OTUD3与p53在乳腺癌中表达及对DNA损伤应答的研究

Expression of OTUD3 and p53 in breast cancer and its response to DNA damage

目的:研究去泛素化酶OTUD3与肿瘤抑制因子p53蛋白在乳腺癌组织中表达相关性及对DNA损伤应答的意义。方法:免疫组化检测80对乳腺癌组织及癌旁正常乳腺组织中去泛素化酶OTUD3蛋白表达情况;Western Blot检测其中10对新鲜组织标本中OTUD3与p53及其下游p21蛋白的表达;紫外线照射损伤乳腺癌MCF7细胞DNA,并用CHX处理细胞,Western Blot检测OTUD3与p53蛋白水平变化;在ATM野生型(ATM+/+)与ATM敲除(ATM-/-)细胞中重复DNA损伤实验,Western Blot检测OTUD3与p53蛋白水平变化。结果:乳腺癌组织中OTUD3的阳性表达率(42.5%)显著低于癌旁正常组织阳性表达率(83.8%,P<0.05);OTUD3与p53在乳腺癌组织中表达低于癌旁组织,且两者表达一致;OTUD3和p53能够响应DNA损伤并且OTUD3对损伤的应答可能与其泛素化酶活性有关。结论:OTUD3是一个潜在的抑癌分子,其表达下降参与乳腺癌的发生,并且在DNA损伤情况下,OTUD3可能通过去泛素化作用对p53蛋白产生影响。

Objective: To investigate the correlation between expression of deubiquitinase OTUD3 and tumor suppressor p53 protein in breast cancer(BC) tissues and its response to DNA damage. Methods: Immunohistochemistry was used to detect the expression of OTUD3 in 80 pairs of BC tissues and the adjacent normal tissues. Western Blot was used to detect the expressions of OTUD3, p53 and its downstream p21 protein in 10 pairs of fresh tissue samples. Breast cancer MCF7 cells were damaged by Ultraviolet irradiation, and were treated with CHX. The changes of OTUD3 and p53 protein levels were detected by Western Blot. Repeated DNA damage experiments were performed in ATM wild-type(ATM+/+) and ATM-/-(ATM-/-) cells, and changes in OTUD3 and p53 protein levels were detected by Western Blot. Results: The positive expression rate of OTUD3 in BC tissues(42.5%)was significantly lower than the adjacent normal tissues(83.8%, P<0.05). OTUD3 and p53 expressed less in BC tissues than in adjacent tissues, and they were positively correlated. OTUD3 and p53 can respond to DNA damage and the response of OTUD3 to damage may be related to its ubiquitin enzyme activity. Conclusion: OTUD3 is a potential tumor suppressor molecule, and its decreased expression is involved in the occurrence of breast cancer. In the case of DNA damage,OTUD3 may affect p53 protein through deubiquitination.