目的：探讨泛素特异性蛋白酶53（ubiquitin specific peptidase 53，USP53）在结直肠癌组织中的表达水平及其过表达对人结直肠癌HCT116细胞功能的影响。方法：运用Real-time PCR及IHC方法检测结直肠癌及癌旁组织中USP53的表达情况；利用UCSC CANCER BROWSER提供的TCGA数据库，检测USP53 mRNA表达水平与临床特征及预后的关系；HCT116细胞中瞬时过表达USP53，利用CCK-8及克隆形成实验检测HCT116细胞增殖变化。结果： 免疫组化结果显示，USP53在癌旁组织中的表达显著高于肿瘤组织\[91.67%（44/48） vs 1875% (9/48), P<0.01\]。癌旁组织中USP53 mRNA水平也高于癌组织\[(0.85±0.32) vs (0.46±0.27), P<0.05\]。组织中USP53 mRNA表达水平与预后有关，表达越低预后越差（P<0.05）。过表达USP53后，细胞克隆形成数目显著下降\[(123±27.22） vs (338±55.24)个，P<0.01\]； CCK-8实验结果显示，肿瘤细胞增殖受到显著抑制\[(0.14±0.01） vs (0.18±004)，P<0.05; (0.23±0.01）vs (0.32±0.01)，P<0.01；(045±0.03） vs (0.80±0.05)，P<0.01；(0.83±0.03）vs (1.18±0.10)，P<001\]。结论： USP53在结直肠癌中表达下调与不良预后相关，USP53可抑制肿瘤细胞增殖，提示USP53可作为诊断及治疗结直肠癌的新靶标。

Objective:To investigate the expression of ubiquitin specific peptidose 53（USP53） in colorectal cancer tissues and its over-expression on human colorectal cancer(CRC) HCT116 cells. Methods: Real-time PCR and IHC were used to examine the expression level of USP53 in colorectal cancerous tissues and the para-cancerous tissues; TCGA database, provided by UCSC CANCER BROWSER, was used to validate the relationship between USP53 mRNA expression and clinical characteristics as well as prognosis; After over-expressing USP53in HCT116, the changes in cell proliferation were measured by CCK-8 assay and colony formation assay. Results: IHC showed that the expression level of USP53 was higher in the normal para-cancerous tissues than that in cancerous tissues (91.67%\[44/48\] vs 18.75% \[9/48\], P<001); the same was also found in the mRNA level (\[0.46±0.27\] vs \[0.85±0.32\], F=0.925, P<0.05). The mRNA level of USP53in CRC was negatively correlated with the prognosis (P<0.05); Over-expression of USP53 in HCT116 cell significantly decreased the colony formation (\[123±27.22\] vs \[338±55.24\]，P<0.01); CCK-8 assay also showed that over-expression of USP53 also significantly inhibited the proliferation of HCT116 cells (\[0.14±0.01\] vs \[0.18±0.04\]，P<0.05, \[0.23±0.01\] vs \[0.32±0.01\]，P<0.01，\[0.45±0.03\] vs \[0.80±0.05\]，P<001，\[0.83±0.03\] vs \[1.18±0.10\]，P<0.01). Conclusion: USP53 was downregulated in CRC, which is correlated with the poor prognosis; and up-regulation of USP53 could inhibit the proliferation of HCT116 cells in vitro, indicating USP53 could be used as a diagnostic and therapeutic target for colorectal cancer.

国家自然科学基金资助项目（No. 81372636；No. 81302089）；国家高技术研究发展计划（863计划）（No.SQ2014SFOZD00314）；上海杰出青年教师计划（No.ZZjdyx13074）