Table 2_Prognostic biomarkers and regulatory mechanisms associated with lysine β-hydroxybutyrylation modification in prostate cancer.xlsx

BackgroundProstate cancer (PCa) is a highly prevalent malignant tumor in males. Lysine β-hydroxybutyrylation (Kbhb), an emerging post-translational modification, plays a critical role in tumorigenic processes. However, its functional mechanism in PCa remains elusive. This study aims to identify Kbhb-related prognostic genes in PCa and provide novel insights for its diagnosis, prognosis and treatment.
MethodsCandidate genes were obtained through differential expression analysis and intersection analysis. Univariate Cox proportional hazards model and least absolute shrinkage and selection operator (LASSO) regression were employed to screen Kbhb-related prognostic genes, and a risk model was constructed and validated. The expression levels of Kbhb modification and related prognostic genes were validated using Western blotting (WB), real-time quantitative PCR (RT-qPCR) and immunohistochemistry (IHC). Additionally, clinical correlation analysis, nomogram development and validation, immune infiltration analysis, tumor mutation burden (TMB) analysis, gene set enrichment analysis (GSEA), drug sensitivity prediction, molecular regulatory network analysis, drug targeting analysis, and molecular docking were performed.
ResultsThree genes--kinesin family member 4A (KIF4A), TPX2 microtubule nucleation factor (TPX2), and aurora kinase B (AURKB)—were identified as Kbhb-related prognostic genes. Results of WB indicated that the butyrylation level of the H3K27 (H3K27-Bu) protein was significantly upregulated in PCa tissues. RT-qPCR and IHC results demonstrated that the expression levels of KIF4A, TPX2, and AURKB were significantly higher in the PCa than normal tissues. A risk model based on these genes demonstrated discriminatory ability (AUC >0.6) and served as an independent prognostic factor alongside prostate-specific antigen (PSA). The prognostic nomogram showed high accuracy (AUC 0.82–0.88). High-risk patients exhibited distinct immune infiltration profiles and higher mutation frequencies in tumor protein 53 (TP53), Titin (TTN), and speckle-type POZ protein (SPOP). Drug sensitivity analysis linked the risk score to 24 compounds, while molecular docking suggested that estradiol and bisphenol A could target the identified hub genes.
ConclusionThis study identified KIF4A, TPX2, and AURKB as reliable prognostic biomarkers for PCa. These findings provide a theoretical basis for understanding Kbhb-mediated mechanisms in PCa and offer novel targets for early diagnosis and precision therapy.

背景
前列腺癌（Prostate cancer, PCa）是男性高发的恶性肿瘤。赖氨酸β-羟丁酰化（Lysine β-hydroxybutyrylation, Kbhb）作为一种新兴的转录后修饰，在肿瘤发生过程中发挥关键作用，但其在前列腺癌中的功能机制仍不明晰。本研究旨在筛选前列腺癌中与Kbhb相关的预后基因，为前列腺癌的诊断、预后评估及治疗提供新的视角。
方法
候选基因通过差异表达分析与交集分析获得。采用单变量Cox比例风险模型与最小绝对收缩和选择算子（Least absolute shrinkage and selection operator, LASSO）回归筛选与Kbhb相关的预后基因，构建并验证风险模型。利用蛋白质印迹（Western blotting, WB）、实时定量聚合酶链反应（real-time quantitative PCR, RT-qPCR）及免疫组织化学（immunohistochemistry, IHC）验证Kbhb修饰及相关预后基因的表达水平。此外，本研究还开展了临床相关性分析、列线图（nomogram）的构建与验证、免疫浸润分析、肿瘤突变负荷（tumor mutation burden, TMB）分析、基因集富集分析（gene set enrichment analysis, GSEA）、药物敏感性预测、分子调控网络分析、药物靶向分析及分子对接实验。
结果
共筛选出驱动蛋白家族成员4A（kinesin family member 4A, KIF4A）、TPX2微管成核因子（TPX2 microtubule nucleation factor, TPX2）及极光激酶B（aurora kinase B, AURKB）三个与Kbhb相关的预后基因。蛋白质印迹结果显示，H3K27位点的丁酰化蛋白（H3K27-Bu）在前列腺癌组织中的表达水平显著上调。实时定量聚合酶链反应与免疫组织化学结果表明，KIF4A、TPX2及AURKB在前列腺癌组织中的表达水平显著高于正常组织。基于上述基因构建的风险模型具有良好的区分能力（受试者工作特征曲线下面积AUC>0.6），且可作为独立于前列腺特异性抗原（prostate-specific antigen, PSA）的预后因素。预后列线图展现出较高的预测准确性（AUC 0.82–0.88）。高风险组患者呈现出独特的免疫浸润特征，且肿瘤蛋白53（tumor protein 53, TP53）、肌联蛋白（Titin, TTN）及斑点型POZ蛋白（speckle-type POZ protein, SPOP）的突变频率更高。药物敏感性分析将风险评分与24种化合物建立关联，分子对接结果提示雌二醇（estradiol）与双酚A（bisphenol A）可靶向本研究鉴定的核心基因。
结论
本研究鉴定出KIF4A、TPX2及AURKB可作为前列腺癌可靠的预后生物标志物。上述研究结果为阐明Kbhb介导的前列腺癌发生机制提供了理论依据，同时为前列腺癌的早期诊断与精准治疗提供了全新的靶点。