title: Identification of a novel urokinase receptor splice variant and its prognostic relevance in breast cancer.
abstract: The cellular receptor for urokinase-type plasminogen activator, uPAR, plays a central role in both cell surface-associated proteolysis and cellular adhesion. In the present study, we systematically searched for splice variants of uPAR mRNA in human cells and tumor tissues by qualitative RT-PCR using specific primers for uPAR exons 1 and 6. Beside the wild-type (wt) uPAR mRNA and the previously described splice variant lacking exon 5 (uPAR-del5), a novel splice variant lacking both exons 4 and 5 (uPAR-del4/5) was found predominantly in various cancer cell lines. To elucidate whether alternatively spliced uPAR mRNA may be translated and post-translationally processed, we generated stably transfected Chinese hamster ovary cells, which harbor expression plasmids of wt uPAR and various uPAR variants including uPAR-del5 and uPAR-del4/5. By ELISA, flow cytofluorometry, and Western blot analysis, we confirmed synthesis and secretion of wt uPAR and the uPAR variants by the use of domain-specific monoclonal antibodies against uPAR. For quantification of uPAR mRNA variants, we established two highly sensitive real-time RT-PCR assays based on LightCycler technology. Study of their expression in a representative set of breast cancer tissues indicated that the novel mRNA variant uPAR-del4/5 was expressed very frequently and independently of uPAR mRNA variants covering exon 4 (uPAR-wt and uPAR-del5). Higher uPAR-del4/5 expression was significantly associated with shorter disease-free survival (p = 0.0004) of breast cancer patients. These results suggest that uPAR-del4/5 mRNA may serve as a novel prognostic marker in breast cancer.
authors.affiliation: Institut für Pathlogie, Technische Universität Dresden, Germany. t.luther@labor-bautzen.de
authors.forename: Thomas
authors.initials: T
authors.lastname: Luther
authors.forename: Matthias
authors.initials: M
authors.lastname: Kotzsch
authors.forename: Axel
authors.initials: A
authors.lastname: Meye
authors.forename: Thomaz
authors.initials: T
authors.lastname: Langerholc
authors.forename: Susanne
authors.initials: S
authors.lastname: Füssel
authors.forename: Natalie
authors.initials: N
authors.lastname: Olbricht
authors.forename: Sybille
authors.initials: S
authors.lastname: Albrecht
authors.forename: Detlev
authors.initials: D
authors.lastname: Ockert
authors.forename: Bernd
authors.initials: B
authors.lastname: Muehlenweg
authors.forename: Katrin
authors.initials: K
authors.lastname: Friedrich
authors.forename: Marianne
authors.initials: M
authors.lastname: Grosser
authors.forename: Manfred
authors.initials: M
authors.lastname: Schmitt
authors.forename: Gustavo
authors.initials: G
authors.lastname: Baretton
authors.forename: Viktor
authors.initials: V
authors.lastname: Magdolen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017398:Alternative Splicing; D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000235:genetics*; D016466:CHO Cells; D045744:Cell Line, Tumor; D006224:Cricetinae; D018572:Disease-Free Survival; D004797:Enzyme-Linked Immunosorbent Assay; D005091:Exons; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008875:Middle Aged; D008957:Models, Genetic; D010957:Plasmids / Q000378:metabolism; D017395:Plasminogen Activator Inhibitor 1 / Q000378:metabolism; D011379:Prognosis; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000096:biosynthesis* / Q000235:genetics*; D055293:Receptors, Urokinase Plasminogen Activator; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014162:Transfection
chemical_list: D000911:Antibodies, Monoclonal; C524898:PLAUR protein, human; D017395:Plasminogen Activator Inhibitor 1; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator