PDF(Pubmed)
Abstract：
Immunotherapy for pancreatic ductal carcinoma (PDAC) remains disappointing due to the repressive tumor microenvironment and T cell exhaustion, in which the roles of interferon-stimulated genes were largely unknown. Here, we focused on a typical interferon-stimulated gene, GBP4, and investigated its potential diagnostic and therapeutic value in pancreatic cancer. Expression analysis on both local samples and public databases indicated that GBP4 was one of the most dominant GBP family members present in the PDAC microenvironment, and the expression level of GBP4 was negatively associated with patient survival. We then identified DNA hypo-methylation in regulatory regions of GBP4 in PDAC, and validated its regulatory role on GBP4 expression via performing targeted methylation using dCas9-SunTag-DNMAT3A-sgRNA-targeted methylation system on selected DNA locus. After that, we investigated the downstream functions of GBP4, and chemotaxis assays indicated that GBP4 overexpression significantly improved the infiltration of CD8+T cells, but also induced upregulation of immune checkpoint genes and T cell exhaustion. Lastly, in vitro T cell killing assays using primary organoids suggested that the PDAC samples with high level of GBP4 expression displayed significantly higher sensitivity to anti-PD-1 treatment. Taken together, our studies revealed the expression patterns and epigenetic regulatory mechanisms of GBP4 in pancreatic cancer and clarified the effects of GBP4 on T cell exhaustion and antitumor immunology.
摘要：
由于抑制性肿瘤微环境和T细胞耗竭，胰腺导管癌（PDAC）的免疫治疗仍然令人失望。其中干扰素刺激基因的作用在很大程度上是未知的。这里,我们专注于一个典型的干扰素刺激基因，GBP4，并研究其在胰腺癌中的潜在诊断和治疗价值。对本地样本和公共数据库的表达分析表明，GBP4是PDAC微环境中最主要的GBP家族成员之一。GBP4的表达水平与患者生存率呈负相关。然后我们鉴定了PDAC中GBP4调控区的DNA低甲基化，并通过在选定的DNA基因座上使用dCas9-SunTag-DNMAT3A-sgRNA靶向甲基化系统进行靶向甲基化来验证其对GBP4表达的调节作用。之后,我们研究了GBP4的下游功能，趋化试验表明GBP4过表达显著改善了CD8+T细胞的浸润，而且还诱导了免疫检查点基因的上调和T细胞耗竭。最后,使用初级类器官的体外T细胞杀伤试验表明,具有高水平GBP4表达的PDAC样品显示出抗PD-1治疗的显著更高的敏感性。一起来看,我们的研究揭示了GBP4在胰腺癌中的表达模式和表观遗传调控机制,阐明了GBP4对T细胞耗竭和抗肿瘤免疫学的影响.
