V-domain Ig-containing Suppressor Of T Cell Activation Research Articles

VISTA/CTLA4/PD1 coexpression on tumor cells confers a favorable immune microenvironment and better prognosis in high-grade serous ovarian carcinoma.

Immunotherapy by blocking immune checkpoints programmed death/ligand (PD1/PDL1) and cytotoxic T-lymphocyte-associated protein 4(CTLA4) has emerged as new therapeutic targets in cancer. However, their efficacy has been limited due to resistance. A new- checkpoint V-domain Ig-containing suppressor of T cell activation (VISTA) has appeared, but the use of its inhibition effect in combination with antibodies targeting PDL1/PD1and CTLA4 has not been reported in ovarian cancer. In this study, we investigated the expressions of VISTA, CTLA4, and PDL1 using immunohistochemistry (IHC)on 135 Formalin-Fixed Paraffin-Embedded (FFPE)tissue samples of High-grade serous carcinoma (HGSOC). VISTA, CTLA4, PDL1, PD1, CD8, CD4, and FOXP3 mRNA extracted from 429 patients with ovarian cancer in the Cancer Genome Atlas (TCGA) database was included as a validation cohort. Correlations between these checkpoints, tumor-infiltrating- lymphocytes (TILs), and survival were analyzed. CTLA4 was detectable in 87.3% of samples, VISTA in 64.7%, PD1 in 56.7%, and PDL1 in 48.1%. PDL1 was the only tested protein associated with an advanced stage (p=0.05). VISTA was associated with PDL1, PD1, and CTLA4 expressions (p=0.005, p=0.001, p=0.008, respectively), consistent with mRNA level analysis from the TCGA database. Univariate analyses showed only VISTA expression (p=0.04) correlated with overall survival (OS). Multivariate analyses showed that VISTA expression (p=0.01) and the coexpression of VISTA+/CTLA4+/PD1+ (p=0.05) were associated with better OS independently of the clinicopathological features. Kaplan-Meier analysis showed that the coexpression of the VISTA+/CTLA4+/PDL1+ and VISTA+/CTLA4+/PD1+ checkpoints on tumor cells (TCs)were associated with OS (p=0.02 and p<0.001; respectively). VISTA+/CTLA4+/PD1+ in TCs and CD4+/CD8+TILswere associated with better 2-yer OS. This correlation may refer to the role of VISTA as a receptor in the TCs and not in the immune cells. Thus, targeting combination therapy blocking VISTA, CTLA4, and PD1 could be a novel and attractive strategy for HGSOC treatment, considering the ambivalent role of VISTA in the HGSOC tumor cells.

T lymphocytes induce human cancer cells derived from solid malignant tumors to secrete galectin-9 which facilitates immunosuppression in cooperation with other immune checkpoint proteins

BackgroundGalectin-9 is a member of the family of lectin proteins and crucially regulates human immune responses, particularly because of its ability to suppress the anticancer activities of T lymphocytes and...

