目的：基于TCGA数据库分析Deltex E3泛素连接酶2（DTX2）在肾透明细胞癌（ccRCC）组织中的表达水平及临床意义，探讨DTX2 对ccRCC 细胞增殖、迁移和侵袭的影响。方法：利用TIMER 数据库分析DTX2 在泛癌组织中的表达水平，通过UALCAN 数据库进一步验证ccRCC 组织和癌旁组织中DTX2 mRNA 和蛋白表达差异。使用UALCAN 数据库中的TCGA-ccRCC 队列数据集，分析ccRCC 中DTX2表达与患者临床病理特征的相关性。通过K-M plot 数据库分析DTX2表达与ccRCC 患者预后的相关性。利用DAVID数据库对DTX2相关基因进行GO和KEGG通路富集分析。通过qPCR 法检测DTX2基因在人胚肾293（HEK293）细胞和ccRCC 细胞A498、Caki-1 中的表达水平。利用siRNA 技术分别将DTX2 siRNA 及其阴性对照质粒转入A498、Caki-1细胞，采用CCK-8法、平板克隆实验、划痕实验及Transwell 侵袭实验分别检测敲低DTX2对细胞增殖、迁移和侵袭的影响。结果：TCGA数据库分析结果表明，与癌旁组织相比，ccRCC 组织中DTX2 mRNA和蛋白均呈高表达（均P<0.01）。DTX2表达水平与ccRCC 患者的病理分期、临床分级、不同亚型和淋巴结转移相关联（均P<0.01），DTX2高表达与患者的不良预后具有相关性（均P<0.01）。GO功能和KEGG通路富集分析结果显示，DTX2表达相关基因主要参与蛋白酶体介导的泛素依赖性蛋白质分解代谢等生物学过程，并主要富集到了mTOR信号通路等与肿瘤的相关信号通路中（均P<0.05）。体外细胞实验结果表明， A498 和Caki-1细胞中DTX2表达水平高于HEK293 细胞；敲低DTX2表达可显著降低A498 和Caki-1细胞的增殖、迁移及侵袭能力（均P<0.01）。结论：DTX2在ccRCC 组织和细胞中呈高表达，其高表达患者的预后较差。敲低DTX2表达可抑制ccRCC 细胞增殖、迁移和侵袭，DTX2有望成为ccRCC新的生物标志物和治疗靶点。

Objective:To analyze the expression level and clinical significance of Deltex E3 ubiquitin ligase 2 (DTX2) in clear cell renal cell carcinoma (ccRCC) based on TCGA database, and explore the effect of DTX2 on the proliferation, migration and invasion of ccRCC cells. Methods: TIMER database was utilized to analyze the expression level of DTX2 in pan-cancer tissues, while UALCAN database was used for further verification of the differences in mRNA and protein expressions of DTX2 in ccRCC and adjacent tissues. TCGA-ccRCC cohort dataset in UALCAN database was employed to examine the correlation between DTX2 expression in ccRCC and clinicopathological features of patients. The correlation between DTX2 expression and the prognosis of ccRCC patients was analyzed using K-M plot database. Using DAVID database, gene ontology (GO) analysis and Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analysis were performed to explore DTX2-related genes. The expression levels of DTX2 gene in human embryonic kidney 293 (HEK293) cells and ccRCC A498 and Caki-1 cells were detected by qPCR. SiRNA technology was employed to transfect DTX2 siRNA and its negative control plasmids into ccRCC A498 and Caki-1 cells. CCK-8 cell proliferation assay, plate clone formation assay, scratch wound assay, and Transwell migration assay were performed to detect respectively the effects of knockdown DTX2 on the proliferation, migration and invasion of ccRCC cells. Results: Analysis of TCGA database showed that, compared with adjacent tissues, both DTX2 mRNA and protein were highly expressed in ccRCC tissues (all P<0.01). The expression level of DTX2 was associated with the pathological stage, clinical grade, different subtype, and lymph node metastasis of ccRCC patients (all P<0.01). High DTX2 expression was correlated with poor prognosis in patients (all P<0.01). The results of GO function analysis and KEGG pathway enrichment analysis and showed that genes related to DTX2 expression were mainly involved in biological processes such as proteasome-mediated ubiquitin-dependent protein catabolic process, and these genes were primarily enriched in tumor-related signaling pathways such as the mTOR signaling pathway (all P<0.05).The results of in vitro cell experiments showed that the expression levels of DTX2 in A498 and Caki-1 cells were higher than those in HEK293 cells; knockdown of DTX2 expression significantly lowered the proliferation, migration and invasion abilities of A498 and Caki-1 cells (all P<0.01). Conclusion: High expression of DTX2 is observed in ccRCC tissues and cells, and its high expression is associated with poor prognosis in patients. Knockdown of DTX2 expression may inhibit the proliferation, migration and invasion of ccRCC cells. DTX2 is expected to become a new biomarker and therapeutic target for ccRCC.

国家自然科学基金（No. 82160502）；宿州学院博士科研启动基金（No. 2023BSK021）