Loss of Endocan tumorigenic properties after alternative splicing of exon 2.
BACKGROUND
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. 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 endocanDelta2.


METHODS
Stable, endocanDelta2-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 endocanDelta2 expressing cell lines subcutaneously in SCID mice. Biochemical properties of endocan and endocanDelta2 were studied after production of recombinant proteins in various cell lines of human and murine origin.


RESULTS
Our results showed that the exon 2 deletion impairs synthesis of the glycan chain, known to be involved in the pro-tumoral effect of endocan. EndocanDelta2 did not promote tumor formation by 293 cells implanted in the skin of severe combined immunodeficient (SCID) mice.


CONCLUSIONS
Our 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.
Depontieu
Florence
F
INSERM U774, Lille 59019, France. fdepont2@jhmi.edu
Grigoriu
Bogdan-Dragos
BD
Scherpereel
Arnaud
A
Adam
Estelle
E
Delehedde
Maryse
M
Gosset
Philippe
P
Lassalle
Philippe
P
D017398:Alternative Splicing; D000818:Animals; D016466:CHO Cells; D002471:Cell Transformation, Neoplastic / Q000235:genetics* / Q000378:metabolism; D006224:Cricetinae; D003412:Cricetulus; D018076:DNA, Complementary / Q000235:genetics; D042783:Endothelial Cells / Q000378:metabolism / Q000502:physiology; D005091:Exons; D017353:Gene Deletion; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism; D051379:Mice; D016513:Mice, SCID; D009363:Neoplasm Proteins / Q000235:genetics* / Q000378:metabolism; D011134:Polysaccharides / Q000096:biosynthesis; D020033:Protein Isoforms; D011509:Proteoglycans / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction
D018076:DNA, Complementary; C101134:ESM1 protein, human; D009363:Neoplasm Proteins; D011134:Polysaccharides; D020033:Protein Isoforms; D011509:Proteoglycans; D012333:RNA, Messenger