title: Clinical significance of heparanase splice variant (t5) in renal cell carcinoma: evaluation by a novel t5-specific monoclonal antibody.
abstract: T5 is a novel splice variant of heparanase, an endo-β-D-glucuronidase capable of cleaving heparan sulfate side chains at a limited number of sites. T5 splice variant is endowed with pro-tumorigenic properties, enhancing cell proliferation, anchorage independent growth and tumor xenograft development despite lack of heparan sulfate-degrading activity typical of heparanase. T5 is over expressed in the majority of human renal cell carcinoma biopsies examined, suggesting that this splice variant is clinically relevant. T5 is thought to assume a distinct three-dimensional conformation compared with the wild type heparanase protein. We sought to exploit this presumed feature by generating monoclonal antibodies that will recognize the unique structure of T5 without, or with minimal recognition of heparanase, thus enabling more accurate assessment of the clinical relevance of T5. We provide evidence that such a monoclonal antibody, 9c9, preferentially recognizes T5 compared with heparanase by ELISA, immunoblotting and immunohistochemistry. In order to uncover the clinical significance of T5, a cohort of renal cell carcinoma specimens was subjected to immunostaining applying the 9c9 antibody. Notably, T5 staining intensity was significantly associated with tumor size (p = 0.004) and tumor grade (p = 0.02). Our results suggest that T5 is a functional, pro-tumorigenic entity.
authors.affiliation: Cancer and Vascular Biology Research Center, Rappaport Faculty of Medicine, Technion, Haifa, Israel.
authors.forename: Uri
authors.initials: U
authors.lastname: Barash
authors.forename: Gil
authors.initials: G
authors.lastname: Arvatz
authors.forename: Roy
authors.initials: R
authors.lastname: Farfara
authors.forename: Inna
authors.initials: I
authors.lastname: Naroditsky
authors.forename: Ilana
authors.initials: I
authors.lastname: Doweck
authors.forename: Sari
authors.initials: S
authors.lastname: Feld
authors.forename: Ofer
authors.initials: O
authors.lastname: Ben-Izhak
authors.forename: Neta
authors.initials: N
authors.lastname: Ilan
authors.forename: Ofer
authors.initials: O
authors.lastname: Nativ
authors.forename: Israel
authors.initials: I
authors.lastname: Vlodavsky
mesh_terms: D017398:Alternative Splicing / Q000235:genetics*; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity / Q000276:immunology*; D002292:Carcinoma, Renal Cell / Q000201:enzymology* / Q000473:pathology; D045744:Cell Line, Tumor; D003710:Demography; D005260:Female; D005966:Glucuronidase / Q000235:genetics* / Q000276:immunology*; D006258:Head and Neck Neoplasms / Q000201:enzymology; D006801:Humans; D007680:Kidney Neoplasms / Q000201:enzymology* / Q000473:pathology; D008297:Male; D013194:Staining and Labeling; D000099175:Heparanase
chemical_list: D000911:Antibodies, Monoclonal; D005966:Glucuronidase; D000099175:Heparanase