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<h3>Background</h3> Cancers affect a large number of people worldwide and sometimes have mortality rates of over 90% (pancreatic ductal adenocarcinoma (PDAC), high grade glioblastomas). Currently, immunotherapeutic strategies fail in number of cancer cases due to a lack of understanding of the molecular mechanisms operated by these cancers to evade immune surveillance. Recent evidence demonstrated that the protein galectin-9 is highly expressed in majority of cancer cells. Importantly, this protein is a crucial part of the immune evasion machinery operated by human malignant tumours. Understanding the biochemistry of this immune evasion machinery is required for designing highly efficient and affordable personalised targeted immunotherapy of human cancers. <h3>Materials and Methods</h3> We used, glioblastoma, PDAC, breast and renal cancer cell lines as cancer cell models. Jurkat T lymphocytes, TALL-104 cytotoxic T cells and primary human and mouse CD3-positive T lymphocytes were employed for immune evasion studies. C57 BL16 mice were used for <i>in vivo</i> studies. Western blot analysis, on-cell and in-cell Western, ELISA, qRT-PCR, chromatin immunoprecipitation (ChIP) assays as well as a variety of biochemical tests were used to conduct the studies. <h3>Results</h3> We found that T cells trigger galectin-9 expression and secretion (in most cases requires Tim-3 protein (T cell immunoglobulin and mucine domain containing protein 3)) in a variety of human cancer cells including but not limited to glioblastoma, PDAC, breast and renal cancers. Galectin-9 triggers exhaustion and often death of cytotoxic T cells. Other immune checkpoint proteins including VISTA (V-domain Ig-containing suppressor of T cell activation) and PD-L1 (ligand of programmed cell death protein 1) promote apoptotic death of cytotoxic T cells induced by galectin-9. Activity of T helpers, required to induce cytotoxic T lymphocytes is also suppressed by galectin-9 in cooperation with VISTA and PD-L1. We discovered that expression of all these immune checkpoint proteins is differentially controlled by the autocrine transforming growth factor beta type 1 (TGF-β)-Smad3 pathway as well as several types of interferons. <h3>Conclusions</h3> The immune evasion machinery triggered by TGF-β-Smad3 and interferon pathways and operated by galectin-9, Tim-3, VISTA and PD-L1 should be considered as a potential target for personalised immunotherapy of cancer. Importantly, blood and tumour sample tests could help mapping the exact immune evasion networks employed by each tumour and the pathways responsible to produce respective immune checkpoint proteins. As such, personalised targeted immunotherapy could be adapted. Further investigations required to map the immune evasion machinery for each type of cancer and design the best targets for personalised immunotherapy of human malignancies. <h3>Disclosure Information</h3> <b>V.V. Sumbayev:</b> None. <b>I. Yasinska:</b> None. <b>S. Schlichtner:</b> None. <b>G.S. Lall:</b> None. <b>E. Fasler-Kan:</b> None. <b>B.F. Gibbs:</b> None.

Expression and clinical significance of VISTA and PD-L1 in adrenocortical carcinoma.

Adrenocortical carcinoma (ACC) is a rare malignancy with a poor prognosis and challenging management. The present study aimed to investigate the expression of programmed death ligand-1 (PD-L1) and V-domain Ig-containing suppressor of T cell activation (VISTA) in ACC and their associations with clinicopathological features and survival outcomes. Immunohistochemistry was performed on formalin-fixed paraffin-embedded specimens from 54 ACC patients. Chi-square/Fisher's exact tests or independent samples t/Mann-Whitney U tests were performed to assess correlations between immunoscores and clinicopathological parameters. The Kaplan-Meier method and Cox regression were conducted for survival analysis and to identify independent predictors of overall (OS) and disease-free (DFS) survival. Results showed that VISTA was expressed in tumor cells (TCs) and tumor-infiltrating immune cells (TICs) in 81.5% (44/54) and 40.7% (22/54) of the patients, respectively. PD-L1 positivity was found in either TCs or TICs in 11.1% (6/54) of the patients. Patients with positive VISTA expression in TCs had a higher tumor stage (56.9% vs 20%, P = 0.036) and Ki-67 index (30.50 ± 23.51% vs 14.76 ± 11.75%, P = 0.006). However, PD-L1 positivity in either TCs or TICs had no association with patient clinicopathological features. A higher VISTA expression intensity, a larger area and a higher immunoscore were associated with increased risks of disease progression and overall mortality, but PD-L1 expression in TCs or TICs was not associated with OS or DFS. In conclusion, positive TC VISTA expression was correlated with pathological parameters related to malignancy in ACC patients. This finding provides novel evidence of the value of VISTA, in addition to PD-L1, as an immunotherapeutic target in ACC.

Expression of the Immune Checkpoint Protein VISTA Is Differentially Regulated by the TGF-β1 - Smad3 Signaling Pathway in Rapidly Proliferating Human Cells and T Lymphocytes.

Immune checkpoint proteins play crucial roles in human embryonic development but are also used by cancer cells to escape immune surveillance. These proteins and biochemical pathways associated with them form a complex machinery capable of blocking the ability of cytotoxic immune lymphoid cells to attack cancer cells and, ultimately, to fully suppress anti-tumor immunity. One of the more recently discovered immune checkpoint proteins is V-domain Ig-containing suppressor of T cell activation (VISTA), which plays a crucial role in anti-cancer immune evasion pathways. The biochemical mechanisms underlying regulation of VISTA expression remain unknown. Here, we report for the first time that VISTA expression is controlled by the transforming growth factor beta type 1 (TGF-β)-Smad3 signaling pathway. However, in T lymphocytes, we found that VISTA expression was differentially regulated by TGF-β depending on their immune profile. Taken together, our results demonstrate the differential biochemical control of VISTA expression in human T cells and various types of rapidly proliferating cells, including cancer cells, fetal cells and keratinocytes.

Analysis of the immune checkpoint V-domain Ig-containing suppressor of T-cell activation (VISTA) in endometrial cancer

V-domain Ig-containing suppressor of T-cell activation (VISTA) is a novel immune checkpoint protein and a potential immunotherapeutic target. However, its expression in endometrial cancer has not been clearly defined. This study aimed to investigate VISTA expression and determine its associations with clinicopathological features, molecular subtypes, programmed cell death-ligand 1 (PD-L1) expression, CD8+ T-cell count, and survival in a cohort of 839 patients with endometrial cancer. Using direct sequencing of the polymerase epsilon (POLE) exonuclease domain and immunohistochemistry for mismatch repair (MMR) proteins and p53, we stratified endometrial cancers into four molecular subtypes: POLE ultramutated, MMR-deficient, p53-mutant, and nonspecific molecular profile (NSMP). PD-L1, CD8, and VISTA were detected via immunohistochemistry. VISTA was expressed in the immune cells of 76.6% (643/839) of the samples and in the tumor cells of 6.8% (57/839). VISTA positivity in the immune cells was frequent in tumors staged I–III, those with positive PD-L1 or high CD8+ T-cell density, and those representing POLE ultramutated and MMR-deficient subtypes. Furthermore, VISTA positivity in tumor cells was more frequent in clear cell carcinoma samples. VISTA in immune cells was associated with improved survival in the entire cohort as well as in the endometrioid histology, stage I, PD-L1-negative, MMR-deficient, MMR-proficient, and high and low number of CD8+ T-cell-infiltrated tumor subgroups. VISTA in immune cells was a prognostic factor overall, as well as in patients with endometrioid histology, independent of molecular subtype or CD8+ T-cell density. The data produced by this study, which was the largest to focus on VISTA expression in patients with endometrial cancer to date, suggest that VISTA is a predictor of improved survival.

Ligand-Receptor Interactions of Galectin-9 and VISTA Suppress Human T Lymphocyte Cytotoxic Activity.

Acute myeloid leukemia (AML), a blood/bone marrow cancer, is a severe and often fatal malignancy. AML cells are capable of impairing the anti-cancer activities of cytotoxic lymphoid cells. This includes the inactivation of natural killer (NK) cells and killing of T lymphocytes. Here we report for the first time that V-domain Ig-containing suppressor of T cell activation (VISTA), a protein expressed by T cells, recognizes galectin-9 secreted by AML cells as a ligand. Importantly, we found that soluble VISTA released by AML cells enhances the effect of galectin-9, most likely by forming multiprotein complexes on the surface of T cells and possibly creating a molecular barrier. These events cause changes in the plasma membrane potential of T cells leading to activation of granzyme B inside cytotoxic T cells, resulting in apoptosis.

Expression and clinical significance of PD-L1, B7-H3, B7-H4 and VISTA in craniopharyngioma.

