Pancancer analysis of NDUFA4L2 with focused role in tumor progression and metastasis of colon adenocarcinoma.

Colon adenocarcinoma (COAD) is a prevalent gastrointestinal malignant disease with a high mortality rate, and identification of novel prognostic biomarkers and therapeutic targets is urgently needed. Although NDUFA4L2 has high expressions in various tumors and affects tumor progression, its role in COAD remains unclear. The role of NDUFA4L2 in COAD was analyzed utilizing datasets available from public databases including The Cancer Genome Atlas, The Genotype-Tissue Expression (GTEx), Gene Expression Omnibus, Alabama Cancer Database (UALCAN), and The Human Protein Atlas databases. The prognostic value of NDUFA4L2 was determined using Kaplan-Meier analysis and Cox regression analysis. To investigate the possible mechanism underlying the role of NDUFA4L2 in COAD, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and gene set enrichment analysis (GSEA) were employed. The correlation between NDUFA4L2 expression and immune cell infiltration levels was examined through single-sample gene set enrichment analysis (ssGSEA). The NDUFA4L2 expression levels in COAD patients and cell lines were validated through immunohistochemistry, immunofluorescence, qRT-PCR, and Western blot. Wound healing assay was also performed to evaluate the effect of NDUFA4L2 on COAD metastasis. Furthermore, the NDUFA4L2 mediated competing endogenous RNA (ceRNA) regulatory network was predicted and constructed through a variety of databases. The comprehensive pan-cancer analysis showed that NDUFA4L2 possesses diagnostic and prognostic value in many cancers, especially in COAD. GO-KEGG and GSEA analyses indicated that NDUFA4L2 was associated with multiple biological functions including epithelial-mesenchymal transition and adaptation to hypoxia. The ssGSEA analysis showed that NDUFA4L2 expression was associated with immune infiltration. In vitro experiments confirmed upregulation of NDUFA4L2 in COAD tissues and cell lines, and NDUFA4L2 overexpression significantly promoted migration of COAD cells. In addition, the C9orf139 /miR-194-3p axis was speculated as the possible upstream regulators of NDUFA4L2 in COAD. This study demonstrated that NDUFA4L2 upregulation was correlated with tumor progression, relapsed prognosis and aggressive migration of COAD, suggesting that NDUFA4L2 can act as an effective prognostic biomarker and a promising therapeutic target for COAD treatment.