Mechanism of USP39 inhibiting radiation sensitivity of tumor cells / 西安交通大学学报(医学版)

Objective: To investigate the biological effects of ubiquitin-specific peptidase 39 (USP39) on the DNA damage response pathway of tumor cells. Methods: Tumor cells (293T, HeLa, U2OS, T47D) were cultured in DMEM medium or RPMI-1640 containing 100 mL/L FBS in a humidified atmosphere containing 50 mL/L CO2 at 37 ℃. The effect of knockdown of USP39 on the radiosensitivity of tumor cells was detected by MTS[3-(4,5-diethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-etrazolium, inner salt]. The efficiency of HR repair and NHEJ repair was detected by cytometry. The expression of DNA damage-responsive proteins by knockdown of USP39 was examined by Western blot. The proteins interacting with USP39 were detected by co-immunoprecipitation, protein purification and mass spectrometry, and then gene ontology analysis was performed. DNA damage was induced by micro-irradiation and its recruitment to DNA damage sites was detected by agonistic confocal microscopy. Results: Knockdown of USP39 resulted in increased radiosensitivity of tumor cells (P<0.05). Knockdown of USP39 inhibited homologous recombination and non-homologous end joining repair efficiency of tumor cells (P<0.05). Knockdown of USP39 promoted the expression of DNA damage response protein. USP39 aggregated to DNA damage sites; USP39 interacting proteins were involved in multiple signaling pathways associated with DNA damage response. Conclusion: USP39 plays an important role in the DNA damage response.

Expression and Clinical Significance of USP39 in Colon Cancer / 医学研究杂志

Objective To explore the expression of USP39 in tissues of colon cancer (CRC),investigate the association of the expression levels of USP39 and clinicopathological features of CRC patients,and analyze the relevance of USP39 and survival and prognosis of CRC patients.Methods Expressions of USP39 were analyzed by immunohistochemistry in 77 CRC patients.Spearman's rank test,K-M survival curves,and Cox proportional hazards risk were conducted to analyze the clinical relevance of USP39 in CRC.Results Immunohistochemistry revealed that the positive rate of USP39 was upregulated in CRC tissues compare with adjacent tissues Spearman rank correlation showed that positive USP39 expression was significantly associated with TNM stage,lymph node status and venous invasion of CRC patients.Kaplan-Meier curves showed that positive USP39 expression was inversely correlated with 5 years overall and progression-free survival time of CRC patients.Cox proportional hazards risk analysis revealed that USP39 was an independent prognostic factor for CRC.Conclusion USP39 expression is upregulated in tissues of CRC,and USP39 is a potential survival and prognosis biomarker in CRC.

Knockdown of ubiquitin-specific peptidase 39 inhibited the growth of osteosarcoma cells and induced apoptosis in vitro

BACKGROUND: Ubiquitin specific peptidase 39 (USP39), an essential factor in the assembly of the mature spliceosome complex, has an aberrant expression in several cancer. However, its function and the corresponding mechanism on human osteosarcoma has not been fully explored yet. METHODS: The mRNA and DNA copies of USP39 were increased in osteosarcoma cancer tissues compared with the one in human normal tissues according to datasets from the publicly available Oncomine database. A further western blot analysis also demonstrated an aberrant endogenous expression of USP39 in three different osteosarcoma cells. Then lentivirus-mediated short hairpin RNA (shRNA) was designed to silence USP39 in human osteosarcoma cell line U2OS, which is used to test the impact of USP39-silencing on cellular proliferation, colony formation, cell cycle distribution and apoptosis. RESULTS: Knockdown of USP39 expression in U2OS cell significantly decreased cell proliferation, impaired colony formation ability. A further analysis indicated suppression of USP39 arrested cell cycle progression at G2/M phase via p21 dependent way. In addition, the results of Annexin V/7-AAD staining suggested the knockdown of USP39 could promote U2OS cell apoptosis through PARP cleavage. CONCLUSIONS: These results uncover the critical role of USP39 in regulating cancer cell mitosis and indicate USP39 is critical for osteosarcoma tumorigenesis.

Effects of lentivirus-mediated siRNA interference of USP39 on proliferation and migration of mice vascular smooth muscle cell / 中国生化药物杂志

Objective To investigate the effect of lentivirus-mediated siRNA interference of USP39 on proliferation and migration of mice vascular smooth muscle cell in vitro.Methods Five siRNAs of siControl, siRNAUSP39-70, siRNAUSP39-71, siRNAUSP39-72 and siRNAUSP39-73 were designed and sythezied,mice VSMCs were infected with the lentivirus for delivering siRNAUSP39-73, and the stably transfected cells were selected by puromycin.The interference efficiency of siRNAUSP39-73 was assessed with Western blot.The effect of USP39 interference on the proliferation of VSMCs was determined by cells counting and MTT assay.Transwell assay was used to detect the migration of VSMCs.Results Recombinant lentiviral vector siRNAUSP39-73 was successfully transfected into mice VSMCs.Comparing with siControl group and Normal group, USP39 protein level of siRNAUSP39-73 VSMCs were decreased(P<0.05), and the proliferation and migration ability were all inhibited(P<0.05).Conclusion Targeted down-regulation of USP39 expression can inhibit the proliferation and migration of mice VSMCs in vitro.