Cezanne-1特异性去泛素化IGF-1R的机制及其对肺癌靶向治疗增效作用研究

Insulin like growth factor-1 receptor (IGF-1R) signaling pathway plays predominant roles in carcinogensis, thus targeting IGF -1R provokes great intrigue novel treatment strategies in cancer treatment including non-small cell lung cancer (NSCLC)..Our previous studies showed that the using of tyrosine kinase inhibitors （TKIs）and anti-IGF-1R mAbs could cause IGF-1R ubiquitination and endocytosis/down-regulation, and could regulate the following signaling pathways. Our screen results showed that cezanne-1 could combine with IGF -1R, and the over-expression of cezanne-1 may decrease the ubiquitination of IGF -1R and inhibit receptor down-regulation. The detection of the lung cancer samples suggested that cezanne-1 and IGF -1R were highly expressed compared with normal tissues, and the highly expression was associated with poor prognosis. Therefore, we hypothesis that cezanne-1 plays as a specific deubiquitylating enzyme (DUB) and regulates the downstream signaling pathway of IGF -1R..Based on the above results, we designed the current study aiming to illustrate the mechanisms of cezanndomaine-1 in deubiquitinating IGF-1R in molecular, cellular, and animal levels; and figure out the functional domain of cezanne-1 and its preferred Lysine- ubiquitin linkages. Further, we attempt to combine the inhibition of cezanne-1 with TKIs or anti-IGF-1R mAbs in treatment of NSCLC, hoping to see therapeutic enhance effect.

IGF-1R信号通路在肿瘤的发生发展中发挥重要作用，针对肺癌IGF-1R的靶向治疗是当前研究热点。泛素化与去泛素化是一对动态可逆的修饰过程，调控受体内吞下调并影响下游信号转导通路。.我们发现TKIs、anti-IGF-1R mAbs可引起IGF-1R 泛素化内吞下调及相应下游信号通路变化： cezanne-1可与IGF-1R结合，转染cezanne-1质粒可减少IGF-1R泛素化、抑制其内吞下调；肺癌组织中IGF-1R、cezanne-1高表达，且与不良预后相关。我们推测cezanne-1可作为IGF-1R的特异性去泛素化酶，在NSCLC的信号转导中发挥重要作用。.本研究拟从分子、细胞和动物水平探讨cezanne-1去泛素化IGF-1R、调控信号转导的机制，明确其功能结构域及特异性去泛素化连接；探讨在NSCLC的靶向治疗中抑制cezanne-1的增效作用，为肺癌靶向治疗提供理论基础和新思路

肺癌作为全世界因癌症死亡人数最多的恶性肿瘤，深入了解肺癌发生发展的分子机制对肺癌的诊断及治疗有重要意义。胰岛素样生长因子1受体（IGF-1R）通路在非小细胞肺癌的发生、发展中发挥重要的作用，泛素化与去泛素化在IGF-1R内吞下调过程中发挥重要作用，Cezanne-1 (OTUD7B)作为一种新的去泛素化酶，是否可以通过降低IGF-1R去泛素化水平、促进非小细胞肺癌进展值得探究。.在本研究中，根据临床样本和相关数据库分析结果，无论是肺腺癌还是肺鳞癌，Cezanne-1高表达组的病人预后都明显低于低表达组（p<0.05）。提示Cezanne-1可能具有促进NSCLC进展的作用。细胞实验及小鼠成瘤实验证实Cezanne-1过表达通过细胞增殖信号的过度激活促进了NSCLC肿瘤的进展。同时，我们发现在NSCLC中Cezanne-1可能对IGF-1R的量具有正向调控作用。在IGF-1诱导下，Cezanne-1增强AKT（ser473）、JNK（Thr183/Tyr185）磷酸化水平，下调p38（T180/Y182）、ERK1/2（T202/Y204），证实其对IGF-1R通路的正向调控作用。这些提示Cezanne可能通过IGF-1R发挥对NSCLC的促癌作用。.进一步研究中，我们发现Cezanne-1与IGF-1R存在内源性的结合作用。Cezanne-1的下调促进了IGF-1R的降解，Cezanne-1的过表达则显著下调IGF-1R的泛素化水平，并具有剂量依赖性，应用蛋白酶体抑制剂则明显抑制IGF-1R的降解，这提示Cezanne-1通过去泛素化调节IGF-1R的稳定性。另外，激活IGF-1R信号通路能明显改善敲低Cezanne-1对NSCLC细胞增殖的抑制作用。因此通过本研究，我们认为Cezanne-1通过去泛素化调控IGF-1R信号通路促进非小细胞肺癌进展。.本项目以IGF-1R通路的去泛素化为切入点，明确了Cezanne-1作为IGF-1R 的特异性去泛素化酶，证实了Cezanne-1在非小细胞肺癌中的作用，丰富了IGF-1R受体泛素化内吞下调动态过程的具体机制，为将来提高针对NSCLC的靶向治疗疗效、开拓新靶点提供理论依据。