BACKGROUND: Correct function of the immune system depends on close cooperation between stimulation and inhibition signals, which protect an organism from outside microorganisms and other agents, but also protects healthy tissues against possible self-destructing attacks of the immune system. However, the inhibitory mechanisms can be abused by cancer cells that evade immune responses and, in fact, they help develop cancer. Therefore, one of the characteristics of cancer cells is the ability to evade immune recognition. Immunotherapy is a treatment method that stimulates the immune system to fight cancer. The checkpoints of the immune system can be considered as effective and specific therapeutic targets. Programmed cell death signaling pathway (PD-1/PD-L1) is one of the most discussed inhibition pathways in recent years. Blockage of PD-1/PD-L1 interaction restores mechanisms of immune response and increases antitumor immune activity. Monoclonal antibodies blocking PD-1 receptor or its ligand PD-L1 have already shown clinical efficacy. However, it is important to carry out research to explore the mechanisms of PD-1/PD-L1 pathway to find new factors, which influence its activity and, of course, to illuminate the variability of this pathway which naturally originates in the diversity of the tumor milieu. Obtained results could be utilized to achieve maximal anticancer effect after inhibition of PD-1/PD-L1 signaling pathway useful in clinical practice. AIM: The aim of the article is to summarize current knowledge about PD-1/PD-L1 signaling pathway and to discuss its role in antitumor immune response.Key words: programmed cell death pathway - tumor escape - PD-1 - PD-L1 - CD274This work was supported by the project MEYS - NPS I - LO1413.The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study.The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers.Submitted: 13. 6. 2016Accepted: 4. 8. 2016.

• MeSH
• antigeny CD274 antagonisté a inhibitory   metabolismus   MeSH
• antigeny CD279 antagonisté a inhibitory   metabolismus   MeSH
• lidé MeSH
• nádory farmakoterapie   imunologie   metabolismus   MeSH
• signální transdukce MeSH
• únik nádoru z imunitní kontroly imunologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• antigeny CD274 MeSH
• antigeny CD279 MeSH
• CD274 protein, human MeSH Prohlížeč
• PDCD1 protein, human MeSH Prohlížeč

Fumarate hydratase-deficient renal cell carcinoma (FH-RCC) is a rare and aggressive tumor affecting mostly younger patients. This is the first study to assess the expression of programmed death-1 (PD-1) receptor/PD-1 ligand (PD-L1) in FH-RCC. Formalin-fixed paraffin-embedded samples from 13 FH-RCCs collected in an international multi-institutional study, were evaluated by immunohistochemistry (IHC) for PD-1/PD-L1 reactivity in tumor cells and tumor infiltrating lymphocytes (TILs). PD-1/PD-L1 expression was further evaluated by qPCR. By IHC, PD-1 was negative in tumor cells in all 13 cases. PD-L1 was positive in tumor cells in 2/13 cases, weak positive in 7/13, and negative in 4/13 cases, respectively. In TILs, PD-1 was positive in 1/13, weak positive in 3/13, and negative in 9/13 cases. In TILs, PD-L1 was weak positive by IHC in 5/13, and negative in 8/13 cases, respectively. qPCR confirmed the result for 2 of 3 IHC weak positive PD-1 samples. Of 7 IHC weak positive samples (in tumor cells), PD-L1 mRNA was detected in all 7 tumors. The majority of FH-RCCs did not express PD-1/PD-L1 by IHC, which was confirmed by molecular analysis. PD-1/PD-L1 expression in FH-RCC is restricted to a proportion of cases which may benefit from targeted therapies.

• Klíčová slova
• Fumarate hydratase-deficient renal cell carcinoma, Kidney, PD-1 ligand (PD-L1) receptor, Programmed death-1 (PD-1) receptor,
• MeSH
• antigeny CD274 metabolismus   MeSH
• antigeny CD279 metabolismus   MeSH
• dospělí MeSH
• fumarasa nedostatek   metabolismus   MeSH
• imunohistochemie metody   MeSH
• karcinom z renálních buněk metabolismus   patologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• nádory ledvin metabolismus   patologie   MeSH
• přežití bez známek nemoci MeSH
• tumor infiltrující lymfocyty metabolismus   patologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antigeny CD274 MeSH
• antigeny CD279 MeSH
• CD274 protein, human MeSH Prohlížeč
• fumarasa MeSH
• PDCD1 protein, human MeSH Prohlížeč

