Integrative Multi-Omics Analysis and Experiments Validation Identify COX5B as a Novel Therapeutic Target for Lung Adenocarcinoma.

BACKGROUND: A significant proportion of patients still cannot benefit from existing targeted therapies and immunotherapies, making the search for new treatment strategies extremely urgent. In this study, we combined integrate public data analysis with experimental validation to identify novel prognostic biomarkers and therapeutic targets for lung adenocarcinoma (LUAD). METHODS: We analyzed RNA and protein databases to assess the expression levels of cytochrome C oxidase 5B (COX5B) in LUAD. Several computational algorithms were employed to investigate the relationship between COX5B and immune infiltration in LUAD. To further elucidate the role of COX5B in LUAD, we utilized multiple experimental approaches, including quantitative reverse transcription PCR assays, western blot, immunohistochemistry, electron microscopy, flow cytometry, and EdU proliferation assays. RESULTS: We revealed that COX5B was significantly elevated in LUAD and positively correlated with poor prognosis of LUAD patients. Analysis of co-expression network indicated that COX5B may take part in the intracellular adenosine triphosphate (ATP) synthesis through the oxidative phosphorylation pathway. There was a negative correlation between COX5B expression and immune infiltration in LUAD. Furthermore, we validated that COX5B levels were significantly elevated in both LUAD tissues and cell lines. Specifically, immunohistochemistry (IHC) assays revealed a 2.32-fold increase of COX5B in tumor tissues compared to that in adjacent normal tissues (p = 0.0044). Additionally, COX5B knockdown disrupted the redox homeostasis, ultimately suppressed the proliferation of LUAD cells. Subsequent investigations demonstrated that berberine effectively targeted COX5B, diminishing its protein expression and consequently inhibiting cell proliferation and tumor growth in LUAD. CONCLUSIONS: This study established that upregulated COX5B was positive associated with poor patient prognosis in LUAD, elucidating the mechanisms by which berberine targets COX5B to inhibit tumor growth, thereby providing a novel therapeutic target and strategy for the clinical management of LUAD.