scholarly journals High Contrast PET Imaging of GRPR Expression in Prostate Cancer Using Cobalt-Labeled Bombesin Antagonist RM26

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Bogdan Mitran ◽  
Helge Thisgaard ◽  
Ulrika Rosenström ◽  
Johan Hygum Dam ◽  
Mats Larhed ◽  
...  
Keyword(s):  
Binding Specificity ◽  
Hepatic Uptake ◽  
High Contrast ◽  
Agent Based ◽  
Pet Ct ◽  
Rapid Clearance ◽  
Grpr Antagonist ◽  
High Yields

High gastrin releasing peptide receptor (GRPR) expression is associated with numerous cancers including prostate and breast cancer. The aim of the current study was to develop a 55Co-labeled PET agent based on GRPR antagonist RM26 for visualization of GRPR-expressing tumors. Labeling with 57Co and 55Co, stability, binding specificity, and in vitro and in vivo characteristics of 57Co-NOTA-PEG2-RM26 were studied. NOTA-PEG2-RM26 was successfully radiolabeled with 57Co and 55Co with high yields and demonstrated high stability. The radiopeptide showed retained binding specificity to GRPR in vitro and in vivo. 57Co-NOTA-PEG2-RM26 biodistribution in mice was characterized by rapid clearance of radioactivity from blood and normal non-GRPR-expressing organs and low hepatic uptake. The clearance was predominantly renal with a low degree of radioactivity reabsorption. Tumor-to-blood ratios were approximately 200 (3 h pi) and 1000 (24 h pi). The favorable biodistribution of cobalt-labeled NOTA-PEG2-RM26 translated into high contrast preclinical PET/CT (using 55Co) and SPECT/CT (using 57Co) images of PC-3 xenografts. The initial biological results suggest that 55Co-NOTA-PEG2-RM26 is a promising tracer for PET visualization of GRPR-expressing tumors.

scholarly journals Preclinical Evaluation of the Copper-64 Labeled GRPR-Antagonist RM26 in Comparison with the Cobalt-55 Labeled Counterpart for PET-Imaging of Prostate Cancer

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5993
Author(s):  
Christina Baun ◽  
Bogdan Mitran ◽  
Sara S. Rinne ◽  
Johan H. Dam ◽  
Birgitte B. Olsen ◽  
...  
Keyword(s):  
Pet Imaging ◽  
Late Time ◽  
Vitro Binding ◽  
Pet Ct ◽  
Liver And Pancreas ◽  
Prostate Cancers ◽  
Grpr Antagonist ◽  
Late Time Point

Gastrin-releasing peptide receptor (GRPR) is overexpressed in the majority of prostate cancers. This study aimed to investigate the potential of 64Cu (radionuclide for late time-point PET-imaging) for imaging of GRPR expression using NOTA-PEG2-RM26 and NODAGA-PEG2-RM26. Methods: NOTA/NODAGA-PEG2-RM26 were labeled with 64Cu and evaluated in GRPR-expressing PC-3 cells. Biodistribution of [64Cu]Cu-NOTA/NODAGA-PEG2-RM26 was studied in PC-3 xenografted mice and compared to the biodistribution of [57Co]Co-NOTA/NODAGA-PEG2-RM26 at 3 and 24 h p.i. Preclinical PET/CT imaging was performed in tumor-bearing mice. NOTA/NODAGA-PEG2-RM26 were stably labeled with 64Cu with quantitative yields. In vitro, binding of [64Cu]Cu-NOTA/NODAGA-PEG2-RM26 was rapid and GRPR-specific with slow internalization. In vivo, [64Cu]Cu-NOTA/NODAGA-PEG2-RM26 bound specifically to GRPR-expressing tumors with fast clearance from blood and normal organs and displayed generally comparable biodistribution profiles to [57Co]Co-NOTA/NODAGA-PEG2-RM26; tumor uptake exceeded normal tissue uptake 3 h p.i.. Tumor-to-organ ratios did not increase significantly with time. [64Cu]Cu-NOTA-PEG2-RM26 had a significantly higher liver and pancreas uptake compared to other agents. 57Co-labeled radioconjugates showed overall higher tumor-to-non-tumor ratios, compared to the 64Cu-labeled counterparts. [64Cu]Cu-NOTA/NODAGA-PEG2-RM26 was able to visualize GRPR-expression in a murine PC model using PET. However, [55/57Co]Co-NOTA/NODAGA-PEG2-RM26 provided better in vivo stability and overall higher tumor-to-non-tumor ratios compared with the 64Cu-labeled conjugates.

