Search

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.)

Background: Previously, we reported that a novel fusion protein consisting of an amino-terminal fragment of urokinase linked to the amino terminus of the enzyme L-methioninase inhibited MCF-7 breast cancer cells in vitro to a greater extent than treatment with L-methioninase., Materials and Methods: The fusion protein, L-methioninase and a mutated fusion protein without L-methioninase activity were produced by recombinant methods. The effects of fusion protein, L-methioninase, and mutated fusion protein treatment on the proliferation and motility of SK-LU-i lung and PC-3 prostate and cancer cells were measured in vitro using a culture wounding assay., Results: The fusion protein produced a dose-dependent inhibition of the proliferation and motility of both cancer cell lines. In addition, the fusion protein was found to be significantly more effective than L-methioninase alone or mutated fusion protein., Conclusion: Our results suggest that this fusion protein has potential as a selective therapeutic agent for the treatment of various methionine-dependent cancers.

Background: We previously reported that a novel fusion protein (consisting of an amino-terminal fragment of urokinase which binds to the urokinase receptor, and L-methioninase which depletes methionine and arrests the growth of methionine-dependent tumors) inhibited MCF-7 breast cancer cells in vitro., Materials and Methods: We produced this fusion protein, L-methioninase, and a mutated fusion protein without L-methioninase activity by recombinant methods. MCF-7 cell proliferation and mobility were measured in vitro in a culture wounding assay. Protein binding to MCF-7 cells was measured by immunocytochemical localization. MCF-7 tumor xenograft growth was measured in nude mice., Results: The fusion protein was significantly more effective than L-methioninase in either the in vitro or in vivo assays. The binding assay showed that the unmutated and mutated fusion protein bound to the cells, but L-methioninase did not., Conclusion: Our results suggest that this fusion protein has potential as a therapeutic agent for cancer treatment.

It has been shown that methionine depletion inhibits tumor cell growth and reduces tumor cell survival. A novel fusion protein targeted specifically to tumor cells was developed. The fusion protein contained two components: the amino terminal fragment of human urokinase (amino acids 1-49) that binds to the urokinase receptor protein expressed on the surface of invasive cancer cells, and the enzyme L-methioninase (containing 398 amino acids) which depletes methionine and arrests the growth of methionine-dependent tumors. The influence of the fusion protein on the growth and motility of human breast cancer cells was examined using a culture wounding assay. It was determined that MCF-7 breast cancer cells, used in this study, were methionine-dependent and that the fusion protein bound specifically to urokinase receptors of the surface of the cancer cells. Further treatment of the cancer cells with fusion protein over the concentration range 10(-8) to 10(-6) M produced a dose-dependent inhibition of both the migration and proliferation index of MCF-7 cells in the culture wounding assay over a period of 1 to 3 days. The results of this study suggest that this novel fusion protein may serve as a prototype for specific targeting of methioninase and perhaps other cytotoxic agents to cancer cells.