Selective growth inhibition of cancer cells by L-methioninase-containing fusion protein targeted to the urokinase receptor.

BACKGROUND: We have reported the development of a novel fusion protein (FP) consisting of an amino-terminal fragment of urokinase linked to the amino terminus of the enzyme L-methioninase (L-M). The present study compared the effect of this novel FP on the proliferation of human ovarian, skin, breast endometrial and pancreatic cancer cell lines.
METHODS: The FP, L-M and a mutated FP, with reduced L-M activity, were produced by recombinant methods. The effect of treatment with FP, L-M and mutated FP on the proliferation of the cancer cells was measured in vitro using an MTS assay.
RESULTS: The inhibitory effect of the FP was found to be significantly greater than that of L-M alone or the mutated FP. In addition, the FP produced a greater inhibitory effect on an ovarian cancer cell line than on comparable normal, non-cancerous cells. Further, the FP produced a dose-dependent inhibition of the proliferation of pancreatic cancer cell lines.
CONCLUSION: These results suggest that this FP is a potent and selective inhibitor of the proliferation of various cancer cell lines and has potential as a therapeutic agent for the treatment of various methionine-dependent cancers. Copyright 2009 S. Karger AG, Basel.