Trastuzumab Labeled to High Specific Activity with 111In by Conjugation to G4 PAMAM Dendrimers Derivatized with Multiple DTPA Chelators Exhibits Increased Cytotoxic Potency on HER2-Positive Breast Cancer Cells
Trastuzumab Labeled to High Specific Activity with 111In by Conjugation to G4 PAMAM Dendrimers Derivatized with Multiple DTPA Chelators Exhibits Increased Cytotoxic Potency on HER2-Positive Breast Cancer Cells
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DOI：
10.1007/s11095-013-1044-1
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发表时间：
2013-08-01
影响因子：
3.7
通讯作者：
Reilly, Raymond M.
中科院分区：
文献类型：
--
作者：
Chan, Conrad;Cai, Zhongli;Reilly, Raymond M.
将曲妥珠单抗结合/不结合NLS肽与DTPA衍生的G4 PAMAM树状大分子结合，并测定In-111标记的特异性放射性（SA）、HER2免疫反应性和乳腺癌（BC）细胞毒性。G4树状大分子与DTPA反应，然后通过巯基偶联得到马来酰亚胺衍生曲妥珠单抗。用60 MBq In-111孵育2 ~ 20 μ g测定可获得的SA。检测HER2免疫反应性、内化和核输入。将in -111- dtpa - g4 -曲妥珠单抗（5.9 MBq/mu g）与in -111- dtpa - nls -曲妥珠单抗（0.5 MBq/mu g）分别对高或低HER2密度的SK-Br-3或MDA-MB-231细胞的克隆生存（CS）的影响进行比较。测定DNA双链断裂（DSBs）。dtpa - g4 -曲妥珠单抗用In-111标记SA (23.6 MBq/mu g)，比In-111- dtpa - nls -曲妥珠单抗高100倍。in -111- dtpa - g4 -曲妥珠单抗和in -111- dtpa - g4 - nls -曲妥珠单抗保留了HER2免疫反应性，并被内化和输入到BC细胞的细胞核中。g4放射免疫偶联物对SK-Br-3和MDA-MB-231细胞的细胞毒性分别比in -111- dtpa - nls -曲妥珠单抗高2-4倍和9倍，这与DNA dsb的增加有关。曲妥珠单抗与30dtpa修饰的G4 PAMAM树状大分子结合，允许高SA In-111标记，增加其对高或低HER2密度的BC细胞的细胞毒性效力。
To conjugate trastuzumab with/without NLS peptides to G4 PAMAM dendrimers derivatized with DTPA and determine the specific radioactivity (SA) for In-111 labeling, HER2 immunoreactivity and cytotoxicity on breast cancer (BC) cells.G4 dendrimers were reacted with DTPA then conjugated through a thiol to maleimide-derivatized trastuzumab. The SA achievable was determined by incubating 2 to 20 mu g with 60 MBq of In-111. HER2 immunoreactivity, internalization and nuclear importation were measured. The effect of In-111-DTPA-G4-trastuzumab (5.9 MBq/mu g) on the clonogenic survival (CS) of SK-Br-3 or MDA-MB-231 cells with high or low HER2 density, respectively was compared to In-111-DTPA-NLS-trastuzumab (0.5 MBq/mu g). DNA double-strand breaks (DSBs) were measured.DTPA-G4-trastuzumab was labeled with In-111 to a SA (23.6 MBq/mu g) which was 100-fold higher than In-111-DTPA-NLS-trastuzumab. In-111-DTPA-G4-trastuzumab and In-111-DTPA-G4-NLS-trastuzumab retained HER2 immunoreactivity and were internalized and imported into the nucleus of BC cells. G4-radioimmunoconjugates were 2-4 fold and 9-fold more cytotoxic to SK-Br-3 and MDA-MB-231 cells, respectively than In-111-DTPA-NLS-trastuzumab which was associated with an increase in DNA DSBs.Conjugation of trastuzumab to G4 PAMAM dendrimers modified with 30 DTPA permitted high SA In-111 labeling which increased their cytotoxic potency for BC cells with high or low HER2 density.