Relationship between immune checkpoint proteins and neoadjuvant chemotherapy response in breast cancer.

INTRODUCTION: Following major developments in cancer immunotherapy, treatments targeting immune checkpoint proteins (ICP) gained interest in breast cancer, though studies mostly focus on patients with metastatic disease as well as patients nonresponsive to the conventional treatments. Herein, we aimed to investigate the levels of ICP in tumor stroma and tumor infiltrating lymphocytes, and tumor tissue prior to neoadjuvant chemotherapy administration to evaluate the relationship between ICP levels, clinicopathological parameters, and NAC response. MATERIALS AND METHODS: This study was conducted with 51 patients where PD-1, PD-L1, CTLA-4, TIM-3, CD24 and CD44 levels were investigated in CD45+ cells while CD326, CD24, CD44 and PD-L1 protein expression levels were investigated in CD45- population. In addition, CD44 and CD24 levels were evaluated in the tumor stroma. TIL levels were investigated according to the TILS Working Group. Treatment responses after NAC were evaluated according to the MD Anderson RCB score. RESULTS: Our results revealed positive correlation between CTLA-4 and CD44 expression in cases with high TIL levels as well as TIL levels and CTLA-4 expression in cases with partial response. Similarly, positive correlation was detected between TIM3 and PD-L1 levels in cases with good response. In addition, a negative correlation between TILs after NAC and PD-1/PD-L1 expression in lymphocytes in cases with partial complete response. CONCLUSIONS: Our study provides preliminary data about the correlation between ICP and clinicopathological status and NAC response in breast cancer, in addition to underlining the requirement for further research to determine their potential as therapeutic targets.

Synergistic effects of immune checkpoints and checkpoint inhibitors in inflammatory neuropathies: Implications and mechanisms.

Immune checkpoint molecules play pivotal roles in the regulation of immune homeostasis. Disruption of the immune checkpoints causes autoimmune/inflammatory as well as malignant disorders. Over the past few years, the immune checkpoint molecules with inhibitory function emerged as potential therapeutic targets in oncological conditions. The inhibition of the function of these molecules by using immune checkpoint inhibitors (ICIs) has brought paradigmatic changes in cancer therapy due to their remarkable clinical benefits, not only in improving the quality of life but also in prolonging the survival time of cancer patients. Unfortunately, the ICIs soon turned out to be a "double-edged sword" as the use of ICIs caused multiple immune-related adverse effects (irAEs). The development of inflammatory neuropathies such as Guillain-Barré syndrome (GBS) and Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP) as the secondary effects of immunotherapy appeared very challenging as these conditions result in significant and often permanent disability. The underlying mechanism(s) through which ICIs trigger inflammatory neuropathies are currently not known. Compelling evidence suggests autoimmune reaction and/or inflammation as the independent risk mechanism of inflammatory neuropathies. There is a lack of understanding as to whether prior exposure to the risk factors of inflammatory neuropathies, the presence of germline genetic variants in immune function-related genes, genetic variations within immune checkpoint molecules, the existence of autoantibodies, and activated/memory T cells act as determining factors for ICI-induced inflammatory neuropathies. Herein, we highlight the available pieces of evidence, discuss the mechanistic basis, and propose a few testable hypotheses on inflammatory neuropathies as irAEs of immunotherapy.

Siglec-9 acts as an immune-checkpoint molecule on macrophages in glioblastoma, restricting T-cell priming and immunotherapy response.

Neoadjuvant immune-checkpoint blockade therapy only benefits a limited fraction of patients with glioblastoma multiforme (GBM). Thus, targeting other immunomodulators on myeloid cells is an attractive therapeutic option. Here, we performed single-cell RNA sequencing and spatial transcriptomics of patients with GBM treated with neoadjuvant anti-PD-1 therapy. We identified unique monocyte-derived tumor-associated macrophage subpopulations with functional plasticity that highly expressed the immunosuppressive SIGLEC9 gene and preferentially accumulated in the nonresponders to anti-PD-1 treatment. Deletion of Siglece (murine homolog) resulted in dramatically restrained tumor development and prolonged survival in mouse models. Mechanistically, targeting Siglece directly activated both CD4+ T cells and CD8+ T cells through antigen presentation, secreted chemokines and co-stimulatory factor interactions. Furthermore, Siglece deletion synergized with anti-PD-1/PD-L1 treatment to improve antitumor efficacy. Our data demonstrated that Siglec-9 is an immune-checkpoint molecule on macrophages that can be targeted to enhance anti-PD-1/PD-L1 therapeutic efficacy for GBM treatment.

