^(131)I-B2-S22-AFA对HER-2高表达乳腺癌细胞的杀伤作用  

The killing effect of ^(131)I-labeled B2-S22-AFA on breast cancer cells with high HER-2 expression

作　　者：李亚梅 关晏星[1] 陈学忠 张青[1] 张庆[1] 章梦芝 

机构地区：[1]南昌大学第一附属医院核医学科,南昌330006

出　　处：《核技术》2017年第12期17-25,共9页Nuclear Techniques

基　　金：江西省赣鄱英才555工程项目;江西省自然科学基金项目(No.2007GZY1419)资助~~

摘　　要：人类表皮生长因子受体2(Human Epidermal Growth Factor Receptor 2,HER-2)是乳腺癌最重要的致病基因。本文探讨^(131)I标记的HER-2特异结合小分子模拟肽B2-S22-AFA对乳腺癌细胞的特异性杀伤作用。采用溴代琥珀酰亚胺法(N-Bromide Succinimide,NBS)进行^(131)I标记B2-S22-AFA,测定标记率、放化纯度、稳定性及免疫活性。用Western Blot法和免疫组化法测定人乳腺癌SKBR3及MDA-MB-231Her-2细胞HER-2表达,观察不同浓度表皮生长因子(Epidermal Growth Factor,EGF)条件下B2-S22-AFA对细胞生长的抑制率。设B2-S22-AFA组(B2-S22-AFA终浓度1μg·mL^(–1))、^(131)I-B2-S22-AFA组(^(131)I-B2-S22-AFA终浓度144 kBq·μg^(–1)·mL)、^(131)I组(^(131)I终浓度144 kBq·mL^(–1))、阴性对照组及试剂空白组,每组EGF终浓度均5.0 pg·mL^(–1),采用四唑盐比色法(Methyl Thiazolyl Tetrazolium,MTT)测定SKBR3和MDA-MB-231细胞增殖活性,观察^(131)I-B2-S22-AFA、B2-S22-AFA及^(131)I作用不同时间对两种细胞生长的抑制率。结果显示,HER-2在SKBR3细胞呈强阳性表达,在MDA-MB-231细胞呈弱(或低)表达。^(131)I-B2-S22-AFA标记率、放化纯度及比活度分别为64.8%–79.6%、95.0%–97.6%、151.7 MBq·mg^(–1),在37°C血清中放置4 h、12 h、24 h、48 h、72 h的放化纯度分别95.4%、93.5%、91.4%、88.2%、77.4%,^(131)I-B2-S22-AFA与SKBR3细胞及MDA-MB-231细胞的最大结合率分别(66.47±3.24)%和(3.89±0.81)%(3次)。当EGF存在时,B2-S22-AFA可明显抑制SKBR3细胞生长;无EGF时,B2-S22-AFA无此作用。^(131)I-B2-S22-AFA对SKBR3细胞的杀伤作用较B2-S22-AFA和^(131)I明显增强(均p<0.05),B2-S22-AFA对SKBR3细胞杀伤作用显著高于^(131)I(p<0.05),^(131)I-B2-S22-AFA和B2-S22-AFA对MDA-MB-231细胞均无杀伤作用。综上所述,^(131)I-B2-S22-AFA可显著加强、加速B2-S22-AFA对HER-2高表达乳腺癌细胞的特异性杀伤作用。Background： B2-S22-AFA is a kind of small molecule mimetic polypeptide that can conjugate to epidermal growth factor receptor 2 （HER-2） specifically and has obvious depressant effect on breast cancer cells with overexpressing HER-2. Purpose： This study aims to investigate the specific killing effect of 131^I-labeled B2-S22-AFA on breast cancer cell with overexpressing HER-2. Methods： 131^I-B2-S22-AFA was prepared by using N-bromosuccinimide method to measure the labeling efficiency, radiochemical purity, stability, and immunocompetence. The expression levels of HER-2 in SKBR3 and MDA-MB-231 cells were detected by Immunohistochemistry and Western Blot. The inhibitory rate of B2-S22-AFA on cell growth was observed with epidermal growth factors （EGF） at different concentrations. Five groups i.e, B2-S22-AFA group （B2-S22-AFA final concentration： 1 μg·mL^-1）, 131I-B2-S22-AFA group （131^I-B2-S22-AFA final concentration： 144 kBq/1μg·mL^-1）, 131^I group （131^I final concentration： 144 kBq·mL^-1）, negative control group and reagent blank group, were selected for contrast tests with the final concentration of EGF in each group at 5.0 pg＇mL 1. The proliferation and activity of cells were measured by Methyl thiazolyl tetrazolium assay. The inhibitory rates were compared among 131^I-B2-S22-AFA group, B2-S22-AFA group and 131^I group in the growth of the two kinds of cells at different time. Results： 1） HER-2 receptors were strongly expressed in SKBR3 cells while weakly （low） or no expressed in MDA-MB-231 cells. The radiochemical purity, labeling rate and specific activity of 131^I-B2-S22-AFA were 95.0%-97.6%, 64.8%-79.6% and 151.7 MBq·mg^-1, respectively. Radiochemical purity of 131^I-B2-S22-AFA was 95.4%, 93.5%, 91.4%, 88.2% and 77.4% when it was placed at 37 ℃ in serum for 4 h, 12 h, 24 h, 48 h and 72 h, respectively. The maximum binding rates of SKBR3 and MDA-MB-231 cells were （66.47±3.24）% and （3.89±0.81）% （tested for 3 times） respectively. 2） The inhibitor

关 键 词：乳腺癌 同位素标记 131^I-B2-S22.AFA 表皮生长因子受体2 

分 类 号：R817.8[医药卫生—影像医学与核医学]