-mediated immunosuppression and mechanisms underlying this.

Methods

Human GBM-derived cells were cultured in the presence/absence of IFN-γ. EV’s were harvested. PD-L1, IDO1, and EV-associated protein expression was assessed. GBM EV’s (+/-IFN-γ) were cultured with healthy donor monocytes. Immunosuppressive myeloid-derived suppressor cell (MDSC) and non-classical monocyte (NCM) frequency was determined. Impact of GBM (+/-IFN-γ) EV-treated monocytes on CD3/CD28-mediated T cell proliferation was assessed. The impact of PD-L1 and IDO1 knockdown in GBM EV’s in this system was evaluated.

Results

IFN-γ exposure increased PD-L1 and IDO1 expression in GBM cells and EV’s without altering EV size or frequency. IFN-γ-exposed GBM EVs induced more MDSC and NCM differentiation in monocytes and these monocytes caused more T cell inhibition than IFN-γ-naive GBM EVs. PD-L1 and/or IDO1 knockdown in GBM cells abrogated the immunosuppressive effects of IFN-γ-exposed GBM EVs on monocytes.

Conclusions

IFN-γ exposure such as might occur during an anti-tumor immune response results in superinduction of GBM EVs’ baseline immunosuppressive effects on monocytes. These effects are mediated by increased PD-L1 and IDO1 expression in GBM EV’s. This data highlights mechanisms of GBM EV-mediated immunosuppression and identifies therapeutic targets (PD-L1, IDO1) to reverse these effects.

Neurosurgery at the crossroads of immunology and nanotechnology. New reality in the COVID-19 pandemic

Neurosurgery as one of the most technologically demanding medical fields rapidly adapts the newest developments from multiple scientific disciplines for treating brain tumors. Despite half a century of clinical trials, survival for brain primary tumors such as glioblastoma (GBM), the most common primary brain cancer, or rare ones including primary central nervous system lymphoma (PCNSL), is dismal. Cancer therapy and research have currently shifted toward targeted approaches, and personalized therapies. The orchestration of novel and effective blood-brain barrier (BBB) drug delivery approaches, targeting of cancer cells and regulating tumor microenvironment including the immune system are the key themes of this review. As the global pandemic due to SARS-CoV-2 virus continues, neurosurgery and neuro-oncology must wrestle with the issues related to treatment-related immune dysfunction. The selection of chemotherapeutic treatments, even rare cases of hypersensitivity reactions (HSRs) that occur among immunocompromised people, and number of vaccinations they have to get are emerging as a new chapter for modern Nano neurosurgery.

Multifunctional Nanopolymers for Blood-Brain Barrier Delivery and Inhibition of Glioblastoma Growth through EGFR/EGFRvIII, c-Myc, and PD-1

Glioblastoma (GBM) is the most prevalent primary brain cancer in the pediatric and adult population. It is known as an untreatable tumor in urgent need of new therapeutic approaches. The objective of this work was to develop multifunctional nanomedicines to treat GBM in clinical practice using combination therapy for several targets. We developed multifunctional nanopolymers (MNPs) based on a naturally derived biopolymer, poly(β-L-malic) acid, which are suitable for central nervous system (CNS) treatment. These MNPs contain several anticancer functional moieties with the capacity of crossing the blood–brain barrier (BBB), targeting GBM cells and suppressing two important molecular markers, tyrosine kinase transmembrane receptors EGFR/EGFRvIII and c-Myc nuclear transcription factor. The reproducible syntheses of MNPs where monoclonal antibodies are replaced with AP-2 peptide for effective BBB delivery were presented. The active anticancer inhibitors of mRNA/protein syntheses were Morpholino antisense oligonucleotides (AONs). Two ways of covalent AON-polymer attachments with and without disulfide bonds were explored. These MNPs bearing AONs to EGFR/EGFRvIII and c-Myc, as well as in a combination with the polymer-attached checkpoint inhibitor anti-PD-1 antibody, orchestrated a multi-pronged attack on intracranial mouse GBM to successfully block tumor growth and significantly increase survival of brain tumor-bearing animals.

