多胺通过调节p-糖蛋白诱导肿瘤细胞多药耐药的机制研究

Polyamines as small molecules have a wide range of biological functions, and have close relationship with tumorigenesis, development and metastasis, but there are few reports on its role in cancer multidrug resistance (MDR), especially its mechanisms of participation in MDR have not been reported. Based on results of previous studies and our recent pre-research work in terms of polyamines and tumor MDR, we propose that "polyamines may induce MDR in tumor cells through regulation of P-glycoprotein (P-gp)". In this project, changes of polyamines in the process of sensitive cell to MDR cell and the change of resistance in the MDR cell with blocking the synthesis of polyamines are used to investigate the relationship between polyamines and MDR. Subsequently, we build a new model of polyamine-mediated MDR cell and detect changes in the expression of P-gp simultaneously to reveal the quantitative relationship of polyamines and MDR or P-gp. Based on this, we will investigate the related signaling pathways and clarify the mechanism of the polyamine-mediated MDR through regulating P-gp using Ras, MAPKs, PKC and others as key targets by means of a variety of molecular biology methods. The development of this subject will helpful to find new target to overcome MDR, reveal the mechanism of MDR, and will give the foundation, experimental evidence and new light on prevention and treatment of tumor MDR.

多胺作为一种具有广泛生物学功能的小分子物质，与肿瘤的发生、发展及转移密切相关，但其在肿瘤多药耐药（MDR）方面的研究甚少，尤其是其参与MDR的机制还未见报道。本课题基于前人的研究成果及我们近期在多胺与肿瘤MDR方面的预研工作，提出“多胺可能通过调控P-糖蛋白（P-gp）诱导肿瘤发生MDR”这一研究设想。本项目拟通过检测多胺在敏感细胞耐药形成过程中的变化及阻断耐药细胞多胺合成后细胞耐药性的变化，确定多胺与MDR的关系；随后构建多胺介导的新型肿瘤细胞MDR模型，并同时监测P-gp表达的变化，揭示多胺含量与MDR及P-gp的关系；最终利用多种分子生物学手段，以Ras、MAPKs、PKC等为关键靶点，构建多胺通过调节P-gp调控MDR的信号通路，阐明多胺介导MDR的机制。本研究有利于发现克服MDR的新靶标，揭示MDR产生的机理，对肿瘤MDR的预防和治疗提供理论基础、实验依据及新的思路。

肿瘤多药耐药（MDR）是化疗失败的主要原因，探索MDR产生的因素，深入研究MDR产生的机制是抗MDR的研究热点。多胺作为一种具有广泛生物学功能的小分子物质，与肿瘤的发生、发展及转移有着密切关系。我们通过微环境长期加入多胺（低浓度加量持续诱导法）成功构建两种多胺介导的肿瘤多药耐药细胞模型K562/PA及MCF-7/PA，其阿霉素耐药倍数分别达到16.52及25.26，且耐药性稳定。随后以K562/A02、MCF-7/ADM、K562/PA及MCF-7/PA为细胞模型，研究多胺在MDR中的作用。研究表明多胺在肿瘤细胞多药耐药形成过程中含量的变化与P-gp的表达相关，抑制多胺的合成，P-gp的表达降低，P-gp的功能减弱，细胞耐药得到逆转，证实多胺是多药耐药形成的重要因素，且其通过促进P-gp上调而诱导肿瘤多药耐药产生；进一步机制研究表明，多胺通过Ras/Raf/JNK及PKC/JNK信号通路调节P-gp 而诱导肿瘤细胞多药耐药。本研究有利于发现克服MDR的新靶标，揭示MDR产生的机理，对肿瘤MDR的预防和治疗提供理论基础、实验依据及新的思路。

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