Checkpoint Cytotoxic T Lymphocyte Antigen-4 Research Articles

The Expression of Immune Checkpoint Inhibitors PDL-1 and CTLA-4 in Pancreatic Versus Non-Pancreatic Periampullary Adenocarcinoma: An Immunohistochemical Study

Background: Periampullary cancers constitute about 5% of gastrointestinal malignancies. They are comprised of tumors of diverse origins and are generally subdivided into pancreatic and non-pancreatic carcinomas. Immune checkpoint regulators, cytotoxic T-lymphocyte antigen 4 (CTLA-4), and the programmed cell death ligand-1 (PDL-1) have emerged as promising new targets for cancer therapeutics. Aim: This study aims to determine the possible role of immune checkpoint inhibitors PDL-1 and CTLA-4 in periampullary carcinoma of pancreatic and non-pancreatic adenocarcinoma subtypes, in an attempt to investigate the possible introduction of their related immunotherapy in the management of these tumors. Materials and Methods: Expression of immune inhibitory molecules was examined by immunohistochemistry in 40 cases including (20) pancreatic adenocarcinoma and (20) non-pancreatic adenocarcinoma. The association between markers and clinicopathological parameters was evaluated. Results: Statistically significant differences in the immunoexpression of both CTLA-4 and PDL-1 in the two studied groups were noticed with higher expression in non-pancreatic adenocarcinoma in relation to pancreatic adenocarcinoma (P=0.004, P=0.008) respectively. PDL-1 expression was positive in 15% and 55% of pancreatic and non-pancreatic adenocarcinoma cases, respectively with a significant correlation with lymph nodes metastasis in non-pancreatic adenocarcinoma cases. CTLA-4 was positive in 20% of pancreatic carcinoma with a significant correlation with lymph node metastasis, perineural invasion and T stage. In non-pancreatic periampullary adenocarcinoma, CTLA-4 was positive in 65% of cases with a significant association with lymph nodes metastasis and T stage. Conclusions: Immunotherapy using anti-PDL-1 and CTLA-4 are proposed as a novel promising management tool in non-pancreatic periampullary adenocarcinoma not in pancreatic adenocarcinomas.

AML-273: The Immune Checkpoints CTLA-4 and LAG-3 Expression is Up-Regulated in Acute Myeloid Leukemia

Context One of the fundamental hallmarks of cancer is the incapacity of the immune system to eliminate malignancy. Cytotoxic T lymphocyte antigen-4 (CTLA-4) and lymphocyte activation gene-3 (LAG-3) are considered major inhibitory immune checkpoints expressed on T cells. Objective To investigate mRNA expression of CTLA-4 and LAG-3, as well as their diagnostic and prognostic value in acute myeloid leukemia (AML) patients. Design and Setting we conducted case control study on de novo AML patients recruited from Internal medicine department, clinical hematology and stem cell transplantation unit, Ain Shams University Hospitals, Cairo, Egypt. The study was held from November 2018 to February 2019 with one year follow up of enrolled cases. Patients and Participants A total of 60 newly diagnosed AML patients and 15 healthy controls were recruited. Results Significantly up-regulated CTLA-4 (P= 0.005) and LAG-3 (P = 0.02) mRNA expressions were found in AML patients as compared with the healthy control group. AML patients with unfavorable prognosis also showed significant up-regulation of CTLA-4 (P= 0.006) and LAG-3 (P = 0.001) mRNA expressions as compared to those with favorable prognosis. Moreover, multiple stepwise linear regression analysis confirmed that patients prognosis was an independent predictor of both CTLA-4 (P = 0.003) and LAG-3 (P 0.619) as well as moderate predictive value for unfavorable prognosis (AUC = 0.760, sensitivity = 70%, specificity =100% for a cut-off probability >0.617). Conclusions It is clear from this current study that both CTLA-4 and LAG-3 may be promising prognostic markers in AML patients.

Ipilimumab and Its Derived EGFR Aptamer-Based Conjugate Induce Efficient NK Cell Activation against Cancer Cells.