scholarly journals [99mTc]Tc-DB15 in GRPR-Targeted Tumor Imaging with SPECT: From Preclinical Evaluation to the First Clinical Outcomes

Cancers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 5093
Author(s):  
Berthold A. Nock ◽  
Aikaterini Kaloudi ◽  
Panagiotis Kanellopoulos ◽  
Barbara Janota ◽  
Barbara Bromińska ◽  
...  
Keyword(s):  
Tumor Imaging ◽  
Pharmacokinetic Profile ◽  
Diglycolic Acid ◽  
Preclinical Evaluation ◽  
Peptide Receptor ◽  
Gastrin Releasing Peptide ◽  
Specific Uptake ◽  
Grpr Antagonist

Diagnostic imaging and radionuclide therapy of prostate (PC) and breast cancer (BC) using radiolabeled gastrin-releasing peptide receptor (GRPR)-antagonists represents a promising approach. We herein propose the GRPR-antagonist based radiotracer [99mTc]Tc-DB15 ([99mTc]Tc-N4-AMA-DGA-DPhe6,Sar11,LeuNHEt13]BBN(6-13); N4: 6-carboxy-1,4,8,11-tetraazaundecane, AMA: aminomethyl-aniline, DGA: diglycolic acid) as a new diagnostic tool for GRPR-positive tumors applying SPECT/CT. The uptake of [99mTc]Tc-DB15 was tested in vitro in mammary (T-47D) and prostate cancer (PC-3) cells and in vivo in T-47D or PC-3 xenograft-bearing mice as well as in BC patients. DB15 showed high GRPR-affinity (IC50 = 0.37 ± 0.03 nM) and [99mTc]Tc-DB15 strongly bound to the cell-membrane of T-47D and PC-3 cells, according to a radiolabeled antagonist profile. In mice, the radiotracer showed high and prolonged GRPR-specific uptake in PC-3 (e.g., 25.56 ± 2.78 %IA/g vs. 0.72 ± 0.12 %IA/g in block; 4 h pi) and T-47D (e.g., 15.82 ± 3.20 %IA/g vs. 3.82 ± 0.30 %IA/g in block; 4 h pi) tumors, while rapidly clearing from background. In patients with advanced BC, the tracer could reveal several bone and soft tissue metastases on SPECT/CT. The attractive pharmacokinetic profile of [99mTc]DB15 in mice and its capability to target GRPR-positive BC lesions in patients highlight its prospects for a broader clinical use, an option currently being explored by ongoing clinical studies.

scholarly journals Tumor- and Osteoblast-Derived Periostin in Prostate Cancer bone Metastases

2022 ◽  
Vol 11 ◽  
Author(s):  
Chuan-Yu Sun ◽  
Yuan-Yuan Mi ◽  
Sheng-Yang Ge ◽  
Qing-Feng Hu ◽  
Ke Xu ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Bone Metastasis ◽  
Integrin Αvβ3 ◽  
Integrin Receptors ◽  
Secreted Expression ◽  
Metastatic Lesions ◽  
Promising Therapeutic Target ◽  
Pet Ct

Exploring the biological function of periostin (POSTN) in prostate cancer (PCa) bone metastasis is of importance. It was observed that the expression of POSTN was high in PCa, especially highest in PCa metastasized to bone. In this study, we found that inhibiting POSTN in PCa cells could significantly alleviate PCa bone metastasis in vivo, suggesting POSTN is a promising therapeutic target. Since, due to the secreted expression of POSTN in osteoblasts and PCa, we hypothesized the positive feedback loop between osteoblasts and PCa mediated by POSTN in PCa bone metastasis. The in vitro experiments demonstrated that osteoblast-derived POSTN promoted PCa cell proliferation and invasion and PCa cell-derived POSTN promotes proliferation of osteoblasts. Furthermore, we found that POSTN regulated PCa and osteoblast function through integrin receptors. Finally, 18F-Alfatide II was used as the molecule probe of integrin αvβ3 in PET-CT, revealing high intake in metastatic lesions. Our findings together indicate that targeting POSTN in PCa cells as well as in the osteoblastic may be an effective treatment for PCa bone metastasis.

scholarly journals Evaluating Hepatobiliary Transport with 18F-Labeled Bile Acids: The Effect of Radiolabel Position and Bile Acid Structure on Radiosynthesis and In Vitro and In Vivo Performance

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Stef De Lombaerde ◽  
Ken Kersemans ◽  
Sara Neyt ◽  
Jeroen Verhoeven ◽  
Christian Vanhove ◽  
...  
Keyword(s):  
Bile Acid ◽  
Bile Acids ◽  
Membrane Vesicles ◽  
Hepatic Uptake ◽  
Hepatobiliary Transport ◽  
Bile Acid Transporters ◽  
Significant Difference ◽  
The Impact

Introduction. An in vivo determination of bile acid hepatobiliary transport efficiency can be of use in liver disease and preclinical drug development. Given the increased interest in bile acid Positron Emission Tomography- (PET-) imaging, a further understanding of the impact of 18-fluorine substitution on bile acid handling in vitro and in vivo can be of significance. Methods. A number of bile acid analogues were conceived for nucleophilic substitution with [18F]fluoride: cholic acid analogues of which the 3-, 7-, or 12-OH function is substituted with a fluorine atom (3α-[18F]FCA; 7β-[18F]FCA; 12β-[18F]FCA); a glycocholic and chenodeoxycholic acid analogue, substituted on the 3-position (3β-[18F]FGCA and 3β-[18F]FCDCA, resp.). Uptake by the bile acid transporters NTCP and OATP1B1 was evaluated with competition assays in transfected CHO and HEK cell lines and efflux by BSEP in membrane vesicles. PET-scans with the tracers were performed in wild-type mice (n=3 per group): hepatobiliary transport was monitored and compared to a reference tracer, namely, 3β-[18F]FCA. Results. Compounds 3α-[18F]FCA, 3β-[18F]FGCA, and 3β-[18F]FCDCA were synthesized in moderate radiochemical yields (4–10% n.d.c.) and high radiochemical purity (>99%); 7β-[18F]FCA and 12β-[18F]FCA could not be synthesized and included further in this study. In vitro evaluation showed that 3α-FCA, 3β-FGCA, and 3β-FCDCA all had a low micromolar Ki-value for NTCP, OATP1B1, and BSEP. In vivo, 3α-[18F]FCA, 3β-[18F]FGCA, and 3β-[18F]FCDCA displayed hepatobiliary transport with varying efficiency. A slight yet significant difference in uptake and efflux rate was noticed between the 3α-[18F]FCA and 3β-[18F]FCA epimers. Conjugation of 3β-[18F]FCA with glycine had no significant effect in vivo. Compound 3β-[18F]FCDCA showed a significantly slower hepatic uptake and efflux towards gallbladder and intestines. Conclusion. A set of 18F labeled bile acids was synthesized that are substrates of the bile acid transporters in vitro and in vivo and can serve as PET-biomarkers for hepatobiliary transport of bile acids.

scholarly journals Incorporation of a Hydrophilic Spacer Reduces Hepatic Uptake of HER2-Targeting Affibody–DM1 Drug Conjugates

