18F-Labeled phosphopeptide-cell-penetrating peptide dimers with enhanced cell uptake properties in human cancer cells

Radiopharmacological evaluation of 18F-labeled phosphatidylserine-binding peptides for molecular imaging of apoptosis

“…A similar trend was also observed by Burtea et al when the authors analyzed cell binding in apoptotic cells with Gd-DTPA-conjugated LIKKPF [10]. The observed substantial baseline uptake of both peptides ([ 18 F]FBAM-CLIKKPF and Gd-DTPA-g-LIKKPF) in untreated Jurkat cells could be explained by the lysine-rich and therefore basic and cationic nature of the LIKKPF peptide backbone, which may possess characteristics of a cellpenetrating peptide [19,20]. Taken together, results from our competitive radiometric PS-binding assay and data on cell binding in Jurkat cells (control and drug-treated) demonstrated that PS binding of both peptides LIKKPF and PGDLSR is several orders of magnitude lower compared to wild-type annexin V. Moreover, radiolabeled peptide [ 18 F]FBAM-CLIKKPF showed significantly higher uptake in drugtreated Jurkat cells, possibly as a result of specific interaction with elevated levels of PS as well as possible unspecific cell-penetrating peptide properties of the lysine-rich radiopeptide [ 18 F]FBAM-CLIKKPF.…”

Novel Imidazolium Salt–Peptide Conjugates and Their Antimicrobial Activity

“…20 Furthermore, we used sC18 as an efficient delivery system for cytostatic drugs 21,22 as well as for imaging probes. 23,24 In all these studies sC18 itself behaved non-toxic to human cells, however, antimicrobial activity in the micromolar range against Escherichia coli and Micrococcus luteus has been observed. (unpublished results) The LL-37 peptide also belongs to the group of the cathelicidins and is a two amino acid truncated form of FALL-39, 25 which was identified as an antimicrobial peptide expressed in bone marrow.…”

How Far Are We from Dose On Demand of Short-Lived Radiopharmaceuticals?

“…An alternative route to radiolabel a peptide is through the use of a prosthetic group as an indirect radiolabeling method. [ 18 F]SFB [23] and even, the most abundantly used PET tracer, [ 18 F]FDG [24] have been utilized as prosthetic groups for the radiolabeling of peptides. Although both prosthetic groups were synthesized on macroscale equipment, the subsequent peptide radiolabeling was performed under microfluidic conditions.…”