Emerging Landscape of Immunotherapy for Primary Central Nervous System Lymphoma

Simple Summary

Primary central nervous system lymphoma (PCNSL) is characterized by its location in the central nervous system comprising the brain, the eye, the cerebrospinal fluid and the spinal cord and a poor prognosis with the current chemotherapies. Immunotherapies represent a new paradigm in the care of patients with B-cell lymphoma, but, till recently, immunotherapies studies excluded patients with PCNSL because of the lack of knowledge on the immune network in the brain. Recent studies shed a new light on the origin and characteristics of the CNS immune cells. We review the current experimental preclinical and clinical developments of immunotherapies in CNS lymphoma as well as the effects of targeted therapies on the brain microenvironment. We provide perspectives for improving the efficacy of immunotherapies in the specific setting of PCNSL for a better prognosis of this disease.

Abstract

Primary central nervous system lymphoma (PCNSL) is, mainly, a diffuse large B-cell lymphoma (DLBCL) with a non-germinal center B-cell (non-GCB) origin. It is associated with a poor prognosis and an unmet medical need. Immunotherapy has emerged as one of the most promising areas of research and is now part of the standard treatment for many solid and hematologic tumors. This new class of therapy generated great enthusiasm for the treatment of relapsed/refractory PCNSL. Here, we discuss the challenges of immunotherapy for PCNSL represented by the lymphoma cell itself and the specific immune brain microenvironment. We review the current clinical development from the anti-CD20 monoclonal antibody to CAR-T cells, as well as immune checkpoint inhibitors and targeted therapies with off-tumor effects on the brain microenvironment. Perspectives for improving the efficacy of immunotherapies and optimizing their therapeutic role in PCNSL are suggested.

Targeted Therapies and Immune Checkpoint Inhibitors in Primary CNS Lymphoma

This review article outlines the current development of emerging treatment strategies for primary central nervous system lymphoma, a rare brain tumor with, thus far, limited therapeutic options. Small molecule targeted tyrosine kinase inhibitors, immunomodulatory agents, and immune checkpoint inhibitors will be discussed. The mechanisms of action, results of completed clinical studies, ongoing clinical trials, and future perspectives are summarized. Among the most promising clinical developments in the field of CNS lymphomas is ibrutinib, an inhibitor of Bruton's tyrosine kinase, which relays activation of nuclear factor kappa B upon integration of constitutive B cell receptor and Toll-like receptor signals. Down-stream of nuclear factor kappa B, the thalidomide analogs lenalidomide and pomalidomide exert immunomodulatory functions and are currently explored against CNS lymphomas. Finally, immune checkpoint inhibitors, such as drugs targeting the PD-1 pathway, may become novel therapeutic options to unleash anti-tumor immunity in patients with primary CNS lymphoma.

PD-1 and LAG-3 Checkpoint Blockade: Potential Avenues for Therapy in B-Cell Lymphoma

The dependence of cancer on an immunotolerant tumor microenvironment (TME) is well established. Immunotherapies that overcome tumor-induced immune suppression have been central to recent advancements in oncology. This is highlighted by the success of agents that interrupt PD-1 mediated immune suppression in a range of cancers. However, while PD-1 blockade has been paradigm-shifting in many malignancies, the majority of cancers show high rates of primary resistance to this approach. This has led to a rapid expansion in therapeutic targeting of other immune checkpoint molecules to provide combination immune checkpoint blockade (ICB), with one such promising approach is blockade of Lymphocyte Activation Gene 3 (LAG-3). Clinically, lymphoproliferative disorders show a wide spectrum of responses to ICB. Specific subtypes including classical Hodgkin lymphoma have demonstrated striking efficacy with anti-PD-1 therapy. Conversely, early trials of ICB have been relatively disappointing in common subtypes of Non-Hodgkin lymphoma. In this review, we describe the TME of common lymphoma subtypes with an emphasis on the role of prominent immune checkpoint molecules PD-1 and LAG3. We will also discuss current clinical evidence for ICB in lymphoma and highlight key areas for further investigation where synergistic dual checkpoint blockade of LAG-3 and PD-1 could be used to overcome ICB resistance.

