放射性碘标记RC-160对A549-hSSTR2细胞受体内化及杀伤作用的研究  

Internalization and lethal effect of ^(131)I-RC-160 on A549 lung carcinoma cells transfected with hSSTR2 gene

作　　者：赵明玄[1] 汪静[1] 王喆[1] 冯秀亮[2] 张瑞[3] 林国成[1] 邓敬兰[1] 

机构地区：[1]第四军医大学西京医院核医学科,西安710032 [2]第四军医大学西京医院实验外科,西安710032 [3]第四军医大学基础部生物化学与分子生物学教研室

出　　处：《中华核医学杂志》2007年第2期73-76,共4页Chinese Journal of Nuclear Medicine

基　　金：国家自然科学基金(30270414;30570526);全军医药卫生科研基金(01MB120)

摘　　要：目的研究^(125)I-伐普肽(RC-160)对转染人生长抑素2型受体(hSSTR2)基因的肺腺癌A549细胞(A549-hSSTR2)受体内化的规律,以及^(131)I-RC-160对 A549-hSSTR2细胞的杀伤作用。方法采用放射性配基结合分析法,以^(125)I-RC-160为放射性配基,测定 A549-hSSTR2细胞及未转染 hSSTR2基因的 A549(A549-pc3)细胞与^(125)I-RC-160在37℃温育不同时间(0.25,0.5,1,4,8,20和24 h)的内化率;采用四甲基偶氮唑蓝(MTT)法测不同浓度^(131)I-RC-160、Na^(131)I、RC-160对 A549-hSSTR2细胞及A549-pc3细胞作用24,48,72和96 h 的杀伤作用。结果 37℃条件下温育,^(125)I-RC-160迅速与 A549-hSSTR2受体结合并使受体发生内化。在温育1h 时,A549-hSSTR2细胞结合(膜结合+内化)的放射性计数为总计数的(18.2±1.9)%,明显高于 A549-pc3组[(5.7±1.4)%,P<0.01]。1 h 后,A549-hSSTR2细胞膜受体内化率(内化部分放射性计数与总放射性计数比)随时间的延长继续增加,膜结合率(膜结合部分放射性与总放射性计数比)随时间的延长逐渐减少。至24 h 时,受体内化率达(13.0±1.1)%,膜结合率为(3.9±2.2)%。^(131)I-RC-160对 A549-hSSTR2细胞的杀伤作用较对 A549-pc3细胞明显增强,并呈一定的剂量-效应和时间-效应关系,在96 h 时,3700 kBq/ml ^(131)I-RC-160对A549-hSSTR2的抑制率达(78.8±5.9)%。结论 ^(125)I-RC-160可以使转染 hSSTR2基因的细胞膜受体内化;^(125)I-RC-160对 A549-hSSTR2细胞的杀伤作用较强,这为外源性受体基因介导核素靶向性内照射治疗肿瘤提供了实验依据。Objective Introducing new gene to make an useful expression of the host cell is of clinical potential. In the current study, the internalization of the radioiodinated somatostatin analog ^125I-RC- 160 by A549 lung carcinoma cells transfected with human somatostatin receptor subtype 2 （hSSTIL2） gene （A549-hSSTR2）, and the lethal effect of ^131I-RC-160 on A549-hSSTR2 cells were investigated. Methods A549-hSSTR2 cells expressing hSSTR2 or A549-pc3 cells without hSSTR2 expression were incubated at 37℃ with ^125I-RC-160 for different time（0.25,0.5, 1,4, 8, 20 and 24 h）. The internalization of the radioligand was determined at the end of incubation. By using 3-（4,5-dimethyhhiazol-2-yl）-2,5-diphenyhetrazolium bromide （MTT） assay, the lethal effect of various dosage of ^131I-RC-160, Na^131I, RC-160 on A549-hSSTR2 and A549-pc3 after 24, 48, 72, 96 h incubation were measured. Results ^125I-RC-160 was rapidly internalized mediated via the membrane receptor of A549-hSSTR2. The binding radioactivity of A549-hSSTR2 cells[ （18.2 ±1.9）% of total amount added] was higher than that of A549-pe3 cells （5.7± 1.4）% after 1 h of incubation （P 〈0.05 ）. The internalization showed time-dependent manner with concomitant decrease of membrane binding. ^131I-RC-160 had stronger growth-inhibit effect on A549-hSSTR2 cells than on A549-pc3 cells. Conclusion ^125I-RC-160 could internalize the A459-hSSTR2 cells with enhanced lethal effect than A549-pc3 control, proving the concept of exogenous receptor gene mediated internal radiation therapy of cancers.

关 键 词：肺肿瘤 肿瘤细胞 培养的 受体 生长抑素 类似物和衍生物 放射疗法 

分 类 号：R734.2[医药卫生—肿瘤]