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Expression of urokinase plasminogen activator and the urokinase plasminogen activator receptor in myeloma cells
Author(s) -
Hjertner Öyvind,
Qvigstad Gunnar,
HjorthHansen Henrik,
Seidel Carina,
Woodliff Jeffery,
Epstein Joshua,
Waage Anders,
Sundan Anders,
Börset Magne
Publication year - 2000
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1046/j.1365-2141.2000.02089.x
Subject(s) - urokinase receptor , cell culture , plasminogen activator , microbiology and biotechnology , urokinase , cell , cancer research , chemistry , biology , biochemistry , endocrinology , genetics
Binding of urokinase (uPA) to its receptor (uPAR; CD87) focuses proteolytic activity on the cell surface and this system is of importance in malignant matrix degradation and tumour invasion. By immunocytochemistry and flow cytometry, we found that primary myeloma cells and myeloma cell lines expressed uPA and uPAR. Soluble uPA was present in cell line supernatants and lysates in low concentrations. In cell lines, uPA and uPAR were located both on the cell surface and intracellularly, but the expression of both proteins was low. Higher levels of uPAR was detected on the cell surface of primary myeloma cells. When primary myeloma cells were gated by CD45 expression, stronger expression was found on immature CD45 + cells than on mature CD45 −/dim cells. Finally, both myeloma cell lines and primary cells were able to cleave a uPA‐specific substrate showing that the uPA system is functionally active. We conclude that myeloma cells are able to produce uPA and uPAR. This opens up a possible role of the uPA system in myeloma cell invasion and in the proteolytic digestion of bone matrix.