Mechanisms of Macrophage Plasticity in the Tumor Environment: Manipulating Activation State to Improve Outcomes

Macrophages are a specialized class of innate immune cells with multifaceted roles in modulation of the inflammatory response, homeostasis, and wound healing. While developmentally derived or originating from circulating monocytes, naïve macrophages can adopt a spectrum of context-dependent activation states ranging from pro-inflammatory (classically activated, M1) to pro-wound healing (alternatively activated, M2). Tumors are known to exploit macrophage polarization states to foster a tumor-permissive milieu, particularly by skewing macrophages toward a pro-tumor (M2) phenotype. These pro-tumoral macrophages can support cancer progression by several mechanisms including immune suppression, growth factor production, promotion of angiogenesis and tissue remodeling. By preventing the adoption of this pro-tumor phenotype or reprogramming these macrophages to a more pro-inflammatory state, it may be possible to inhibit tumor growth. Here, we describe types of tumor-derived signaling that facilitate macrophage reprogramming, including paracrine signaling and activation of innate immune checkpoints. We also describe intervention strategies targeting macrophage plasticity to limit disease progression and address their implications in cancer chemo- and immunotherapy.

PD-L1 and IDO1 are potential targets for treatment in patients with primary diffuse large B-cell lymphoma of the CNS

BACKGROUND

Programmed cell death 1 (PD-1) and its ligands PD-L1 and PD-L2, as well as Indoleamine 2,3-deoxygenase (IDO1) can be expressed both by tumor and microenvironmental cells and are crucial for tumor immune escape. We aimed to evaluate the role of PD-1, its ligands and IDO1 in a cohort of patients with primary diffuse large B-cell lymphoma of the CNS (PCNSL).

MATERIAL AND METHODS

Tissue microarrays (TMAs) were constructed in 45 PCNSL cases. RNA extraction from whole tissue sections and RNA sequencing were successfully performed in 33 cases. Immunohistochemical stainings for PD-1, PD-L1/paired box protein 5 (PAX-5), PD-L2/PAX-5 and IDO1, and Epstein-Barr virus encoding RNA (EBER) in situ hybridization were analyzed.

RESULTS

High proportions of PD-L1 and PD-L2 positive tumor cells were observed in 11% and 9% of cases, respectively. High proportions of PD-L1 and PD-L2 positive leukocytes were observed in 55% and 51% of cases, respectively. RNA sequencing revealed that gene expression of IDO1 was high in patients with high proportion of PD-L1 positive leukocytes (p = .01). Protein expression of IDO1 in leukocytes was detected in 14/45 cases, in 79% of these cases a high proportion of PD-L1 positive leukocytes was observed. Gene expression of IDO1 was high in EBER-positive cases (p = .0009) and protein expression of IDO1 was detected in five of six EBER-positive cases.

CONCLUSION

Our study shows a significant association between gene and protein expression of IDO1 and protein expression of PD-L1 in the tumor microenvironment of PCNSL, possibly of importance for prediction of response to immunotherapies.

Macrophage CCL22 expression promotes lymphangiogenesis in patients with tongue squamous cell carcinoma via IL-4/STAT6 in the tumor microenvironment

