Dong Xiao, Wu Lixia, Gong Libao, Huang Daijia, Guo Jinfeng, Ma Meng, Xiao Li, Xu Shuangwei, Chang Jianhua, Che Xu, Hang Junjie
Department of Oncology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, China.
Department of Oncology, Shanghai JingAn District ZhaBei Central Hospital, Shanghai 200070, China.
Life Sci. 2025 Jul 1;372:123631. doi: 10.1016/j.lfs.2025.123631. Epub 2025 Apr 11.
Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy which lacks effective therapeutic targets. We previously demonstrated that low PPP3CB expression correlates with poor prognosis in PDAC. This study aims to investigate the function and underlying mechanism of PPP3CB in pancreatic cancer progression.
We analyzed PPP3CB expression via immunohistochemistry in PDAC specimens and investigated its prognostic value by statistical method. Differentially expressed genes were analyzed by qRT-PCR and Western blot. Mass spectrometry, Co-IP, ChIP-seq, luciferase analysis, flow cytometry, immunofluorescence and confocal microscopy were performed to investigate the underlying mechanisms of PPP3CB and regulation of ATOH8/Sp1 axis. Mice xenograft models were employed to assess the malignant behaviors in vivo.
We found that PPP3CB expression was higher in patients with early-stage PDAC than in those with late-stage PDAC. PPP3CB overexpression impaired PDAC proliferation and metastasis in vitro and in vivo, whereas its depletion or treatment with CsA-a PPP3CB inhibitor, had the opposite effect. Liquid chromatography-tandem mass spectrometry predicted an interaction between PPP3CB and ATOH8. Further investigation confirmed that PPP3CB interacts with ATOH8 and enhances its nuclear translocation in PDAC cells. ChIP-seq and luciferase analyses showed that ATOH8 binds to the promoter of Sp1, a well-known oncogenic transcription factor in PDAC. Furthermore, PPP3CB transcriptionally inhibits Sp1 expression and suppresses pancreatic cancer metastases by increasing ATOH8 nuclear content.
These findings suggest a novel role for PPP3CB in preventing PDAC progression by promoting ATOH8 nuclear translocation and transcriptionally inhibiting Sp1. Consequently, PPP3CB emerges as a potential therapeutic target for PDAC.
胰腺导管腺癌（PDAC）是一种极具致死性的恶性肿瘤，缺乏有效的治疗靶点。我们之前证明低水平的PPP3CB表达与PDAC的不良预后相关。本研究旨在探讨PPP3CB在胰腺癌进展中的功能及潜在机制。
我们通过免疫组化分析了PDAC标本中PPP3CB的表达，并通过统计学方法研究其预后价值。采用qRT-PCR和蛋白质免疫印迹分析差异表达基因。进行了质谱分析、免疫共沉淀、染色质免疫沉淀测序、荧光素酶分析、流式细胞术、免疫荧光和共聚焦显微镜检查，以研究PPP3CB的潜在机制及对ATOH8/Sp1轴的调控。采用小鼠异种移植模型评估体内的恶性行为。
我们发现早期PDAC患者的PPP3CB表达高于晚期患者。PPP3CB过表达在体外和体内均损害PDAC的增殖和转移，而其缺失或用CsA（一种PPP3CB抑制剂）处理则产生相反的效果。液相色谱-串联质谱预测PPP3CB与ATOH8之间存在相互作用。进一步研究证实，PPP3CB与ATOH8相互作用并增强其在PDAC细胞中的核转位。染色质免疫沉淀测序和荧光素酶分析表明，ATOH8与Sp1（PDAC中一种著名的致癌转录因子）的启动子结合。此外，PPP3CB通过增加ATOH8核含量转录抑制Sp1表达并抑制胰腺癌转移。
这些发现表明PPP3CB通过促进ATOH8核转位和转录抑制Sp1在预防PDAC进展中具有新作用。因此，PPP3CB成为PDAC的一个潜在治疗靶点。
