Wang Jiatong, Wong Chi Hin, Zhu Yinxin, Yao Xiaoqiang, Ng Kelvin K C, Zhou Chengzhi, To Ka Fai, Chen Yangchao
School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin NT, Hong Kong.
Department of Surgery, The Chinese University of Hong Kong, Shatin NT, Hong Kong.
Biomark Res. 2023 Aug 8;11(1):74. doi: 10.1186/s40364-023-00514-4.
Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with a dismal prognosis, and despite significant advances in our understanding of its genetic drivers, like KRAS, TP53, CDKN2A, and SMAD4, effective therapies remain limited. Here, we identified a new therapeutic target GRIN2D and then explored its functions and mechanisms in PDAC progression.
We performed a genome-wide RNAi screen in a PDAC xenograft model and identified GRIN2D, which encodes the GluN2D subunit of N-methyl-D-aspartate receptors (NMDARs), as a potential oncogene. Western blot, immunohistochemistry, and analysis on Gene Expression Omnibus were used for detecting the expression of GRIN2D in PDAC. Cellular experiments were conducted for exploring the functions of GRIN2D in vitro while subcutaneous and orthotopic injections were used in in vivo study. To clarify the mechanism, we used RNA sequencing and cellular experiments to identify the related signaling pathway. Cellular assays, RT-qPCR, and western blot helped identify the impacts of the NMDAR antagonist memantine.
We demonstrated that GRIN2D was highly expressed in PDAC cells, and further promoted oncogenic functions. Mechanistically, transcriptome profiling identified GRIN2D-regulated genes in PDAC cells. We found that GRIN2D promoted PDAC progression by activating the p38 MAPK signaling pathway and transcription factor CREB, which in turn promoted the expression of HMGA2 and IL20RB. The upregulated GRIN2D could effectively promote tumor growth and liver metastasis in PDAC. We also investigated the therapeutic potential of NMDAR antagonism in PDAC and found that memantine reduced the expression of GRIN2D and inhibited PDAC progression.
Our results suggested that NMDA receptor GRIN2D plays important oncogenic roles in PDAC and represents a novel therapeutic target.
胰腺导管腺癌（PDAC）是一种预后极差的毁灭性疾病，尽管我们对其基因驱动因素（如KRAS、TP53、CDKN2A和SMAD4）的理解有了显著进展，但有效的治疗方法仍然有限。在此，我们鉴定了一个新的治疗靶点GRIN2D，然后探讨了其在PDAC进展中的功能和机制。
我们在PDAC异种移植模型中进行了全基因组RNA干扰筛选，鉴定出GRIN2D作为一种潜在的癌基因，它编码N-甲基-D-天冬氨酸受体（NMDARs）的GluN2D亚基。采用蛋白质免疫印迹法、免疫组织化学法以及对基因表达综合数据库的分析来检测GRIN2D在PDAC中的表达。进行细胞实验以在体外探索GRIN2D的功能，同时在体内研究中采用皮下注射和原位注射。为阐明机制，我们使用RNA测序和细胞实验来鉴定相关信号通路。细胞实验、逆转录定量聚合酶链反应和蛋白质免疫印迹法有助于确定NMDAR拮抗剂美金刚的影响。
我们证明GRIN2D在PDAC细胞中高表达，并进一步促进致癌功能。从机制上讲，转录组分析确定了PDAC细胞中GRIN2D调控的基因。我们发现GRIN2D通过激活p38丝裂原活化蛋白激酶信号通路和转录因子CREB来促进PDAC进展，进而促进HMGA2和IL20RB的表达。上调的GRIN2D可有效促进PDAC的肿瘤生长和肝转移。我们还研究了NMDAR拮抗作用在PDAC中的治疗潜力，发现美金刚可降低GRIN2D的表达并抑制PDAC进展。
我们的结果表明，NMDA受体GRIN2D在PDAC中发挥重要的致癌作用，并代表一个新的治疗靶点。
