期刊
MOLECULAR PHARMACEUTICS
卷 7, 期 6, 页码 2194-2206出版社
AMER CHEMICAL SOC
DOI: 10.1021/mp100207t
关键词
Gold nanoparticles(AuNPs); antibody per nanoparticle; trastuzumab (Herceptin); HER-2; PEGylation; X-radiation; radiosensitization; breast cancer; DNA damage
资金
- Canadian Breast Cancer Research Alliance [019374]
- Canadian Institute of Health Research
- U.S Army Department of Defense [W81XWH-08-1-0519, P00002]
- University of Toronto
Our purpose was to develop a human epidermal growth factor receptor-2 (HER-2) targeted nanotechnology-based radiosensitizer. HER-2 is overexpressed in 20-30% of all breast cancers and up to 2-fold higher in locally advanced disease (LABC). Trastuzumab was derivatized with a polyethylene glycol (OPSS-PEG-SVA) cross-linker to produce trastuzumab-PEG-OPSS. These immunoconjugates were analyzed by SDS-PAGE, and their immunoreactivity was assessed by flow cytometry using HER-2 overexpressing SK-BR-3 breast cancer cells. Reacting trastuzumab with increasing ratios of PEG resulted in an increase in molecular weight from approximately 148 kDa to 243 kDa, associated with increasing PEG substitution (0.6 to 18.9 PEG chains per trastuzumab). Attachment of approximately 7 PEG chains per trastuzumab resulted in 56% retention in immunoreactivity assessed by flow cytometry. The conjugates were then linked to 30 nm AuNPs. Using a novel (123)iodine-radiotracer based assay that overcomes the current limitations of spectrophotometric quantification of biological molecules on AuNPs we estimate 14.3 +/- 2.7 antibodies were attached to each AuNP when 2 x 10(11) AuNPs were reacted with 20 mu g of trastuzumab-PEG-OPSS. Specificity of trastuzumab-PEG-AuNPs for HER-2 and internalization in SK-BR-3 cells was demonstrated by comparing the uptake of trastuzumab-PEG-AuNPs or PEG-AuNPs by darkfield microscopy. The ability of trastuzumab-PEG-AuNPs in combination with 300 kVp X-rays to enhance DNA double strand breaks (DSBs) in SK-BR-3 cells was assessed by immunofluorescence using the gamma-H2AX assay. gamma-H2AX assay results revealed 5.1-fold higher DNA-DSBs with trastuzumab-PEG-AuNPs and X-radiation as compared to treatment with X-radiation alone. The trastuzumab-PEG-AuNPs are a promising targeted nanotechnology-based radiosensitizer for improving LABC therapy. The design and systematic approaches taken to surface modify and characterize trastuzumab-PEG-AuNPs described in this study would have application to other molecularly targeted AuNPs for cancer treatment.
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