Macrophage mannose receptor CD206 targeting of fluoride-18 labeled mannosylated dextran: A validation study in mice.

Purpose: Aluminum fluoride-18-labeled 1,4,7-triazacyclononane-1,4,7-triacetic acid-conjugated mannosylated dextran derivative (Al[F]F-NOTA-D10CM) is a new tracer for PET imaging. We report here on in vitro and in vivo validation of the tracer's ability to target the macrophage mannose receptor CD206.

Methods: First, the uptake of intravenously (i.

Aluminum Fluoride-18 Labeled Mannosylated Dextran: Radiosynthesis and Initial Preclinical Positron Emission Tomography Studies.

Purpose: In addition to being expressed on liver sinusoidal endothelial cells, mannose receptors are also found on antigen-presenting cells, including macrophages, which are mainly involved in the inflammation process. Dextran derivatives of various sizes containing cysteine and mannose moieties have previously been labeled with Tc and used for single-photon emission computed tomography imaging of sentinel lymph nodes. In this study, we radiolabeled 21.

Evaluation of Rhenium and Technetium-99m Complexes Bearing Quinazoline Derivatives as Potential EGFR Agents.

Τhe Epidermal Growth Factor Receptor tyrosine kinase inhibitor (EGFR-TKI) 6-amino-4-[(3-bromophenyl) amino]quinazoline was derivatized with 6-bromohexanoyl-chloride and coupled with the tridentate chelating agents N-(2-pyridylmethyl) aminoethyl acetic acid (PAMA) and (+)-cysteine bearing the donor atom set NNO and SNO, respectively. The rhenium precursors ReBr(CO) and -[NEt][ReBr(CO)] were used for the preparation of the Re complexes -[Re(NNO)(CO)] () and -[Re(SNO)(CO)] () which were characterized by NMR and IR spectroscopies. Subsequently, the new potential EGFR inhibitors were labeled with the -[Tc(CO)] core in high yield and radiochemical purity (>90%) by ligand exchange reaction using the -[Tc][Tc(OH)(CO)] precursor.

Synthesis and preclinical evaluation of rhenium and technetium-99m "4 + 1" mixed-ligand complexes bearing quinazoline derivatives as potential EGFR imaging agents.

Epidermal growth factor receptors (EGFR) of tyrosine kinase (TK) have shown high expression levels in most cancers and are considered a promising target for cancer diagnosis and therapy. Expanding the investigation for novel targeted radiopharmaceuticals, an EGFR inhibitor such as 4-aminoquinazoline derivatives along with a radionuclide such as technetium-99m (Tc) could be ideal. Thus, we report herein the synthesis, characterization, and biological evaluation of new "4 + 1" mixed-ligand Re- and Tc-complexes of the general formula [Tc][Tc(NS)(CN-R)] bearing tris(2-mercaptoethyl)-amine (NS) as the tetradentate tripodal ligand and a series of isocyanide derivatives (CN-R) of tyrosine kinase inhibitor (3-bromophenyl)quinazoline-4,6-diamine as the monodentate ligand.

Synthesis and Characterization of Novel [2 + 1] Tricarbonyl Rhenium Complexes with the Hydrophilic Phosphine Ligands PTA and CAP.

In the pursuit of hydrophilic model -[Re(CO)] complexes for (radio) pharmaceutical applications, six novel [2 + 1] mixed-ligand complexes of the general type -[Re(CO)(bid)P] were synthesized and characterized, where bid is a bidentate ligand bearing either (N, O) or (S, S') donor atom sets and P is the hydrophilic phosphine 1,3,5-triaza-7-phosphoadamantane (PTA) or its macrocyclic homologue 1,4,7-triaza-9-phosphatricyclo[5.3.2.

Biological evaluation of complexes of cyclopentadienyl M(CO) (M = Re, Tc) with high blood-brain barrier penetration potential as brain cancer agents.

To address the major medical need for effective chemotherapeutics/diagnostics for brain cancer, in this work three cyclopentadienyl M(CO) (M = Re, Tc) complexes, which cross the blood-brain barrier (BBB) in high % and are designed to mimic the anticancer agent 2-phenylbenzothiazole, are in vitro and in vivo evaluated for anticancer action. The study includes cytotoxicity and uptake studies in cancer and healthy neuronal cell lines, mechanistic investigation of potential anticancer pathways, and biodistribution studies in mice bearing glioblastoma xenografts. The stable Re complexes exhibit selective uptake and significant antiproliferative effect, particularly against U-251 MG glioblastoma cells, with no significant toxicity in healthy neurons, demonstrating the suitability of this type of complexes to serve as selective therapeutic/imaging agents for brain cancer.

Synthesis and In Vitro Evaluation of Gold Nanoparticles Functionalized with Thiol Ligands for Robust Radiolabeling with Tc.

Radiolabeled gold nanoparticles (AuNPs) have been widely used for cancer diagnosis and therapy over recent decades. In this study, we focused on the development and in vitro evaluation of four new Au nanoconjugates radiolabeled with technetium-99m (Tc) via thiol-bearing ligands attached to the NP surface. More specifically, AuNPs of two different sizes (2 nm and 20 nm, referred to as Au and Au, respectively) were functionalized with two bifunctional thiol ligands (referred to as LH and LH).

Synthesis and evaluation of new mixed "2 + 1" Re, Tc and Re tricarbonyl dithiocarbamate complexes with different monodentate ligands.

A series of "2 + 1" mixed ligand tricarbonyl complexes of the general formula fac-[Re/Tc/Re(CO)(DDTC)(L)] containing diethyldithiocarbamate (DDTC) as a monoanionic bidentate ligand and a series of monodentate ligands L was synthesized, characterized and evaluated. The impact of ligand L on the radiochemical yield (RCY) and biodistribution of the final compounds was also investigated. DDTC and the appropriate L ligand [cyclohexyl isocyanide (cisc), tert-butyl isocyanide (tbi), triphenylphosphine (PPh), methyldiphenylphosphine (PPhMe), triphenylarsine (AsPh), imidazole (im), and 4-aminopyridine (4AP)] readily reacted in equimolar amounts with the [EtN][Re(CO)Br] precursor to afford fac-[Re(CO)(DDTC)(cisc)], Re1, fac-[Re(CO)(DDTC)(tbi)], Re2, fac-[Re(CO)(DDTC)(PPh)], Re3, fac-[Re(CO)(DDTC)(PPhMe)], Re4, fac-[Re(CO)(DDTC)(AsPh)], Re5, fac-[Re(CO)(DDTC)(im)], Re6 and fac-[Re(CO)(DDTC)(4AP)], Re7, complexes in high yields (>80%).