Objective: Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers. Since αvβ6 integrin has been reported as a promising target for PDAC diagnosis, we previously developed H-Cys(mal-NOTA-Ga)-(Gly)6-A20FMDV2-NH ([Ga]CG6) as an αvβ6 integrin-targeting probe. Although [Ga]CG6 specifically binds to αvβ6 integrin-positive xenografts, the uptake of [Ga]CG6 in the organs surrounding the pancreas, such as the liver and spleen, was comparable to that in the αvβ6 integrin-positive xenografts. We hypothesized that the undesirable accumulation of [Ga]CG6 in those organs was caused by the positive charges of [Ga]CG6 (+ 3). In this study, we aimed to decrease [Ga]CG6 uptake in the liver and spleen by reducing the electric charges of the probe.
Methods: We synthesized H-Cys(mal-NOTA-Ga)-(Asp)6-A20FMDV2-NH ([Ga]CD6) and evaluated its affinity to αvβ6 integrin via in vitro competitive binding assay. Isoelectric points of the probes were determined by electrophoresis. Biodistribution study, autoradiography, and immunostaining for β6 integrin were conducted using αvβ6 integrin-positive and negative tumor-bearing mice.
Results: In vitro competitive binding assay showed that the alteration of the linker had a negligible impact on the affinity of [Ga]CG6 to αvβ6 integrin. The results of electrophoresis revealed that [Ga]CG6 was positively charged whereas [Ga]CD6 was negatively charged. In the biodistribution study, the uptake of [Ga]CD6 in the αvβ6 integrin-positive xenografts was significantly higher than that in the αvβ6 integrin-negative ones at 60 and 120 min. The uptake of [Ga]CD6 in the liver and spleen was more than two-fold lower than that of [Ga]CG6 at both time points. In the immunohistochemistry study, the radioactivity accumulated areas in the autoradiogram of the αvβ6 integrin-positive xenograft roughly coincided with β6 integrin-expressing areas.
Conclusion: We have successfully reduced the nonspecific uptake in the liver and spleen by altering the linker amino acid from G6 to D6. [Ga]CD6 overcame the drawbacks of [Ga]CG6 in its biodistribution.
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http://dx.doi.org/10.1007/s12149-020-01483-6 | DOI Listing |
Br J Cancer
November 2024
Division of Cancer and Genetics, Cardiff University School of Medicine, Heath Park, Cardiff, CF14 4XN, UK.
Background: Pancreatic ductal adenocarcinoma (PDAC) represent an unmet clinical need. Approximately 90% of PDACs express high levels of αvβ6 integrin. We have previously described Ad5-A20, an adenovirus vector with ablated native means of cell entry and retargeted to αvβ6 integrin by incorporation of an A20 peptide.
View Article and Find Full Text PDFImmunity
May 2024
Institute for Immunology, Tsinghua University, Beijing, China; School of Basic Medical Sciences, Tsinghua University, Beijing, China; Tsinghua-Peking Center for Life Sciences, Beijing, China; Beijing Key Laboratory for Immunological Research on Chronic Diseases, Beijing, China; The State Key Laboratory of Membrane Biology, Beijing, China. Electronic address:
A specialized population of mast cells residing within epithelial layers, currently known as intraepithelial mast cells (IEMCs), was originally observed over a century ago, yet their physiological functions have remained enigmatic. In this study, we unveil an unexpected and crucial role of IEMCs in driving gasdermin C-mediated type 2 immunity. During helminth infection, αEβ7 integrin-positive IEMCs engaged in extensive intercellular crosstalk with neighboring intestinal epithelial cells (IECs).
View Article and Find Full Text PDFBioengineering (Basel)
March 2023
Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao 266021, China.
The emergence of induced pluripotent stem cell (iPSC) technology has provided a new approach to regenerating decellularized trabecular meshwork (TM) in glaucoma. We have previously generated iPSC-derived TM (iPSC-TM) using a medium conditioned by TM cells and verified its function in tissue regeneration. Because of the heterogeneity of iPSCs and the isolated TM cells, iPSC-TM cells appear to be heterogeneous, which impedes our understanding of how the decellularized TM may be regenerated.
View Article and Find Full Text PDFJ Am Chem Soc
June 2022
Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
Delivery of functional proteins into the intracellular space has been a challenging task that could lead to a myriad of therapeutic applications. We report herein a novel bioconjugation strategy for enzyme modification and selective delivery into cancer cells for lock-and-key-type activation of photosensitizers. Using a bifunctional linker containing a bis(bromomethyl)phenyl group and an -phthalaldehyde moiety, it could induce cyclization of the peptide sequence Ac-NH-CRGDfC-CONH through site-specific dibenzylation with the two cysteine residues and further coupling with β-galactosidase via the phthalaldehyde-amine capture reaction.
View Article and Find Full Text PDFFront Med (Lausanne)
December 2021
Turku PET Centre, University of Turku, Turku, Finland.
The Gallium-labeled 1,4,7-triazacyclononane-1-glutaric acid-4,7-diacetic acid conjugated radiolabelled arginine-glycine-aspartic acid peptide ([Ga]Ga-NODAGA-RGD) is a positron emission tomography (PET) tracer binding to cell surface receptor αβ integrin that is upregulated during angiogenesis and inflammation. We studied whether αβ targeting PET imaging can detect myocardial inflammation in a rat model of autoimmune myocarditis. To induce myocarditis, rats ( = 8) were immunized with porcine cardiac myosin in complete Freund's adjuvant on days 0 and 7.
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