Local Immunosuppression Research Articles

Cell-based immunotherapy of glioblastoma multiforme.

Glioblastoma multiforme (GBM) is the most aggressive and lethal primary glial brain tumor. It has an unfavorable prognosis and relatively ineffective treatment protocols, with the median survival of patients being ~15 months. Tumor resistance to treatment is associated with its cancer stem cells (CSCs). At present, there is no medication or technologies that have the ability to completely eradicate CSCs, and immunotherapy (IT) is only able to prolong the patient's life. The present review aimed to investigate systemic solutions for issues associated with immunosuppression, such as ineffective IT and the creation of optimal conditions for CSCs to fulfill their lethal potential. The present review also investigated the main methods involved in local immunosuppression treatment, and highlighted the associated disadvantages. In addition, novel treatment options and targets for the elimination and regulation of CSCs with adaptive and active IT are discussed. Antagonists of TGF-β inhibitors, immune checkpoints and other targeted medication are also summarized. The role of normal hematopoietic stem cells (HSCs) in the mechanisms underlying systemic immune suppression development in cases of GBM is analyzed, and the potential reprogramming of HSCs during their interaction with cancer cells is discussed. Moreover, the present review emphasizes the importance of the aforementioned interactions in the development of immune tolerance and the inactivation of the immune system in neoplastic processes. The possibility of solving the problem of systemic immunosuppression during transplantation of donor HSCs is discussed.

Cell Communication Network factor 4 promotes tumor-induced immunosuppression in melanoma.

Cell Communication Network factor 4 (CCN4/WISP1) is a matricellular protein secreted by cancer cells that promotes metastasis by inducing the epithelial-mesenchymal transition. While metastasis limits survival, limited anti-tumor immunity also associates with poor patient outcomes with recent work linking these two clinical correlates. Motivated by increased CCN4 correlating with dampened anti-tumor immunity in primary melanoma, we test for a direct causal link by knocking out CCN4 (CCN4 KO) in the B16F0 and YUMM1.7 mouse melanoma models. Tumor growth is reduced when CCN4 KO melanoma cells are implanted in immunocompetent but not in immunodeficient mice. Correspondingly, CD45+ tumor-infiltrating leukocytes are significantly increased in CCN4 KO tumors, with increased natural killer and CD8+ T cells and reduced myeloid-derived suppressor cells (MDSC). Among mechanisms linked to local immunosuppression, CCN4 suppresses IFN-gamma release by CD8+ T cells and enhances tumor secretion of MDSC-attracting chemokines like CCL2 and CXCL1. Finally, CCN4 KO potentiates the anti-tumor effect of immune checkpoint blockade (ICB) therapy. Overall, our results suggest that CCN4 promotes tumor-induced immunosuppression and is a potential target for therapeutic combinations with ICB.

Immune Disregulation in Cutaneous Squamous Cell Carcinoma of Patients with Recessive Dystrophic Epidermolysis Bullosa: A Single Pilot Study.

