Department of Gastroenterology, the Central Hospital of Wuhan, Key Laboratory for Molecular Diagnosis of Hubei Province, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430014, China.
Department of Gastrointestinal Surgery, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China.
Curr Med Sci. 2024 Jun;44(3):529-544. doi: 10.1007/s11596-024-2871-5. Epub 2024 May 29.
To uncover the mechanisms underlying the development of colorectal cancer (CRC), we applied bioinformatic analyses to identify key genes and experimentally validated their possible roles in CRC onset and progression.
We performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis on differentially expressed genes (DEGs), constructed a protein-protein interaction (PPI) network to find the top 10 hub genes, and analyzed their expression in colon adenocarcinoma (COAD) and rectum adenocarcinoma (READ). We also studied the correlation between these genes and immune cell infiltration and prognosis and validated the expression of SLC9A2 in CRC tissues and cell lines using qRT-PCR and Western blotting. Functional experiments were conducted in vitro to investigate the effects of SLC9A2 on tumor growth and metastasis.
We found 130 DEGs, with 45 up-regulated and 85 down-regulated in CRC. GO analysis indicated that these DEGs were primarily enriched in functions related to the regulation of cellular pH, zymogen granules, and transmembrane transporter activity. KEGG pathway analysis revealed that the DEGs played pivotal roles in pancreatic secretion, rheumatoid arthritis, and the IL-17 signaling pathway. We identified 10 hub genes: CXCL1, SLC26A3, CXCL2, MMP7, MMP1, SLC9A2, SLC4A4, CLCA1, CLCA4, and ZG16. GO enrichment analysis showed that these hub genes were predominantly involved in the positive regulation of transcription. Gene expression analysis revealed that CXCL1, CXCL2, MMP1, and MMP7 were highly expressed in CRC, whereas CLCA1, CLCA4, SLC4A4, SLC9A2, SLC26A3, and ZG16 were expressed at lower levels. Survival analysis revealed that 5 key genes were significantly associated with the prognosis of CRC. Both mRNA and protein expression levels of SLC9A2 were markedly reduced in CRC tissues and cell lines. Importantly, SLC9A2 overexpression in SW480 cells led to a notable inhibition of cell proliferation, migration, and invasion. Western blotting analysis revealed that the expression levels of phosphorylated ERK (p-ERK) and phosphorylated JNK (p-JNK) proteins were significantly increased, whereas there were no significant changes in the expression levels of ERK and JNK following SLC9A2 overexpression. Correlation analysis indicated a potential link between SLC9A2 expression and the MAPK signaling pathway.
Our study suggests that SLC9A2 acts as a tumor suppressor through the MAPK pathway and could be a potential target for CRC diagnosis and therapy.
为了揭示结直肠癌（CRC）发生发展的机制，我们应用生物信息学分析方法鉴定关键基因，并通过实验验证其在 CRC 发生和进展中的可能作用。
我们对差异表达基因（DEGs）进行基因本体论（GO）和京都基因与基因组百科全书（KEGG）通路分析，构建蛋白质-蛋白质相互作用（PPI）网络以找到前 10 个枢纽基因，并分析它们在结肠腺癌（COAD）和直肠腺癌（READ）中的表达。我们还研究了这些基因与免疫细胞浸润和预后的相关性，并通过 qRT-PCR 和 Western blot 验证了 SLC9A2 在 CRC 组织和细胞系中的表达。体外功能实验研究了 SLC9A2 对肿瘤生长和转移的影响。
我们发现 130 个 DEGs，其中 45 个上调，85 个下调。GO 分析表明，这些 DEGs主要富集在与细胞 pH 调节、酶原颗粒和跨膜转运体活性相关的功能中。KEGG 通路分析显示，DEGs 在胰腺分泌、类风湿关节炎和 IL-17 信号通路中发挥关键作用。我们鉴定出 10 个枢纽基因：CXCL1、SLC26A3、CXCL2、MMP7、MMP1、SLC9A2、SLC4A4、CLCA1、CLCA4 和 ZG16。GO 富集分析表明，这些枢纽基因主要参与转录的正调控。基因表达分析显示，CXCL1、CXCL2、MMP1 和 MMP7 在 CRC 中高表达，而 CLCA1、CLCA4、SLC4A4、SLC9A2、SLC26A3 和 ZG16 表达水平较低。生存分析显示，5 个关键基因与 CRC 的预后显著相关。SLC9A2 在 CRC 组织和细胞系中的 mRNA 和蛋白表达水平均明显降低。重要的是，SW480 细胞中 SLC9A2 的过表达导致细胞增殖、迁移和侵袭显著抑制。Western blot 分析显示，磷酸化 ERK（p-ERK）和磷酸化 JNK（p-JNK）蛋白的表达水平显著增加，而 SLC9A2 过表达后 ERK 和 JNK 的表达水平没有明显变化。相关性分析表明，SLC9A2 表达与 MAPK 信号通路之间存在潜在联系。
我们的研究表明，SLC9A2 通过 MAPK 通路发挥肿瘤抑制作用，可能成为 CRC 诊断和治疗的潜在靶点。