BackgroundCraniopharyngioma (CP) is a common refractory tumor of the central nervous system. However, little is known about the expression and clinical significance of B7 family ligands/receptors in CP patients. Thus, we conducted the present study to address this issue in a cohort of 132 CP cases.MethodsWe mapped and quantified the expression of B7 family ligands/receptors molecules programmed cell death ligand 1 (PD-L1), B7-H3, B7-H4 and V-domain Ig-containing suppressor of T cell activation (VISTA) in 89 adamantinomatous-type CP and 43 papillary-type CP samples using immunohistochemistry and immunofluorescence. Associations between the marker levels, clinicopathological variables and survival were evaluated.ResultsThe positive rates of PD-L1, B7-H3, B7-H4 and VISTA in the cohort of 132 CP cases were 76.5%, 100%, 40.2% and 80.3%, respectively. The cut-off values of PD-L1, B7-H3, B7-H4 and PD-L1 expression were determined by survival receiver operating characteristic (ROC) package, which was 70, 182, 0 and 20, respectively. Elevated expressions of PD-L1, B7-H3, B7-H4 and VISTA were significantly associated with some clinicopathological characteristics. Kaplan-Meier analysis indicated that higher VISTA expressions correlated with better overall survival (OS) and progression-free survival (PFS) (p=0.0053 and p=0.0066, respectively). Multivariate Cox regression analysis indicated that VISTA was an independent prognostic factor for OS (p=0.018) but not for PFS (p=0.898).ConclusionsWe found variable expression of PD-L1, B7-H3, B7-H4 and VISTA proteins in CPs. The results suggest that the expression level of VISTA may be used as an important indicator to predict the OS and PFS of CPs. B7 family ligands/receptors could be potential immunotherapeutic targets when treating CPs.

Prognostic value of VISTA in solid tumours: a systematic review and meta-analysis

In the last few years, V-domain Ig-containing suppressor of T cell activation(VISTA) has been reported as a prognostic biomarker in articles including various solid tumours. However, their conclusions have been controversial. For this reason, we performed this meta-analysis to further verify the prognostic value of VISTA in solid tumours. All relevant literature was identified from PubMed, Embase, the Cochrane Library and Web of Science. Ten studies, including 2, 440 patients, were eligible for the analysis. The pooled results showed that high expression of VISTA was associated with favourable overall survival (OS) than that seen with low expression of VISTA (7 studies, hazard ratio (HR) = 0.75, 95% confidence interval (CI): 0.66–0.86, P < 0.001). In addition, high expression of VISTA significantly correlated with high numbers of CD8 (+) tumour infiltrating lymphocytes (TILs) (3 studies, risk ratio (RR) = 1.80, 95% CI: 1.41–2.31, P < 0.001). In conclusion, these results indicate that VISTA is a potential prognostic biomarker in solid tumours.

Defining the Signature of VISTA on Myeloid Cell Chemokine Responsiveness.

The role of negative checkpoint regulators (NCRs) in human health and disease cannot be overstated. V-domain Ig-containing Suppressor of T-cell Activation (VISTA) is an Ig superfamily protein predominantly expressed within the hematopoietic compartment and has been studied for its role in the negative regulation of T cell responses. The findings presented in this study show that, unlike all other NCRs, VISTA deficiency dramatically impacts on macrophage cytokine and chemokine production, as well as the chemotactic response of VISTA-deficient macrophages. A select group of inflammatory chemokines, including CCL2, CCL3, CCL4, and CCL5, was strikingly elevated in culture supernatants from VISTA KO macrophages. VISTA deficiency also altered chemokine receptor recycling and profoundly disrupted myeloid chemotaxis. The impact of VISTA deficiency on chemotaxis in vivo was apparent with the reduced ability of both KO macrophages and MDSCs to migrate to the tumor microenvironment. This is the first demonstration of an NCR impacting on myeloid mediator production and chemotaxis, and will guide the use of anti-VISTA therapeutics to manipulate the chemotaxis of inflammatory macrophages or immunosuppressive MDSCs in inflammatory diseases and cancer.

Expression of the checkpoint receptors LAG-3, TIM-3 and VISTA in peripheral T cell lymphomas

AimsPeripheral T cell lymphomas represent approximately 10%–15% of non-Hodgkin lymphomas and are characterised by an aggressive clinical courses and poor outcomes. Ligands provided by constituents of the tumour microenvironment engage...

V-domain Ig-containing suppressor of T-cell activation (VISTA), a potentially targetable immune checkpoint molecule, is highly expressed in epithelioid malignant pleural mesothelioma.