Background: Cutaneous squamous cell carcinoma (cSCC) is one of the most devastating complications of recessive dystrophic epidermolysis bullosa (RDEB). We recently demonstrated a reduction in immune cell peritumoral infiltration in RDEB patients with cSCC, together with a reduction in CD3+, CD4+, CD68+ and CD20 lymphocytes as compared to primary and secondary cSCC in patients without RDEB. Recently, new molecules, such as high mobility group box 1 (HMGB1), T cell immunoglobulin, mucin domain 3 (TIM-3) and Heme oxygenase-1 (HO-1), have been shown to play a role in antitumoral immunity. Objective: Patients with RDEB are known to be at increased risk of developing skin cancers, including the dreaded squamous cell carcinoma of the. Tendentially, cSCCs that arise in the context of EBDR are more aggressive and lead to statistically significant bad outcomes compared to cSCCs developed on the skin of patients without EBDR. In an attempt to study the microenvironment of these lesions, we conducted an immunohistochemical analysis study of proteins that could be actively involved in the genesis of this type of malignant neoplasms. Methods: In this retrospective study, the OH1-HMGB1-TIM3 activation axis, as correlated to the T lymphocytes cell count, was assessed in biopsy samples from 31 consecutive cases consisting of 12 RDEB patients with cSCC, 12 patients with primary cSCC and 7 RDEB patients with pseudoepitheliomatous cutaneous hyperplasia. Parametric Student’s t-test was applied for normally distributed values, such as CD4+ and CD8+, and non-parametric Mann–Whitney test for non-normally distributed values, such as HMGB-1, TIM-3 and HO-1. Results: In RDEB patients with cSCC and with pseudoepitheliomatous hyperplasia, the expression of CD4 T helper lymphocytes was lower than in the peritumoral infiltrate found in primary cSCC. CD8 cytotoxic T lymphocytes were increased in primary cSCC compared to the other two groups. An increased HMGB1 expression was evident in both primary and RDEB cSCC. TIM3 expression was higher in RDEB patients with cSCC compared to the other two groups. A significantly reduced immunohistochemical expression of HO-1 was evident in the tumoral microenvironment of cSCC-RDEB as compared to primary cSCC. Conclusions: These data suggest that a reduced immune cell peritumoral infiltration in RDEB patients could be responsible, in the complexity of the mechanisms of carcinogenesis and host response, of the particular aggressiveness of the cSCC of RDEB patients, creating a substrate for greater local immunosuppression, which, potentially, can “open the doors” to development and eventual metastasis by this malignant neoplasm.

Vitamin D Effect on the Severity of Chronic Pelvic Pain in Patients with Ovarian Endometriosis Combined with Pelvic Inflammatory Diseases

Numerous publications in recent years indicate the impact of vitamin D deficiency on the course and severity of a number of gynecological diseases, including endometrial disease. As this transmitter is associated with immune disorders, its involvement in local immunosuppression in the progression of the systemic inflammatory response in the case of endometrial disease is not excluded. Considering the pathogenetic links between vitamin D metabolism and the severity of pelvic pain, it became appropriate to study the relationship between this parameter and the intensity of pelvic pain in patients with ovarian endometriomas associated with chronic pelvic inflammatory diseases, which was the objective of this research. Materials and methods of research. The study included 90 patients with ovarian endometriosis aged 20 to 41 years. The main group consisted of 44 patients with endometrioma combined with pelvic inflammatory diseases; the comparison group consisted of 46 patients with isolated ovarian endometrioma. The control group included 30 relatively healthy women without gynecological and somatic pathology. At the initial stage, the level of 25-hydroxyvitamin-D3 (25 (OH) D) was determined in patients of the three groups by mass spectrometry using standard methods. Analysis and discussion of research results. Patients with ovarian endometrial cysts on the background of pelvic inflammatory disease were statistically significantly older compared with the group of isolated endometriomas; more than half of the observations were patients aged 36-40 years (p<0.05). Laparoscopic diagnostic and therapeutic techniques allowed to present objective signs of combination of ovarian endometrioma with manifestations of external genital endometriosis: severe manifestations of external genital endometriosis were diagnosed in 31.8% vs. 15.21% in the comparison group. Depending on the severity of the pain syndrome according to VAS, patients of the main group were stratified as follows: 22.7% noted pelvic pain of low intensity, 40.9% – moderate pain, 25.0% – severe pain; in the comparison group there were no manifestations of severe pelvic pain. The combination of pelvic inflammatory disease with ovarian endometriosis was accompanied by an increase in the share of vitamin D deficiency – in 38.64% and the share of severe pain – in 25.0%.
 Conclusion. A significantly moderate inverse correlation was found between the verification of the manifestations of external genital endometriosis and the level of vitamin D in the blood serum. The obtained data dictated the need to assess the therapeutic potential of vitamin D in combination with nonsteroidal anti-inflammatory drugs to enhance the analgesic effect and reduce the drug load.

Functional virus-specific memory T cells survey glioblastoma.

