USP35调控BIRC3抑制NF-κB信号通路在非小细胞肺癌中的机制研究

Lung cancer is the leading cause of cancer-related death of high morbidity and mortality worldwide. Non-small cell lung cancer (NSCLC) is the most common histological type of lung cancer, most of the NSCLC patients are diagnosed with advanced stages, treatment options are limited.In recent years, improved understanding of molecular drivers of carcinogenesis has led to significant progress in the management of treatment for patients with advanced NSCLC. . Deubiquitinases have a close relation with cancer development and progression due to their oncogenic and tumor suppressive functions.USP35 is a newly identified deubiquitinase. But up to now.there is little known about the biological roles of USP35. Previous work have demonstrated that USP35 expression is down-regulated in NSCLC cells and tissues, overexpression of USP35 could inhibit the NSCLC cells proliferation in vitro and tumorigenesis in vivo. Deubiquitinases has been suggested to play a critical role in tumor progression through regulation of target substrates deubiquitination. We screened target substrates of USP35, of which BIRC3 was identified as a potential USP35-interacting protein, over-expression of USP35 dramatically decreased the BIRC3 ubiquitination. In conclusion, we speculate that USP35 plays a tumor suppressor role in NSCLC through de-ubiquitination of BIRC3. we will systematically analyze the role, molecular mechanism and clinical significance of USP35 in NSCLC through the molecular, cellular, animal and clinical sample. Our findings not only further elucidated new molecular and genetic mechanism of USP35 in NSCLC but also identified USP35 may serve as a potential therapeutic target to help us control the human NSCLC progression.

肺癌是世界上发病率和死亡率最高的疾病，非小细胞肺癌(NSCLC)是肺癌最常见的组织学类型，多数NSCLC患者确诊时已是晚期，治疗方案选择有限，近年来分子靶向治疗已成为治疗晚期NSCLC的研究热点。.去泛素化酶功能异常与肿瘤发生发展及预后密切相关，USP35是新近鉴定的去泛素化酶，目前研究报道甚少，我们前期研究发现，NSCLC中USP35表达显著降低，过表达USP35可抑制NSCLC细胞增殖和肿瘤形成；去泛素化酶主要通过调控靶蛋白参与肿瘤进程，前期研究还发现USP35与BIRC3存在相互作用，过表达USP35可显著降低BIRC3泛素化水平。综上我们推测，USP35可能通过去泛素化BIRC3发挥对NSCLC抑制作用。本课题将从分子、细胞、动物和临床实验系统分析USP35在NSCLC中的作用、机理及临床意义，为阐明NSCLC发生发展新的分子机制以及NSCLC治疗寻找新的分子靶点提供可信实验依据。

USP35通过去泛素化不同靶底物影响多种肿瘤的发生和发展，其在非小细胞肺癌（NSCLC）中的功能和调控机制尚不清楚。在本研究中，我们揭示了USP35调控NSCLC顺铂耐药的分子机制。USP35敲低能增强NSCLC细胞对顺铂的敏感性。通过CO-IP结合质谱分析我们筛选到USP35的一个靶底物-凋亡抑制因子BIRC3，并证实USP35与BIRC3存在相互作用。USP35通过其去泛素化酶活性去除BIRC3蛋白K48泛素链进而稳定BIRC3。USP35过表达导致NSCLC细胞中BIRC3蛋白水平升高，USP35干扰导致NSCLC细胞中BIRC3蛋白水平降低。USP35过表达会延长BIRC3蛋白半衰期，防止其被蛋白酶体降解。USP35敲低会加速BIRC3蛋白降解。细胞表型实验证实USP35敲低会通过引起BIRC3蛋白水平降低进而促进顺铂诱导的NSCLC细胞的凋亡。除此之外，我们在收集到的肺癌标本中检测了USP35和BIRC3蛋白表达量，二者存在显著正相关性。本课题首次揭示了USP35调控NSCLC顺铂耐药的分子机制，完善了BIRC3蛋白被去泛素化调控的研究。本研究通过阐释USP35通过调控BIRC3在NSCLC耐药的机制，为肺癌的治疗提供潜在的新靶点。