Monoclonal antibodies targeting immune checkpoints have revolutionized oncology. Yet, the effectiveness of these treatments varies significantly among patients, and they are associated with unexpected adverse events, including hyperprogression. The murine research model used in drug development fails to recapitulate both the functional human immune system and the population heterogeneity. Hence, a novel model is urgently needed to study the consequences of immune checkpoint blockade. Dogs appear to be uniquely suited for this role. Approximately 1 in 4 companion dogs dies from cancer, yet no antibodies are commercially available for use in veterinary oncology. Here we characterize two novel antibodies that bind canine PD-1 with sub-nanomolar affinity as measured by SPR. Both antibodies block the clinically crucial PD-1/PD-L1 interaction in a competitive ELISA assay. Additionally, the antibodies were tested with a broad range of assays including Western Blot, ELISA, flow cytometry, immunofluorescence and immunohistochemistry. The antibodies appear to bind two distinct epitopes as predicted by molecular modeling and peptide phage display. Our study provides new tools for canine oncology research and a potential veterinary therapeutic.

• Klíčová slova
• PD-1, PD-L1, cancer immunotherapy, canine cancer, comparative oncology, immune checkpoint, monoclonal antibody, veterinary oncology,
• MeSH
• antigeny CD274 imunologie   antagonisté a inhibitory   metabolismus   MeSH
• antigeny CD279 * antagonisté a inhibitory   imunologie   MeSH
• epitopy imunologie   MeSH
• inhibitory kontrolních bodů imunologie   farmakologie   MeSH
• lidé MeSH
• monoklonální protilátky * imunologie   MeSH
• nádory imunologie   veterinární   farmakoterapie   MeSH
• nemoci psů imunologie   farmakoterapie   MeSH
• psi * MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• psi * MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• antigeny CD274 MeSH
• antigeny CD279 * MeSH
• epitopy MeSH
• inhibitory kontrolních bodů MeSH
• monoklonální protilátky * MeSH

Trichothecene mycotoxins have a strong immunosuppressive effect, which may even escape host immune surveillance and damage the immune repair to show an "immune evasion" effect. Increasing lines of evidence have shown that hypoxia and hypoxia-inducible factors (HIFs) are key mediators of trichothecenes, and these toxins appear to be closely related to the "immune evasion" mechanisms. Therefore, we used RAW264.7 cell model to explore the association of T-2 toxins with "immune evasion" process and hypoxia, as well as their cross-linking effects induced by T-2 toxin. Our results showed that HIF-1α is an important toxicity target of T-2 toxin, which could induce intracellular hypoxia. T-2 toxin induced an "immune evasion" process by activating the PD-1/PD-L1 signaling pathway. Interestingly, when HIF-1α activation was blocked, the "immune evasion" process regulated by PD-1/PD-L1 signaling was activated, resulting in the cells damage, suggesting that hypoxia induced by T-2 toxin plays a protective role for RAW264.7 cell damage. Thus, our work shows that HIF-1α inhibits T-2 toxin-mediated "immune evasion" process by negatively regulating PD-1/PD-L1signaling. This study contributes to a better understanding of the immunotoxicity mechanism of trichothecenes.

• Klíčová slova
• HIF-1α, Hypoxia, Immune evasion, PD-1/PD-L1, T-2 toxin,
• MeSH
• antigeny CD274 metabolismus   MeSH
• antigeny CD279 metabolismus   MeSH
• faktor 1 indukovatelný hypoxií - podjednotka alfa farmakologie   MeSH
• hypoxie MeSH
• lidé MeSH
• T-2 toxin * toxicita   MeSH
• trichotheceny * toxicita   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antigeny CD274 MeSH
• antigeny CD279 MeSH
• faktor 1 indukovatelný hypoxií - podjednotka alfa MeSH
• T-2 toxin * MeSH
• trichotheceny * MeSH

