UCHL1 促进非小细胞肺癌细胞 PD-L1 表达
- 作者列表："Mao R","Tan X","Xiao Y","Wang X","Wei Z","Wang J","Wang X","Zhou H","Zhang L","Shi Y
:PD-L1 expressed on the cancer cells can cause immune escape of NSCLC. Elucidation of the regulatory mechanisms of the PD-L1 expression is a prerequisite for establishment of new tumor immunotherapy strategies. Deubiquitinase UCHL1 is a regulator of cellular signaling transduction and expressed aberrantly in NSCLC. But it is not known whether UCHL1 regulates the expression of PD-L1 in NSCLC cells. In the present study, we found that UCHL1 promotes the expression of PD-L1 in NSCLC cell lines. Besides, UCHL1 expressed in NSCLC cells inhibited activation of Jurkat cells through upregulation of PD-L1 expression in vitro experiments. Moreover, the mechanism for UCHL1 to upregulate PD-L1 expression is that UCHL1 facilitated activation of AKT-P65 signaling pathway. In conclusion, these results demonstrated that UCHL1 promoted PD-L1 expression in NSCLC cells. This finding implied that inhibition of UCHL1 might suppress immune escape of NSCLC via downregulation of PD-L1 expression in NSCLC cells.
: PD-L1 在癌细胞上的表达可引起 NSCLC 的免疫逃逸。阐明 PD-L1 的表达调控机制是建立新的肿瘤免疫治疗策略的前提。去泛素化酶 UCHL1 是细胞信号转导的调节因子，在 NSCLC 中表达异常。但 UCHL1 是否调控 NSCLC 细胞 PD-L1 的表达尚不清楚。在本研究中，我们发现 UCHL1 促进 NSCLC 细胞系中 PD-L1 的表达。此外，在体外实验中，NSCLC 细胞表达的 UCHL1 通过上调 PD-L1 的表达抑制 Jurkat 细胞的活化。此外，UCHL1 上调 PD-L1 表达的机制是 UCHL1 促进了 AKT-P65 信号通路的激活。总之，这些结果证明 UCHL1 促进 NSCLC 细胞 PD-L1 表达。这一发现意味着抑制 UCHL1 可能通过下调 NSCLC 细胞中 PD-L1 的表达来抑制 NSCLC 的免疫逃逸。
METHODS::Macrophages (MΦ) play a critical role in tumor growth, immunosuppression and inhibition of adaptive immune responses in cancer. Hence, targeting signaling pathways in MΦs that promote tumor immunosuppression will provide therapeutic benefit. PI3Kγ has been recently established by our group and others as a novel immuno-oncology target. Herein, we report that a macrophage Syk-PI3K axis drives polarization of immunosuppressive MΦs which establish an immunosuppressive tumor microenvironment in in vivo syngeneic tumor models. Genetic or pharmacological inhibition of Syk and/or PI3Kγ in MΦs promotes a pro-inflammatory MΦphenotype, restores CD8+ T cell activity, destabilizes HIF under hypoxia, and stimulates an antitumor immune response. Assay for Transposase-accessible Chromatin using Sequencing (ATAC-seq) analyses on the bone marrow derived macrophages (BMDMs) show that inhibition of Syk kinase promotes activation and binding of NF-κB motif in SykMC-KO BMDMs, thus stimulating immunostimulatory transcriptional programming in MΦs to suppress tumor growth. Finally, we have developed in silico the "first in class" dual Syk/PI3K inhibitor, SRX3207, for the combinatorial inhibition of Syk and PI3K in one small molecule. This chemotype demonstrates efficacy in multiple tumor models and represents a novel combinatorial approach to activate antitumor immunity.
METHODS::Dysfunction of invariant natural killer T (iNKT) cells in tumor microenvironment hinders their anti-tumor efficacy, and the underlying mechanisms remain unclear. Here we report that iNKT cells increase lipid biosynthesis after activation, and that is promoted by PPARγ and PLZF synergically through enhancing transcription of Srebf1. Among those lipids, cholesterol is required for the optimal IFN-γ production from iNKT cells. Lactic acid in tumor microenvironment reduces expression of PPARγ in intratumoral iNKT cells and consequently diminishes their cholesterol synthesis and IFN-γ production. Importantly, PPARγ agonist pioglitazone, a thiazolidinedione drug for type 2 diabetes, successfully restores IFN-γ production in tumor-infiltrating iNKT cells from both human patients and mouse models. Combination of pioglitazone and alpha-galactosylceramide treatments significantly enhances iNKT cell-mediated anti-tumor immune responses and prolongs survival of tumor-bearing mice. Our studies provide a strategy to augment the anti-tumor efficacy of iNKT cell-based immunotherapies via promoting their lipid biosynthesis.
METHODS::Near-infrared photoimmunotherapy (NIR-PIT) is a newly developed and selective cancer treatment that induces necrotic and immunogenic cell death and utilizes a monoclonal antibody conjugated to a photo-absorber dye, IR700DX, activated by NIR light. Although CD44 is surface cancer marker associated with drug resistance, anti-CD44-IR700 NIR-PIT results in inhibited cell growth and prolonged survival in multiple tumor types. Meanwhile, anti-CD25-IR700-targeted NIR-PIT has been reported to achieve selective and local depletion of FOXP3+CD25+CD4+ regulatory T cells (Tregs), which are primary immunosuppressive cells in the tumor microenvironment (TME), resulting in activation of local antitumor immunity. Combined NIR-PIT with CD44- and CD25-targeted agents has the potential to directly eliminate tumor cells and also amplify the immune response by removing FOXP3+CD25+CD4+ Tregs from the TME. We investigated the difference in therapeutic effects of CD44-targeted NIR-PIT alone, CD25-targeted NIR-PIT alone, and the combination of CD44- and CD25-targeted NIR-PIT in several syngeneic tumor models, including MC38-luc, LL/2, and MOC1. The combined NIR-PIT showed significant tumor growth inhibition and prolonged survival compared with CD44-targeted NIR-PIT alone in all tumor models and showed prolonged survival compared with CD25-targeted NIR-PIT alone in MC38-luc and LL/2 tumors. Combined CD44/CD25 NIR-PIT also resulted in some complete remissions, whereas this was not achieved with either type of NIR-PIT alone. Therefore, combined NIR-PIT simultaneously targeting cancer antigens and immunosuppressive cells in the TME may be more effective than either type of NIR-PIT alone and may have potential to induce prolonged immune responses in treated tumors.