The C-C motif chemokine ligand 22 (CCL22) chemokine is produced by M2-like tumor-associated macrophages (TAMs) in the tumor microenvironment. Chemokine C-C motif receptor 4 (CCR4), the CCL22 receptor, on T helper2 (Th2) cells leads to a Th2 cytokine-dominant environment. In our previous study, lymph node metastasis was the main predictor of tongue squamous cell carcinoma (SCC) via CCL22. Therefore, the present study aimed to investigate the effects of CCL22 and a Th2 cytokine-predominant tumor microenvironment on vascular endothelial growth factor (VEGF)-C expression and lymphangiogenesis. The post-operative courses of 110 patients with early-stage tongue SCC with a histopathological diagnosis based on the 8th TNM classification were followed up (mean/median follow-up time, 47.1/42.0 months) from surgery until death or the last follow-up visit, and subsequent lymph node relapse was assessed. Lymphangiogenesis and the immunohistochemical expression of several markers (CCL22, CCR4 and VEGF-C) were evaluated. The Kaplan-Meier method was used to plot lymph node relapse-free survival and overall survival curves, which were compared using the log-rank test. In vitro, the association between CCL22 and VEGF-C by interleukin (IL)-4/signal transducer and activator of transcription 6 (STAT6) stimulation was examined. Lymphangiogenesis was significantly associated with lymph node relapse (P<0.001) and a CCL22⁺ macrophage ratio (P<0.001). CCL22⁺ TAMs were positive for VEGF-C and surrounded by CCR4⁺ cells. Additionally, VEGF-C expression was increased in IL-4/STAT6-stimulated macrophages. In addition, the STAT6 signaling pathway was activated in the SCC cells in the deeply invaded part of the tumor along with the aggregated macrophages. In conclusion, TAM CCL22 expression led to lymph node relapse via VEGF-C expression within the tumor microenvironment and the IL-4/STAT6 signaling pathway in early stage tongue SCC. Additionally, the worst pattern of invasion and depth of invasion were revealed to be useful parameters for lymph node relapse in patients with tongue SCC. The present study suggested that CCL22 contributed to the role of M2-like differentiated TAMs in prognosis and lymph node relapse via IL-4/STAT6 and VEGF. The IL-4/STAT6 signaling pathway may be a new molecular target for tongue SCC.

The immune contexture of primary central nervous system diffuse large B cell lymphoma associates with patient survival and specific cell signaling

Rationale: Primary central nervous system diffuse large B-cell lymphoma (PCNSL) is a rare and aggressive entity that resides in an immune-privileged site. The tumor microenvironment (TME) and the disruption of the immune surveillance influence lymphoma pathogenesis and immunotherapy resistance. Despite growing knowledge on heterogeneous therapeutic responses, no comprehensive description of the PCNSL TME is available. We hence investigated the immune subtypes of PCNSL and their association with molecular signaling and survival. Methods: Analysis of PCNSL transcriptomes (sequencing, n = 20; microarrays, n = 34). Integrated correlation analysis and signaling pathway topology enabled us to infer intercellular interactions. Immunohistopathology and digital imaging were used to validate bioinformatic results. Results: Transcriptomics revealed three immune subtypes: immune-rich, poor, and intermediate. The immune-rich subtype was associated to better survival and characterized by hyper-activation of STAT3 signaling and inflammatory signaling, e.g., IFNγ and TNF-α, resembling the hot subtype described in primary testicular lymphoma and solid cancer. WNT/β-catenin, HIPPO, and NOTCH signaling were hyper-activated in the immune-poor subtype. HLA down-modulation was clearly associated with a low or intermediate immune infiltration and the absence of T-cell activation. Moreover, HLA class I down-regulation was also correlated with worse survival with implications on immune-intermediate PCNSL that frequently feature reduced HLA expression. A ligand-receptor intercellular network revealed high expression of two immune checkpoints, i.e., CTLA-4/CD86 and TIM-3/LAGLS9. TIM-3 and galectin-9 proteins were clearly upregulated in PCNSL. Conclusion: Altogether, our study reveals that patient stratification according to immune subtypes, HLA status, and immune checkpoint molecule quantification should be considered prior to immune checkpoint inhibitor therapy. Moreover, TIM-3 protein should be considered an axis for future therapeutic development.

Immune Checkpoint Molecules in Primary Diffuse Large B-Cell Lymphoma of the Central Nervous System

Introduction:

Primary Diffuse Large B Cell Lymphoma of CNS (PCNSL) is a rare variant of Diffuse Large B Cell Lymphoma (DLBCL) and presents with an aggressive clinical course and usually resistant to commonly used therapy regimens. Recently, role of immune checkpoint molecules including PD-1 and PD-L1 confirmed in some solid tumors and lymphoma resulting tumor cells escape the immune system and help to survive and to spread. Inhibitors of PD-1 and PD-L1 have shown lasting responses in several solid and some hematological tumors, while limited studies evaluate checkpoint molecules on PCNSL.