The immune checkpoint CTLA-4 (cytotoxic T-lymphocyte-antigen 4), which inhibits the co-stimulatory CD28 signal on T cells, has been recently found expressed on other cell populations, such as tumor and natural killer (NK) cells. We tested for the first time the effects of ipilimumab, the human anti-CTLA4 mAb in clinical use, on these cells and found that it inhibits the growth of tumor cells expressing CTLA-4 also in the absence of lymphocytes, and efficiently activates NK cells, thus suggesting an important unexplored role of NK cells in ipilimumab-modulated immune responses. Interestingly, the epidermal growth factor receptor (EGFR) has been shown to play a key role in tumor cell escape from immune surveillance, and in cytotoxic T lymphocyte inhibition. Thus, we tested combinatorial treatments of ipilimumab with an anti-EGFR aptamer endowed with anti-tumor activity, and constructed for the first time a novel bispecific immunoconjugate, made up of these two compounds. The novel immunoconjugate binds to the target cells, induces the activation of lymphocytes, including NK cells, and inhibits the growth of tumor target cells more efficiently than the parental compounds, by strongly enhancing the cytotoxic activity of both human peripheral blood mononuclear cells and NK cells against tumor cells.

Autophagy-lysosome inhibitor chloroquine prevents CTLA-4 degradation of T cells and attenuates acute rejection in murine skin and heart transplantation

Background: The immune checkpoint cytotoxic T lymphocyte antigen-4 (CTLA-4), induced upon T cell activation but degraded quickly, has been targeted in the clinical therapy of advanced cancers and autoimmune diseases. However, whether inhibiting CTLA-4 degradation ameliorates transplant rejection remains unknown.Methods: The CTLA-4 expression in activated murine T cells treated with the inhibitors mediating protein degradation was detected by flow cytometry (FCM). CD45.1 mice, which received TEa T cells and underwent heart transplantation, were administrated with the inhibitor. Subsequently, CTLA-4 expression of TEa T cells was analyzed. Murine skin and heart transplantation models were built, then the survival and histopathology of the allografts, and T cell subsets in the spleens of each group were compared.Results: Chloroquine (CQ) was identified as an inhibitor of CTLA-4 degradation, which augmented both surface and total CTLA-4 expression in T cells. It considerably prolonged the skin and heart allograft survival time and reduced the infiltration of inflammatory cells in allografts. Besides decreasing the frequencies of the CD4+ and CD8+ effector T cells, especially IFN-γ producing T cells, CQ also increased the proportion of regulatory T cells in the spleen. The CTLA-4 blockade abrogated the benefits of CQ on the survival of heart allografts. Moreover, CQ enhanced CTLA-4 expression in activated human T cells and reduced the secretion of IFN-γ in human mixed lymphocyte reaction.Conclusion: Targeting CTLA-4 degradation provides a novel means to prevent transplant rejection and induce transplant tolerance.

Antisense targeting of CD47 enhances human cytotoxic T-cell activity and increases survival of micebearing B16 melanoma when combined with anti-CTLA4 and tumor irradiation.

Antibodies targeting the T-cell immune checkpoint cytotoxic T-lymphocyte antigen-4 (CTLA4) enhance the effectiveness of radiotherapy for melanoma patients, but many remain resistant. To further improve response rates, we explored combining anti-CTLA4 blockade with antisense suppression of CD47, an inhibitory receptor on T cells that limit T-cell receptor signaling and killing of irradiated target cells. Human melanoma data from The Cancer Genome Atlas revealed positive correlations between CD47 mRNA expression and expression of T-cell regulators including CTLA4 and its counter receptors CD80 and CD86. Antisense suppression of CD47 on human T cells in vitro using a translational blocking morpholino (CD47m) alone or combined with anti-CTLA4 enhanced antigen-dependent killing of irradiated melanoma cells. Correspondingly, the treatment of locally irradiated B16F10 melanomas in C57BL/6 mice using combined blockade of CD47 and CTLA4 significantly increased the survival of mice relative to either treatment alone. CD47m alone or in combination with anti-CTLA4 increased CD3+ T-cell infiltration in irradiated tumors. Anti-CTLA4 also increased CD3+ and CD8+ T-cell infiltration as well as markers of NK cells in non-irradiated tumors. Anti-CTLA4 combined with CD47m resulted in the greatest increase in intratumoral granzyme B, interferon-γ, and NK-cell marker mRNA expression. These data suggest that combining CTLA4 and CD47 blockade could provide a survival benefit by enhancing adaptive T- and NK-cell immunity in irradiated tumors.