V-domain Ig-containing suppressor of T-cell activation (VISTA) is an immune checkpoint gene that inhibits anti-tumor immune responses. Since most malignant pleural mesotheliomas do not respond to anti-programmed cell death(-ligand)1 (PD-(L)1)/cytotoxic T-lymphocyte-associated protein 4 (CTLA4) therapy and given the recent finding of The Cancer Genome Atlas Study that pleural mesothelioma displays the highest expression of VISTA among all cancers studied, we examined VISTA expression in a large pleural mesothelioma cohort. VISTA and PD-L1 immunohistochemistry were performed on tissue microarray of immunotherapy-naive pleural mesotheliomas (254 epithelioid, 24 biphasic and 41 sarcomatoid) and ten whole-tissue sections of benign pleura (VISTA only). Percentages of tumor and inflammatory cells with positive staining were assessed. Optimal prognostic cutoff percentages were determined using maximally selected rank statistics. Overall survival was evaluated using Kaplan-Meier methods and Cox proportional hazard analysis. All benign mesothelium expressed VISTA. Eighty-five percent of 319 and 38% of 304 mesotheliomas expressed VISTA and PD-L1 (88% and 33% of epithelioid, 90% and 43% of biphasic, and 42% and 75% of sarcomatoid), respectively. Median VISTA score was significantly higher in epithelioid (50%) (vs. biphasic [20%] and sarcomatoid [0]) (p < 0.001), while median PD-L1 score was significantly higher in sarcomatoid tumors (20%) (vs. biphasic and epithelioid [both 0%]) (p < 0.001). VISTA and PD-L1 were expressed in inflammatory cells in 94% (n = 317) and 24% (n = 303) of mesothelioma, respectively. Optimal prognostic cutoffs for VISTA and PD-L1 were 40% and 30%, respectively. On multivariable analysis, VISTA and PD-L1 expression in mesothelioma were associated with better and worse overall survival (p = 0.001 and p = 0.002), respectively, independent of histology. In a large cohort of mesothelioma, we report frequent expression of VISTA and infrequent expression of PD-L1 with favorable and unfavorable survival correlations, respectively. These findings may explain poor responses to anti-PD-(L)1 immunotherapy and suggest VISTA as a potential novel target in pleural mesothelioma.

Inhibition of allogeneic islet graft rejection by VISTA-conjugated liposome

The Ig superfamily member V-domain Ig-containing suppressor of T-cell activation (VISTA) is a negative regulator with broad-spectrum activities and has reported that blockade of VISTA or combination with other negative checkpoint receptors sufficiently break tumor tolerance. However, it remains unclear whether VISTA could induce allogeneic T-cell hyporesponsiveness and inhibit allograft rejection. Here we found VISTA treatment significantly inhibited lymphocyte proliferation and activation in allogeneic MLR assay through impairing SYK-VAV pathway. Interestingly, though neither VISTA protein nor VISTA-Fc fusion protein administration exerted satisfactory immunosuppressive effect on allograft survival due to their short half-life in circulation, this problem was solved by conjugating VISTA protein on liposome by biotin-streptavidin system, which markedly prolonged its circulating half-life to 60 h. With islet transplant model, administration of VISTA-conjugated liposome could markedly prolong allograft survival by inhibition of SYK-VAV pathway, thus maintained the normal blood glucose level of recipients during treatment period. The results indicate VISTA is a promising therapeutic target to treat allograft rejection of islet transplantation.