Method:

In this study, we investigated PD-1 and PD-L1 expression by immunostaining on 71 patients with PCNSL and correlation with demographic data, location of the tumor, proliferation rate, cell of origin, and CD8 positive T cell infiltration in tumor microenvironment.

Results:

16 from71 showed PD-1 expression, while PD-L1 expression were 42/71. No association was determined between PD-1/PD-L1 expression and gender, cell of origin, and proliferation rate, but a highly significant difference was determined between the infiltration of CD8 positive T cells in two groups of PD-1/PD-L1 positive and negative.

Conclusion:

This study revealed expression of check point molecules in remarkable number of PCNSL which may open new therapeutic recommendations in this aggressive lymphoma type.

Molecular profiling of primary central nervous system lymphomas - predictive and prognostic value?

PURPOSE OF REVIEW

Primary central nervous system lymphoma (PCNSL) is a rare but aggressive variant of non-Hodgkin lymphoma. The diagnostic gold standard remains the pathologic review of tumor tissue mainly collected though biopsies. The majority of PCNSL are diffuse large B cell lymphoma (DLBCL). Biopsies are invasive procedures, and there have been efforts to develop minimally invasive diagnostic testing using serum and cerebral spinal fluid. This article reviews multiple markers that could potentially serve as future diagnostic tools and predictors of treatment response.

RECENT FINDINGS

Many studies have attempted to classify DLBCL into different subtypes for prognostic purposes using methods such as immunohistochemistry. PCNSL often falls under the activated B-cell-like subgroup, and further genomic sequencing has identified alterations in genes within the B-cell receptor signaling axis at increased frequencies. Two such genes, MYD88 and CD79B, implicate the involvement of the NF-kB (nuclear factor kappa-light-chain enhancer of activated B cells) pathway, and targeted agents to this pathway are currently being used in the treatment of relapsed/refractory PCNSL.

SUMMARY

Although recent genomic profiling of PCNSL has increased the understanding of drivers in this disease and has also led to the introduction of targeted inhibitors, these markers have not yet been used for diagnostic and/or prognostic purposes. Further studies will need to evaluate if they hold great diagnostic potential.

GSEA-assisted gene signatures valid for combinations of prognostic markers in PCNSL

Primary central nervous system lymphoma (PCNSL) is a brain malignant non-Hodgkin’s B-cell lymphoma. The standard treatments are high-dose methotrexate (MTX)-based chemotherapies and deferred whole brain radiotherapy. However, MTX resistance-dependent global expression and signaling pathway changes and their relationship with prognoses have not yet been elucidated. Here, we conducted a global expression analysis with next-generation sequencing and gene set enrichment analysis (GSEA) in MTX-resistant PCNSL cell lines (HKBML-MTX and TK-MTX) and PCNSL tissues. In rank scores, genes listed in HKBML-MTX and TK-MTX were enriched in PCNSL with poor prognoses. In fold changes, a part of differentially-expressed genes in PCNSL tissues were also detected in HKBML-MTX and TK-MTX cells; FOXD2-AS1 and MMP19 were commonly expressed in both HKBML-MTX and TK-MTX, FABP5 and CD70 were HKBML-MTX-specifically expressed, and CLCN2, HOXB9, INE1, and LRP5L were TK-MTX-specifically expressed, which may provide a combination of prognostic markers on MTX-sensitivities in PCNSL. Additionally, PCNSL subgroups, divided with hierarchical clustering and Kaplan-Meier methods, included twenty commonly expressed genes in both HKBML-MTX and TK-MTX, ten HKBML-MTX-specifically expressed genes, and two TK-MTX-specifically expressed genes. These results suggest that the GSEA-assisted gene signatures can provide a combination for prognostic markers in recurrent PCNSL with MTX resistances.

