基因组学与应用生物学

细胞分裂周期相关蛋白8(cell division cycle associated 8, CDCA8)作为细胞周期调控关键分子,已被证实在肺癌、乳腺癌等多种恶性肿瘤中异常高表达,且与肿瘤增殖、侵袭及不良预后密切相关,但目前其在肝细胞癌(hepatocellular carcinoma, HCC)中的表达模式、调控机制及临床价值尚未明确。本研究基于癌症基因组图谱(the cancer genome atlas, TCGA)数据库,联合TIMER 2.0、 UALCAN及Kaplan-Meier Plotter等生物信息学工具,系统分析CDCA8在HCC中的m RNA表达水平、启动子甲基化状态、临床预后意义、免疫细胞浸润关联性及蛋白相互作用网络,并通过体外实验验证其对肝癌细胞生物学行为的调控作用。同时基于基因表达综合(gene expression omnibus, GEO)数据库分析了CDCA8在HCC中的m RNA表达水平。结果显示, CDCA8 m RNA在HCC组织中呈显著高表达,且与肿瘤分化程度呈负相关,其启动子区域甲基化水平显著降低并随分化程度下降进一步下调; CDCA8高表达与HCC患者总生存期(overall survival, OS)缩短存在显著相关性,在男性患者中该相关性更为突出,提示其或可作为HCC预后评估的候选参考指标。免疫浸润分析结果表明, CDCA8表达与CD4~+T细胞、CD8~+T细胞、巨噬细胞及NK细胞浸润水平呈正相关;蛋白质-蛋白质相互作用(protein-protein interaction, PPI)网络分析显示其可与BUB1有丝分裂检查点丝氨酸/苏氨酸激酶B(BUB1 mitotic checkpoint serine/threonine kinase B,BUB1B)、细胞周期蛋白依赖性激酶1(cyclin dependent kinase 1,CDK1)、细胞分裂周期蛋白20(cell division cycle 20, CDC20)等核心蛋白互作,上述互作蛋白富集于细胞周期及染色体分离相关生物学过程。体外实验证实,沉默CDCA8可显著抑制肝细胞癌细胞的增殖与迁移能力。综上,本研究仅明确CDCA8在HCC中呈启动子低甲基化相关的高表达特征,其表达水平与肿瘤恶性表型、患者预后及免疫微环境浸润特征存在多项相关性,与细胞周期相关蛋白的互作提示其可能与相关生物学过程存在潜在联系。CDCA8可作为HCC中与增殖及预后相关的候选分子,为后续研究提供前期参考数据。

Cell division cycle associated 8( CDCA8), a key regulator of the cell cycle, has been demonstrated to be abnormally overexpressed in various malignant tumors such as lung cancer and breast cancer, and is closely associated with tumor proliferation, invasion, and poor prognosis. However, its expression pattern, regulatory mechanism, and clinical significance in hepatocellular carcinoma( HCC) remain unclear. In this study, based on the cancer genome atlas( TCGA) database, we systematically analyzed the m RNA expression level, promoter methylation status, clinical prognostic significance, correlation with immune cell infiltration and proteinprotein interaction( PPI) network of CDCA8 in HCC by using bioinformatics tools including TIMER 2. 0, UALCAN and Kaplan-Meier Plotter, and further verified the regulatory effect of CDCA8 on the biological behaviors of HCC cells through in vitro experiments. Meanwhile, we analyzed the m RNA expression level of CDCA8 in HCC based on the data from the gene expression omnibus(GEO) database. Results showed that CDCA8 m RNA was significantly upregulated in HCC tissues, and this expression was negatively correlated with tumor differentiation grade. The methylation level in the CDCA8 promoter region was remarkably decreased, with a further reduction as tumor differentiation deteriorated. High CDCA8 expression was significantly associated with shortened overall survival( OS) in HCC patients, and this correlation was more pronounced in male patients, suggesting that CDCA8 may serve as a candidate reference indicator for HCC prognosis evaluation. Immune infiltration analysis revealed a positive correlation between CDCA8 expression and the infiltration levels of CD4⁺ T cells, CD8⁺ T cells, macrophages, and NK cells. Protein-protein interaction( PPI) network analysis demonstrated that CDCA8 could interact with core proteins including BUB1 mitotic checkpoint serine/threonine kinase B( BUB1B), cyclin dependent kinase 1( CDK1), and cell division cycle 20( CDC20), and these interacting proteins were enriched in biological processes related to cell cycle regulation and chromosome segregation. In vitro experiments showed that silencing CDCA8 significantly inhibited the proliferation and migration of HCC cells. In conclusion, this study only confirmed that CDCA8 exhibits a high expression pattern in HCC, which is associated with low promoter methylation. CDCA8 expression was correlated with multiple features including tumor malignant phenotypes, patient prognosis, and immune microenvironment infiltration. The interactions between CDCA8 and cell cyclerelated proteins suggest a potential association with relevant biological processes. CDCA8 may serve as a candidate molecule related to proliferation and prognosis in HCC, providing preliminary reference data for future research.