Glioblastoma multiforme (GBM) is among the most aggressive, treatment-resistant cancers, and despite standard of care surgery, radiation and chemotherapy, is invariably fatal. GBM is marked by local and systemic immunosuppression, contributing to resistance to existing immunotherapies that have had success in other tumor types. Memory T cells specific for previous infections reside in tissues throughout the host and are capable of rapid and potent immune activation. Here, we show that virus-specific memory CD8 + T cells expressing tissue-resident markers populate the mouse and human glioblastoma microenvironment. Reactivating virus-specific memory T cells through intratumoral delivery of adjuvant-free virus-derived peptide triggered local immune activation. This delivery translated to antineoplastic effects, which improved survival in a murine glioblastoma model. Our results indicate that virus-specific memory T cells are a significant part of the glioblastoma immune microenvironment and may be leveraged to promote anti-tumoral immunity.

Local Dexamethasone Administration Delays Allogeneic Islet Graft Rejection in the Anterior Chamber of the Eye of Non-Human Primates

Pancreatic islet transplantation into the anterior chamber of the eye (ACE) has been shown to improve glycemic control and metabolic parameters of diabetes in both murine and primate models. This novel transplantation site also allows the delivery of therapeutic agents, such as immunosuppressive drugs, locally to prevent islet graft rejection and circumvent unwanted systemic side effects. Local intravitreal administration of micronized dexamethasone implant was performed prior to allogeneic islet transplantation into the ACEs of non-human primates. Two study groups were observed namely allogeneic graft without immunosuppression (n = 4 eyes) and allogeneic graft with local immunosuppression (n = 8 eyes). Survival of islet grafts and dexamethasone concentration in the ACE were assessed in parallel for 24 weeks. Allogeneic islet grafts with local dexamethasone treatment showed significantly better survival than those with no immunosuppression (median survival time- 15 weeks vs 3 weeks, log-rank test p<0.0001). Around 73% of the grafts still survived at week 10 with a single local dexamethasone implant, where the control group showed no graft survival. Dexamethasone treated islet grafts revealed a good functional response to high glucose stimulation despite there was a transient suppression of insulin secretion from week 8 to 12. Our findings show a significant improvement of allografts survival in the ACE with local dexamethasone treatment. These results highlight the feasibility of local administration of pharmacological compounds in the ACE to improve islet graft survival and function. By eliminating the need for systemic immunosuppression, these findings may impact clinical islet transplantation in the treatment of diabetes, and the ACE may serve as a novel therapeutic islet transplantation site with high potential for local pharmacological intervention.

The Impact of Intragastric Microbiota Transfer on the Development of Colorectal Liver Metastasis in a Murine Model

Introduction: Several factors influence the development of colorectal liver metastases (CRLM) including surgical-stress induced systemic and hepatic localized immunosuppression. Previous research demonstrated effects of microbiota on various liver diseases as well as the immune system. We examined the effects of microbiota transfer on CRLM and on T-cell liver migration in a murine model. Methods: The murine model of CLRM was splenic injection of GFP-marked colorectal murine cancer cells (MC38-GFP). Mice received intragastric-gavages of different microbiota compositions: commercial probiotics, naïve-mice feces, high-fat-diet fed mice feces, and saline control. On day 9-11 mice were sacrificed and assessment of liver metastases was performed using in vivo imaging system. We assessed influenced of intragastric microbiota administration on T-cell liver migration. Following “sham” laparotomy, mice received intragastric-gavages of probiotics or saline control, and later injected with activated T-cells. The mice were sacrificed 4 days later, migration of the injected T-cells into the liver was examined using flow cytometry. Results: Mice receiving intragastric Probiotics developed significantly more liver metastasis than control (6.302 ± 1.318, N=14 vs 3 ± 0.6, N=14, P=0.0314*). The other groups' liver metastasis load was similar to their respective controls. Mice receiving intragastric probiotics had a lower percentage of administered T-cells compared to control )0.842% ± 0.116%, N=5, vs 1.3% ± 0.149%, N=4, p=0.042*). Conclusion: In a murine model, intragastric probiotics administration was associated with increased metastatic spread. Livers of probiotics treated mice accumulated less activated T-cells, possibly resulting in localized immunosuppression. Further investigation is needed to decipher the liver-microbiome relationship, and its attribution to antitumoral processes.

