Integrative Multi-Omics Analysis and Experimental Validation Identify SPOP as a Prognostic Biomarker and Immune Regulator in Lung Adenocarcinoma

Background: The speckle-type POZ protein (SPOP) has emerged as an important regulator of protein degradation in various cancers. However, the precise role of SPOP in lung adenocarcinoma (LUAD) remains unclear, particularly in relation to its expression patterns, prognostic significance, and potential as a therapeutic target. This study aimed to investigate the expression, prognostic value, and biological functions of SPOP in LUAD, and to explore its potential as a biomarker for personalized treatment strategies. Methods: We performed a comprehensive analysis of SPOP expression using multiple public datasets, including TCGA, TCGA-GTEx, and GEO. Survival analyses were conducted through Cox regression and Kaplan-Meier methods to assess the prognostic significance of SPOP in LUAD. Gene Set Variation Analysis (GSVA) and Gene Set Enrichment Analysis (GSEA) were employed to uncover biological pathways associated with SPOP expression. Immune microenvironment analysis and drug sensitivity data from the GDSC database were used to explore the potential role of SPOP in immune modulation and therapeutic response. The biological role of SPOP in LUAD was further explored through molecular docking analysis and experimental validation. Results: SPOP expression was significantly reduced in LUAD compared to normal tissues, with lower expression correlating with poor overall survival (OS), disease-specific survival (DSS), and progression-free interval (PFI). Cox regression analysis confirmed that SPOP is an independent prognostic factor for LUAD. Functional analyses revealed that low SPOP expression was associated with disrupted immune regulation and altered metabolic pathways, potentially driving tumor progression. Immune profiling identified significant correlations between SPOP expression and immune cell recruitment, inflammatory signaling, and LUAD subtypes. Drug sensitivity analysis suggested that low SPOP expression is linked to increased sensitivity to zibotentan and 5-fluorouracil. Additionally, molecular docking analysis revealed key interaction sites between SPOP and NANOG, and SPOP knockdown in A549 and T24 cells resulted in downregulation of immune markers CD47 and CD155. Conclusion: SPOP is a reliable independent prognostic biomarker in LUAD, influencing tumor progression, immune microenvironment, and therapeutic response. Our findings support the potential of SPOP as a novel therapeutic target for personalized treatment strategies in LUAD.