Distribution of neocarzinostatin conjugated to biotinylated chimeric monoclonal antibody Fab fragments after adminstration of avidin

Abstract

Summary We have developed chimeric Fab fragments of MAb A7 (chA7Fab) and have reported on their potential usefulness as a carrier of neocarzinostatin (NCS). However, a large amount of chA7Fab accumulates in the kidneys which might cause renal failure. This was one of the major side-effects of the chA7Fab-NCS immunoconjugate administered to humans. To decrease the kidney accumulation of chA7Fab, chA7Fab was biotinylated and administered with a subsequent injection of avidin to nude mice with pancreatic cancer. The accumulation of biotinylated chA7Fab in the blood and the kidneys decreased significantly after the injection of avidin. In a separate experiment with biotinylated chA7Fab-NCS, the blood and kidney accumulation decreased significantly after the injection of avidin. These findings suggest that the injection of biotinylated chA7Fab complexed with NCS followed by avidin may be safer and may permit the administration of larger doses of NCS without the subsequent development of renal failure.

Intramolecular C–C Bond Formation Links Anthraquinone and Enediyne Scaffolds in Tiancimycin Biosynthesis

“…Enediyne natural products, which feature a macrocyclic ring encompassing a 1,5-diyne-3-ene motif that serves as the molecular warhead critical to their potent DNA cleavage activities, can be classified according to the size of the macrocycle and their DNA-targeting peripheral moieties . The nine-membered enediynes, exemplified by the chromophores C-1027 and neocarzinostatin (NCS), are typically unstable without their cognate apoproteins (Figure S1A); − however, the 10-membered enediynes typically exist as discrete small molecules. These 10-membered enediynes can be further subdivided into the anthraquinone-fused enediynes ( 1 – 6 ; Figure A) and the glycosylated calicheamicin (CAL)-type enediynes (Figure S1B).…”