Presence Of Programmed Death-1 Research Articles

206. Determining the Effect of Endogenous PD-1 Expression on the Co-Stimulatory Potential of the PD1:CD28 Chimera

Adoptive immunotherapy is an emerging field of study involving genetic alteration of the immune system to enhance its effectiveness in eliminating cancer. A previous study created a novel chimera (PD1:CD28) containing the extracellular portion of an inhibitory molecule, Programmed Death 1 (PD-1), and the intracellular portion of a co-stimulatory molecule, CD28, resulting in tumor induced co-stimulation of T cells. Given that endogenous PD-1 expression is likely to up-regulate on T cells in the tumor microenvironment, the current study aims to determine whether the presence of PD-1 on the cell surface negatively impacts T cell stimulation by the PD1:CD28 chimera. Endogenous PD1 was tagged with a red fluorescent protein, mCherry, and PD1:CD28 with a green fluorescent protein, GFP. Fusion proteins were transfected into H9 cells and positive expression was detected via flow cytometric analysis and fluorescence microscopy. Stable cell lines expressing both PD1:mCherry and PD1:CD28:GFP fusion proteins are being examined for downstream signaling markers, proliferation, and cytokine expression following exposure to Programmed Death Ligand 1 (PD-L1), as compared to cells engineered to express only PD1:mCherry or PD1:CD28:GFP. This study will provide further insight into the ability of the PD1:CD28 chimera to overcome PD-1 mediated tumor immune evasion.

Programmed death-1in cancer stem cells may serve as a novel immunotherapy marker

Scientific objective Head and neck cancers (HNC) are among the most prevalent and deadly cancers. Despite advances in treatment and improvement in patient’s quality of life, survival rates have not improved in these patients. Increasing evidence shows that the initiation, growth and metastasis of cancer are directed by a small functional subpopulation of cancer cells defined as cancer stem cells (CSCc). Multipotency and differentiation into the tumor cells, plasticity and selfrenewal are among the most exclusive features of CSCs. Programmed death 1 (PD-1) protein, is an inhibitory T cell receptor which is able to muffle the immune response of activated T cells, helping cancer cells to evade the host defense system. Thus, we have examined the presence of CSCs in HNCs and if there is any correlation between HNC development and PD-1 expression. Technical approach/methods Using tissue microarrays, we employed immunohistochemistry and immunofluorescent protocols to explore if CSCs marker, CD44, is expressed within the tumor microenvironment. In addition, we investigated the presence of PD-1 expressing cells as inhibitors of antitumor immunity. Results/interpretation We observed that a subpopulation of HNC expressed CD44 which is suggestive of the presence of CSCs within the tumor. Moreover, PD-1 was expressed within the tumor microenvironment thereby indicating the pivotal role of PD-1 in the suppression of the host immune system and its significance for tumor survival and progression of cancer. Collectively, the results not only re-emphasize the role of CSCs in initiation and establishment of HNC, but also suggest PD-1 as a novel therapeutic target in anticancer frontier. Outlook/expert recommendations The present study suggests, for the first time, a relation between cancer stem cells and programmed cell death 1 in head and neck cancer. Our findings indicate that the presence of cancer stem cells in the head and neck tumor and their association with the tumor structure may play a crucial role not only in the establishment of the tumor, but also, in the induction of immunosuppression status of the immune system against head and neck tumors. Therefore, subsequent studies should determine whether any alteration in the presence and activity of cancer stem cells within the tumor microenvironment can up-regulate the immune responses against tumor growth and progression in the head and neck cancer. The primary therapeutic impact of such stimulation of immune system will results in the focal disruptions of the tumor capsule, which selectively favor tumor stem cells proliferation and invasion.

The presence of programmed death 1 (PD-1)-positive tumor-infiltrating lymphocytes is associated with poor prognosis in human breast cancer