Prognostic Significance of Immune-checkpoint Molecule PD-L1 in Classical Hodgkin Lymphoma: A Clinicopathologic Study of 120 Cases.

BACKGROUND/AIM: Classic Hodgkin lymphoma (cHL) is a common B-cell malignancy. Despite the good prognosis, in some patients the standard chemotherapy and radiotherapy-based approach does not lead to long-term remission, and these patients eventually relapse. Moreover, the primary refractory disease is of major concern regarding prognosis. PATIENTS AND METHODS: We performed a retrospective analysis to evaluate PD-L1 expression in 120 patients with classic Hodgkin lymphoma (cHL). RESULTS: The median follow-up of the entire group of patients was 90 months. After initial therapy, complete remission was achieved in 113 (94.2%) patients. During the follow-up, cHL relapse/refractory disease was reported in 23 (19.2%) cases. A total of five patients died during the follow-up period, all from cHL progression. When determining PD-L1 expression on Hodgkin-Reed-Sternberg (HRS) cells, 37 cases (30.8%) were evaluated as negative, and 83 cases (69.2%) as positive. In the negative PD-L1 group of patients, no cHL relapse/refractory disease was observed during the follow-up period. However, out of 83 patients with positive PD-L1 expression on HRS cells, 23 (28%) showed relapse/refractory cHL. CONCLUSION: A significantly higher relapse rate was observed in PD-L1-positive patients diagnosed with cHL.

Role of Surgical Pathologist for the Detection of Immuno-oncologic Predictive Factors in Non-small Cell Lung Cancers.

Until very recently, surgery, chemotherapy, and radiation therapy have been the mainstay of treatment in non-small cell carcinomas (NSCLCs). However, recent advances in molecular immunology have unveiled some of the complexity of the mechanisms regulating cellular immune responses and led to the successful targeting of immune checkpoints in attempts to enhance antitumor T-cell responses. Immune checkpoint molecules such as cytotoxic T-lymphocyte associated protein-4, programmed cell death protein-1, and programmed death ligand (PD-L) 1 have been shown to play central roles in evading cancer immunity. Thus, these molecules have been targeted by inhibitors for the management of cancers forming the basis of immunotherapy. Advanced NSCLC has been the paradigm for the benefits of immunotherapy in any cancer. Treatment decisions are made based on the expression of PD-L1 on the tumor cells and the presence or absence of driver mutations. Patients with high PD-L1 expression (≥50%) and no driver mutations are treated with single-agent immunotherapy whereas, for all other patients with a lower level of PD-L1 expression, a combination of chemotherapy and immunotherapy is preferred. Thus, PD-L1 blockers are the only immunotherapeutic agents approved in advanced NSCLC without any oncogenic driver mutations. PD-L1 immunohistochemistry, however, may not be the best biomarker in view of its dynamic nature in time and space, and the benefits may be seen regardless of PD -L1 expression. Each immunotherapy molecule is prescribed based on the levels of PD-L1 expression as assessed by a Food and Drug Administration-approved companion diagnostic assay. Other biomarkers that have been studied include tumor mutational burden, the T-effector signature, tumor-infiltrating lymphocytes, radiomic assays, inflammation index, presence or absence of immune-related adverse events and specific driver mutations, and gut as well as local microbiome. At the current time, none of these biomarkers are routinely used in the clinical decision-making process for immunotherapy in NSCLC. However, in individual cases, they can be useful adjuncts to conventional therapy. This review describes our current understanding of the role of biomarkers as predictors of response to immune checkpoint molecules. To begin with a brief on cancer immunology in general and in NSCLC, in particular, is discussed. In the end, recent advancements in laboratory techniques for refining biomarker assays are described.

