The present invention provides a linker for preparing antibody-drug conjugates and antibody-drug conjugates prepared by the linker, as well as use of the antibody-drug conjugates in a medicament for treating tumor. The linker is capable of coupling simultaneously with the thiol group or amino group on the antibody or functional fragment of the antibody, especially it is capable of coupling with 2, 3 or 4 thiol groups on the antibody or functional fragment of the antibody. A coupled product is uniform and structurally stable.
Prostate-specific membrane antigen (PSMA) has been identified as a diagnostic and therapeutic target for prostate cancer. (S)-2-[3-[(R)-1-Carboxy-2-mercaptoethyl]ureido-pentanedioic acid (Cys-CO-Glu) were used to design novel PSMA targeting probes by nucleophilic conjugate addition between cysteine and maleimide based reagents. 3 ([I-123]IGLCE) was synthesized by this strategy and showed high affinity for PSMA. Results of binding inhibition assays of these derivatives suggested the importance of an aromatic group and succinimide moiety for high affinity. [I-123]3 was evaluated in vivo with PSMA positive LNCaP and PSMA negative PC-3 human prostate cancer xenograft bearing mice. [I-125]3 accumulated in LNCaP tumors but not in PC-3 tumors, and the accumulation was inhibited by 2-(phosphonomethyl)pentanedioic acid (2-PMPA). Use of [I-123]3 provided positive images of LNCaP tumors in single photon emission tomography scans. These results warrant further evaluation of [I-123]3 and its derivatives as radiolabeled probes for the diagnosis of prostate cancer.
WO2008/34124
申请人:——
公开号:——
公开(公告)日:——
A Novel Radioiodination Reagent for Protein Radiopharmaceuticals with <scp>l</scp>-Lysine as a Plasma-Stable Metabolizable Linkage To Liberate <i>m</i>-Iodohippuric Acid after Lysosomal Proteolysis
Radiochemical design of polypeptides using metabolizable linkages would be attractive to enhance target-selective localization of radioactivity for diagnostic and therapeutic nuclear medicine. However, while use of ester bonds as the linkage allows selective release of the designed radiometabolite from covalently conjugated polypeptides after lysosomal proteolysis in nontarget tissues, low plasma stability of ester bonds causes a decrease in radioactivity levels of the target. In pursuit of new metabolizable linkages that provide stable attachment of radiolabels with polypeptide in plasma while facilitating rapid and selective release of designed radiometabolites of rapid urinary excretion in lysosomes, a new radioiodination reagent with L-lysine as the metabolizable Linkage to liberate m-iodohippuric acid (L-HML) was designed and synthesized. Stabilities of the metabolizable linkage in serum and cleavabilities of the linkage in lysosomal proteolysis in hepatic cells were investigated after conjugation of [I-131]-L-HML with galactosyl-neoglycoalbumin (NGA). For comparison, a radioiodination reagent with an ester bond to release m-iodohippuric acid (MIH) was conjugated with NGA under similar conditions. When incubated in human serum, [I-131]-L-HML-NGA liberated less than 3% of the initial radioactivity after 24 h, whereas [I-125]MIH-NGA released more than 60% of its radioactivity during the same interval. In biodistribution studies, [I-131]-L-HML-NGA demonstrated radioactivity elimination from murine liver at a rate and excretion route similar to [I-125]MIH-NGA. Analyses of murine urine after injection of [I-131]-L-HML-NGA indicated a single radioactivity peak at fractions identical to those of m-iodohippuric acid. Biodistribution studies of radioiodinated NGAs with D-lysine or cadaverine as the linkages demonstrated a delayed elimination rate from murine liver with significantly higher radioactivity being excreted in the feces at 24 h postinjection. Thus, L-HML is the first reagent that allows stable attachment of radiolabel with polypeptide in serum while facilitating selective release of a radiometabolite with rapid urinary excretion from covalently conjugated polypeptides after lysosomal proteolysis at a rate similar to that of ester bonds. Thus, L-HML is potentially useful for the radioiodination of polypeptides for diagnostic and therapeutic purposes.
Aqueous-Soluble, Non-Reversible Lipid Conjugate of Salmon Calcitonin: Synthesis, Characterization and In Vivo Activity
PURPOSE: A novel, non-reversible, aqueous-based lipidization strategy with palmitic acid as a model lipid was evaluated for conjugation with salmon calcitonin (sCT). MATERIALS AND METHODS: A water-soluble epsilon-maleimido lysine derivative of palmitic acid was synthesized from reaction of palmitic acid N-succinimidyl ester and epsilon-maleimido lysine. The latter was generated from reaction of alpha-Boc-lysine