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Project description:PD-L1 is a ligand for the inhibitory PD1 receptor on T cells and its expression in some cancers inhibits anti-cancer immune response. In melanoma, PD-L1 expression is induced in response to immune stimuli but in a proportion of melanomas it is constitutively expressed. Factors that drive constitutive expression of PD-L1 are unknown. Here we performed genome-scale methylation analysis of six cell lines that constitutively express PD-L1 (PD-L1 positive, referred to as PD-L1CON) and six cell lines that only express PD-L1 after treatment with IFN- (PD-L1 negative, referred to as PD-L1IND)
2018-05-24 | GSE107621 | GEO
Project description:PD-L1 is a ligand for the inhibitory PD1 receptor on T cells and its expression in some cancers inhibits anti-cancer immune response. In melanoma, PD-L1 expression is induced in response to immune stimuli but in a proportion of melanomas it is constitutively expressed. Factors that drive constitutive expression of PD-L1 are unknown. Here we performed RNA-Seq analysis of six cell lines that constitutively express PD-L1 (PD-L1 positive, referred to as PD-L1CON) and six cell lines that only express PD-L1 after treatment with IFN- (PD-L1 negative, referred to as PD-L1IND)
2018-05-24 | GSE107620 | GEO
Project description:Global hypomethylation mediated changes regulate constitutive PD-L1 expression in melanoma
| PRJNA420852 | ENA
Project description:Global hypomethylation mediated changes regulate constitutive PD-L1 expression in melanoma [RRBS]
| PRJNA420862 | ENA
Project description:Constitutive expression of the immune checkpoint, PD-L1, inhibits anti-tumor immune responses in cancer, although the factors involved in PD-L1 regulation are poorly understood. Here we show that loss of global DNA methylation, particularly in intergenic regions and repeat elements, is associated with constitutive (PD-L1CON), versus inducible (PD-L1IND), PD-L1 expression in melanoma cell lines. We further show this is accompanied by transcriptomic up-regulation. De novo epigenetic regulators (e.g., DNMT3A) are strongly correlated with PD-L1 expression and methylome status. Accordingly, decitabine-mediated inhibition of global methylation in melanoma cells leads to increased PD-L1 expression. Moreover, viral mimicry and immune response genes are highly expressed in lymphocyte-negative plus PD-L1-positive melanomas, versus PD-L1-negative melanomas in The Cancer Genome Atlas (TCGA). In summary, using integrated genomic analysis we identified that global DNA methylation influences PD-L1 expression in melanoma, and hence melanoma's ability to evade anti-tumor immune responses. These results have implications for combining epigenetic therapy with immunotherapy.
| S-EPMC6147024 | biostudies-literature
Project description:Global hypomethylation mediated changes regulate constitutive PD-L1 expression in melanoma [RNA-Seq]
| PRJNA420861 | ENA
Project description:Oncogenic driver mutations in several tumor types promote constitutive PD-L1 expression, a crucial ligand in PD-1-mediated tumor immune escape. Our studies in melanoma suggest a different mechanism-one of "adaptive immune resistance" in which PD-L1 expression is primarily driven by cytokine induction and is independent of BRAF mutational status.
