~(131)I-Herceptin对HER2过表达乳腺癌细胞Bcl-xL表达的影响

目的:探讨131I-Herceptin对HER2过表达乳腺癌细胞Bcl-x L表达的影响。方法:采用Iodogen法制备131I-Herceptin,超滤法纯化后测定其标记率、放射化学纯度和免疫结合率。通过免疫荧光法检测乳腺癌细胞表面HER2表达水平。131I(4.625 MBq/m L)、Herceptin(125μg/m L)及131I-Herceptin(4.625 MBq/m L)干预乳腺癌BT474细胞后,Western blot检测细胞中Bcl-x L的表达。结果:131I-Herceptin的标记率、放射化学纯度和免疫结合率分别为(89.71±2.93)%、(91.80±1.43)%和(58.84±3.35)%。BT474细胞膜表面HER2表达水平明显高于MDA-MB-231细胞。Herceptin、131I-Herceptin组BT474细胞内Bcl-x L表达水平明显低于对照组及131I组(均P0.01),而Herceptin与131I-Herceptin组之间细胞内Bcl-x L含量差异无统计学意义(P0.05)。结论:131I-Herceptin保留Herceptin对HER2过表达乳腺癌细胞Bcl-x L表达的抑制作用并促进细胞凋亡,进而与131I产生协同作用,较Herceptin更有效地杀伤HER2过表达乳腺癌细胞。

Effect of 131I-Herceptin on the Expression of Bcl-xL in HER2 Overexpressed Breast Cancer Cells

Objective:To explore the effect of 131I-Herceptin on the expression of Bcl-xL in HER2 overexpressed breast cancer cells.Methods:Herceptin was labeled with 131I using the Iodogen method and 131I-Herceptin was isolated by ultrafiltration membrane, then the labeling efficiency, radiochemical purity and immunoreactivity were measured. The expression levels of HER2 on the surface of different breast cancer cells were detected by immunofluorescence. HER2 overexpressed breast cancer cell line BT474 was respectively treated by normal medium, 131I (4.625 MBq/mL), Herceptin (125 ug/mL) and 131I-Herceptin (4.625 MBq/mL), then the expression of Bcl-xL were detected by Western blot analysis.Results:The labeling efficiency, radiochemical purity and immunoreactivity of 131I-Herceptin were (89.71± 2.93)%, (91.80± 1.43)% and (58.84± 3.35)% respectively. The immunofluorescence indicated that the expression level of HER2 in BT474 cells was significantly higher than that of MDA-MB-231 cells. The Bcl-xL expressions of both Herceptin and 131I-Herceptin groups were much lower than those of control and 131I groups (all P<0.01), while there was no significant difference of Bcl-xL expression between Herceptin and 131I-Herceptin (P>0.05).Conclusion:131I-Herceptin enhances apoptosis by retaining the effect of Herceptin on down-regulation Bcl-xL, thus can exert synergistic effects with 131I and kill HER2 overexpressed breast cancer cells more effectively than Herceptin.