An Inflammatory Response Related Gene Signature Associated with Survival Outcome and Gemcitabine Response in Patients with Pancreatic Ductal Adenocarcinoma.

Background: Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive tumors with an extremely low 5-year survival rate. Accumulating evidence has unveiled that inflammatory response promotes tumor progression, enhances angiogenesis, and causes local immunosuppression. Herein, we aim to develop an inflammatory related prognostic signature, and found it could be used to predict gemcitabine response in PDAC. Methods: PDAC cohorts with mRNA expression profiles and clinical information were systematically collected from the four public databases. An inflammatory response related genes (IRRGs) prognostic signature was constructed by LASSO regression analysis. Kaplan–Meier survival analysis, receiver operating characteristic analysis, principal component analysis, and univariate and multivariate Cox analyses were carried out to evaluate effectiveness, and reliability of the signature. The correlation between gemcitabine response and risk score was evaluated in the TCGA-PAAD cohort. The GDSC database, pRRophetic algorithm, and connectivity map analysis were used to predict gemcitabine sensitivity and identify potential drugs for the treatment of PDAC. Finally, we analyzed differences in frequencies of gene mutations, infiltration of immune cells, as well as biological functions between different subgroups divided by the prognostic signature. Results: We established a seven IRRGs (ADM, DCBLD2, EREG, ITGA5, MIF, TREM1, and BTG2) signature which divided the PDAC patients into low- and high-risk groups. Prognostic value of the signature was validated in 11 PDAC cohorts consisting of 1337 PDAC patients from 6 countries. A nomogram that integrated the IRRGs signature and clinicopathologic factors of PDAC patients was constructed. The risk score showed positive correlation with gemcitabine resistance. Two drugs (BMS-536924 and dasatinib) might have potential therapeutic implications in high-risk PDAC patients. We found that the high-risk group had higher frequencies of KRAS, TP53, and CDKN2A mutations, increased infiltration of macrophages M0, neutrophils, and macrophages M2 cells, as well as upregulated hypoxia and glycolysis pathways, while the low-risk group had increased infiltration of CD8+ T, naïve B, and plasma and macrophages M1 cells. Conclusion: We constructed and validated an IRRGs signature that could be used to predict the prognosis and gemcitabine response of patients with PDAC, as well as two drugs (BMS-536924 and dasatinib) may contribute to PDAC treatment.

Local Immunosuppression in Wuzhishan Pig to Rhesus Monkey Descemet’s Stripping Automated Endothelial Keratoplasty: An Innovative Method to Promote the Survival of Xenografts

Introduction: Corneal xenotransplantation is an effective solution for human corneal shortage. We investigated the feasibility and efficacy of different postoperative protocols on xeno-Descemet’s stripping automated endothelial keratoplasty (DSAEK) grafts. Methods: Thirty rhesus monkeys were randomly divided into three groups: control group (C) and only Descemet’s membrane (DM) stripping, DSAEK 1 (D1) and DSAEK 2 (D2) groups, DM stripping followed by endothelial keratoplasty. Betamethasone 3.5 mg was subconjunctivally injected in groups control and D1 postoperatively, whereas rhesus monkeys in group D2 received topical 0.1% tacrolimus and topical steroids. All groups were evaluated by slit lamp, anterior segment optical coherence tomography, and laser scanning confocal microscopy for at least 9 months. Results: Twenty-four monkeys met the inclusion criteria. Nine months after the DSAEK surgery, most corneas were transparent. Graft rejection was observed in 25% and 28.57% of the cases in group D1 and group D2 (p > 0.05), respectively. Corneal endothelium densities in DSAEK groups were 2,715.83 ± 516.20/mm2 (D1) and 2,220.00 ± 565.13/mm2 (D2) (p > 0.05). Conclusions: Xenogeneic corneal endothelial grafts can survive and function in rhesus monkey eyes for a prolonged period of time with subconjunctival steroid or topical tacrolimus and steroid treatment. Furthermore, topical drugs are more suitable for clinical use.