In-depth characterization of the tumor microenvironment in central nervous system lymphoma reveals implications for immune-checkpoint therapy

Primary central nervous system lymphoma (PCNSL) is a rare type of non-Hodgkin lymphoma with an aggressive clinical course. To investigate the potential of immune-checkpoint therapy, we retrospectively studied the tumor microenvironment (TME) using high-plex immunohistochemistry in 22 PCNSL and compared to 7 secondary CNS lymphomas (SCNSL) and 7 "other" CNSL lymphomas with the presence of the Epstein-Barr virus and/or compromised immunity. The TME in PCNSL was predominantly composed of CD8+ cytotoxic T cells and CD163+ phagocytes. Despite molecular differences between PCNSL and SCNSL, the cellular composition and the functional spectrum of cytotoxic T cells were similar. But cytotoxic T cell activation was significantly influenced by pre-biopsy corticosteroids intake, tumor expression of PD-L1 and the presence of EBV. The presence of low numbers of CD8+ T cells and geographic-type necrosis each predicted inferior outcome in PCNSL. Both M1-like (CD68 + CD163^low) and M2-like (CD68 + CD163^high) phagocytes were identified, and an increased ratio of M1-like/M2-like phagocytes was associated with a better survival. PD-L1 was expressed in lymphoma cells in 28% of cases, while PD1 was expressed in only 0.4% of all CD8+ T cells. TIM-3, a marker for T cell exhaustion, was significantly more expressed in CD8^posPD-1^pos T cells compared to CD8^posPD-1^neg T cells, and a similar increased expression was observed in M2-like pro-tumoral phagocytes. In conclusion, the clinical impact of TME composition supports the use of immune-checkpoint therapies in PCNSL. Based on observed differences in immune-checkpoint expression, combinations that boost cytotoxic T cell activation (by blocking TIM-3 or TGFBR1) prior to the administration of PD-L1 inhibition could be of interest.

miR-101, miR-548b, miR-554, and miR-1202 are reliable prognosis predictors of the miRNAs associated with cancer immunity in primary central nervous system lymphoma

MicroRNAs (miRNAs) inhibit protein function by silencing the translation of target mRNAs. However, in primary central nervous system lymphoma (PCNSL), the expression and functions of miRNAs are inadequately known. Here, we examined the expression of 847 miRNAs in 40 PCNSL patients with a microarray and investigated for the miRNA predictors associated with cancer immunity-related genes such as T helper cell type 1/2 (Th-1/Th-2) and regulatory T cell (T-reg) status, and stimulatory and inhibitory checkpoint genes, for prognosis prediction in PCNSL. The aim of this study is to find promising prognosis markers based on the miRNA expression in PCNSL. We detected 334 miRNAs related to 66 cancer immunity-related genes in the microarray profiling. Variable importance measured by the random survival forest analysis and Cox proportional hazards regression model elucidated that 11 miRNAs successfully constitute the survival formulae dividing the Kaplan-Meier curve of the respective PCNSL subgroups. On the other hand, univariate analysis shortlisted 23 miRNAs for overall survival times, with four miRNAs clearly dividing the survival curves-miR-101/548b/554/1202. These miRNAs regulated Th-1/Th-2 status, T-reg cell status, and immune checkpoints. The miRNAs were also associated with gene ontology terms as Ras/MAP-kinase, ubiquitin ligase, PRC2 and acetylation, CDK, and phosphorylation, and several diseases including acquired immunodeficiency syndrome, glioma, and those related to blood and hippocampus with statistical significance. In conclusion, the results demonstrated that the four miRNAs comprising miR-101/548b/554/1202 associated with cancer immunity can be a useful prognostic marker in PCNSL and would help us understand target pathways for PCNSL treatments.

Promising Prognosis Marker Candidates on the Status of Epithelial-Mesenchymal Transition and Glioma Stem Cells in Glioblastoma

