| 1. |
|
|
| 2. |
- Altai, Mohamed, et al.
(författare)
-
Order of amino acids in C-terminal cysteine-containing peptide-based chelators influences cellular processing and biodistribution of Tc-99m-labeled recombinant Affibody molecules
- 2012
-
Ingår i: Amino Acids. - : Springer Science and Business Media LLC. - 0939-4451 .- 1438-2199. ; 42:5, s. 1975-1985
-
Tidskriftsartikel (refereegranskat)abstract
- Affibody molecules constitute a novel class of molecular display selected affinity proteins based on non-immunoglobulin scaffold. Preclinical investigations and pilot clinical data have demonstrated that Affibody molecules provide high contrast imaging of tumor-associated molecular targets shortly after injection. The use of cysteine-containing peptide-based chelators at the C-terminus of recombinant Affibody molecules enabled site-specific labeling with the radionuclide Tc-99m. Earlier studies have demonstrated that position, composition and the order of amino acids in peptide-based chelators influence labeling stability, cellular processing and biodistribution of Affibody molecules. To investigate the influence of the amino acid order, a series of anti-HER2 Affibody molecules, containing GSGC, GEGC and GKGC chelators have been prepared and characterized. The affinity to HER2, cellular processing of Tc-99m-labeled Affibody molecules and their biodistribution were investigated. These properties were compared with that of the previously studied Tc-99m-labeled Affibody molecules containing GGSC, GGEC and GGKC chelators. All variants displayed picomolar affinities to HER2. The substitution of a single amino acid in the chelator had an appreciable influence on the cellular processing of Tc-99m. The biodistribution of all Tc-99m-labeled Affibody molecules was in general comparable, with the main difference in uptake and retention of radioactivity in excretory organs. The hepatic accumulation of radioactivity was higher for the lysine-containing chelators and the renal retention of Tc-99m was significantly affected by the amino acid composition of chelators. The order of amino acids influenced renal uptake of some conjugates at 1 h after injection, but the difference decreased at later time points. Such information can be helpful for the development of other scaffold protein-based imaging and therapeutic radiolabeled conjugates.
|
|
| 3. |
- Altai, Mohamed, et al.
(författare)
-
Selection of an optimal cysteine-containing peptide-based chelator for labeling of affibody molecules with (188)Re.
- 2014
-
Ingår i: European Journal of Medicinal Chemistry. - : Elsevier BV. - 0223-5234 .- 1768-3254. ; 87, s. 519-28
-
Tidskriftsartikel (refereegranskat)abstract
- Affibody molecules constitute a class of small (7 kDa) scaffold proteins that can be engineered to have excellent tumor targeting properties. High reabsorption in kidneys complicates development of affibody molecules for radionuclide therapy. In this study, we evaluated the influence of the composition of cysteine-containing C-terminal peptide-based chelators on the biodistribution and renal retention of (188)Re-labeled anti-HER2 affibody molecules. Biodistribution of affibody molecules containing GGXC or GXGC peptide chelators (where X is G, S, E or K) was compared with biodistribution of a parental affibody molecule ZHER2:2395 having a KVDC peptide chelator. All constructs retained low picomolar affinity to HER2-expressing cells after labeling. The biodistribution of all (188)Re-labeled affibody molecules was in general comparable, with the main observed difference found in the uptake and retention of radioactivity in excretory organs. The (188)Re-ZHER2:V2 affibody molecule with a GGGC chelator provided the lowest uptake in all organs and tissues. The renal retention of (188)Re-ZHER2:V2 (3.1 ± 0.5 %ID/g at 4 h after injection) was 55-fold lower than retention of the parental (188)Re-ZHER2:2395 (172 ± 32 %ID/g). We show that engineering of cysteine-containing peptide-based chelators can be used for significant improvement of biodistribution of (188)Re-labeled scaffold proteins, particularly reduction of their uptake in excretory organs.
|
|
| 4. |
- Altai, Mohamed, et al.