Cytokine profiling identifies circulating IL-6 and IL-15 as prognostic stratifiers in patients with non-small cell lung cancer receiving anti-PD-1/PD-L1 blockade therapy.

Whether circulating levels of specific cytokines at baseline link with treatment efficacy of immune checkpoint blockade (ICB) therapy in patients with non-small cell lung cancer remains unknown. In this study, serum samples were collected in two independent, prospective, multicenter cohorts before the initiation of ICB. Twenty cytokines were quantified, and cutoff values were determined by receiver operating characteristic analyses to predict non-durable benefit. The associations of each dichotomized cytokine status with survival outcomes were assessed. In the discovery cohort (atezolizumab cohort; N = 81), there were significant differences in progression-free survival (PFS) in accordance with the levels of IL-6 (log-rank test, P = 0.0014), IL-15 (P = 0.00011), MCP-1 (P = 0.013), MIP-1ß (P = 0.0035), and PDGF-AB/BB (P = 0.016). Of these, levels of IL-6 and IL-15 were also significantly prognostic in the validation cohort (nivolumab cohort, N = 139) for PFS (log-rank test, P = 0.011 for IL-6 and P = 0.00065 for IL-15) and overall survival (OS; P = 3.3E-6 for IL-6 and P = 0.0022 for IL-15). In the merged cohort, IL-6high and IL-15high were identified as independent unfavorable prognostic factors for PFS and OS. The combined IL-6 and IL-15 status stratified patient survival outcomes into three distinct groups for both PFS and OS. In conclusion, combined assessment of circulating IL-6 and IL-15 levels at baseline provides valuable information to stratify the clinical outcome of patients with non-small cell lung cancer treated with ICB. Further studies are required to decipher the mechanistic basis of this finding.

Immune checkpoint molecule Tim-3 promotes NKT cell apoptosis and predicts poorer prognosis in Sepsis.

BACKGROUND: Sepsis is a leading cause of death among critically ill patients, which is defined as life-threatening organ dysfunction caused by a deregulated host immune response to infection. Immune checkpoint molecule Tim-3 plays important and complex roles in regulating immune responses and in inducing immune tolerance. Although immune checkpoint blockade would be expected as a promising therapeutic strategy for sepsis, but the underlying mechanism remain unknown, especially under clinical conditions. METHODS: Tim-3 expression and apoptosis in NKT cells were compared in septic patients (27 patients with sepsis and 28 patients with septic shock). Phenotypic and functional characterization of Tim-3+ NKT cells were analysed, and then the relationship between Tim-3 + NKT cells and clinical prognosis were investigated in septic patients. α-lactose (Tim-3/Galectin-9 signalling inhibitor) and Tim-3 mutant mice (targeting mutation of the Tim-3 cytoplasmic domain) were utilized to evaluate the protective effect of Tim-3 signalling blockade following septic challenge. RESULTS: There is a close correlation between Tim-3 expression and the functional status of NKT cells in septic patients, Upregulated Tim-3 expression promoted NKT cell activation and apoptosis during the early stage of sepsis, and it was associated with worse disease severity and poorer prognosis in septic patients. Blockade of the Tim-3/Galectin-9 signal axis using α-lactose inhibited in vitro apoptosis of NKT cells isolated from septic patients. Impaired activity of Tim-3 protected mice following septic challenge. CONCLUSIONS: Overall, these findings demonstrated that immune checkpoint molecule Tim-3 in NKT cells plays a critical role in the immunopathogenesis of septic patients. Blockade of immune checkpoint molecule Tim-3 may be a promising immunomodulatory strategy in future clinical practice for the management of sepsis.

A novel anti-PD-L1/IL-15 immunocytokine overcomes resistance to PD-L1 blockade and elicits potent antitumor immunity.

