c-Met kinase binding proteins

Abstract

Polypeptides comprising monomer domains that bind to c-Met, or portions thereof, are provided.

Description

BACKGROUND OF THE INVENTION [0001] Hepatocyte Growth Factor / Scatter Factor (HGF / SF) is a mesenchyme-derived pleiotropic factor, which regulates cell growth, cell motility, and morphogenesis of various types of cells and mediates epithelial-mesenchymal interactions responsible for morphogenic tissue interactions during embryonic development and organogenesis. Although HGF was originally identified as a potent mitogen for hepatocytes, it has also been identified as an angiogenic growth factor. [0002] Met was first identified in the 1980s as an oncogene and is the receptor for HGF. The proto-oncogene c-Met, was found to encode a receptor tyrosine kinase. In response to HGF treatment a range of activities are observed: phosphorylation of receptor, docking of signaling intermediates Gab-1 / Grb2, culminating in activation of kinases such as P13K, ERK1 and 2, and AKT. These activities aid in cell growth, survival, migration, and neovascularisation. [0003] Inappropriate expression or signali...

AI Technical Summary

Benefits of technology

[0169] A significant advantage of the present invention is that known ligands, or unknown ligands can be used to select the monomer domains and / or multimers. No prior information regarding ligand structure is required to isolate the monomer domains of interest or the multimers of interest. The monomer domains and / or multimers identified can have biological activity, which is meant to include at least specific binding affinity for a selected or desired ligand, and, in some instances, will further include the ability to block the binding of other compounds, to stimulate or inhibit metabolic pathways, to act as a signal or messenger, to stimulate or inhibit cellular activity, and the like. Monomer domains can be generated to function as ligands for receptors where the natural ligand for the receptor has not yet been identified (orphan receptors). These orphan ligands can be created to either block or activate the receptor top which they bind.

[0170] A single ligand can be used, or optionally a variety of ligands can be used to select the monomer domains and / or multimers. A monomer domain of the present invention can bind a single ligand or a variety of ligands. A multimer of the present invention can have multiple discrete binding sites for a single ligand, or optionally, can have multiple binding sites for a variety of ligands.

[0171] In some embodiments, the multimer comprises monomer domains with specificities for different proteins. The different proteins can be related or unrelated. Examples of related proteins including members of a protein family or different serotypes of a virus. Alternatively, the monomer domains of a multimer can target different molecules in a physiological pathway (e.g., different blood coagulation proteins). In yet other embodiments, monomer domains bind to proteins in unrelated pathways (e.g., two domains bind to blood factors, two other domains bind to inflammation-related proteins and a fifth binds to serum albumin). In another embodiment, a multimer is comprised of monomer domains that bind to different pathogens or contaminants of interest. Such multimers are useful as a single detection agent capable of detecting for the possibility of any of a number of pathogens or contaminants.

[0172] In some embodiments, the multimers of the invention bind to the same or other multimers to form aggregates. Aggregation can be mediated, for example, by the presence of hydrophobic domains on two monomer domains, resulting in the formation of non-covalent interactions between two monomer domains. Alternatively, aggregation may be facilitated by one or more monomer domains in a multimer having binding specificity for a monomer domain in another multimer. Aggregates can also form due to the presence of affinity peptides on the monomer domains or multimers. Aggregates can contain more target molecule binding domains than a single multimer.

[0173] Multimers with affinity for both a cell surface target and a second target may provide for increased avidity effects. In some cases, membrane fluidity can be more flexible than protein linkers in optimizing (by self-assembly) the spacing and valency of the interactions. In some cases, multimers will bind to two different targets, each on a different cell or one on a cell and another on a molecule with multiple binding sites. See. e.g., FIGS. 16 and 17.

[0174] In some embodiments, the monomers or multimers of the present invention are linked to another polypeptide to form a fusion protein. Any polypeptide in the art may be used as a fusion partner, though it can be useful if the fusion partner forms multimers. For example, monomers or multimers of the invention may, for example, be fused to the following locations or combinations of locations of an antibody:

Problems solved by technology

First, mouse and human cell lines that ectopically overexpress HGF and / or Met become tumorigenic and metastatic in athymic nude mice.

Secondly, downregulation of Met or HGF expression in human tumour cells decreases their tumorigenic potential.

Third, a large number of studies show that HGF and / or Met are frequently expressed in carcinomas, in other types of human solid tumours and in their metastases, and that HGF and / or Met over- or misexpression often correlates with poor prognosis.

Fourth, unequivocal evidence that implicates Met in human cancer is provided by the activating mutations that have been discovered in both sporadic and inherited forms of human renal papillary carcinomas.

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