Therapeutic Radiopharmaceuticals Targeting Integrin ?v?6.

ABSTRACT: The epithelial integrin ?v?6 is expressed by many malignant carcinoma cell types, including pancreatic cancer, and thus represents a promising target for radionuclide therapy. The peptide cyclo(FRGDLAFp(NMe)K) was decorated with different chelators (DOTPI, DOTAGA, and DOTA). The Lu(III) complexes of these conjugates exhibited comparable ?v?6 integrin affinities (IC50 ranging from 0.3 to 0.8 nM) and good selectivities against other integrins (IC50 for ?v?8 >43 nM; for ?5?1 >238 nM; and for ?v?3, ?v?5, and ?IIb?3 >1000 nM). Although different formal charges of the Lu(III) chelates (ranging from 0 to 4) resulted in strongly varying degrees of hydrophilicity (log D ranging from -3.0 to -4.1), biodistributions in murine H2009 xenografts of the Lu-177-labeled compounds (except the DOTPI derivative) were quite similar and comparable to our previously reported ?v?6 integrin positron emission tomography tracer Ga-68-avebehexin. Hence, combinations of existing Ga-68- and Lu-177-labeled c(FRGDLAFp(NMe)K) derivatives could be utilized for ?v?6 integrin-targeted theranostics, whereas our data nonetheless suggest that further improvement of pharmacokinetics might be necessary to ensure clinical success.

SUBMITTER: Farber SF 

PROVIDER: S-EPMC6045477 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature