Immunotherapy targeting the Programmed Death (PD-1) receptor/ligand (L) "checkpoint" rapidly gains ground in the treatment of many cancer types. To increase treatment scope and efficacy, predictive... Show moreImmunotherapy targeting the Programmed Death (PD-1) receptor/ligand (L) "checkpoint" rapidly gains ground in the treatment of many cancer types. To increase treatment scope and efficacy, predictive biomarkers and rational selection of co-treatments are required. To meet these demands, we must understand PD-1 function in detail. We here outline recent insights into the regulation of the CD8(+) T cell response by PD-1. The prevailing view has been that blockade of PD-1/ligand (L) interaction "reinvigorates" cytotoxic T lymphocytes (CTL) that were rendered dysfunctional in the tumor microenvironment (TME). However, this review stresses that tumors continuously communicate with adjacent draining lymph nodes (LNs) and that the PD-1 checkpoint also operates during T cell priming. We clarify the role of the PD-(L)1 system at the T cell/DC interface, where it regulates T cell receptor (TCR) signaling and CD28 costimulation and thus controls activation of tumor-specific T cells. We also highlight the importance of CD4(+) T cell help during priming, which allows DCs to provide other costimulatory and cytokine signals required for optimal CTL differentiation and likely avoidance of a dysfunctional state. Therefore, we pose that PD-(L)1 blockade should exploit LN function and be combined with "help" signals to optimize CTL efficacy. Show less
The prognosis of recurrent or metastatic endometrial cancer is poor, with five-year survival of only 10-20 %. First-line therapy consists of either platinum-based chemotherapy or hormonal therapy.... Show moreThe prognosis of recurrent or metastatic endometrial cancer is poor, with five-year survival of only 10-20 %. First-line therapy consists of either platinum-based chemotherapy or hormonal therapy. No standard subsequent-line therapy has been identified. In recent years, significant progress has been made in the knowledge on underlying molecular biology of endometrial cancer and potential targets for therapy have been identified. Targeted therapies as poly (ADP-ribose) polymerase (PARP) inhibitors and immunotherapy as PD-1/PD-L1 checkpoint inhibitors have the potential to be effective against specific subtypes of endometrial cancer. Preclinical studies have shown that combining these agents may result in a synergistic effect. In this review, we focus on the molecular basis of checkpoint inhibition and targeted therapy as PARP inhibition in endometrial cancer and summarize available clinical data, and ongoing and planned clinical trials that investigate these agents as mono- or combination therapies in endometrial cancer and where relevant, other gynecological cancers. Show less
Kortekaas, K.E.; Santegoets, S.J.; Abdulrahman, Z.; Ham, V.J. van; Tol, M. van der; Ehsan, I.; ... ; Burg, S.H. van der 2019
In cancer and chronic infectious diseases, immune checkpoint-blockade of inhibitory receptors can enhance T-cell immunity. In tuberculosis (TB), a chronic infectious disease, prolonged antigen... Show moreIn cancer and chronic infectious diseases, immune checkpoint-blockade of inhibitory receptors can enhance T-cell immunity. In tuberculosis (TB), a chronic infectious disease, prolonged antigen exposure can potentially drive terminal T-cell differentiation towards functional 'exhaustion': in human TB T-cells express PD-1 (programmed cell death protein-1) and CTLA-4 (cytotoxic T-lymphocyte-associated protein-4). However, in murine TB not PD-1 but rather killer cell lectin-like receptor subfamily-G1 (KLRG1) was a superior indicator of terminal T-cell differentiation. We therefore compared expression of KLRG1, PD-1 and CTLA-4 on T-cells in different stages of human TB, and also analysed their induction following BCG-vaccination. KLRG1, PD-1 and CTLA-4-expression were highest on in vitro BCG-stimulated CD4(+) T-cells following recent TB-treatment; KLRG1 and PD-1-expression on CD4(+) T-cells in active - but not latent TB were only slightly increased compared to healthy donors. BCG-vaccination induced KLRG1-expression on BCG-stimulated CD8(+) but not CD4(+) T-cells, while neither PD-1 nor CTLA-4-expression increased. KLRG1-expressing CD8(+) T-cells exhibited markedly decreased proliferation, whereas PD-1(+) T-cells proliferated after in vitro BCG-stimulation. Thus, we demonstrate the presence of increased KLRG1-expressing T-cells in TB-treated individuals, and present KLRG1 as a marker of decreased human T-cell proliferation following BCG-vaccination. These results expand our understanding of cell-mediated immune control of mycobacterial infections. (c) 2015 Elsevier Ltd. All rights reserved. Show less
HPVs need to avoid immune responses of the host in order to establish persistent infection. HPVs achieve this by dampening innate immunity of keratinocytes, the major cell type targeted by HPV. As... Show moreHPVs need to avoid immune responses of the host in order to establish persistent infection. HPVs achieve this by dampening innate immunity of keratinocytes, the major cell type targeted by HPV. As there is reduced production of danger signals including antimicrobial molecules, proinflammatory cytokines and chemokines by keratinocytes, HPV infection remains undetected by the immune system. However, our further data showed that PRR signaling is not completely blocked by hrHPV. Thus, the activation of innate and adaptive immunity at the site of HPV infection is slowed down but not prevented. In order for cancers to grow out they need to suppress the local effector cells. We focused on the role of the PD-1 receptor and its ligands PD-L1 and PD-L2, our data showed that the majority (81%) of the tumors from cervical cancer patients do not express PD-L1. Furthermore, PD-L1 expression was not associated with patient survival. Finally, we presented evidence that the chemokine receptor CXCR7 expression predicts poor disease-free and disease-specific survival in cervical cancer patients. Show less
Cetinozman, F.; Koens, L.; Jansen, P.M.; Willemze, R. 2014