Programmed death 1 (PD-1) is a co-inhibitory receptor in the CD28/CTL-4 family, and functions as a negative regulator of the immune system. Tumor-infiltrating lymphocytes (TIL) in many epithelial cancers express PD-1, suggesting that antitumor immunity may be modulated by the PD-1/PD-L1 signaling pathway, and promising results from two recent clinical trials with monoclonal antibodies targeting PD-1 or PD-L1 confirm the clinical relevance of this pathway in human cancer. To explore the role of PD-1(+) TIL in human breast cancer, we performed immunohistochemistry studies on a tissue microarray encompassing 660 breast cancer cases with detailed clinical annotation and outcomes data. PD-1(+) TIL were present in 104 (15.8%) of the 660 breast cancer cases. Their presence was associated with tumor size, grade, and lymph node status, and was differentially associated with the intrinsic subtypes of breast cancer. In univariate survival analyses, the presence of PD-1(+) TIL was associated with a significantly worse overall survival (HR=2.736, p<0.001). In subset analyses, the presence of PD-1(+) TIL was associated with significantly worse overall survival in the luminal B HER2(-) subtype (HR=2.678, p<0.001), the luminal B HER2(+) subtype (HR=3.689, p<0.001), and the basal-like subtype (HR=3.140, p<0.001). This is the first study to demonstrate that the presence of PD-1(+) TIL is associated with poor prognosis in human breast cancer, with important implications for the potential application of antibody therapies targeting the PD-1/PD-L1 signaling pathway in this disease.

Inhibitory Signals Mediated by Programmed Death‐1 Are Involved With T‐Cell Function in Chronic Periodontitis

Inhibitory signals mediated via molecules such as programmed death-1 (PD-1) play a critical role in downmodulating immune responses and maintaining peripheral tolerance. We investigated the involvement of cytokines and PD-1 engagement in mediating the T-cell unresponsiveness to bacterial and ubiquitous antigens in periodontal diseases. Gingival and peripheral blood samples from healthy individuals and patients with chronic periodontitis were collected and used for the subsequent assays. Leukocytes in the lesion site and blood were evaluated using flow cytometry. The production of interferon-gamma, interleukin-10, and transforming growth factor-beta proteins was evaluated by enzyme-linked immunosorbent assay (ELISA), and the presence of PD-1+ cells in the inflamed gingiva was confirmed by immunofluorescence confocal microscopy for CD4 and PD-1 colocalization. T cells from patients with chronic periodontitis proliferated poorly in response to Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans) antigen. T-cell unresponsiveness was not associated with imbalanced cytokine production. However, T cells from patients with chronic periodontitis expressed significantly higher levels of PD-1 either upon isolation or after culture with antigens. Moreover, PD-1 blocking did not result in significant T-cell proliferation in cells cultured with phytohemagglutinin or bacterial antigens. The blockade of PD-1 resulted in the increased production of IFN-gamma. In addition, CD4+ and CD8+ T cells expressing PD-1 accumulated in lesions with chronic periodontitis. These data show that PD-1 engagement could be involved in the modulation of IFN-gamma production by T cells in patients with chronic periodontitis.

Increased programmed death-1+ tumor-infiltrating lymphocytes in classical Hodgkin lymphoma substantiate reduced overall survival

Programmed death-1 (PD-1), a protein that is physiologically expressed by germinal center-associated helper T cells, has an inhibitory function on T-cell activity. The distribution of PD-1+ lymphocytes in the microenvironment of Hodgkin lymphoma is not random and can serve as a diagnostic marker. We measured the number of PD-1+ lymphocytes in Hodgkin lymphoma and correlated it with the remaining background lymphocyte populations and known biological and clinical key data on a tissue microarray platform encompassing 280 cases of classical Hodgkin lymphoma and 3 cases of nodular lymphocyte-predominant Hodgkin lymphoma. Prognostic cutoff scores were determined by receiver operating curve analysis. The number of PD-1+ tumor-infiltrating lymphocytes in 189 evaluable cases was median of 27 and mean of 269 cells/mm(2), being higher in lymphocyte-rich classical Hodgkin lymphoma and lower in the mixed cellularity variant. Rimming of tumor cells by PD-1+ cells was observed in all cases of nodular lymphocyte-predominant Hodgkin lymphoma but only in 1% of classical Hodgkin lymphomas, particularly in lymphocyte-rich and -mixed cellularity variants. Thus, the presence of PD-1+ rosettes around neoplastic cells is typical but not exclusive for nodular lymphocyte-predominant Hodgkin lymphoma because it may be encountered in classical Hodgkin lymphoma. The PD-1+ cell amount was lower in classical Hodgkin lymphoma cases with 9p24 gains (PD-1 ligand 2 locus) and in cases with higher numbers of FOXP3+ regulatory T cells. An increased amount of PD-1+ tumor-infiltrating lymphocytes above the prognostic cutoff score (23 cells/mm(2)) was a stage-independent negative prognostic factor of overall survival as opposed to the number of FOXP3+ regulatory T cells. Along with the latter, PD-1+ cells might represent important lymphoma/host microenvironment modulators.