The
MET oncogene encodes for a tyrosine kinase, the high affinity receptor of hepatocyte growth factor (HGF). The HGF/MET axis drives a complex biological program known as ‘invasive growth’ including cell-cell dissociation (scattering), extracellular matrix degradation, dissemination at distant sites, cell proliferation, and survival [
1]. These processes, pivotal during embryonal development, tissue homeostasis, and wound healing, are aberrantly harnessed by cancer cells during tumor progression [
2,
3]. In a limited number of cases - 2-3%, COSMIC database [
4] - the presence of a genetic lesion makes
MET the ‘
driver’ gene of malignancy (MET
addiction) [
5,
6]. Nevertheless, activation of the MET kinase is relevant not only in cases of oncogene addiction: in fact, cancer cells exploit the MET-driven invasive growth program to arrange and sustain the adaptive response to adverse micro-environmental conditions. Through ligand activated MET signalling, tumors survive in hypoxia conditions [
7], fight immune attacks [
8,
9], resist radiotherapy [
10], and sustain the clonal expansion occurring after resistance to targeted treatments [
11,
12]. In these situations, MET, although not being a
driver, represents an extremely useful ‘
expedient’ (MET
expedience) for cancer cells survival and spreading [
13]. MET
expedience is pro-metastatic in a wide spectrum of tumor types, including colon-rectal, ovarian, and pancreatic cancers, and correlates with aggressive phenotype and severe clinical prognosis [
14‐
16]. We previously demonstrated that concomitant targeting of HGF and MET has therapeutic efficacy in counteracting MET expedience [
17]. Co-targeting was obtained by combining the activity of a soluble recombinant MET extracellular domain (decoyMET) with a MET antibody (MvDN30). DecoyMET is a recombinant protein featuring a dual inhibitory activity: on one side it binds HGF with high affinity; on the other, it dimerizes with full size MET receptors, working as a ‘
dominant negative’ [
18]. MvDN30 is an antibody endowed with a peculiar mechanism of action, the enhancement of the physiological rate of MET shedding [
19]. Concomitant delivery of the two separate molecules – while somehow cumbersome - resulted in quenching of HGF and elimination of MET receptor from the cell surface, showing that simultaneous targeting of HGF and MET was non-redundant and synergic. In this study, we engineer a fusion protein assembling in a single agent the inhibitory properties toward the ligand and the receptor, providing a novel tool to fight metastatic spread driven by MET
expedience.