Despite the demonstrated immense potential of immune checkpoint inhibitors in various types of cancers, only a minority of patients respond to these therapies. Immunocytokines designed to deliver an immune-activating cytokine directly to the immunosuppressive tumor microenvironment (TME) and block the immune checkpoint simultaneously may provide a strategic advantage over the combination of two single agents. To increase the response rate to checkpoint blockade, in this study, we developed a novel immunocytokine (LH01) composed of the antibody against programmed death-ligand 1 (PD-L1) fused to interleukin (IL)-15 receptor alpha-sushi domain/IL-15 complex. We demonstrate that LH01 efficiently binds mouse or human PD-L1 and maintains IL-15 stimulatory activity. In syngeneic mouse models, LH01 showed improved antitumor efficacy and safety versus anti-PD-L1 plus LH02 (Fc-sushi-IL15) combination and overcame resistance to anti-PD-L1 treatment. Mechanistically, the dual anti-immunosuppressive function of LH01 activated both the innate and adaptive immune responses and induced a favorable and immunostimulatory TME. Furthermore, combination therapy with LH01 and bevacizumab exerts synergistic antitumor effects in an HT29 colorectal xenograft model. Collectively, our results provide supporting evidence that fusion of anti-PD-L1 and IL-15 might be a potent strategy to treat patients with cold tumors or resistance to checkpoint blockade.

The evolving role of checkpoint inhibitors in the treatment of urothelial carcinoma.

The most prevalent pathological subtype of bladder and upper urinary tract malignancy is urothelial carcinoma (UC). Traditional therapies mainly include surgical resection, chemotherapy and radiotherapy. Checkpoint inhibitors, which are monoclonal antibodies developed to specifically target immune checkpoint molecules, have recently emerged as potential treatment options for UC patients, especially those targeting the programmed cell death protein 1 (PD-1) and its ligand (PD-L1). However, anti-PD-1/PD-L1 therapy does not work for a considerable number of UC patients. Current antitumour immunotherapy research hotspots include seeking biomarkers that might predict therapeutic effects and exploring novel immune checkpoint molecules crucial for the antitumour immune response. Hence, we will recapitulate the latest preclinical and clinical trials of 5 PD-1/PD-L1 inhibitors, 1 cytotoxic T-lymphocyte-associated protein 4 inhibitor and combination therapies for UC treatment, including combined immunotherapy and immunotherapy with chemotherapy or radiotherapy. We will also summarize other potential immune checkpoint molecules found in ongoing UC studies. Moreover, we will highlight the role of biomarkers linked with the oncological efficacy of anti-PD-1/PD-L1 immunotherapy and address the mechanisms of immunotherapy drug resistance in UC, with the hope of providing more systematic guidance for its application and development.

Soluble B7-CD28 Family Inhibitory Immune Checkpoint Proteins and Anti-Cancer Immunotherapy.

Co-inhibitory B7-CD28 family member proteins negatively regulate T cell responses and are extensively involved in tumor immune evasion. Blockade of classical CTLA-4 (cytotoxic T lymphocyte-associated antigen-4) and PD-1 (programmed cell death protein-1) checkpoint pathways have become the cornerstone of anti-cancer immunotherapy. New inhibitory checkpoint proteins such as B7-H3, B7-H4, and BTLA (B and T lymphocyte attenuator) are being discovered and investigated for their potential in anti-cancer immunotherapy. In addition, soluble forms of these molecules also exist in sera of healthy individuals and elevated levels are found in chronic infections, autoimmune diseases, and cancers. Soluble forms are generated by proteolytic shedding or alternative splicing. Elevated circulating levels of these inhibitory soluble checkpoint molecules in cancer have been correlated with advance stage, metastatic status, and prognosis which underscore their broader involvement in immune regulation. In addition to their potential as biomarker, understanding their mechanism of production, biological activity, and pathological interactions may also pave the way for their clinical use as a therapeutic target. Here we review these aspects of soluble checkpoint molecules and elucidate on their potential for anti-cancer immunotherapy.