Hypoxia Regulates Endogenous Double-Stranded RNA Production via Reduced Mitochondrial DNA Transcription.

Hypoxia is a common phenomenon in solid tumours strongly linked to the hallmarks of cancer. Hypoxia promotes local immunosuppression and downregulates type I interferon (IFN) expression and signalling, which contribute to the success of many cancer therapies. Double-stranded RNA (dsRNA), transiently generated during mitochondrial transcription, endogenously activates the type I IFN pathway. We report the effects of hypoxia on the generation of mitochondrial dsRNA (mtdsRNA) in breast cancer. We found a significant decrease in dsRNA production in different cell lines under hypoxia. This effect was HIF1α/2α-independent. mtdsRNA was responsible for induction of type I IFN and significantly decreased after hypoxia. Mitochondrially encoded gene expression was downregulated and mtdsRNA bound by the dsRNA-specific J2 antibody was decreased during hypoxia. These findings reveal a new mechanism of hypoxia-induced immunosuppression that could be targeted by hypoxia-activated therapies.

Biointerfacing Antagonizing T-Cell Inhibitory Nanoparticles Potentiate Hepatocellular Carcinoma Checkpoint Blockade Therapy.

Hepatocellular carcinoma (HCC) is one of the most fatal malignancies with few effective treatment options all around the world. The efficacy of the arisen immune checkpoint therapy is still uncertain due to local immunosuppression. In order to further overcome T cell suppression in the tumor immune microenvironment while promoting the immune response of antigen-presenting cells, a biointerfacing antagonizing T-cell inhibitory nanoparticles (BAT NPs) has been developed by cloaking platelet membrane on the PLGA microsphere surface to load T-cell immunoglobulin domain and mucin domain-3 antibodies (anti-TIM-3) as well as PD-L1. Notably, in addition to activating the proliferation and migration of T cells, the contained anti-TIM-3 can cooperate with PD-L1 checkpoint blockade to exert therapeutic effects. Furthermore, the components of BAT NPs like anti-TIM-3 and platelet can act together for collagen deposition in tumor starvation treatment. Thus, a novel targeting therapeutic strategy that can effectively reverse the immune-inhibiting microenvironment is effectively applied to PD-L1 checkpoint combination therapy. Such therapeutic effect can subsequently activate the effector T lymphocytes and antigen presentation of dendritic cells as well as the polarization of M1-type macrophages. Last, the study presented the synergistic effect of immune therapeutic adjuvants and BAT NPs components in achieving tumor inhibition and prolonging tumor-burden survival.

Abstract PO-033: Bacterial cytotoxin therapy limits tumor growth for pancreatic ductal adenocarcinoma

Abstract Treating pancreatic ductal adenocarcinoma (PDAC) with systemic chemotherapeutic drugs has remained a challenge, due in part to the hypovascularized and poorly perfused nature of PDAC tumors. Limited blood flow within the tumor tissue creates an extremely hypoxic microenvironment and impedes the accumulation of drugs. Moreover, local immunosuppression in PDAC has so far limited the efficacy of immunotherapy approaches. However, these very features that have interfered with systemic therapy in PDAC (hypoperfusion, hypoxia, and immunosuppression) are potential advantages for the use of bacterial therapies. Bacteria have been used as a directed cancer therapy for over 100 years, starting with Dr. William Coley’s use of heat killed bacteria (Coley’s Toxin) against sarcomas in 1893. Recent developments in the field of synthetic biology have made it possible to engineer complex logical circuits into bacteria, enabling the manufacture of anticancer therapies directly within the tumor parenchyma. Bacteria can actively migrate through tissues, they can thrive in hypoxic microenvironments, and they benefit from the local immune suppression. We have therefore worked to develop novel bacterial strains for targeting PDAC. We began by testing a range of bacteria-derived toxins that could be used as a payload to target PDAC. These toxins were produced by an engineered strain of a non-toxic, probiotic E. coli Nissle 1917. We identified four pore-forming toxins that significantly reduced viability of the cells compared to bacterially produced GFP: hemolysin E, heat stable enterotoxin, magainin, and theta toxin. We then performed a secondary screen using a novel PDAC explant model system developed in our lab, in which thick slices of murine or human PDAC are culture intact for up to 7 days. Consistent with the monolayer screen, two of the candidate compounds, heat stable enterotoxin and theta toxin, significantly increased tissue death compared to non-toxic GFP-producing bacteria. Finally, we delivered live bacteria producing either toxins or GFP into KPC mouse tumors through intratumoral injection. While GFP-producing strains did not induce a change in tumor growth kinetics, theta toxin treatment demonstrated an immediate, prolonged stabilization of tumor volume for more than a month. Histological analyses of treated tumors demonstrated that diffuse populations of bacteria co-localized with regions of tumor necrosis and cell death. Most interestingly, while there was minimal spread of bacteria to healthy non-target tissues, translocation of the bacteria did occur to regions of liver metastases and secondary papilloma tumors, suggesting a mechanism for diffuse treatment of known and unknown metastases following the initial treatment of the primary tumor. Together these studies demonstrate that cytotoxic bacterial therapy is an effective candidate strategy to circumvent the difficulties in systemic treatment of PDAC. Citation Format: Amanda R. Decker, Tetsuhiro Harimoto, Steve A. Sastra, Tal Danino, Kenneth P. Olive. Bacterial cytotoxin therapy limits tumor growth for pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr PO-033.

