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| 2. |
- Mattsson, Sören, et al.
(författare)
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Swedish Cancer Society radiation therapy research investigation
- 2002
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Ingår i: Acta Oncologica. - 0284-186X .- 1651-226X. ; 41:7-8, s. 596-603
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Tidskriftsartikel (refereegranskat)abstract
- In an investigation by the Swedish Cancer Society, the present status, critical issues and future aspects and prospects were described by an expert group for each of nine major areas of radiation research. A summary of the investigation is presented in this report. A more extensive summary (in Swedish) can be found at www.Cancerfonden.se. It is concluded that radiation therapy plays an increasingly important role in curative and palliative tumour treatment and presents a considerable challenge to research. Several suggestions are made that could improve the possibilities for high-quality radiation therapy research in Sweden.
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| 3. |
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| 4. |
- Nordberg, Erika, et al.
(författare)
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Cellular studies of binding, internalization and retention of a radiolabeled EGFR-binding affibody molecule
- 2007
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Ingår i: Nuclear Medicine and Biology. - : Elsevier BV. - 0969-8051 .- 1872-9614. ; 34:6, s. 609-618
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: The cellular binding and processing of an epidermal growth factor receptor (EGFR) targeting affibody molecule, (Z(EGFR:955))(2), was studied. This new and small molecule is aimed for applications in nuclear medicine. The natural ligand epidermal growth factor (EGF) and the antibody cetuximab were studied for comparison. METHODS: All experiments were made with cultured A431 squamous carcinoma cells. Receptor specificity, binding time patterns, retention and preliminary receptor binding site localization studies were all made after (125)I labeling. Internalization was studied using Oregon Green 488, Alexa Fluor 488 and CypHer5E markers. RESULTS: [(125)I](Z(EGFR:955))(2) and [(125)I]cetuximab gave a maximum cellular uptake of (125)I within 4 to 8 h of incubation, while [(125)I]EGF gave a maximum uptake already after 2 h. The retention studies showed that the cell-associated fraction of (125)I after 48 h of incubation was approximately 20% when delivered as [(125)I](Z(EGFR:955))(2) and approximately 25% when delivered as [(125)I]cetuximab. [(125)I]EGF-mediated delivery gave a faster (125)I release, where almost all cell-associated radioactivity had disappeared within 24 h. All three substances were internalized as demonstrated with confocal microscopy. Competitive binding studies showed that both EGF and cetuximab inhibited binding of (Z(EGFR:955))(2) and indicated that the three substances competed for an overlapping binding site. CONCLUSION: The results gave information on cellular processing of radionuclides when delivered with (Z(EGFR:955))(2) in comparison to delivery with EGF and cetuximab. Competition assays suggested that [(125)I](Z(EGFR:955))(2) bind to Domain III of EGFR. The affibody molecule (Z(EGFR:955))(2) can be a candidate for EGFR imaging applications in nuclear medicine.
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| 5. |
- Nordberg, Erika, et al.
(författare)
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Cellular uptake of radioiodine delivered by trastuzumab can be modified by the addition of epidermal growth factor.
- 2005
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Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 32:7, s. 771-7
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The purpose of this study was to analyse whether non-radiolabelled epidermal growth factor (EGF) can modify the cellular uptake of 125I when delivered as [125I]trastuzumab. 125I was used as a marker for the diagnostically and therapeutically more interesting isotopes 123I (SPECT), 124I (PET) and 131I (therapy). METHODS: The cell-associated radioactivity was measured in squamous carcinoma A431 cells following addition of [125I]trastuzumab. Different concentrations of [125I]trastuzumab and unlabelled EGF were used, and the total, membrane-bound and internalised radioactivity was measured. We also analysed how EGF and trastuzumab affected the cell growth. RESULTS: It was generally found that the cellular 125I uptake was decreased by the addition of EGF when [125I]trastuzumab was added for short incubation times. However, if the incubation times were longer, EGF increased the 125I uptake. This shift came earlier when higher [125I]trastuzumab concentrations were applied. The addition of EGF also influenced cell proliferation, and concentrations above 10 ng/ml reduced cell growth by approximately 20% after 24 h of incubation. CONCLUSION: By adding unlabelled EGF, it was possible to modify the cellular uptake of [125I]trastuzumab. This points towards new approaches for the modification of radionuclide uptake in EGFR- and HER2-positive tumours.
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| 6. |
- Nordberg, Erika, et al.
