Objective: The dishevelled-associated activator of morphogenesis 1 (DAAM1) has been reported to be closely associated with human cancers. However, its involvement in human gastric cancer (GC) remains largely unexplored. This study aimed to investigate the clinical significance and biological roles of Daam1 in human GC.
Methods: Daam1 protein expression was examined in 124 cases of gastric adenocarcinomas using immunohistochemistry. Daam1 plasmid and siRNA transfection were carried out in SGC7901 and AGS cell lines. CCK-8, colony formation, Annexin V/PI, JC-1 staining, and Western blotting were used to explore the biological functions and potential underlying mechanisms of Daam1 in GC cells.
Results: Our results showed that Daam1 was overexpressed in GC specimens. A high Daam1 level was associated with tumor-node-metastasis (TNM) stage, T status, nodal metastasis, and poor patient survival. Analysis of the Oncomine dataset revealed upregulation of Daam1 mRNA in GC tissues. Western blot showed that Daam1 protein expression was higher in GC cell lines compared to the normal GES-1 cell line. CCK-8 and colony formation assays showed that ectopic Daam1 expression upregulated the cell growth rate and colony number in SGC-7901 cells, while Daam1 siRNA knockdown downregulated the growth rate and colony number in AGS cells. CCK-8 and Annexin V/PI apoptosis assays demonstrated that Daam1 overexpression decreased cisplatin sensitivity and downregulated cisplatin-induced apoptosis. JC1 staining showed that Daam1 overexpression upregulated, while Daam1 depletion downregulated mitochondrial membrane potential. Mechanistically, Daam1 overexpression downregulated p21 and upregulated p-ERK and p-AKT. The increased proliferation rate and decreased cisplatin sensitivity/apoptosis induced by ectopic Daam1 were reversed after treatment with AKT and ERK inhibitors.
Conclusion: Taken together, our results showed that Daam1 overexpression was associated with poor prognosis and promoted malignant activity via regulation of ERK and AKT pathways in GC cells, indicating Daam1 is a malignant biomarker and potential therapeutic target in GC.

Keywords: Daam1, ERK, AKT, apoptosis, gastric cancer


中文翻译：

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Daam1 过表达促进胃癌进展并调节 ERK 和 AKT 信号通路

目的：据报道，蓬乱相关的形态发生激活因子 1 (DAAM1) 与人类癌症密切相关。然而，它在人类胃癌 (GC) 中的作用在很大程度上仍未得到探索。本研究旨在探讨 Daam1 在人类 GC 中的临床意义和生物学作用。
方法：采用免疫组织化学方法检测 124 例胃腺癌患者 Daam1 蛋白的表达。在 SGC7901 和 AGS 细胞系中进行 Daam1 质粒和 siRNA 转染。CCK-8、集落形成、Annexin V/PI、JC-1染色和Western印迹用于探索Daam1在GC细胞中的生物学功能和潜在的潜在机制。
结果：我们的结果表明，Daam1 在 GC 标本中过表达。高 Daam1 水平与肿瘤淋巴结转移 (TNM) 分期、T 状态、淋巴结转移和患者生存率差有关。Oncomine 数据集的分析揭示了 GC 组织中 Daam1 mRNA 的上调。Western印迹显示，与正常的GES-1细胞系相比，GC细胞系中的Daam1蛋白表达更高。CCK-8 和集落形成测定表明，异位 Daam1 表达上调 SGC-7901 细胞中的细胞生长速率和集落数，而 Daam1 siRNA 敲低下调 AGS 细胞中的生长速率和集落数。CCK-8 和 Annexin V/PI 细胞凋亡测定表明，Daam1 过表达降低了顺铂敏感性并下调了顺铂诱导的细胞凋亡。JC1 染色显示 Daam1 过表达上调，而 Daam1 耗竭下调线粒体膜电位。机制上，Daam1 过表达下调 p21 并上调 p-ERK 和 p-AKT。用 AKT 和 ERK 抑制剂治疗后，异位 Daam1 诱导的增殖率增加和顺铂敏感性/细胞凋亡降低被逆转。
结论：综上所述，我们的研究结果表明，Daam1 过表达与不良预后相关，并通过调节 GC 细胞中的 ERK 和 AKT 通路促进恶性活动，表明 Daam1 是 GC 的恶性生物标志物和潜在的治疗靶点。

关键词： Daam1，ERK，AKT，细胞凋亡，胃癌