[γ干扰素对乳腺癌细胞系中Her-2/neu表达及131I-赫赛汀抗肿瘤活性的影响]

[Effects of interferon-gamma on Her-2/neu expression and antitumor activity of 131I-Herceptin in breast cancer cell lines].

作者信息

Fan Yi-Xiang, Luo Rong-Cheng, Fang Yong-Xin, Yan Xiao, Lu Cheng-Wei

机构信息

Department of Oncology, Nanfang Hospital, South Medical University, Guangzhou, Guangdong 510515, P. R. China.

出版信息

Ai Zheng. 2006 Apr;25(4):443-6.

PMID:16613677

Abstract

BACKGROUND & OBJECTIVE: Herceptin plays an important role in treating metastatic breast cancer by targeting Her2/neu, therefore, combining Herceptin with iodine-131 (131I) might enhance its antitumor activity. This study was to up-regulate Her2/neu expression by interferon-gamma (IFN-gamma), and explore its effect on binding and antitumor activity of 131I-Herceptin in breast cancer cell lines MCF-7, SKBR-3 and BT-474.

METHODS

MCF-7, SKBR-3 and BT-474 cells were cultured with or without IFN-gamma (500 U/ml) for 48 h. The positive rate and mean fluorescence intensity (MFI) of Her2/neu on the 3 cell lines were tested by flow cytometry. Herceptin was labeled with 131I by Iodogen method, and its radiochemical purity (RCP) was tested by size-exclusion high-pressure liquid chromatography (HPLC). The binding rate of 131I-Herceptin on cells was measured by non-competitive saturation analysis, and its killing effect was estimated by colony-forming assay. The positive rate and MFI of Her2/neu, binding rate of 131I-Herceptin, and colony-forming rate were compared between IFN-gamma-induced group and control group by t test.

RESULTS

For MCF-7 cells, the positive rate and MFI of Her2/neu were significantly higher in IFN-gamma-induced cells than in control cells [(15.2+/-4.7)% vs. (8.5+/-1.9)%, t=3.515, P<0.05; 121+/-17 vs. 38+/-7, t=7.823, P<0.002]; for SKBR-3 and BT-474 cells, no obvious difference of Her2/neu positive rate was observed between IFN-gamma-induced cells and control cells [(99.7+/-0.9)% vs. (98.9+/-1.1)%, P>0.05; (99.5+/-1.2)% vs. (98.1+/-0.9)%, P>0.05], but the MFI of Her2/neu was significantly higher in IFN-gamma-induced cells than in control cells (1,608+/-201 vs. 952+/-125, t=4.802, P<0.01; 1,968+/-192 vs. 1,020+/-98, t=7.614, P<0.002). The binding rates of Her2/neu were increased from (5.2+/-1.4)% to (12.3+/-3.4)% by 2.4 folds in MCF-7 cells, from (35.8+/-4.5)% to (48.9+/-7.1)% by 1.4 folds in SKBR-3 cells, and from (37.2+/-3.6)% to (59.5+/-8.7)% by 1.6 folds in BT-474 cells after inducement with IFN-gamma. The colony-forming rates were significantly lower in IFN-gamma-induced MCF-7, SKBR-3 and BT-474 cells than in control cells [(30+/-4)% vs. (49+/-3)%, t=6.574, P<0.05; (23+/-5)% vs. (37+/-6)%, t=3.105, P<0.05; (19+/-6)% vs. (34+/-5)%, t=3.323, P<0.05].

CONCLUSION

IFN-gamma can up-regulate Her-2/neu expression and increase the binding of 131I-Herceptin, hence, improve the inhibitory effect of 131I-Herceptin on proliferation of breast cancer cells.

摘要

背景与目的

赫赛汀通过靶向Her2/neu在转移性乳腺癌治疗中发挥重要作用，因此，将赫赛汀与碘-131（131I）联合使用可能会增强其抗肿瘤活性。本研究旨在通过γ干扰素（IFN-γ）上调Her2/neu表达，并探讨其对131I-赫赛汀在乳腺癌细胞系MCF-7、SKBR-3和BT-474中的结合及抗肿瘤活性的影响。

方法

MCF-7、SKBR-3和BT-474细胞在有或无IFN-γ（500 U/ml）的条件下培养48小时。通过流式细胞术检测这3种细胞系上Her2/neu的阳性率和平均荧光强度（MFI）。采用Iodogen法用131I标记赫赛汀，通过尺寸排阻高压液相色谱（HPLC）检测其放射化学纯度（RCP）。采用非竞争性饱和分析法测定131I-赫赛汀在细胞上的结合率，通过集落形成试验评估其杀伤效果。采用t检验比较IFN-γ诱导组和对照组之间Her2/neu的阳性率和MFI、131I-赫赛汀的结合率以及集落形成率。

结果

对于MCF-7细胞，IFN-γ诱导的细胞中Her2/neu的阳性率和MFI显著高于对照细胞[（15.2±4.7）%对（8.5±1.9）%，t = 3.515，P < 0.05；121±17对38±7，t = 7.823，P < 0.002]；对于SKBR-3和BT-474细胞，IFN-γ诱导的细胞与对照细胞之间Her2/neu阳性率无明显差异[（99.7±0.9）%对（98.9±1.1）%，P > 0.05；（99.5±1.2）%对（98.1±0.9）%，P > 0.05]，但IFN-γ诱导的细胞中Her2/neu的MFI显著高于对照细胞（1608±201对952±125，t = 4.802，P < 0.01；1968±192对1020±98，t = 7.614，P < 0.002）。经IFN-γ诱导后，MCF-7细胞中Her2/neu的结合率从（5.2±1.4）%提高到（12.3±3.4）%，提高了2.4倍；SKBR-3细胞中从（35.8±4.5）%提高到（48.9±7.1）%，提高了1.4倍；BT-474细胞中从（37.2±3.6）%提高到（59.5±8.7）%，提高了1.6倍。IFN-γ诱导的MCF-7、SKBR-3和BT-474细胞的集落形成率显著低于对照细胞[（30±4）%对（49±3）%，t = 6.574，P < 0.05；（23±5）%对（37±6）%，t = 3.105，P < 0.05；（19±6）%对（34±5）%，t = 3.323，P < 0.05]。