Programmed cell death protein 1 (PD-1)/PD-1 ligand 1 (PD-L1) blockade is a promising therapy for various cancer types, but most patients are still resistant. Therefore, a larger number of predictive biomarkers is necessary. In this study, we assessed whether a loss-of-function mutation of the interferon (IFN)-γ receptor 1 (IFNGR1) in tumor cells can interfere with anti-PD-L1 therapy. For this purpose, we used the mouse oncogenic TC-1 cell line expressing PD-L1 and major histocompatibility complex class I (MHC-I) molecules and its TC-1/A9 clone with reversibly downregulated PD-L1 and MHC-I expression. Using the CRISPR/Cas9 system, we generated cells with deactivated IFNGR1 (TC-1/dIfngr1 and TC-1/A9/dIfngr1). In tumors, IFNGR1 deactivation did not lead to PD-L1 or MHC-I reduction on tumor cells. From potential inducers, mainly IFN-α and IFN-β enhanced PD-L1 and MHC-I expression on TC-1/dIfngr1 and TC-1/A9/dIfngr1 cells in vitro. Neutralization of the IFN-α/IFN-β receptor confirmed the effect of these cytokines in vivo. Combined immunotherapy with PD-L1 blockade and DNA vaccination showed that IFNGR1 deactivation did not reduce tumor sensitivity to anti-PD-L1. Thus, the impairment of IFN-γ signaling may not be sufficient for PD-L1 and MHC-I reduction on tumor cells and resistance to PD-L1 blockade, and thus should not be used as a single predictive marker for anti-PD-1/PD-L1 cancer therapy.

• Klíčová slova
• IFN-α, IFN-β, IFNGR1, MHC class I, PD-1/PD-L1, cancer, immune checkpoint therapy,
• MeSH
• antigeny CD274 antagonisté a inhibitory   MeSH
• antigeny CD279 antagonisté a inhibitory   MeSH
• experimentální nádory farmakoterapie   imunologie   metabolismus   patologie   MeSH
• imunoterapie MeSH
• interferon gama antagonisté a inhibitory   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• nádorové buňky kultivované MeSH
• protinádorové látky imunologicky aktivní farmakologie   MeSH
• transformované buněčné linie účinky léků   imunologie   metabolismus   patologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antigeny CD274 MeSH
• antigeny CD279 MeSH
• Cd274 protein, mouse MeSH Prohlížeč
• interferon gama MeSH
• Pdcd1 protein, mouse MeSH Prohlížeč
• protinádorové látky imunologicky aktivní MeSH

The therapy of different advanced-stage malignancies with monoclonal antibodies blocking programmed cell death protein 1 (PD-1)/PD-1 ligand 1 (PD-L1) signaling has had an impressive long-lasting effect in a portion of patients, but in most cases, this therapy was not successful, or a secondary resistance developed. To enhance its efficacy in treated patients, predictive biomarkers are searched for and various combination treatments are intensively investigated. As the downregulation of major histocompatibility complex (MHC) class I molecules is one of the most frequent mechanisms of tumor escape from the host's immunity, it should be considered in PD-1/PD-L1 checkpoint inhibition. The potential for the use of a PD-1/PD-L1 blockade in the treatment of tumors with aberrant MHC class I expression is discussed, and some strategies of combination therapy are suggested.

• Klíčová slova
• MHC class I, PD-1, PD-L1, biomarker, cancer immunotherapy, checkpoint blockade, interferon gamma, tumor escape,
• MeSH
• antigeny CD274 antagonisté a inhibitory   imunologie   MeSH
• antigeny CD279 antagonisté a inhibitory   imunologie   MeSH
• down regulace * MeSH
• geny MHC třídy I MeSH
• imunoterapie metody   MeSH
• lidé MeSH
• MHC antigeny I. třídy genetika   MeSH
• monoklonální protilátky terapeutické užití   MeSH
• nádory genetika   imunologie   terapie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• antigeny CD274 MeSH
• antigeny CD279 MeSH
• MHC antigeny I. třídy MeSH
• monoklonální protilátky MeSH

