Abstract
BackgroundEndocan was originally described as a dermatan sulfate proteoglycan found freely circulating in the blood. Endocan expression confers tumorigenic properties to epithelial cell lines or accelerate the growth of already tumorigenic cells. This molecule is the product of a single gene composed of 3 exons. Previous data showed that endocan mRNA is subject to alternative splicing with possible generation of two protein products. In the present study we identified, and functionally characterized, the alternative spliced product of the endocan gene: the exon 2-deleted endocan, called endocanΔ2.MethodsStable, endocanΔ2-overexpressing cell lines were generated to investigate the biological activities of this new alternatively spliced product of endocan gene. Tumorigenesis was studied by inoculating endocan and endocanΔ2 expressing cell lines subcutaneously in SCID mice. Biochemical properties of endocan and endocanΔ2 were studied after production of recombinant proteins in various cell lines of human and murine origin.ResultsOur results showed that the exon 2 deletion impairs synthesis of the glycan chain, known to be involved in the pro-tumoral effect of endocan. EndocanΔ2 did not promote tumor formation by 293 cells implanted in the skin of severe combined immunodeficient (SCID) mice.ConclusionOur results emphasize the key role of the polypeptide sequence encoded by the exon 2 of endocan gene in tumorigenesis, and suggest that this sequence could be a target for future therapies against cancer.
Highlights
Endocan was originally described as a dermatan sulfate proteoglycan found freely circulating in the blood
We show here that the two alternative spliced products are expressed in resting human umbilical vein endothelial cells (HUVEC) (Fig. 1B)
This was consistent with immunoprecipitation studies from endothelial cell lysates, which revealed 2 bands at 18 and 14 kilo Daltons (kDa), the first band corresponding to endocan, the second band was suspected to correspond to the endocanΔ2 polypeptide (Fig. 2B lanes 1 and 4). This statement was further confirmed when HEK 293 cells transfected by endocanΔ2 cDNA generated the 14 kDa band (Fig. 2B lane 6), and other bands of 26, 38 and 50 kDa disappearing under reducing conditions. These results indicated that endocanΔ2 mRNA is primate specific, and is efficiently translated in HUVEC in a 14 kDa protein
Summary
Endocan was originally described as a dermatan sulfate proteoglycan found freely circulating in the blood. Endocan expression confers tumorigenic properties to epithelial cell lines or accelerate the growth of already tumorigenic cells This molecule is the product of a single gene composed of 3 exons. BMC Cancer 2008, 8:14 http://www.biomedcentral.com/1471-2407/8/14 ents of the tumor stroma and the vascular bed and are present at the cell surface and in the extracellular matrix [1]. They are constituted of a protein core with one or more covalently attached glycosaminoglycan (GAG) chains. Previously named Endothelial Specific Molecule-1 (ESM-1), a dermatan sulfate proteoglycan which is found freely circulating in the blood, is secreted by endothelial cells and is preferentially expressed in lung and kidney tissues [12,13,14,15,16] Proteoglycans are produced by both tumor cells and cells from the tumor stroma and can interact with growth factors, cytokines and integrins regulating their actions, thereby potentially contributing to tumor growth and progression [5,6,7,8,9,10,11].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