Abstract 4046: The different immune evasion mechanisms in human prostate cancer

Abstract Cancer development is associated with a number of genetic and epigenetic alternations. Normally, these alterations are detected by the immune system in a process called immune surveillance, where cancer cell killing is mediated by cytotoxic T lymphocytes (CTL) and natural killer cells (NK cells). Yet, tumor progression and development indicate that cancer cells have acquired mechanisms to avoid immune destruction. Various immune evasion mechanisms have been reported before such as impaired antigen presentation and activation of CTL and NK cells, immunosuppression, and induction of tolerance. Although current treatment methods are shifting towards more targeted strategies in prostate cancer, such as immunotherapy, a better understanding of the cancer-immune interactions and immune evasion mechanisms is yet to be established. More immunotherapies are being developed and approved by the FDA for treating cancer. In prostate cancer, Sipuleucel-T, an autologous cellular immunotherapy, was approved by FDA for the treatment of asymptomatic or minimally symptomatic metastatic castrate resistant (hormone refractory) prostate cancer. Intensive investigation on other immunotherapies is ongoing in prostate cancer. These include blockade of negative checkpoint regulators (PD-1, CTLA4) and Ig superfamily member V-domain Ig-containing suppressor of T-cell activation (VISTA), chimeric antigen receptor-modified T (CAR-T) cells against prostate lineage-unique proteins (PLUPs), and monoclonal antibodies targeting immunoinhibitory molecules. However, the optimal choice of treatment for a prostate cancer patient needs to target their specific mechanisms of immune evasion, which are poorly studied. In this study, we will use The Cancer Genome Atlas RNA-seq data to check for immune evasion gene expression in prostate cancer patients to identify at the different mechanisms by which cancer avoids immune destruction. We will use a sequential biclustering algorithm developed by our group, to group prostate cancer patients based on their similarities in immune evasion gene expression. A similar unpublished work was done by our group on breast cancer where we identified 7 different groups of patients, each with different mechanisms or combination of evasion mechanism. We also showed that triple negative breast cancer can be immunogenic and non-immunogenic. This group-based identification of evasion mechanisms will not only provide a better understanding of the different immune evasion mechanisms in prostate cancer, but will also shed light on potential combinations of mechanism. This in turn, will help guide the choice of single and combined immunotherapeutic approches. Citation Format: Mayassa J. Bou-Dargham, Yuhang Liu, Qing-Xiang Amy Sang, Jinfeng Zhang. The different immune evasion mechanisms in human prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4046.

VISTA Deficiency Accelerates the Development of Fatal Murine Lupus Nephritis.

The targeting of negative checkpoint regulators as a means of augmenting antitumor immune responses is now an increasingly used and remarkably effective approach to the treatment of several human malignancies. The negative checkpoint regulator VISTA (V-domain Ig-containing suppressor of T cell activation; also known as programmed death 1 homolog or as death domain 1α) suppresses T cell responses and regulates myeloid activities. We proposed that exploitation of the VISTA pathway is a novel strategy for the treatment of human autoimmune disease, and therefore we undertook this study to determine the impact of VISTA genetic deficiency on lupus development in a lupus-prone mouse strain. To evaluate whether genetic deficiency of VISTA affects the development of lupus, we interbred VISTA-deficient mice with Sle1.Sle3 mice, a well-characterized model of systemic lupus erythematosus (SLE). We demonstrated that the development of proteinuria and glomerulonephritis in these mice, designated Sle1.Sle3 VISTA-/- mice, was greatly accelerated and more severe compared to that in Sle1.Sle3 and C57BL/6 VISTA-/- mice. Analysis of cells from Sle1.Sle3 VISTA-/- mice showed enhanced activation of splenic CD4+ T cells and myeloid cell populations. No increase in titers of autoantibodies was seen in Sle1.Sle3 VISTA-/- mice. Most striking was a significant increase in proinflammatory cytokines, chemokines, and interferon (IFN)-regulated genes associated with SLE, such as IFNα, IFNγ, tumor necrosis factor, interleukin-10, and CXCL10, in Sle1.Sle3 VISTA-/- mice. This study demonstrates for the first time that loss of VISTA in murine SLE exacerbates disease due to enhanced myeloid and T cell activation and cytokine production, including a robust IFNα signature, and supports a strategy of enhancement of the immunosuppressive activity of VISTA for the treatment of human lupus.

Immunoregulatory functions of VISTA.

Utilization of negative checkpoint regulators (NCRs) for cancer immunotherapy has garnered significant interest with the completion of clinical trials demonstrating efficacy. While the results of monotherapy treatments are compelling, there is increasing emphasis on combination treatments in an effort to increase response rates to treatment. One of the most recently discovered NCRs is VISTA (V-domain Ig-containing Suppressor of T cell Activation). In this review, we describe the functions of this molecule in the context of cancer immunotherapy. We also discuss factors that may influence the use of anti-VISTA antibody in combination therapy and how genomic analysis may assist in providing indications for treatment.