Synthesis, characterization, and biological studies of emissive rhenium-glutamine conjugates.
Two new rhenium complexes containing pyridine-triazole (pyta) and quinoline-triazole (quinta) ligands with attached glutamine-targeting agents have been characterized and tested for uptake in the HT-29 human colon adenocarcinoma cell line. The glutamine moiety in Re(CO)3Br(pyta) (1) and Re(CO)3Br(quinta) (2) remains pendant in solution. Both complexes exhibit absorptions in the 300-400-nm range with metal-to-ligand charge transfer (MLCT) character, as predicted by time-dependent density functional theory calculations. Geometrical analysis by theoretical calculations provides information on the cationic complexes 1 (+) and 2 (+) resulting from aquo for halide ligand exchange under aqueous conditions. The emissive properties of both complexes were studied under aqueous conditions, and the measured quantum yields were 0.46 % for 1 (+) and 0.18 % for 2 (+). The large Stokes shifts and oxygen sensitivity of the emission suggest a (3)MLCT process for both complexes. Cell studies in the HT-29 cell line demonstrate that both complexes are nontoxic over a large concentration range (0-1.4 mM). Preliminary uptake studies show that 2 (+), but not 1 (+), displays significant concentration-dependent uptake at 3 and 24 h.
Department of Chemistry, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada.
Rachel
R
Huang
Graeme
G
Langille
Ravanjir K
RK
Gill
Cindy Mei Jin
CM
Li
Yuji
Y
Mikata
May Q
MQ
Wong
Donald T
DT
Yapp
Tim
T
Storr
D001692:Biological Transport; D060326:Chemistry Techniques, Synthetic; D005973:Glutamine / Q000737:chemistry*; D019073:HT29 Cells; D006801:Humans; D008958:Models, Molecular; D008968:Molecular Conformation; D055620:Optical Phenomena; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000378:metabolism / Q000633:toxicity; D012211:Rhenium / Q000737:chemistry*
D009942:Organometallic Compounds; D005973:Glutamine; D012211:Rhenium