The treatment of cancer, especially of various types of solid tumors, has been revolutionized by the blockade of the PD-1/PD-L1 pathway by immune checkpoint inhibitors. Their success amongst hematologic malignancies, however, has been limited so far to the treatment of classic Hodgkin's lymphoma, which portrays a typical overexpression of PD-1 ligands (PD-L1, PD-L2) as a consequence of changes in chromosome 9p24.1. Their current application in multiple myeloma (MM) is rather uncertain, as discordant results have been reported by distinct research groups concerning especially the expression of PD-1/PD-L1 molecules on malignant plasma cells or on the responsible immune effector cell populations, respectively. In MM it seems that an approach based on combination treatment might be appropriate as unsatisfactory results have been yielded by monotherapy with PD-1/PD-L1 inhibitors. Immunomodulatory drugs, which are the current cornerstone of MM treatment, are the most logical partners as they possess many possibly synergistic effects. Nevertheless, the initially optimistic results have become disappointing due to the excessive and unpredictable toxicity of the combination of pembrolizumab with lenalidomide or pomalidomide. The FDA has suspended or put on hold several phase 3 trials in relapsed as well as in newly diagnosed myeloma patients. There are also other potentially synergistic and promising combinations, such as the anti-CD38 monoclonal antibody daratumumab, irradiation, etc. Not only the effective partner but also the correct timing of the initiation of the PD-1/PD-L1 inhibitors treatment seems to be of utmost importance. These strategies are currently being examined in various stages of myeloma such as during consolidation post autologous stem cell transplantation, targeting minimal residual disease or even in high risk smoldering myeloma.

• Klíčová slova
• PD-1, PD-L1, durvalumab, multiple myeloma, nivolumab, pembrolizumab, safety, toxicity,
• MeSH
• antigeny CD279 antagonisté a inhibitory   MeSH
• cílená molekulární terapie MeSH
• imunomodulace účinky léků   MeSH
• klinické zkoušky jako téma MeSH
• lidé MeSH
• mnohočetný myelom farmakoterapie   imunologie   metabolismus   patologie   MeSH
• preklinické hodnocení léčiv MeSH
• protinádorové látky imunologicky aktivní farmakologie   terapeutické užití   MeSH
• protokoly protinádorové kombinované chemoterapie škodlivé účinky   terapeutické užití   MeSH
• signální transdukce účinky léků   MeSH
• T-lymfocyty účinky léků   imunologie   metabolismus   MeSH
• výsledek terapie MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• antigeny CD279 MeSH
• PDCD1 protein, human MeSH Prohlížeč
• protinádorové látky imunologicky aktivní MeSH

INTRODUCTION: Immune checkpoint inhibitors (ICI) have revolutionized the treatment of many malignancies in recent years. However, immune-related adverse events (irAE) are a frequent concern in clinical practice. The safety profile of ICI for the treatment of malignancies in patients diagnosed with autoimmune and cholestatic liver disease (AILD) remains unclear. Due to this uncertainty, these patients were excluded from ICI clinical trials and ICI are withheld from this patient group. In this retrospective multicenter study, we assessed the safety of ICI in patients with AILD. METHODS: We contacted tertiary referral hospitals for the identification of AILD patients under ICI treatment in Europe via the European Reference Network on Hepatological Diseases (ERN RARE-LIVER). Fourteen centers contributed data on AILD patients with malignancies being treated with ICI, another three centers did not treat these patients with ICI due to fear of irAEs. RESULTS: In this study, 22 AILD patients under ICI treatment could be identified. Among these patients, 12 had primary biliary cholangitis (PBC), five had primary sclerosing cholangitis (PSC), four had autoimmune hepatitis (AIH), and one patient had an AIH-PSC variant syndrome. Eleven patients had hepatobiliary cancers and the other 11 patients presented with non-hepatic tumors. The applied ICIs were atezolizumab (n=7), durvalumab (n=5), pembrolizumab (n=4), nivolumab (n=4), spartalizumab (n=1), and in one case combined immunotherapy with nivolumab plus ipilimumab. Among eight patients who presented with grade 1 or 2 irAEs, three demonstrated liver irAEs. Cases with grades ≥ 3 irAEs were not reported. No significant changes in liver tests were observed during the first year after the start of ICI. DISCUSSION: This European multicenter study demonstrates that PD-1/PD-L1 inhibitors appear to be safe in patients with AILD. Further studies on the safety of more potent dual immune checkpoint therapy are needed. We conclude that immunotherapy should not categorically be withheld from patients with AILD.