| S-EPMC4589064 | biostudies-literature
Project description:BackgroundDPY30 is a common subunit of the human SET1/MLL complex and is an essential protein required for the activity of SET1/MLL methyltransferase. DPY30 regulates the histone H3K4 modification, and dysfunction of DPY30 might contribute to the regulation of cancer immune evasion. However, the functions and regulation of DPY30 in the expression of programmed cell death ligand 1 (PD-L1) is still not completely explored.MethodsVarious online databases were used for data processing and visualization, including UALCAN, Oncomine, cBioPortal, SangerBox, TISIDB, TIMER, and GEPIA databases. The expression of DPY30 and PD-L1 in melanoma tissues were evaluated by IHC. Chromatin Immunoprecipitation (ChIP), RT-PCR and flow cytometry were used to elucidate the underlying molecular mechanism of PD-L1 expression regulation and its function.ResultsThe mRNA level of DPY30 in melanoma was higher than in normal tissues. The expression of DPY30 was positively associated with TMB, neoantigens and PD-L1 expression. Furthermore, DPY30 expression showed significant positive correlations with immune suppressor cells and ICP genes involved in T-cell exhaustion. IHC showed that the positive rates of DPY30 and PD-L1 in melanoma tissues were 62% and 58%, respectively. Correlation analysis revealed that DPY30 over-expression was positively associated with PD-L1 expression. Silencing of DPY30 by specific siRNA significantly inhibited PD-L1 expression. ChIP analysis revealed that H3K4me3 levels were enriched in the proximal PD-L1 promoter region in tumor cells. Inhibition of DPY30 still suppressed the PD-L1 level in IFN-γ treated MMAC-SF cells. Furthermore, the apoptosis of PD1+ T-cells in co-culture with MMAC-SF cells by knockdown of DPY30 were markedly reduced.ConclusionThis study shows the roles of DPY30 in regulating the cancer immune evasion in melanoma. Targeting the DPY30-H3K4me3 axis might be an alternative approach to enhance the efficacy of checkpoint immunotherapy.
| S-EPMC9525212 | biostudies-literature
Project description:BackgroundCancer immunotherapies aimed at activating immune system, especially by blocking immune checkpoints, have become a successful modality for treating patients with advanced cancers. However, its clinical practice is frequently conceded by high outcomes, low initial response rates and severe side effects. New strategies are necessary to complement and advance this biological therapy. Erzhi Pills (EZP) have diverse pharmaceutical effects including immune regulation, anti-tumor and anti-senescence. We hypothesized that EZP could exert its antitumor effect through immunomodulation.PurposeThe aim of this study was to investigate the effects of EZP on anti-tumor activities, and define its molecular mechanisms.MethodsBy applying melanoma model with high immune infiltrates, we determined the anti-melanoma effect of EZP. To identify whether this effect was mediated by direct targeting tumor cells, cell viability and apoptosis were examined in vitro. Network pharmacology analysis was used to predict the potential mechanisms of EZP for melanoma via immune response. Flow cytometry, immunohistochemistry (IHC), enzyme-linked immunosorbent assay (ELISA) and crystal violet (CV) experiments were performed to detect T cell infiltrations and functions mediated by EZP. The mechanism of EZP was further investigated by western blotting both in vivo and in vitro.ResultsThe administration of EZP significantly inhibited tumor weight and volume. EZP extract could only slightly reduce cell viability and induce melanoma apoptosis. Network pharmacology analysis predicted that JAK-STAT signaling pathway and T cell receptor signaling pathway might be involved during EZP treatment. Flow cytometry and IHC analyses showed that EZP increased the number of CD4+ T cells and enhanced the function of CD8+ T cells. In co-culture experiments, EZP elevated killing ability of T cells. Western blotting showed that EZP treatment reduced PD-L1 signaling pathway.ConclusionThese findings indicated that EZP exerted anti-melanoma effects by inducing apoptosis and blocking PD-L1 to activate T cells. EZP might represent a promising candidate drug for cancer immunotherapies.
| S-EPMC10839997 | biostudies-literature
Project description:Melanoma is the most serious form of skin cancer. Metastatic melanoma historically carries a poor prognosis and until recently there have been few effective agents available to treat widely disseminated disease. Recognition of the immunogenic nature of melanoma has resulted in the development of various immunotherapeutic approaches, especially with regards to the programmed cell death 1 (PD-1) receptor and its ligand (PD-L1). Antibodies targeting the PD-1 axis have shown enormous potential in the treatment of metastatic melanoma. Here, we will review the immune basis for the disease and discuss approved immunotherapeutic options for advanced melanoma, as well as the current state of development of PD-1 and PD-L1 antibodies and their importance in shaping the future of melanoma treatment.
| S-EPMC4514131 | biostudies-literature