Prognostic factors and outcomes in metastatic uveal melanoma treated with programmed cell death-1 or combined PD-1/cytotoxic T-lymphocyte antigen-4 inhibition

BackgroundUveal melanoma (UM) is an ocular malignancy with high potential for metastatic spread. In contrast to cutaneous melanoma, immunotherapy has not yet shown convincing efficacy in patients with UM. Combined immune checkpoint blockade with checkpoint programmed cell death-1 (PD-1) and checkpoint cytotoxic T-lymphocyte antigen-4 (CTLA-4) inhibition has not been systematically assessed for UM to date. Patients and methodsPatients with metastatic UM treated with either PD-1 inhibitor monotherapy or combined PD-1 inhibitor and ipilimumab (an anti-CTLA-4 monoclonal antibody) were included from 20 German skin cancer centres. Records from 96 cases were analysed for treatment outcomes. Clinical and blood parameters associated with overall survival (OS) or treatment response were identified with multivariate Cox regression and binary logistic regression. ResultsEighty-six patients were treated with PD-1 inhibitors only (n = 54 for pembrolizumab, n = 32 for nivolumab) with a centrally confirmed response rate of 4.7%. Median OS was 14 months for pembrolizumab-treated and 10 months for nivolumab-treated patients (p = 0.765). Fifteen patients were treated with combined immune checkpoint blockade with partial response observed in two cases. Median OS was not reached in this group. Multivariate Cox regression identified Eastern Cooperative Oncology Group (ECOG) performance status (p = 0.002), elevated serum levels of lactate dehydrogenase (LDH) (p = 0.002) and C-reactive protein (CRP) (p = 0.001), and a relative eosinophil count (REC) <1.5% (p = 0.002) as independent risk factors for poor survival. Patients with elevated CRP and LDH and a REC <1.5% were at highest risk for disease progression and death (p = 0.001). ConclusionsBlood markers predict survival in metastatic UM treated with immune checkpoint blockade. Normal serum levels of LDH and CRP and a high REC may help identify patients with better prognosis.

Elevated T cell activation score is associated with improved survival of breast cancer

Immune checkpoints cytotoxic T lymphocyte antigen 4 (CTLA4) and programmed cell death 1 receptor (PD-1) negatively regulate CD8+ T cell functions, impeding the capacity of effector T cells to kill tumors. Here, we study the prognostic significance of CTLA4, PD-1 and T cell activation status in breast cancer. Using a publicly accessed RNA-seq dataset including 1087 breast cancer patients, we performed Kaplan-Meier survival curves and multivariate Cox regression models to evaluate the associations of CTLA4, PD-1, and weighted T cell activation score with patients' overall survival. Survival analyses showed that high CTLA4 but low PD-1 expression was associated with a poor overall survival, and that high T cell activation score was associated with an improved survival. The median survival was 216.6months (95% CI 114.1-244.9) for the T activation group, 127.0months (95% CI 112.3-212.1) for the intermediate, and 120.5months (95% CI 93.8 to ∞) for the exhaustion (Log-rank p=0.084). This association was verified in multivariate Cox regression analysis. The hazard ratios were 0.81 (95% CI 0.56-1.19) for the intermediate group, and 0.48 (95% CI 0.26-0.86) for the activation group, respectively, in comparison to the exhaustion group (p value for trend=0.016). T cell activation score has significantly positive relationship with patients' overall survival, and may serve as a marker of personalized immunotherapy in breast cancer patients. Cocktail rather than single immune checkpoint blockade may yield more benefit for breast cancer patients.

The immune system and cancer evasion strategies: therapeutic concepts.

The complicated interplay between cancer and the host immune system has been studied for decades. New insights into the human immune system as well as the mechanisms by which tumours evade immune control have led to the new and innovative therapeutic strategies that are considered amongst the medical breakthroughs of the last few years. Here, we will review the current understanding of cancer immunology in general, including immune surveillance and immunoediting, with a detailed look at immune cells (T cells, B cells, natural killer cells, macrophages and dendritic cells), immune checkpoints and regulators, sialic acid-binding immunoglobulin-like lectins (Siglecs) and other mechanisms. We will also present examples of new immune therapies able to reverse immune evasion strategies of tumour cells. Finally, we will focus on therapies that are already used in daily oncological practice such as the blockade of immune checkpoints cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed death-1 (PD-1) in patients with metastatic melanoma or advanced lung cancer, or therapies currently being tested in clinical trials such as adoptive T-cell transfer.