EXTH-13. LOCAL DELIVERY OF AN IL-15 SUPERAGONIST USING A REPLICATING RETROVIRUS SIGNIFICANTLY IMPROVES SURVIVAL AND LYMPHOCYTE INFILTRATION IN POORLY IMMUNOGENIC MURINE GLIOBLASTOMA MODELS

Abstract Glioblastoma (GBM) leads to severe systemic and local immunosuppression, and immunotherapies have had limited clinical success. Here, we evaluated the treatment efficacy of RLI, a superagonist of T-cell activator IL-15, delivered to tumor cells using a tumor-selective retroviral replicating vector (RRV) in the syngeneic murine SB28 and Tu2449 GBM models, which are both engineered to be poorly immunogenic with low-mutational burden and known resistance to immunotherapy, and hence more accurate biomimetic models of human GBM. RRV-RLI replicated and spread effectively in cultured murine GBM cells with robust production of functional RLI (165.4 ± 5.3 ng/mL). Stereotactic injection of RRV-RLI into pre-established intracerebral SB28 tumors significantly reduced tumor growth on bioluminescent imaging, and increased median survival compared to control mice (55 vs. 19 days, p=0.002), leading to long-term survival in 12% of treated mice. In the Tu2449 model, imaging results showed complete eradication of intracerebral tumors after RRV-RLI treatment, with long-term survival (median not reached) in &amp;gt; 85% of treated mice, compared to a median survival of 12.5 days in control mice (p=0.001). RRV-RLI treated tumors showed significantly increased CD8 T-cell infiltration, without altering immunosuppressive cell populations. Similarly, broad anti-tumor inflammatory changes, including increased expression of genes involved in T-cell activation and killing, were observed in the NanoString nCounter platform using a 770-gene panel representing various immune cell types. Notably, RLI was not detected in the blood of treated mice, and tumor-localized RRV-RLI gene delivery showed no adverse systemic immune effects in either model. In summary, RRV-mediated RLI immunotherapy results in immunostimulatory and pro-inflammatory changes to the tumor microenvironment and achieves a significant survival benefit in two poorly immunogenic syngeneic murine models of GBM. This tumor-localized immunomodulatory gene therapy has the potential to safely reverse the T-cell depleted immunophenotype of GBM.

