| 1. |
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
- Orlova, Anna, et al.
(författare)
-
On the Selection of a Tracer for PET Imaging of HER2-Expressing Tumors : Direct Comparison of a (124)I-Labeled Affibody Molecule and Trastuzumab in a Murine Xenograft Model
- 2009
-
Ingår i: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 1535-5667 .- 2159-662X .- 0340-6997 .- 1432-105X. ; 50:3, s. 417-425
-
Tidskriftsartikel (refereegranskat)abstract
- Human epidermal growth factor receptor type 2 (HER2) is a tyrosine kinase, which is often overexpressed in many carcinomas. Imaging HER2 expression in malignant tumors can provide important prognostic and predictive diagnostic information. The use of anti-HER2 tracers labeled with positron-emitting radionuclides may increase the sensitivity of HER2 imaging. The goal of this study was to compare directly 2 approaches for developing anti-HER2 PET tracers: a (124)I-labeled monoclonal antibody and a small (7-kDa) scaffold protein, the Affibody molecule, Methods: The anti-HER2 Affibody Z(HER2:342) and humanized monoclonal antibody trastuzumab were labeled with (124/125)I using p-iodobenzoate (PIB) as a linker. Cellular processing of both tracers by HER2-expressing cells was investigated. The biodistributions of (124)I-PIB-Z(HER2:342) and (125)I-PIB-trastuzumab were compared in BALB/C nu/nu mice bearing HER2-expressing NCI-N87 xenografts using paired labels. Small-animal PET of (124)I-PIB-Z(HER2:342) and (124)I-PIB-trastuzumab in tumor-bearing mice was performed at 6, 24, and 72 h after injection. Results: Both radioiodinated Z(HER2:342) and trastuzumab bound specifically to HER2-expressing cells in vitro and specifically targeted HER2-expressing xenografts in vivo. Radioiodinated trastuzumab was more rapidly internalized and degraded, which resulted in better retention of radioactivity delivered by Z(HER2:342). Total uptake of trastuzumab in tumors was higher than that of (124)I-PIB-Z(HER2:342). However, tumor-to-organ ratios were appreciably higher for (124)I-PIB-Z(HER2:342) due to the more rapid clearance of radioactivity from blood and normal organs. The ex vivo results were confirmed by small-animal PET. Conclusion: The use of the small scaffold targeting Affibody provides better contrast in HER2 imaging than does the monoclonal antibody.
|
|
| 5. |
|
|
| 6. |
- Sundberg, Åsa Liljegren, et al.
(författare)
-
Treatment of cultured glioma cells with EGFR-TKI gefitinib (‘Iressa’, ZD1839) increases the uptake of astatinated EGF despite absence of gefitinib-mediated growth inhibition
- 2003
-
Ingår i: European Journal of Nuclear Medicine. - : Springer Science and Business Media LLC. - 0340-6997 .- 1432-105X .- 1619-7070 .- 1619-7089. ; 30:5, s. 727-9
-
Tidskriftsartikel (refereegranskat)abstract
- The EGFR-TKI (epidermal growth factor receptor tyrosine kinase inhibitor) gefitinib ("Iressa", ZD1839), a reversible growth inhibitor of EGFR-expressing tumour cells, has been shown to enhance the antitumour effect of ionising radiation, and also to increase the uptake of radioiodinated EGF. Thus, combination of gefitinib treatment and radionuclide targeting is an interesting option for therapy of brain tumours that are difficult to treat with conventional methods. The aim of this study was to evaluate how pre-treatment with gefitinib affects binding of astatinated EGF ((211)At-EGF) to cultured glioma U343 cells, which express high levels of EGFR. The growth of U343 cells in the presence of gefitinib was investigated, and it was found that gefitinib does not significantly inhibit the growth of these cells. Nevertheless, the uptake of (211)At-EGF in U343 cells was markedly increased (up to 3.5 times) in cells pre-treated with gefitinib (1 microM). This indicates that a combination of gefitinib treatment and radionuclide targeting to EGFR might be a useful therapeutic modality, even for patients who do not respond to treatment with gefitinib alone.
|
|
| 7. |
|
|
