Identification of a novel urokinase receptor splice variant and its prognostic relevance in breast cancer

Thomas Luther; Matthias Kotzsch; Axel Meye; Thomaz Langerholc; Susanne Füssel; Natalie Olbricht; Sybille Albrecht; Detlev Ockert; Bernd Muehlenweg; Katrin Friedrich; Marianne Grosser; Manfred Schmitt; Gustavo Baretton; Viktor Magdolen

doi:10.1055/s-0037-1613577

Thrombosis and Haemostasis, Table of Contents

Thromb Haemost 2003; 89(04): 705-717
DOI: 10.1055/s-0037-1613577

Cellular Proteolysis and Oncology

Schattauer GmbH

Identification of a novel urokinase receptor splice variant and its prognostic relevance in breast cancer

Thomas Luther

¹Institut für Pathologie, Technische Universität Dresden, Dresden, Germany

,

Matthias Kotzsch

¹Institut für Pathologie, Technische Universität Dresden, Dresden, Germany

,

Axel Meye

²Klinik für Urologie, Technische Universität Dresden, Dresden, Germany

,

Thomaz Langerholc

³Klinische Forschergruppe der Frauenklinik, Technische Universität München, Munich, Germany

,

Susanne Füssel

²Klinik für Urologie, Technische Universität Dresden, Dresden, Germany

,

Natalie Olbricht

³Klinische Forschergruppe der Frauenklinik, Technische Universität München, Munich, Germany

,

Sybille Albrecht

¹Institut für Pathologie, Technische Universität Dresden, Dresden, Germany

,

Detlev Ockert

⁴Klinik für VTG-Chirurgie, Technische Universität Dresden, Dresden, Germany

,

Bernd Muehlenweg

³Klinische Forschergruppe der Frauenklinik, Technische Universität München, Munich, Germany

,

Katrin Friedrich

¹Institut für Pathologie, Technische Universität Dresden, Dresden, Germany

,

Marianne Grosser

¹Institut für Pathologie, Technische Universität Dresden, Dresden, Germany

,

Manfred Schmitt

³Klinische Forschergruppe der Frauenklinik, Technische Universität München, Munich, Germany

,

Gustavo Baretton

¹Institut für Pathologie, Technische Universität Dresden, Dresden, Germany

,

Viktor Magdolen

³Klinische Forschergruppe der Frauenklinik, Technische Universität München, Munich, Germany

› Author Affiliations

Abstract

Summary

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.

Theme paper: Part of this paper was originally presented at the joint meetings of the 16th International Congress of the International Society of Fibrinolysis and Proteolysis (ISFP) and the 17th International Fibrinogen Workshop of the International Fibrinogen Research Society (IFRS) held in Munich, Germany, September, 2002.

Keywords

Urokinase receptor - cancer - splice variants - mRNA - LightCycler technology

Full Text

References

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