(författare)
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Effects of an EGFR-binding affibody molecule on intracellular signaling pathways
- 2010
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Ingår i: International Journal of Oncology. - : Spandidos Publications. - 1019-6439 .- 1791-2423. ; 36:4, s. 967-972
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Tidskriftsartikel (refereegranskat)abstract
- Effects on intracellular signaling were studied in cells treated with the affibody molecule (Z(EGFR:955))(2) that targets the epithelial growth factor receptor (EGFR). EGFR is over-expressed in many types of cancers and plays a fundamental role in cell signaling and it is of interest to find targeting agents capable of blocking the receptor. The clinically approved antibody cetuximab (Erbitux (R)) and the natural ligand EGF were included as reference molecules. Two EGFR-rich cell lines, A-431 and U-343, were exposed to the three targeting agents and lysed. The cell lysates were immunoprecipitated with the receptors, or directly separated by SDS-Pace. Autophosphorylation of the receptors and phosphorylation of the downstream signaling proteins Erk and Akt, were evaluated by Western blotting. Although the three different agents compete for the same binding site on EGFR, they influenced the signaling differently. The affibody molecule did not induce autophosphorylation of EGFR or my other receptor in the EGFR-family but, in spite of this, induced phosphorylation of Erk in both cell lines and Akt in the A-431 cells. Thus, the results suggest that the signaling pattern induced by (Z(EGFR:955))(2) is only partly similar to that induced by cetuximab. This makes the affibody molecule a potentially interesting alternative to cetuximab for EGFR-targeted therapy since it might give different therapy-related effects on tumor cells and different side effects on normal tissues.
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| 7. |
- Nordberg, Erika, 1980-
(författare)
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EGFR and HER2 Targeting for Radionuclide-Based Imaging and Therapy : Preclinical Studies
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The optimal way to detect and treat cancer is to target cancer cells exclusively without affecting the surrounding tissue. One promising approach is to use radiolabelled molecules to target receptors that are overexpressed in cancer cells. Since the epidermal growth factor receptor (EGFR) family is overexpressed in many types of cancer, it is an attractive target for both diagnostic and therapeutic applications. This thesis can be divided into two parts. In part one (paper I), studies were conducted to modulate radionuclide uptake in tumour cells. The results showed that it was possible to modulate the cellular uptake of 125I delivered by trastuzumab (targeting HER2) by adding EGF (targeting EGFR). In part two (papers II-V) a high affinity EGFR-targeting affibody molecule (ZEGFR:955)2 was selected and analysed both in vitro and in vivo. In papers II, III and V, the results obtained when using (ZEGFR:955)2 were compared with those obtained with the two EGFR-binding molecules, EGF and cetuximab. These studies demonstrated that the affibody molecule bound specifically to EGFR (probably to subdomain III) with high affinity (~50 nM in biosensor analysis and ~1 nM in cellular studies) and produced intracellular signalling changes similar to those with cetuximab. In paper IV, in vivo studies were made, demonstrating that [111In](ZEGFR:955)2 gave a tumour-specific 111In uptake of 3.8±1.4% of injected dose per gram tumour tissue, 4 h post-injection. The tumours could be easily visualized with a gamma camera at this time-point. The results of these studies indicated that the affibody molecule (ZEGFR:955)2 is a possible candidate for radionuclide-based imaging of EGFR-expressing tumours. The biological effects of (ZEGFR:955)2 might be of interest for therapy applications.
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| 8. |
- Nordberg, Erika, et al.
(författare)
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In vivo and in vitro uptake of In-111, delivered with the affibody molecule(Z(EGFR:955))(2), in EGFR expressing tumour cells
- 2008
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Ingår i: Oncology Reports. - : Spandidos Publications. - 1021-335X .- 1791-2431. ; 19:4, s. 853-857
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Tidskriftsartikel (refereegranskat)abstract
- The epidermal growth factor receptor, EGFR, is overexpressed in many carcinomas. Targeting this receptor with radionuclides is important for imaging and therapy applications in nuclear medicine. We investigated the in vitro and in vivo properties of a new high affinity EGFR binding affibody molecule, (Z(EGFR:955))(2), when conjugated with CHXA"-DTPA and labelled with In-111. The binding time patterns and retention studies were performed using cultured squamous carcinoma A431 cells that overexpress EGFR. In the in vivo studies, female BALB/c nu/nu mice carrying tumours from xenografted A431 cells were used. The in vitro studies showed EGFR specific binding, high uptake and good retention of In-111 when delivered as [In-111](Z(EGFR:955))(2). The retention after 72 h of incubation was 38.0 +/- 1.15% of the initial level. The biodistribution study showed a tumour specific In-111 uptake of 3.8 +/- 1.4% of injected dose per gram turnout tissue 4 h post-injection. The tumour to blood ratio was 9.1 and the tumours could easily be visualized with a gamma camera at this time-point. In-111 delivered with [In-111](Z(EGFR:955))(2) gave an EGFR specific uptake and the results indicated that the (Z(EGFR:955))(2) affibody molecule is a candidate for radionuclide-based tumour imaging. Potential therapy applications are discussed.
