缺氧诱导因子HIF-1alpha在人骨肉瘤多药耐药机制中的作用研究

So far multidrug resistance is the most important mechanism of osteosarcoma cells escaping from chemotherapeutics, also the most common and difficult problem of failed combination chemotherapy dealing with osteosarcoma clinically.Tumor cells developing drug resistance is a multi-target,multi-step and multi-factor involved procedure. Its mechanism is complicated, involving several cytokines,protease,and regulating genes.Our previous studies demonstrate that hypoxia inducible factor HIF-1a is closely related with multi-drug resistance of osteosarcoma, and probably plays an important role in it.This project intends to find out the relationship between expression,distribution of HIF-1a and multidrug resistance of osteosarcoma, on that basis we will examin the mechanism of HIF-1a involed in multidurg resistance of osteosarcoma by in vitro hypoxia cell model.Mice with HIF-1a or its downsteam genes inhibited will be used to testify whether tumor cells become sensitive to drugs or not.This project will uncover the mechanism of multidrug resistance of osteosarcoma further, and supply a new way of clinical therapy on osteosarcoma and as well as experimental basis.

肿瘤细胞产生多药耐药（MDR）是目前骨肉瘤细胞逃避化疗药物攻击的最重要的细胞防御机制，也是临床骨肉瘤联合化疗失败最常见又最难解决的一个问题。肿瘤细胞产生耐药性是一个多靶点、多步骤、多因素参与的过程，机制复杂，有多种细胞因子、蛋白酶类和调控基因的参与。本课题组前期研究证明，缺氧诱导因子HIF-1a 与骨肉瘤多药耐药密切相关，可能在其产生过程中发挥了极其重要的作用。本研究拟在明确HIF-1a 的表达分布与骨肉瘤细胞多药耐药相互关系的基础上，利用体外缺氧模型研究HIF-1a 参与骨肉瘤细胞多药耐药的作用机制。进一步通过小鼠体内试验证实HIF-1a 或其调控的下游基因表达受到抑制的小鼠是否重新恢复了对多种骨肉瘤化疗药物的敏感性。通过本课题对HIF-1a 功能及其下游调控基因的深入研究将有助于进一步阐明骨肉瘤多药耐药的生成机理，为骨肉瘤的临床治疗提供新的思路和实验依据。

肿瘤细胞多药耐药一直是临床上迫切解决又束手无策的一个难点。我们的前期研究表明缺氧诱导因子HIF-1α(hypoxia-inducible factor 1α)可能在人骨肉瘤化疗耐药的产生过程中起着重要作用,本项目在此基础上对HIF-1α的功能及其下游机制进行了研究。在基金的资助下，项目组明确了HIF-1a 在患者骨肉瘤组织中的表达与分布，建立了骨肉瘤细胞的体外缺氧模型，观察了HIF-1α和耐药相关基因的表达及关系，制备了缺氧与常氧的基因表达谱芯片，构建了慢病毒过表达载体及稳定的过表达细胞系，完成了体内和体外的耐药性检测。通过体外实验证实，HIF-1α与骨肉瘤多药耐药密切相关；机制研究发现，HIF-1α能够下调SKA1促进骨肉瘤细胞耐药性的增强。进一步通过裸鼠体内试验证明，过表达SKA1能够有效控制给药肿瘤的体积和重量。本项目的成功开展丰富了人骨肉瘤多药耐药性产生的机理，为骨肉瘤多药耐药的克服及治疗提供了新的方法和思路，并为今后SKA1信号通路的研究提供了基础。