ABSTRACT
The receptor tyrosine kinase (RTK) Met is the cell surface receptor for hepatocyte growth factor (HGF)
involved in invasive growth programs during embryogenesis and tumorgenesis. There is compelling evidence
suggesting important roles for c-Met in colorectal cancer proliferation, migration, invasion, angiogenesis,
and survival. Hence, a molecular inhibitor of an extracellular domain of c-Met receptor that blocks
c-Met-cell surface interactions could be of great thera-peutic importance. In an attempt to develop
molecular inhibitors of c-Met, single chain variable fragment (scFv) phage display libraries Tomlinson IþJ
against a specific synthetic oligopeptide from the extracellular domain of c-Met receptor were screened;
selected scFv were then characterized using various immune techniques. Three c-Met specific scFv (ES1,
ES2, and ES3) were selected following five rounds of panning procedures. The scFv showed specific binding
to c-Met receptor, and significantly inhibited proliferation responses of a human colorectal carcinoma
cell line (HCT-116). Moreover, anti- apoptotic effects of selected scFv antibodies on the HCT-116 cell line
were also evaluated using Annexin V/PI assays. The results demonstrated rates of apoptotic cell death of
46.0, 25.5, and 37.8% among these cells were induced by use of ES1, ES2, and ES3, respectively. The
results demonstrated ability to successfully isolate/char-acterize specific c-Met scFv that could ultimately
have a great therapeutic potential in immuno-therapies against (colorectal) cancers.
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