• Klíčová slova
• PD-1/PD-L1 immune checkpoint inhibitors, autoimmune disease (AID), autoimmune hepatitis (AIH), autoimmune liver diseases (AILD), immune checkpoint inhibitors (ICI), immune related adverse effects (irAEs), primary biliary cholangitis (PBC), primary sclerosing cholangites (PSC),
• MeSH
• antigeny CD274 MeSH
• antigeny CD279 MeSH
• autoimunitní hepatitida * farmakoterapie   MeSH
• cholestáza * MeSH
• inhibitory kontrolních bodů škodlivé účinky   MeSH
• lidé MeSH
• nádory * MeSH
• nivolumab škodlivé účinky   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antigeny CD274 MeSH
• antigeny CD279 MeSH
• inhibitory kontrolních bodů MeSH
• nivolumab MeSH

SKP1-CUL1-F-box protein (SCF) ubiquitin ligases are versatile protein complexes that mediate the ubiquitination of protein substrates. The direct substrate recognition relies on a large family of F-box-domain-containing subunits. One of these substrate receptors is FBXO38, which is encoded by a gene found mutated in families with early-onset distal motor neuronopathy. SCFFBXO38 ubiquitin ligase controls the stability of ZXDB, a nuclear factor associated with the centromeric chromatin protein CENP-B. Loss of FBXO38 in mice results in growth retardation and defects in spermatogenesis characterized by deregulation of the Sertoli cell transcription program and compromised centromere integrity. Moreover, it was reported that SCFFBXO38 mediates the degradation of PD-1, a key immune-checkpoint inhibitor in T cells. Here, we have re-addressed the link between SCFFBXO38 and PD-1 proteolysis. Our data do not support the notion that SCFFBXO38 directly or indirectly controls the abundance and stability of PD-1 in T cells.

• Klíčová slova
• Cullin, FBXO38, Immune Checkpoint, PD-1, Protein Degradation,
• MeSH
• antigeny CD279 * metabolismus   genetika   MeSH
• F-box proteiny * metabolismus   genetika   MeSH
• lidé MeSH
• myši MeSH
• proteinligasy komplexu SCF metabolismus   genetika   MeSH
• proteolýza MeSH
• T-lymfocyty metabolismus   MeSH
• ubikvitinace MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antigeny CD279 * MeSH
• F-box proteiny * MeSH
• Fbxo38 protein, mouse MeSH Prohlížeč
• Pdcd1 protein, mouse MeSH Prohlížeč
• proteinligasy komplexu SCF MeSH

Cell surface expression of PD-1, PD-L1 and PD-L2 immune checkpoints on B and T cells obtained from patients with mantle cell lymphoma shows ambiguous results across many studies and creates obstacles for the implementation of immune checkpoint inhibitors into the therapy of mantle cell lymphoma. Using multiparameter flow cytometry we analysed surface expression of PD-1, PD-L1 and PD-L2 molecules on B and T cells of 31 newly diagnosed mantle cell lymphomas and compared it with the results of 26 newly diagnosed chronic lymphocytic leukaemias and 20 healthy volunteers. To gain insight into the age-dependent changes of surface expression of these immune checkpoints, flow cytometric subanalysis of 30 healthy volunteers of 25-93 years of age was conducted. Overall, we demonstrated weak surface expression of PD-1, PD-L1 and PD-L2 on B and T cells of mantle cell lymphoma patients (< 10 % when compared to healthy individuals). A significant age-dependent increase in the expression of PD-1 and its ligand PD-L2 was observed in healthy volunteers. Our results suggest that neither PD-1 nor its ligands represent relevant druggable targets for the therapy of mantle cell lymphoma. The observed age-dependent changes in healthy population could impact efficiency of immune checkpoint inhibitors and could be at least partly connected with increased incidence of cancer with age.

• MeSH
• antigeny CD273 metabolismus   MeSH
• antigeny CD274 metabolismus   MeSH
• antigeny CD279 metabolismus   MeSH
• B-lymfocyty MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• lymfom z plášťových buněk metabolismus   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• studie případů a kontrol MeSH
• T-lymfocyty MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antigeny CD273 MeSH
• antigeny CD274 MeSH
• antigeny CD279 MeSH
• CD274 protein, human MeSH Prohlížeč
• PDCD1 protein, human MeSH Prohlížeč
• PDCD1LG2 protein, human MeSH Prohlížeč