Multivariable analyses of global expression profiling are valid indicators of the prognosis of various diseases including brain cancers. To identify the candidates for markers of prognosis of glioblastoma, we performed multivariable analyses on the status of epithelial (EPI)-mesenchymal (MES) transition (EMT), glioma (GLI) stem cells (GSCs), molecular target therapy (MTT), and potential glioma biomarkers (PGBs) using the expression data and clinical information from patients. Random forest survival and Cox proportional hazards regression analyses indicated significant variable values for DSG3, CLDN1, CDH11, FN1, HDAC3/7, PTEN, L1CAM, OLIG2, TIMP4, IGFBP2, and GFAP. The analyses also comprised prognosis prediction formulae that could distinguish between the survival curves of the glioblastoma patients. In addition to the genes mentioned above, HDAC1, FLT1, EGFR, MGMT, PGF, STAT3, SIRT1, and GADD45A constituted complex genetic interaction networks. The calculated status scores obtained by principal component analysis indicated that GLI genes covered the status of EPI, GSC, and MTT-related genes. Moreover, survival tree analyses indicated that MES^high, MES^highGLI^low, GSC^highGLI^low, MES^highMTT^low, and PGB^high showed poor prognoses and MES^middle, GSC^low, and PGB^low showed good prognoses, suggesting that enhanced EMT and GSC are associated with poor survival and that lower expression of EPI markers and the pre-stages of EMT are relatively less malignant in glioblastoma. These results demonstrate that the assessment of EMT and GSC enables the prediction of the prognosis of glioblastoma that would help develop novel therapeutics and de novo marker candidates for the prognoses of glioblastoma.

Maf expression in human macrophages and lymph node sinus macrophages in patients with esophageal cancer

The large Maf transcription factors are expressed in immune cells including macrophages and lymphocytes. To investigate the distribution of Maf expression in human organs, immunostaining for Maf was performed using sections of several human organs. High Maf expression was seen in the nucleus of macrophages in the gastrointestinal tract and lymph node sinus macrophages (LySMs). Then, we assessed whether Maf expression in LySMs was correlated with CD169 expression and the clinical prognosis in patients with esophageal cancer. Maf expression was associated with CD169 expression, but Maf expression in LySMs was not associated with the clinical course in patients with esophageal cancer. We determined which cytokines stimulate Maf expression using cultured macrophages. Immunocytochemistry showed that Maf expression was significantly elevated by interferon-γ. These results are the first report of Maf expression in human samples. Maf expression may be a marker for the macrophage population in humans.

Differential expression of N-linked oligosaccharides in methotrexate-resistant primary central nervous system lymphoma cells

Background

Oligosaccharides of glycoprotein, particularly negatively-charged sialylated N-glycans, on the surface of lymphomas play important roles in cell–cell interactions and bind immunoglobulin-like lectins, causing inflammatory responses and bioregulation. However, their characterizations have largely been unknown in central nervous system (CNS) lymphoma.

Methods

Here, we investigated expression patterns of N-linked oligosaccharides of glycoproteins in cells derived from CNS lymphomas and clinical specimens.

Results

We first generated methotrexate (MTX)-resistant cells derived from HKBML and TK as CNS lymphoma, and RAJI as non-CNS lymphoma and determined N-linked oligosaccharide structures in these cells and other non-CNS lymphoma-derived cells including A4/FUK, OYB, and HBL1. Major components of the total oligosaccharides were high-mannose type N-glycans, whose level increased in MTX-resistant HKBML and TK but decreased in MTX-resistant RAJI. We also detected sialylated biantennary galactosylated N-glycans with α1,6-fucosylation, A2G2F, and A2G2FB from HKBML, TK, and RAJI. Sialylated A4G4F was specifically isolated from RAJI. However, the ratios of these sialylated N-glycans slightly decreased against MTX-resistant compared to non-resistant cells. Interestingly, almost all complex-type oligosaccharides were α2,6-sialylated.

Discussion

This is the first study for the expression profile of N-oligosaccharides on MTX-resistant primary CNS lymphoma-derived cells HKBML and TK, and tumor tissues resected from patients with CNS lymphoma,

Conclusion

These results propose a possibility that the differential expression of high-mannose types and sialylated A2G2F, A2G2FB, and A4G4F on the surface of CNS lymphomas may provide a hint for targets for diagnoses and treatments of the oligosaccharide type-specific lymphomas.