Cancers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1168
Author(s):  
Haozhong Ding ◽  
Mohamed Altai ◽  
Sara S. Rinne ◽  
Anzhelika Vorobyeva ◽  
Vladimir Tolmachev ◽  
...  
Keyword(s):  
Therapeutic Potential ◽  
Histopathological Examination ◽  
Specific Binding ◽  
Hepatic Uptake ◽  
In Vitro Cytotoxicity ◽  
Drug Conjugates ◽  
Biodistribution Studies ◽  
Development Approach

Affibody molecules are small affinity-engineered scaffold proteins which can be engineered to bind to desired targets. The therapeutic potential of using an affibody molecule targeting HER2, fused to an albumin-binding domain (ABD) and conjugated with the cytotoxic maytansine derivate MC-DM1 (AffiDC), has been validated. Biodistribution studies in mice revealed an elevated hepatic uptake of the AffiDC, but histopathological examination of livers showed no major signs of toxicity. However, previous clinical experience with antibody drug conjugates have revealed a moderate- to high-grade hepatotoxicity in treated patients, which merits efforts to also minimize hepatic uptake of the AffiDCs. In this study, the aim was to reduce the hepatic uptake of AffiDCs and optimize their in vivo targeting properties. We have investigated if incorporation of hydrophilic glutamate-based spacers adjacent to MC-DM1 in the AffiDC, (ZHER2:2891)2–ABD–MC-DM1, would counteract the hydrophobic nature of MC-DM1 and, hence, reduce hepatic uptake. Two new AffiDCs including either a triglutamate–spacer–, (ZHER2:2891)2–ABD–E3–MC-DM1, or a hexaglutamate–spacer–, (ZHER2:2891)2–ABD–E6–MC-DM1 next to the site of MC-DM1 conjugation were designed. We radiolabeled the hydrophilized AffiDCs and compared them, both in vitro and in vivo, with the previously investigated (ZHER2:2891)2–ABD–MC-DM1 drug conjugate containing no glutamate spacer. All three AffiDCs demonstrated specific binding to HER2 and comparable in vitro cytotoxicity. A comparative biodistribution study of the three radiolabeled AffiDCs showed that the addition of glutamates reduced drug accumulation in the liver while preserving the tumor uptake. These results confirmed the relation between DM1 hydrophobicity and liver accumulation. We believe that the drug development approach described here may also be useful for other affinity protein-based drug conjugates to further improve their in vivo properties and facilitate their clinical translatability.

FATE OF PREFORMED IMMUNE COMPLEXES IN RABBITS AND RHESUS MONKEYS

1971 ◽  
Vol 134 (3) ◽  
pp. 19-31 ◽  
Author(s):  
Mart Mannik ◽  
William P. Arend
Keyword(s):  
Immune Complexes ◽  
Rhesus Monkeys ◽  
Hepatic Uptake ◽  
In Vivo Studies ◽  
Complement Components ◽  
Immune Adherence ◽  
Soluble Immune Complexes ◽  
Lattice Formation

Preformed soluble immune complexes injected into rabbits or rhesus monkeys showed similar characteristics of disappearance from circulation. Complexes made with intact γG-antibodies and exceeding the Ag2Ab2 lattice formation were rapidly removed by the hepatic RES. These complexes fixed complement effectively in vitro. Their hepatic uptake was not dependent upon circulating complement components, since their accumulation in the liver was unchanged in complement depleted rabbits. Similar antigen-antibody complexes made with reduced and alkylated γG-antibodies fixed complement ineffectively in vitro. These complexes possessed different disappearance characteristics and were not rapidly taken up by the liver, regardless of their degree of lattice formation. Both in vitro and in vivo studies failed to suggest any role for the immune adherence receptor on primate erythrocytes in the handling of circulating soluble immune complexes composed of BSA and γG-antibodies to this antigen.

Sign in / Sign up

Export Citation Format

Share Document