Immune checkpoint inhibitors: therapeutic advances in melanoma.

In recent years, new strategies for treating melanoma have been introduced, improving the outlook for this challenging disease. One of the most important advances has been the development of immunotherapy. The better understanding of the role of the immunological system in tumor control has paved the way for strategies to enhance the immune response against cancer cells. Monoclonal antibodies (mAbs) against the immune checkpoints cytotoxic T-lymphocyte antigen-4 (CTLA-4) and programmed cell death protein 1 (PD-1) and its ligand (PD-L1) have demonstrated high activity in melanoma and other tumors. Ipilimumab, an anti CTLA-4 antibody, was the first drug of this class that was approved. Although the response rate with ipilimumab is low (less than 20% of patients have objective responses), 20% of patients have long survival, with similar results in the first and second line settings. Nivolumab and pembrolizumab, both anti PD-1 inhibitors, have been approved for the treatment of melanoma, with response rates of 40% and a demonstrated survival advantage in phase III trials. This has marked a new era in the treatment of metastatic melanoma and much research is now ongoing with other drugs targeting checkpoint inhibitors. In addition, the agonist of activating molecules on T cells and their combinations are being investigated. Herein we review the clinical development of checkpoint inhibitors and their approval for treatment of metastatic melanoma.

In situ vaccination by radiotherapy to improve responses to anti-CTLA-4 treatment

Targeting immune checkpoint receptors has emerged as an effective strategy to induce immune-mediated cancer regression in the subset of patients who have significant pre-existing anti-tumor immunity. For the remainder, effective anti tumor responses may require vaccination. Radiotherapy, traditionally used to achieve local tumor control, has acquired a new role, that of a partner for immunotherapy. Ionizing radiation has pro-inflammatory effects that facilitate tumor rejection. Radiation alters the tumor to enhance the concentration of effector T cells via induction of chemokines, cytokines and adhesion molecules. In parallel, radiation can induce an immunogenic death of cancer cells, promoting cross-presentation of tumor-derived antigens by dendritic cells to T cells. Newly generated anti-tumor immune responses have been demonstrated post-radiation in both murine models and occasional patients, supporting the hypothesis that the irradiated tumor can become an in situ vaccine. It is in this role, that radiation can be applied to induce anti-tumor T cells in lymphocyte-poor tumors, and possibly benefit patients who would otherwise fail to respond to immune checkpoint inhibitors. This review summarizes preclinical and clinical data demonstrating that radiation acts in concert with antibodies targeting the immune checkpoint cytotoxic T-lymphocyte antigen-4 (CTLA-4), to induce therapeutically effective anti-tumor T cell responses in tumors otherwise non responsive to anti-CTLA-4 therapy.

Clinical deployment of antibodies for treatment of melanoma.

The concept of using immunotherapy to treat melanoma has existed for decades. The rationale comes from the knowledge that many patients with melanoma have endogenous immune responses against their tumor cells and clinically meaningful tumor regression can be achieved in a minority of patients using cytokines such as interleukin-2 and adoptive cellular therapy. In the last 5 years there has been a revolution in the clinical management of melanoma in large measure based on the development of antibodies that influence T cell regulatory pathways by overcoming checkpoint inhibition and providing co-stimulation, either of which results in significantly more effective immune-mediated tumor destruction. This review will describe the pre-clinical and clinical application of antagonistic antibodies targeting the T-cell checkpoints cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed death 1 (PD-1), and agonistic antibodies targeting the costimulatory pathways OX40 and 4-1BB. Recent progress and opportunities for future investigation of combination antibody therapy will be described.

T cell receptor diversity evaluation to predict patient response to Ipilimumab in metastatic melanoma

Meeting abstracts Ipilimumab blocks the immunologic checkpoint cytotoxic T lymphocyte antigen-4 (CTLA-4) and improves overall survival in patients with metastatic melanoma. Since only a subset of patients achieves benefit from ipilimumab, biomarkers that can predict patient outcome are needed. CTLA