Blood-brain barrier permeable nano immunoconjugates induce local immune responses for glioma therapy

Brain glioma treatment with checkpoint inhibitor antibodies to cytotoxic T-lymphocyte-associated antigen 4 (a-CTLA-4) and programmed cell death-1 (a-PD-1) was largely unsuccessful due to their inability to cross blood-brain barrier (BBB). Here we describe targeted nanoscale immunoconjugates (NICs) on natural biopolymer scaffold, poly(β-L-malic acid), with covalently attached a-CTLA-4 or a-PD-1 for systemic delivery across the BBB and activation of local brain anti-tumor immune response. NIC treatment of mice bearing intracranial GL261 glioblastoma (GBM) results in an increase of CD8+ T cells, NK cells and macrophages with a decrease of regulatory T cells (Tregs) in the brain tumor area. Survival of GBM-bearing mice treated with NIC combination is significantly longer compared to animals treated with single checkpoint inhibitor-bearing NICs or free a-CTLA-4 and a-PD-1. Our study demonstrates trans-BBB delivery of tumor-targeted polymer-conjugated checkpoint inhibitors as an effective GBM treatment via activation of both systemic and local privileged brain tumor immune response.

Differential expression of individual transcript variants of PD-1 and PD-L2 genes on Th-1/Th-2 status is guaranteed for prognosis prediction in PCNSL

In current molecular medicine, next-generation sequencing (NGS) for transcript variant detection and multivariable analyses are valid methods for evaluating gene expression, cancer mechanisms, and prognoses of patients. We conducted RNA-sequencing on samples from patients with primary central nervous system lymphoma (PCNSL) using NGS and performed multivariable analysis on gene expression data and correlations focused on Th-1/Th-2 helper T cell balance and immune checkpoint to identify diagnosis/prognosis markers and cancer immune pathways in PCNSL. We selected 84 transcript variants to limit the analysis range for Th-1/Th-2 balance and stimulatory and inhibitory checkpoints in 31 PCNSLs. Of these, 21 highly-expressed transcript variants were composed of the formulas for prognoses based on Th-1/Th-2 status and checkpoint activities. Using formulas, Th-1^low, Th-2^high, and stimulatory checkpoint^high resulted in poor prognoses. Further, Th-1^highTh-2^low was associated with good prognoses. On the other hand, CD40-001^high and CD70-001^high as stimulatory genes, and LAG3-001^high, PDCD1 (PD-1)-001/002/003^high, and PDCD1LG2 (PD-L2)-201^low as inhibitory genes were associated with poor prognoses. Interestingly, Th-1^highTh-2^low and Th-1^lowTh-2^high were correlated with stimulatory checkpoint^low as CD70-001^low and inhibitory checkpoint^low as HAVCR2 (TIM-3)-001^low and PDCD1LG2-001/201^low, respectively. Focused on the inhibitory checkpoint, specific variants of CD274 (PD-L1)-001 and PDCD1-002 served severe hazard ratios. In particular, PDCD1-002^high by a cut off score was associated with poor prognoses, in addition to PDCD1-001/003^high, PDCD1LG2-201^low, and LAG3-001^high. These results mainly suggest that expression of transcript variants of PDCD1 and PDCD1LG2 on the Th-1/Th-2 balance enable prognostic prediction in PCNSL. This study provides insights for development of molecular target therapies and identification of diagnosis/prognosis markers in PCNSL.

Glial Cell Expression of PD-L1

The programmed death (PD)-1/PD-L1 pathway is a well-recognized negative immune checkpoint that results in functional inhibition of T-cells. Microglia, the brain-resident immune cells are vital for pathogen detection and initiation of neuroimmune responses. Moreover, microglial cells and astrocytes govern the activity of brain-infiltrating antiviral T-cells through upregulation of PD-L1 expression. While T-cell suppressive responses within brain are undoubtedly beneficial to the host, preventing cytotoxic damage to this vital organ, establishment of a prolonged anti-inflammatory milieu may simultaneously lead to deficiencies in viral clearance. An immune checkpoint blockade targeting the PD-1: PD-L1 (B7-H1; CD274) axis has revolutionized contemporary treatment for a variety of cancers. However, the therapeutic potential of PD1: PD-L1 blockade therapies targeting viral brain reservoirs remains to be determined. For these reasons, it is key to understand both the detrimental and protective functions of this signaling pathway within the brain. This review highlights how glial cells use PD-L1 expression to modulate T-cell effector function and limit detrimental bystander damage, while still retaining an effective defense of the brain.