EXTH-61. MODULATION OF THE IL-27 RECEPTOR SIGNALING PATHWAY IN GLIOBLASTOMA AND ONCOLYTIC VIROTHERAPY

Abstract Glioblastoma (GBM) is the most common primary malignant brain tumor in adults with median overall survival of 14-16 months. Glioblastoma progression involves multiple immunosuppressive pathways hindering the success of cancer immunotherapy. Oncolytic virotherapy is a promising approach to reprogram the glioblastoma microenvironment and restore anti-tumor immunity. Interleukin (IL)-27 receptor signaling pathway regulates development of effector T cells, IL-10 producing T regulatory type 1 (Tr1) cells and induction of co-inhibitory receptors associated with T cell exhaustion in cancer. In this study, we sought to tackle local and systemic GBM-induced immunosuppression using the novel rQNestin34.5v2 oncolytic herpes simplex virus type-1 (HSV-1), engineered to selectively replicate in glioma cells together with genetic disruptions of the IL-27 receptor signaling pathway. The antitumor activity of HSV-1 rQNestin34.5v2 was evaluated in IL-27ra-/- and wild-type C57BL/6 mice harboring orthotopic CT-2A and GL261 glioblastoma and in athymic nude mice harboring orthotopic patient derived glioblastoma xenografts (PDXs) selected from patients that had been treated in a clinical trial of intratumoral administration of HSV-1 rQNestin34.5v2 (ClinicalTrials.gov: NCT03152318). HSV-1 rQNestin34.5v2 exhibited superior capacity to infect glioma cells in vitro triggering release of proinflammatory cytokines and inducing immunogenic cell death in infected cells. Immune phenotyping of GL261 and CT-2A gliomas revealed astrocytes and microglia express the highest levels of IL-27R. Lack of IL-27R signaling decreased expression of the co-inhibitory receptors PD-1 and Tim-3 on circulating CD4+ T cells suggesting altered CD4+ T cell responses. In the tumor microenvironment, lack of IL-27R signaling decreased immune suppression as evidenced by reduced interleukin (IL)-10 secretion by glioma cells. Despite positive functional modifications on CD4+ T cells, global lack of IL-27R signaling promoted tumor growth accompanied by increased circulating myeloid derived suppressor cells (MDSCs) in the GL261 model. Experiments to address the immunoregulatory role of IL-27R signaling during HSV-1 rQNestin34.5v2 virotherapy-induced glioma tissue destruction are ongoing.

Blockade of Tigit on AML-Derived M2 Macrophages Results in Reprograming into the M1 Phenotype and Enhances CD47-Mediated Phagocytosis

Blockade of Tigit on AML-Derived M2 Macrophages Results in Reprograming into the M1 Phenotype and Enhances CD47-Mediated Phagocytosis

Galectins in Glioma: Current Roles in Cancer Progression and Future Directions for Improving Treatment.

Simple SummaryGlioblastomas are among the most common and aggressive brain tumors. The high rate of recurrence and mortality associated with this cancer underscores the need for the development of new therapeutical targets. Galectins are among the new targets that have attracted the attention of many scientists working in the field of cancer. They form a group of small proteins found in many tissues where they accomplish various physiological roles, including regulation of immune response and resistance to cell death. In many types of cancer, however, production of abnormally high levels of galectins by cancer cells can be detrimental to patients. Elevated levels of galectins can, for example, suppress the ability of the host’s immune system to kill cancer cells. They can also provide cancer cells with resistance to drugs-induced cell death. Here, we review the recent progress that has contributed to a better understanding of the mechanisms of actions of galectins in glioblastoma. We also discuss recent development of anti-galectin drugs and the challenges associated with their use in clinical settings, with particular attention to their role in reducing the efficacy of immunotherapy, a promising treatment that exploits the capacity of the immune system to recognize and kill cancer cells.Traditional wisdom suggests that galectins play pivotal roles at different steps in cancer progression. Galectins are particularly well known for their ability to increase the invasiveness of cancer cells and their resistance to drug-induced cell death. They also contribute to the development of local and systemic immunosuppression, allowing cancer cells to escape the host’s immunological defense. This is particularly true in glioma, the most common primary intracranial tumor. Abnormally high production of extracellular galectins in glioma contributes to the establishment of a strong immunosuppressive environment that favors immune escape and tumor progression. Considering the recent development and success of immunotherapy in halting cancer progression, it is logical to foresee that galectin-specific drugs may help to improve the success rate of immunotherapy for glioma. This provides a new perspective to target galectins, whose intracellular roles in cancer progression have already been investigated thoroughly. In this review, we discuss the mechanisms of action of galectins at different steps of glioma progression and the potential of galectin-specific drugs for the treatment of glioma.

