【作者】 师以康；

【导师】 甄永苏；

【作者基本信息】 中国协和医科大学 ， 微生物与生化药学， 2005， 博士

【摘要】 HER2受体是人类表皮生长因子受体家族四个成员之一，该受体被磷酸化后主要引起MAPK和P13K／Akt二个下游细胞信号通路的激活，在细胞的生长、分化和凋亡等生理活动中发挥重要作用。HER2在多种肿瘤中都有较高的表达，HER2高表达的肿瘤患者预示着对化疗的抗性、较高的恶性程度、较高的复发率和较短的生存期。肿瘤患者对化疗药物的敏感性还和肿瘤细胞HER2是否高表达有关系。 肿瘤细胞多药抗药（multidrug resistance，MDR）是肿瘤化疗失败的重要原因，而由mdr1基因编码的P-gp（P-glycoprotein）蛋白介导的多药抗药则是经典的多药抗药机制。P-gp作为跨膜蛋白，对天然的疏水性抗肿瘤药物有较强的外排作用，导致细胞内药物浓度下降，降低了药物对肿瘤生长的抑制作用。 力达霉素（Lidamycin，LDM）是本研究室从一株放线菌（Streptomycesglobisporus sp．C-1027）代谢产物中获得的对肿瘤细胞有强烈杀伤作用的大分子肽类抗肿瘤抗生素。本研究分别构建了HER2和mdr1基因的真核表达质粒，通过转染分别获得了HER2和mdr1高表达的肿瘤细胞株，并用来探讨力达霉素对HER2和mdr1高表达的肿瘤细胞的抗肿瘤活性。 一、LDM与HER2高表达乳腺癌细胞药物敏感性的关系 本研究构建了能在真核细胞表达HER2的真核表达质粒pcDNA3.1／HER2。把该质粒转染到HER2低表达的乳腺癌MCF-7细胞，获得了稳定高表达HER2的MCF-7／HER2细胞，同时获得了用空白质粒pcDNA3.1转染的作为对照的细胞株MCF-7／plasmid细胞。单克隆MCF-7／HER2细胞经RT-PCR和Western blot分析表明，HER2的mRNA和蛋白p185^HER2表达水平大约均是MCF-7／plasmid细胞的50倍。细胞免疫荧光分析证实了MCF-7／HER2细胞p185^HER2蛋白高表达并且更多还原

【Abstract】 The HER2 gene is one of the most studied molecules in the field of cancer research. The HER2 gene encodes a 185-kDa transmembrane glycoprotein which belongs to the epidermal growth factor receptor family. The activated HER2 receptor can mediate the signal transduction of MAPK and PI3K/Akt pathways, which play a crucial role in cell growth, differentiation, and apoptosis. The HER2 gene is amplified and/or overexpressed in many types of human malignancies. Patients with overexpressed HER2 predict a reduced disease-free and overall survival, a poor clinical outcome. Overexpressing HER2 confers cancer cells increased resistance to various cancer therapies.Multidrug resistance (MDR) is one of the biggest obstacles to success in tumor chemotherapy. Overespressing of P-glycoprotein (P-gp) encoded by mdr1 gene is the classic mechanism of causing MDR. As an integral part of plasma membrane, P-gp acts as a drug efflux pump that actively extrudes drugs from tumor cells, thereby decreasing the concentration of chemotherapeutic agents in cancer cells.Lidamycin (LDM), an antibiotic produced by Streptomyces globisporus strain which was isolated in our lab, displayed extremely potent cytotoxicity against tumor cells.Plasmid pcDNA3.1/HER2 and pcDNA3.1/mdrl were conctructed, stably transfected breast cancer cell MCF-7/HER2 and hepatoma cancer cell HepG2/mdr1 was obtained respectively in this study. We explored the antitumor activity of Lidamycin on cancer cells overexpressing HER2 and mdrl gene.1. Chemosensitivity to Lidamycin in Cancer Cells Overexpressing HER2Using plasmid pcDNA3.1/HER2 and control plasmid we obtained transfected更多还原