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| 9. |
- Tilly, Nina, et al.
(författare)
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In vitro determination of toxicity, binding, retention, subcellular distribution and biological efficacy of the boron neutron capture agentDAC-1
- 1996
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Ingår i: Radiotherapy and Oncology. - : Elsevier BV. - 0167-8140 .- 1879-0887. ; 38:1, s. 41-50
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Tidskriftsartikel (refereegranskat)abstract
- In boron neutron capture therapy (BNCT), 10B is delivered selectively to the tumour cells and the nuclide then forms high-LET radiation (4He2+ and 7Li3+) upon neutron capture. Today much research is focused on development of a variety of boron compounds aimed for BNCT. The compounds must be thoroughly analysed in preclinical tests regarding basic characteristics such as binding and subcellular distribution to enable accurate estimations of dose-modifying factors. DAC-1,2-[2-(3-amino-propyl)-1,2-dicarba-closo-dodecaboran (12)-1-yl-methoxy]- 1,3-propanediol was synthesized at our laboratories and the human colon carcinoma cells LS-174T were used as an in vitro model. The boron compound showed a remarkable intracellular accumulation, 20-100 times higher than the boron content in the culture medium, in cultured cells and was not removed by extensive washes. Approximately half of the boron taken up also remained within the cells for at least 4 days. The DAC-1 compound alone was not toxic at boron concentrations below 2.5 micrograms B/g. The intracellular distribution of the boron compound was investigated by subcellular fractionation experiments and low pH treatments. It is possible that DAC-1 binds to some intracellular molecules or to membranes connected with organelles in the cytoplasm or even to the inside of the outer cell membrane. Another possibility is that the compound, due to the somewhat lipophilic properties, is embedded in the membranes. Thermal neutron irradiations were carried out at the Brookhaven Medical Research Reactor (BMRR). At a survival level of 0.1, DAC-1 + thermal neutrons were about 10.5 times more effective in cell inactivation than the thermal neutrons alone. Monte Carlo calculations gave a mean value of the 10B-dependent specific energy, the dose, of 0.22 Gy. The total physical dose during irradiation of DAC-1-containing cells with a neutron fluence of 0.18 x 10(12) n/cm2 was 0.39 Gy. The dose-modifying factor, at survival level 0.1, when comparing irradiation with thermal neutrons with and without DAC-1 was 3.4, while the dose-modifying factor when comparing neutron irradiations of cells with DAC-1 and irradiation of the cells with 60Co-gamma was 7.3. The results are encouraging and in vivo tests of tissue distributions and tumour uptake should now be carried out.
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| 10. |
- Wei, Q., et al.
(författare)
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EGFR, HER2 and HER3 expression in primary colorectal carcinomas and corresponding metastases : Implications for targeted radionuclide therapy
- 2011
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Ingår i: Oncology Reports. - : Spandidos Publications. - 1021-335X .- 1791-2431. ; 25:1, s. 3-11
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Tidskriftsartikel (refereegranskat)abstract
- Members of the epidermal growth factor receptor, EGER, family are interesting as targets for radionuclide therapy using targeting agents labeled with alpha- or beta-emitting radionuclides, especially when EGFR-positive colorectal carcinomas, CRC, are resistant to EGFR inhibiting agents like cetuximab and various tyrosine kinase inhibitors. The expression of EGFR, HER2 and HER3 was therefore analyzed in CRC samples from primary tumors, corresponding lymph node metastases and, in a few cases, liver metastases. The expression of HER2 and EGFR was scored from immunohistochemical preparations using the HercepTest criteria 0, 1+, 2+ or 3+ for cellular membrane staining while HER3 expression was scored as no, weak or strong cytoplasm staining. Material from 60 patients was analyzed. The number of EGFR 2+ or 3+ positive primary tumors was 16 out of 56 (29%) and for lymph node metastases 8 out of 56 (14%) whereas only one out of nine (11%) liver metastases were positive. Thus, there was lower EGFR positivity in the metastases. Only one among 53 patients was strongly HER2 positive and this in both the primary tumor and the metastasis. Eight out of 49 primary tumors (16%) were strongly HER3 positive and the corresponding numbers for lymph node metastases were 9 out of 49 (18%) and for liver metastases 2 out of 9 (22%). The observed number of strongly EGFR positive cases was somewhat low but EGFR might be, for the cases with high EGFR expression in metastases, a target for radionuclide therapy. HER2 seems not to be of such interest due to rare expression, neither HER3 due to mainly expression in the cytoplasm. The requirements for successful EGFR targeted radionuclide therapy are discussed, as well as patient inclusion criteria related to radionuclide therapy.
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