IAPs小分子抑制剂SM-164增敏骨肉瘤阿霉素治疗与逆转耐药的实验研究

Osteosarcoma(OS) is the most common primary malignancy of bone. The chemotherapy resistance mainly generated from the abnormal apoptosis pathway has a strong impact on the therapeutic. It is the same circumstance for the Adriamycin（ADM）treatment of OS. There are high expressions of IAPs in OS. SM-164 is a powerful Smac mimetic, it could release the inhibition on caspases by by IAPs, thereby accelerating the apoptosis in tumor cells. However, if the machanism of the ADM sensitivity and resistance effect is still inexplicit. It is found that SM-164 have an effect on increasing ADM sensitivity on curing OS in our preliminary experiments. In this project, we will make further analysis on critical effection and main apoptosis pathway firstly. Secondly, we are going to set up the ADM resistant human OS cell lines, and observe the effects and mechanisms of SM-164 on postponing and reversing the ADM resistance. Thirdly, we plan to analysis relative effect pathway, detect the main IAPs expression and critical Caspase alteration, use negative control by siRNA silencing or overexpression approach by transfected with adenovirus express on vector to determine if its blockage abrogates or promotes SM-164 chemotherapy sensitivity and reversal of ADM resistance, clarify the causality between key genes and SM-164 effect. Lastly and the internal effect will be verified via the experiments on animals. The successful implementation of this project will elaborate the effect mechanism of Smac mimetics used in OS cells, and it will be a beneficial exploration for Smac mimetics acting as a novel drugs for clinic treatment against OS cells.

骨肉瘤（OS）是最常见的原发恶性骨肿瘤，凋亡通路异常等原因导致的化疗耐药严重影响OS的治疗效果。阿霉素（ADM）治疗OS也存在同样的问题。OS存在IAPs高表达，SM-164是一种功能强大的Smac模拟物，能解除IAPs对caspase的抑制，促进数种肿瘤细胞凋亡，然而，其在OS的化疗增敏和耐药中的作用仍不明确。本课题组前期实验发现SM-164具有增敏ADM的效应。本项目拟进一步分析关键效应IAPs和主要凋亡通路；建立OS的ADM耐药株，观察SM-164延缓OS耐药产生，逆转耐药株对ADM的抗药性，分析相关作用通路；检测主要IAPs的表达和关键caspase的变化，使用siRNA负向调控、质粒转染正向调控关键通路步骤，阐明重要通路基因蛋白与SM-164效应的因果关系，并通过动物实验验证体内作用效果。项目的成功实施，将阐述SM-164在OS的作用机制，为SM-164的临床使用做出有益的探索。

骨肉瘤（OS）是最常见的原发恶性骨肿瘤，凋亡通路异常等原因导致的化疗耐药严重影响OS的治疗效果。阿霉素（ADM）治疗OS也存在同样的问题。OS存在IAPs高表达，SM-164是一种功能强大的Smac模拟物，能解除IAPs对caspase的抑制，促进数种肿瘤细胞凋亡。本课题组在HOS细胞中证实SM-164对ADM的化疗具有增敏作用，SM-164具有诱导抗凋亡相关蛋白cIAP-1和XIAP进行降解的作用。在U-2 OS细胞中，ADM和SM-164能够抑制细胞增殖和促进细胞凋亡，并两种药物具有协同作用，这两种药物可能是通过影响凋亡相关蛋白和抗凋亡相关蛋白来影响细胞凋亡的； XIAP在其中起核心作用。通过培养U-2 OS细胞ADM耐药株，发现联合使用SM-164和ADM引起多个IAPs和 Caspase的表达变化。另外，我们还证实miR-30a通过干扰MEF2D 抑制OS细胞增殖、转移和侵袭能力；FoxM1表达在OS患者中具有潜在的预后标志物作用。本项目的完成，提高了OS化疗增敏和预后分析等方面的认识，为IAPs小分子抑制剂SM-164的临床使用做出有益的探索,并发表SCI论文4篇。