Relationship between induction of phosphorylated H2AX and survival in breast cancer cells exposed to 111In-DTPA-hEGF
Relationship between induction of phosphorylated H2AX and survival in breast cancer cells exposed to 111In-DTPA-hEGF
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DOI：
10.2967/jnumed.108.051805
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发表时间：
2008-08-01
影响因子：
9.3
通讯作者：
Vallis, Katherine A.
中科院分区：
文献类型：
--
作者：
Cai, Zhongli;Chen, Zhuo;Vallis, Katherine A.
俄歇电子发射放射性药物In-111-二乙烯三胺五乙酸人表皮生长因子（In-111-DTPA-hEGF）结合表皮生长因子受体（EGFR），被内化并易位到细胞核。本研究的目的是探讨EGFR表达，DNA损伤，细胞毒性暴露于In-111-DTPA-hEGF之间的关系。方法：乳腺癌细胞株与EGFR表达水平的范围内暴露于In-111-DTPA-hEGF或γ-辐射。细胞系（括号中为每个细胞的EGFR数量）为MDA-MB-468（1.3 x 10（6））、MDA-MB-231（1.3 x 10（5））和MCF-7（1.5 x 10（4））。通过细胞分级分离测量分配到细胞核中的放射性比例。使用γ-H2AX测定评价DNA双链断裂。克隆形成存活测定用于测量细胞毒性。结果：所有数据均表示为平均值+/-SID。在用In-111-DTPAhEGF（5.2 MBq/mL，43 nM）孵育20 h的MDA-MB-468、MDA-MB-231和MCF-7细胞中，易位至细胞核的In-111-DTPA-hEGF量（以mBq/细胞核计）分别为131 +/-6、8.1 +/-0.1和1.1 +/-0.9。每个细胞核的γ-H2AX灶的数量分别为35 +/-15、19 +/-10和1.7 +/-0.3。已证实，在暴露于In-111-DTPA-hEGF（5.2 MBq/mL，43 nM）20 h后，MDA-MB-468（0.013 +/-0.001）和MDA-MB-231（0.5 +/-0.1）中的存活分数（SF）降低，但MCF-7细胞中的SF未降低。MDA-MB-468细胞暴露于DTPA-EGF（43 nM）和In-111-乙酸盐（5.2 MBq/mL）20 h后的SF分别为0.5 +/-0.1和0.53 +/-0.05。MDA-MB-468是对γ射线最敏感的细胞系，2戈伊后SF为0.45 +/-0.04，而MCF-7和MDA-MB-231分别为0.7 +/-0.1和0.8 +/-0.1。在MDA-MB-468细胞中，每个细胞核中的γ-H2AX灶的数量与In-111-DTPA-hEGF的浓度、比活性和孵育时间相关。结论：由（111）InDTPA-hEGF引起的DNA损伤与暴露细胞的EGFR表达水平以及In-111-IDTIPA-hEGF的浓度、比活性和孵育时间相关。γ-H2AX检测可能是预测和监测In-111-DTPA-hEGF治疗结果的有用生物标志物。
The Auger electron-emitting radiopharmaceutical In-111-cliethylenetriaminepentaacetic acid human epidermal growth factor (In-111-DTPA-hEGF) binds the epidermal growth factor receptor (EGFR), is internalized, and translocates to the nucleus. The purpose of this study was to investigate the relationship between EGFR expression, DNA damage, and cytotoxicity in cells exposed to In-111-DTPA-hEGF. Methods: Breast cancer cell lines with a range of EGFR expression levels were exposed to In-111-DTPA-hEGF or gamma-radiation. The cell lines (followed by number of EGFR per cell in parentheses) were MDA-MB-468 (1.3 x 10(6)), MDA-MB-231 (1.3 x 10(5)), and MCF-7 (1.5 x 10(4)). The proportion of radioactivity partitioning into the nucleus was measured by cell fractionation. DNA double-strand breaks were evaluated using the gamma-H2AX assay. Clonogenic survival assays were used to measure cytotoxicity. Results: All data are presented as mean +/- SID. The amount of In-111-DTPA-hEGF that translocated to the nucleus (in mBq/nucleus) in MDA-MB-468, MDA-MB-231, and MCF-7 cells incubated with In-111-DTPAhEGF (5.2 MBq/mL, 43 nM) for 20 h was 131 +/- 6, 8.1 +/- 0.1, and 1.1 +/- 0.9, respectively. The number of gamma-H2AX foci per nucleus was 35 +/- 15,19 +/- 10, and 1.7 +/- 0.3, respectively. Areduction in the surviving fraction (SF) in MDA-MB-468 (0.013 +/- 0.001) and MDA-MB-231 (0.5 +/- 0.1) but not in MCF-7 cells after exposure to In-111-DTPA-hEGF (5.2 MBq/mL, 43 nM) for 20 h has been demonstrated. The SF of MDA-MB-468 cells after exposure to DTPA-EGF (43 nM) and In-111-acetate (5.2 MBq/mL) for 20 h was 0.5 +/- 0.1 and 0.53 +/- 0.05, respectively. MDA-MB-468 was the most sensitive of the cell lines to gamma-irradiation, with an SF after 2 Gy of 0.45 +/- 0.04, compared with 0.7 +/- 0.1 and 0.8 +/- 0.1 for MCF-7 and MDA-MB-231, respectively. The number of gamma-H2AX foci per nucleus in MDA-MB-468 cells correlated with the concentration, specific activity, and incubation time of In-111-DTPA-hEGF. Conclusion: DNA damage caused by (111)InDTPA-hEGF correlates with the EGFR expression level of the exposed cells and with concentration, specific activity, and incubation time of In-111-IDTIPA-hEGIF. The gamma-H2AX assay may be a useful biomarker to predict and monitor the outcome of treatment with In-111-DTPA-hEGF.