(författare)
-
Selection of an optimal cysteine-containing peptide-based chelator for labeling of Affibody molecules with 188-Re
- 2013
-
Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 40:Suppl. 2, s. S219-S220
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Affibody molecules constitute a class of small (7 kDa) scaffold proteins that can be engineered to have excellent tumor targeting properties. High reabsorption in kidneys complicates development of affibody molecules for radionuclide therapy. In this study, we evaluated the influence of the composition of cysteine-containing C-terminal peptide-based chelators on the biodistribution and renal retention of 188Re-labeled anti-HER2 affibody molecules. Biodistribution of affibody molecules containing GGXC or GXGC peptide chelators (where X is G, S, E or K) was compared with biodistribution of a parental affibody molecule ZHER2:2395 having a KVDC peptide chelator. All constructs retained low picomolar affinity to HER2-expressing cells after labeling. The biodistribution of all 188Re-labeled affibody molecules was in general comparable, with the main observed difference found in the uptake and retention of radioactivity in excretory organs. The 188Re-ZHER2:V2 affibody molecule with a GGGC chelator provided the lowest uptake in all organs and tissues. The renal retention of 188Re-ZHER2:V2 (3.1±0.5 %ID/g at 4 h after injection) was 55-fold lower than retention of the parental 188Re-ZHER2:2395 (172±32 %ID/g). We show that engineering of cysteine-containing peptide-based chelators can be used for significant improvement of biodistribution of 188Re-labeled scaffold proteins, particularly reduction of their uptake in excretory organs.
|
|
| 5. |
- Andersson, Jennie, et al.
(författare)
-
In Vitro Therapy Modeling of HER2 Targeting Therapy in Disseminated Prostate Cancer
- 2014
-
Ingår i: International Journal of Oncology. - : Spandidos Publications. - 1019-6439 .- 1791-2423. ; 45:5, s. 2153-2158
-
Tidskriftsartikel (refereegranskat)abstract
- Prostate cancer (PCa) is the most common cancer type among men. Treatments against advanced PCa are limited and in many cases only palliative. In a later, androgent independent, stage of PCa androgen receptors can be activated without interaction with ligand, i.e., by receptors of tyrosine kinase (RTK) family in the outlaw pathway. Human epidermal growth factor receptors HER2 and EGFR belong to RTK-family. HER2 is one of the main actors in the outlaw pathway with EGFR as the preferable heterodimerizing partner. We hypothesized that information on HER2 expression in advanced PCa could be useful for selection of patients for anti-RTK therapy and monitoring of therapy response. A panel of PCa cell lines (LNCap, PC3, DU-145) was subjected to a 8-week treatment using drugs influencing the RTK: trastuzumab (anti‑HER2), 17-DMAG (Hsp90 inhibitor), alone or in combination, and their HER2 and EGFR expressions were compared with non-treated cells. Treatment with trastuzumab decreased proliferation of LNCap and DU-145 cell lines, while 17-DMAG and trastuzumab/17‑DMAG combination affected all three cell lines. HER2 expression was significantly increased in PC3 cells, the most resistant cell line. On the contrary, in responding cells (LNCap and DU-145) HER2 expression decreased, accompanied by increased EGFR expression. However, additional treatment of cells with cetuximab (anti‑EGFR) did not give any additive effect to trastuzumab. In this study the response to anti-RTK therapy proved to vary between different PCa cell lines. We have demonstrated that RTK targeting treatments may affect the phenotypic profile of PCa tumor cells that correlates with therapy outcome. Observation of such changes during treatment could be used for monitoring and an improved therapy outcome.
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Orlova, Anna, et al.
