为了揭示结直肠癌（CRC）发展的潜在机制，我们应用生物信息学分析来识别关键基因，并通过实验验证它们在结直肠癌发病和进展中可能发挥的作用。我们进行了基因本体论（GO）和京都基因和基因组百科全书（KEGG） ）对差异表达基因（DEG）进行通路分析，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，并分析其在结肠腺癌（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之间的相关性，并使用 qRT-PCR 和 Western blotting 验证了 SLC9A2 在 CRC 组织和细胞系中的表达。在体外进行功能实验，研究SLC9A2对肿瘤生长和转移的影响。我们在CRC中发现了130个DEG，其中45个上调，85个下调。 GO分析表明这些DEG主要富集与细胞pH调节、酶原颗粒和跨膜转运蛋白活性相关的功能。 KEGG通路分析显示DEGs在胰腺分泌、类风湿性关节炎和IL-17信号通路中发挥着关键作用。我们鉴定了 10 个中心基因：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向调控。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低水平表达。生存分析显示5个关键基因与CRC预后显着相关。在结直肠癌组织和细胞系中，SLC9A2 的 mRNA 和蛋白表达水平均显着降低。重要的是，SLC9A2 在 SW480 细胞中过度表达导致细胞增殖、迁移和侵袭的显着抑制。 Western blotting分析显示，SLC9A2过表达后，磷酸化ERK（p-ERK）和磷酸化JNK（p-JNK）蛋白的表达水平显着增加，而ERK和JNK的表达水平没有显着变化。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 通路发挥肿瘤抑制因子的作用，可能成为 CRC 诊断和治疗的潜在靶点。© 2024. 华中科技大学。

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.© 2024. Huazhong University of Science and Technology.