Table_4_Downregulation of DUSP9 Promotes Tumor Progression and Contributes to Poor Prognosis in Human Colorectal Cancer.DOCX

BackgroundDual-specificity phosphatase 9 (DUSP9) belongs to the dual-specificity protein phosphatase subfamily. Recently, increasing attention has been paid on the role of DUSP9 in a variety of cancers. However, its functional role in tumor development is still unclear, especially in colorectal cancer (CRC).MethodsThe functional role of DUSP9 in inhibiting the progression of CRC was verified using colony formation assay, wound healing assay, nude mice xenograft model, etc. RNA-seq was performed to assess the gene expression profiling in SW480 cells with DUSP9 stable knockdown and shControl cells. Bisulfite sequencing (BSE) was performed to reveal the methylation status of CpG island in the promoter of DUSP9.ResultsDUSP9 was significantly downregulated in tumor tissues compared with peritumor tissues. Mechanistically, the high methylation status of CpG island in the promoter of DUSP9 may lead to the downregulation of DUSP9 in CRC. Clinically, low DUSP9 expression in CRC was closely associated with depth of invasion, metastasis (TNM) stage, and poor survival, indicating that DUSP9 may be involved in the progression of CRC. Functional study revealed that DUSP9 inhibited proliferation, migration, invasion, and epithelial–mesenchymal transition of CRC cells both in vitro and in vivo. Transcriptome profiling studies revealed that Erk signaling was involved in the tumor progression mediated by DUSP9 silencing, which is confirmed by cell experiments and clinical tissue sample staining analysis.ConclusionOur findings demonstrate that DUSP9 plays a critical role in the progression of CRC, and therapeutic intervention to increase the expression or activity of DUSP9 may be a potential target for CRC treatment in the future.

背景：双特异性磷酸酶9（DUSP9）属于双特异性蛋白磷酸酶亚家族。近期，DUSP9在多种癌症中的角色受到了越来越多的关注。然而，其在肿瘤发生发展中的功能作用尚不明确，尤其是在结直肠癌（CRC）中。方法：通过集落形成试验、伤口愈合试验、裸鼠异种移植模型等验证了DUSP9在抑制CRC进展中的功能作用。对SW480细胞中DUSP9稳定敲低细胞和shControl细胞进行了RNA测序，以评估基因表达谱。通过亚硫酸氢盐测序（BSE）揭示了DUSP9启动子中CpG岛甲基化状态。结果：与癌旁组织相比，肿瘤组织中DUSP9表达显著下调。从机制上讲，DUSP9启动子中CpG岛的高甲基化状态可能导致CRC中DUSP9的下调。临床研究表明，CRC中DUSP9的低表达与侵袭深度、转移（TNM分期）和预后不良密切相关，表明DUSP9可能参与CRC的进展。功能研究揭示了DUSP9在体外和体内均抑制CRC细胞的增殖、迁移、侵袭和上皮-间质转化。转录组分析显示，Erk信号通路参与了DUSP9沉默介导的肿瘤进展，这通过细胞实验和临床组织样本染色分析得到证实。结论：我们的研究结果表明，DUSP9在CRC进展中发挥关键作用，未来针对DUSP9表达或活性的治疗干预可能成为CRC治疗的一个潜在靶点。