Recombinant immunotoxin anti-c-Met/PE38KDEL inhibits proliferation and promotes apoptosis of gastric cancer cells

Background: Our study aims to evaluate the anti-growth effects of recombinant immunotoxin (IT) anti-c-Met/PE38KDEL on gastric cancer cells, and its mechnisms. Methods: Gastric cancer cells were treated with increasing doses of IT and c-Met protein was quantified by Western blotting. Cell proliferation was determined by Cell Counting Kit-8 assay (CCK). [H-3]-leucine incorporation assay was used to evaluate IT inhibition of protein synthesis. Cell apoptosis was quantified by flow cytometry. Caspase activities were measured using colorimetric protease assays. Results: Cell growth and protein synthesis of the gastric cancer cell lines were suppressed by IT in a dose-and time-dependent manner. IT also induced apoptosis in a dose-dependent manner. The apoptosis rates of gastric cancer cell lines MKN-45 and SGC7901 were 19.19% and 27.37%, respectively when treated with 50 ng/ml of IT. There were significant increase ofcaspase-3 activity at 24 hr of IT treatment (100 ng/ml) (P < 0.01) in these gastric cancer cell lines. Conclusions: IT anti-c-Met/PE38KDEL has anti-growth effects on the gastric cancer cell lines in vitro, and it provides an experimental basis for c-Met-targeted therapy towards in vivo testing.