前期发现，由5FU长期诱导建立的人肝癌耐药细胞株，相对亲本细胞PLC/PRF/5，其CD13水平明显上调，可能与其耐药性有关；该耐药株的MAPK相关信号通路蛋白磷酸化水平大多较低，Hsp27、CREB磷酸化水平较高，而CD13抑制剂Bestatin能下调亲本细胞Hsp27的磷酸化水平；5FU和Bestatin都能上调亲本细胞的胞内ROS水平，5FU与Bestatin联合用药及通过分子杂交和协同前药原理设计合成的化合物5FU-Bestatin，对耐药株的敏感性均明显优于单用5FU。因此，本课题拟以CD13-信号转导-关键蛋白-功能变化-耐药为主线，采用多种方法探讨CD13与胞内ROS蓄积、细胞凋亡、细胞主动外排的关系。研究耐药株耐药及Bestatin逆转耐药株耐药的机制，并评价5FU-Bestatin的抑瘤活性。为逆转多药耐药提出思路，为肿瘤治疗评价候选先导化合物。

We previously found that compared to parental PLC/PRF/5 cells, the CD13 level of human hepatocellular carcinoma drug resistant cell line established by long term induced of 5FU were significantly up-regulated. This might be related to drug resistance. Phosphorylation of MAPK signal pathway related protein in resistant strains was very low. However, phosphorylation of Hsp27 and CREB were very high. CD13 inhibitor bestatin could down-regulate the phosphorylation of Hsp27 of parental cells. 5FU and Bestatin could up-regulate the cellular ROS level of parental cells. 5FU combination with Bestatin and compound 5FU-Bestatin which was designed and synthesized according to molecular hybridization and collaborative prodrug principles were all more sensitive to resistant strains than the single use of 5FU. Therefore, in this project we will use a variety of methods to explore the relationship between CD13 and intracellular ROS accumulation, cell apoptosis and cellular efflux using CD13- signal transduction- key protein- functional changes- drug resistance as the main line. Research on mechanism of drug-resistant and reversal of drug-resistant by Bestatin, and evaluate the antitumor activity of 5FU-Bestatin. To propose idea for reversing multidrug resistance and evaluate the candidate lead compound for cancer treatment.