Targeting a methioninase-containing fusion protein to breast cancer urokinase receptors inhibits growth and migration.
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.


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.


CONCLUSIONS
Our results suggest that this fusion protein has potential as a therapeutic agent for cancer treatment.
Zang
Xiao-Ping
XP
Department of Pharmaceutical Science, College of Pharmacy, University of Oklahoma, Health Sciences Center, 1110 N. Stonewall Ave., Oklahoma City, Oklahoma 73117, USA.
Palwai
Naveen R
NR
Lerner
Megan R
MR
Brackett
Daniel J
DJ
Pento
J Thomas
JT
Harrison
Roger G
RG
D000818:Animals; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism* / Q000473:pathology; D013437:Carbon-Sulfur Lyases / Q000008:administration & dosage* / Q000235:genetics; D048708:Cell Growth Processes / Q000187:drug effects; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D006801:Humans; D015552:Injections, Intralesional; D051379:Mice; D008819:Mice, Nude; D016297:Mutagenesis, Site-Directed; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D055293:Receptors, Urokinase Plasminogen Activator; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage* / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
C524898:PLAUR protein, human; C524899:Plaur protein, mouse; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D011993:Recombinant Fusion Proteins; D013437:Carbon-Sulfur Lyases; C021558:L-methionine gamma-lyase