The immune checkpoint VISTA exhibits high expression levels in human gliomas and associates with a poor prognosis

In human gliomas, anti-tumor T cell responses are inhibited through induction of local and systemic immunosuppression. Immune checkpoint blockade is proving to be a success in several types of cancers. However, many studies reported that the treatment of glioblastoma patients with anti-CTLA-4 or anti-PD-1 has no survival benefit compared to standard chemotherapy. This study aimed to investigate the expression and role of VISTA, a newly described immune checkpoint regulator, in human gliomas. mRNA expression was assessed in a total of 87 samples from glioma patients. 57 glioma tissues were taken at different grades. 20 peripheral blood mononuclear cells (PBMC) samples were taken before surgery and ten after surgery, all from the same set of patients. As for the control, ten specimens of PBMC were taken from healthy donors. Protein expression using immunohistochemistry was performed for 30 patients. The Cancer Genome Atlas (TCGA) data set, was also used to investigate VISTA expression through analysis of RNA-seq data of 667 glioma patients. In the Moroccan cohort, VISTA gene expression was significantly upregulated in glioma tissues related to PBMC of healthy donors. This high expression was specific to patient tissues since VISTA expression in PBMC was low when assessed either before or after surgery. Besides, VISTA exhibited higher expression levels in grade III/IV relative to grade I/II glioma patients. Interestingly, VISTA correlated positively with PD-1 expression. PD-1 also showed elevated expressions in higher glioma grades. The TCGA cohort corroborated these observations. Indeed, VISTA was also found to be strongly expressed in high grades. It was positively correlated with other critical immune checkpoints. Finally, increased VISTA transcript levels were associated with weak overall survival of glioma patients. Our study highlighted a correlation between high levels of VISTA expression and poor prognosis in glioma patients. VISTA might be involved in glioma progression and could be considered as a possible new therapeutic target, especially in advanced gliomas.

Human prostate cancer bone metastases have an actionable immunosuppressive microenvironment.

Bone metastases are devastating complications of cancer. They are particularly common in prostate cancer (PCa), represent incurable disease, and are refractory to immunotherapy. We seek to define distinct features of the bone marrow (BM) microenvironment by analyzing single cells from bone metastatic prostate tumors, involved BM, uninvolved BM, and BM from cancer-free, orthopedic patients, and healthy individuals. Metastatic PCa is associated with multifaceted immune distortion, specifically exhaustion of distinct Tcell subsets, appearance of macrophages with states specific to PCa bone metastases. The chemokine CCL20 is notably overexpressed by myeloid cells, as is its cognate CCR6 receptor on Tcells. Disruption of the CCL20-CCR6 axis in mice with syngeneic PCa bone metastases restores Tcell reactivity and significantly prolongs animal survival. Comparative high-resolution analysis of PCa bone metastases shows a targeted approach for relieving local immunosuppression for therapeutic effect.

Advances in Drug Delivery and Theranostics

Advances in Drug Delivery and Theranostics

Designing Clinical Trials for Combination Immunotherapy: A Framework for Glioblastoma.

Immunotherapy has revolutionized treatment for many hard-to-treat cancers but has yet to produce significant improvement in outcomes for patients with glioblastoma. This reflects the multiple and unique mechanisms of immune evasion and escape in this highly heterogeneous tumor. Glioblastoma engenders profound local and systemic immunosuppression and is remarkably effective at inducing T-cell dysfunction, posing a challenge to any immunotherapy-based approach. To overcome these mechanisms, multiple disparate modes of immune-oriented therapy will be required. However, designing trials that can evaluate these combinatorial approaches requires careful consideration. In this review, we explore the immunotherapy resistance mechanisms that have been encountered to date and how combinatorial approaches may address these. We also describe the unique aspects of trial design in both preclinical and clinical settings and consider endpoints and markers of response best suited for an intervention involving multiple agents.