Lin Shuye, Xu Hanli, Pang Mengdi, Zhou Xiaomeng, Pan Yuanming, Zhang Lishu, Guan Xin, Wang Xiaoyue, Lin Bonan, Tian Rongmeng, Chen Keqiang, Zhang Xiaochen, Yang Zijiang, Ji Fengmin, Huang Yingying, Wei Wu, Gong Wanghua, Ren Jianke, Wang Ji Ming, Guo Mingzhou, Huang Jiaqiang
Cancer Research Center, Beijing Chest Hospital, Capital Medical University, Beijing Tuberculosis and Thoracic Tumor Institute, Beijing, China.
College of Life Sciences & Bioengineering, Beijing Jiaotong University, Beijing, China.
Front Oncol. 2022 Apr 11;12:831268. doi: 10.3389/fonc.2022.831268. eCollection 2022.
Hepatocellular carcinoma (HCC) is one of the most lethal human tumors with extensive intratumor heterogeneity (ITH). Serine protease 3 (PRSS3) is an indispensable member of the trypsin family and has been implicated in the pathogenesis of several malignancies, including HCC. However, the paradoxical effects of on carcinogenesis due to an unclear molecular basis impede the utilization of its biomarker potential. We hereby explored the contribution of transcripts to tumor functional heterogeneity by systematically dissecting the expression of four known splice variants of () and their functional relevance to HCC.
The expression and DNA methylation of transcripts and their associated clinical relevance in HCC were analyzed using several publicly available datasets and validated using qPCR-based assays. Functional experiments were performed in gain- and loss-of-function cell models, in which transcript constructs were separately transfected after deleting expression by CRISPR/Cas9 editing.
was aberrantly differentially expressed toward bipolarity from very low ( ) to very high ( ) expression across HCC cell lines and tissues. This was attributable to the disruption of , in which and/or were dominant transcripts leading to expression, whereas and were rarely or minimally expressed. The expression of or was inversely associated with site-specific CpG methylation at the promoter region that distinguished HCC cells and tissues phenotypically between hypermethylated low-expression (m ) and hypomethylated high-expression (um ) groups. displayed distinct functions from oncogenic to tumor-suppressive , or in HCC cells. Clinically, aberrant expression of was translated into divergent relevance in patients with HCC, in which significant epigenetic downregulation of was seen in early HCC and was associated with favorable patient outcome.
These results provide the first evidence for the transcriptional and functional characterization of transcripts in HCC. Aberrant expression of divergent disrupted by site-specific CpG methylation may integrate the effects of oncogenic and tumor-suppressive , resulting in the molecular diversity and functional plasticity of in HCC. Dysregulated expression of by site-specific CpG methylation may have potential diagnostic value for patients with early HCC.
肝细胞癌（HCC）是最致命的人类肿瘤之一，具有广泛的肿瘤内异质性（ITH）。丝氨酸蛋白酶3（PRSS3）是胰蛋白酶家族不可或缺的成员，并且与包括HCC在内的多种恶性肿瘤的发病机制有关。然而，由于分子基础尚不清楚，其对致癌作用的矛盾影响阻碍了其作为生物标志物潜力的利用。我们在此通过系统剖析PRSS3的四种已知剪接变体（PRSS3）的表达及其与HCC的功能相关性，探讨PRSS3转录本对肿瘤功能异质性的贡献。
使用多个公开可用数据集分析PRSS3转录本的表达和DNA甲基化及其在HCC中的相关临床相关性，并使用基于qPCR的检测方法进行验证。在功能获得和功能丧失细胞模型中进行功能实验，其中通过CRISPR/Cas9编辑删除PRSS3表达后分别转染PRSS3转录本构建体。
在HCC细胞系和组织中，PRSS3从极低（）到极高（）表达呈两极异常差异表达。这归因于PRSS3的破坏，其中PRSS3-1和/或PRSS3-2是导致PRSS3表达的主要转录本，而PRSS3-3和PRSS3-4很少或几乎不表达。PRSS3-1或PRSS3-2的表达与PRSS3启动子区域的位点特异性CpG甲基化呈负相关，该甲基化在高甲基化低表达（m）和低甲基化高表达（um）组之间在表型上区分了HCC细胞和组织。PRSS3在HCC细胞中显示出从致癌性PRSS3-1到肿瘤抑制性PRSS3-3或PRSS3-4的不同功能。临床上，PRSS3的异常表达在HCC患者中转化为不同的相关性，其中在早期HCC中观察到PRSS3的显著表观遗传下调，并且与患者的良好预后相关。
这些结果为HCC中PRSS3转录本的转录和功能特征提供了首个证据。位点特异性CpG甲基化破坏的不同PRSS3的异常表达可能整合致癌性PRSS3-1和肿瘤抑制性PRSS3-3或PRSS3-4的作用，导致HCC中PRSS3的分子多样性和功能可塑性。位点特异性CpG甲基化导致的PRSS3表达失调可能对早期HCC患者具有潜在的诊断价值。