(författare)
-
Imaging of HER3-expressing xenografts in mice using a Tc-99m(CO)(3)-HEHEHE-Z(HER3:08699) affibody molecule
- 2014
-
Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 41:7, s. 1450-1459
-
Tidskriftsartikel (refereegranskat)abstract
- Human epidermal growth factor receptor type 3 (HER3) is a transmembrane receptor tyrosine kinase belonging to the HER (ErbB) receptor family. Membranous expression of HER3 is associated with trastuzumab resistance in breast cancer and the transition to androgen independence in prostate cancer. Imaging of HER3 expression in malignant tumors may provide important diagnostic information that can influence patient management. Affibody molecules with low picomolar affinity to HER3 were recently selected. The aim of this study was to investigate the feasibility of HER3 imaging using radiolabeled Affibody molecules. A HER3-binding Affibody molecule, Z(08699), with a HEHEHE-tag on N-terminus was labeled with Tc-99m(CO)(3) using an IsoLink kit. In vitro and in vivo binding specificity and the cellular processing of the labeled binder were evaluated. Biodistribution of Tc-99m(CO)(3)-HEHEHE-Z(08699) was studied over time in mice bearing HER3-expressing xenografts. HEHEHE-Z(08699) was labeled with Tc-99m(CO)(3) with an isolated yield of > 80 % and a purity of > 99 %. Binding of Tc-99m(CO)(3)-HEHEHE-Z(08699) was specific to BT474 and MCF7 (breast cancer), and LS174T (colon cancer) cells. Cellular processing showed rapid binding and relatively quick internalization of the receptor/Affibody molecule complex (70 % of cell-associated radioactivity was internalized after 24 h). The tumor targeting was receptor mediated and the excretion was predominantly renal. Receptor-mediated uptake was also found in the liver, lung, stomach, intestine, and salivary glands. At 4 h pi, tumor-to-blood ratios were 7 +/- 3 for BT474, and 6 +/- 2 for LS174T xenografts. LS174T tumors were visualized by microSPECT 4 h pi. The results of this study suggest the feasibility of HER3-imaging in malignant tumors using Affibody molecules.
|
|
| 10. |
|
|
| 11. |
- Varasteh, Zohreh, et al.
(författare)
-
The Effect of Mini-PEG-Based Spacer Length on Binding and Pharmacokinetic Properties of a Ga-68-Labeled NOTA-Conjugated Antagonistic Analog of Bombesin
- 2014
-
Ingår i: Molecules. - : MDPI AG. - 1431-5157 .- 1420-3049. ; 19:7, s. 10455-10472
-
Tidskriftsartikel (refereegranskat)abstract
- The overexpression of gastrin-releasing peptide receptor (GRPR) in cancer can be used for peptide-receptor mediated radionuclide imaging and therapy. We have previously shown that an antagonist analog of bombesin RM26 conjugated to 1,4,7-triazacyclononane-N, N', N ''-triacetic acid (NOTA) via a diethyleneglycol (PEG(2)) spacer (NOTA-PEG(2)-RM26) and labeled with Ga-68 can be used for imaging of GRPR-expressing tumors. In this study, we evaluated if a variation of mini-PEG spacer length can be used for optimization of targeting properties of the NOTA-conjugated RM26. A series of analogs with different PEG-length (n = 2, 3, 4, 6) was synthesized, radiolabeled and evaluated in vitro and in vivo. The IC50 values of Ga-nat-NOTA-PEG(n)-RM26 (n = 2, 3, 4, 6) were 3.1 +/- 0.2, 3.9 +/- 0.3, 5.4 +/- 0.4 and 5.8 +/- 0.3 nM, respectively. In normal mice all conjugates demonstrated similar biodistribution pattern, however Ga-68-NOTA-PEG(3)-RM26 showed lower liver uptake. Biodistribution of Ga-68-NOTA-PEG(3)-RM26 was evaluated in nude mice bearing PC-3 (prostate cancer) and BT-474 (breast cancer) xenografts. High uptake in tumors (4.6 +/- 0.6% ID/g and 2.8 +/- 0.4% ID/g for PC-3 and BT-474 xenografts, respectively) and high tumor-to-background ratios (tumor/ blood of 44 +/- 12 and 42 +/- 5 for PC-3 and BT-474 xenografts, respectively) were found already at 2 h p.i. of Ga-68-NOTA-PEG(3)-RM26. Results of this study suggest that variation in the length of the PEG spacer can be used for optimization of targeting properties of peptide-chelator conjugates. However, the influence of the mini-PEG length on biodistribution is minor when di-, tri-, tetra- and hexaethylene glycol are compared.
|
|
