神经元外单胺转运蛋白在人肿瘤细胞系的表达(英文)

Extraneuronal monoamine transporter expression in human tumor cell lines

目的：我们先前发现的一个新的氯乙基亚硝脲的类似物２氯乙基３肌氨酸酰胺１亚硝基脲（ＳａｒＣＮＵ） ，是一种通过单胺递质的神经元外转运蛋白（ＥＭＴ） 进入细胞内的选择性的细胞毒素。此药已进入Ｉ期临床试验。在本研究中，我们检测ＥＭＴ 在２３ 个人类肿瘤细胞系里的表达水平，以证实ＥＭＴ 的表达是否与ＳａｒＣＮＵ 的细胞毒性有关。方法：应用反转录多聚酶链反应（ＲＴＰＣＲ） 检测ＥＭＴ 在肿瘤细胞系的表达。同时也用蛋白质印迹技术检测ＤＮＡ 修复蛋白Ｏ６甲基鸟嘌呤ＤＮＡ 甲基转移酶（ ＭＧＭＴ） 和切除修复交叉互补鼠修复缺乏基因２（ＥＲＣＣ２） 。其结果与用硫酸若丹明Ｂ（ＳＲＢ） 抗癌药物比色筛选法检测的ＳａｒＣＮＵ 的细胞毒性相关。结果：几乎所有细胞系都呈ＥＭＴ 表达阳性，其中有５ 个细胞系（ ＭＧＲ１ ，ＭＧＲ２ ，Ｔ９８Ｇ，ＳＫ１，和ＧＢＭ） 呈低水平表达。虽然在ＳａｒＣＮＵ 细胞毒性和ＥＭＴ 表达水平之间没有显著性的线性关系， 但多因素回归分析显示ＳａｒＣＮＵ 细胞毒性与ＥＭＴ 加ＭＧＭＴ 及ＥＲＣＣ－ ２ 表达之间的相关性有显著意义。结论：本研结果示提示ＥＭＴ 和ＤＮＡ 修复因子ＭＧＭＴ、ＥＲＣＣ２ 是ＳａｒＣＮＵ

Objective:We previously have found that 2 chloroethyl 3 sarcosinamide 1 nitrosourea (SarCNU),a new chloroethylnitrosourea analogue, which is in phase I clinical trials, is a selective cytotoxin that enters cells via the extraneuronal transporter for monoamine transmitters (EMT).In the present study,we determined EMT expression in 23 human tumor cell lines in order to verify if EMT expression correlate to SarCNU cytotoxicity.Methods:Reverse transcription polymerase chain reaction (RT PCR) was used for determination of EMT expression in tumor cell lines.We also measured expressions of DNA repair protein O6 methylguanine DNA methyltransferase (MGMT) and excision repair cross complementing rodent repair deficiency gene 2 (ERCC2) by Western blot analysis.The results were correlated to SarCNU cytotoxicity which was determined by the sulforhodamine B (SRB) colorimetric anticancer drug screening assay. Results:Almost all of the cell lines tested were positive for EMT expression,while five cell lines (MGR 1,MGR 2,T98 G,SKI 1,and GBM) were very low expressors.Although there was no significant linear correlation between SarCNU cytotoxicity and EMT expression,multiple regression analysis demonstrated a significant correlation between SarCNU cytotoxicity and EMT plus MGMT and ERCC 2 expression. Conclusions:This study suggests that both EMT and DNA repair factors, specifically,MGMT and ERCC2 are important determinants of SarCNU activity against human tumor cell lines.SarCNU should prove to be a more useful alternative chemotherapeutic agent for treatment of human tumors,since the majority of human tumor cell lines were EMT positive.