1. Article title: 

Design and synthesis of membrane type matrix metalloproteinase (MT-MMP) targeted anti-tumor agents.

2. Article author or authors

Robert A Falconer, Ahmed M Youssef, Javier Gimenez Warren, Goreti R Morais, Andrew Mitchell, Steve D Shnyder, Jason H Gill, Laurence H Patterson, Paul M Loadman

3. Name of journal and date of publication

Cancer Research (2013/4/15)

 
4. Article abstract

Design and synthesis of membrane type matrix metalloproteinase (MT-MMP) targeted anti-tumor agents

Membrane-type matrix metalloproteinases (MT-MMPs) are highly active in tumors, but absent or inactive in normal tissues. MT-MMPs are known to be elevated in the majority of human tumors and to be central to tumor invasion and angiogenesis. Our objective has been to design inactive prodrugs that are converted to a potent drug by selected MMPs within the tumor microenvironment.

We report the design and synthesis of a series of peptide-based conjugates of azademethylcolchicine (a potent colchicine analogue) designed to be selectively cleaved by MT-MMPs in the tumor microenvironment. Azademethylcolchicine was attached to the peptide C-terminus, while the N-terminus is protected from non-specific cleavage by exopeptidases through a masking group. A series of N-terminal masking groups, including unnatural amino acids, substituted aromatic groups, alkyl spacers and more complex endcaps was employed. Insights have been gained into the MT-MMP peptide recognition sequence and the relative importance of individual amino acids with regards MMP-selectivity. The P2’ position in particular has been extensively studied through substitution by both natural amino acid and unnatural amino acids.

We have investigated the efficiency of hydrolytic cleavage of these conjugates to release the active agent in both tumor and normal tissues. Results indicate significant effects of P2’ amino acid substitution upon stability and conversely activation in tumor and normal tissues (liver, kidney, lung plasma), with half-lives of hydrolysis ranging from 2-60 min in tumor and 3-300 min in normal tissues.

In conclusion, a series of peptide-based prodrug conjugates of azademethylcolchicine was synthesized. Hydrolytic activation of these prodrugs in tumor tissue was rapid compared to liver and other normal tissues. From this screen, ICT-2588, which includes tyrosine at the P2’ position, emerged as the agent with a hydrolytic cleavage rate most suited for further evaluation as a tumour activated peptide-based conjugate.