The secretory proprotein convertases furin, PC5, and PC7 activate VEGF-C to induce tumorigenesis.
The secretory factor VEGF-C has been directly implicated in various physiological processes during embryogenesis and human cancers. However, the importance of the conversion of its precursor proVEGF-C to mature VEGF-C in tumorigenesis, and vessel formation and the identity of the protease(s) that regulate these processes is/are not known. The intracellular processing of proVEGF-C that occurs within the dibasic motif HSIIRR(227)SL suggests the involvement of the proprotein convertases (PCs) in this process. In addition, furin and VEGF-C were found to be coordinately expressed in adult mouse tissues. Cotransfection of the furin-deficient colon carcinoma cell line LoVo with proVEGF-C and different PC members revealed that furin, PC5, and PC7 are candidate VEGF-C convertases. This finding is consistent with the in vitro digestions of an internally quenched synthetic fluorogenic peptide mimicking the cleavage site of proVEGF-C ((220)Q-VHSIIRR downward arrow SLP(230)). The processing of proVEGF-C is blocked by the inhibitory prosegments of furin, PC5, and PACE4, as well as by furin-motif variants of alpha2-macroglobulin and alpha1-antitrypsin. Subcutaneous injection of CHO cells stably expressing VEGF-C into nude mice enhanced angiogenesis and lymphangiogenesis, but not tumor growth. In contrast, expression of proVEGF-C obtained following mutation of the cleavage site (HSIIRR(227)SL to HSIISS(227)SL) inhibits angiogenesis and lymphangiogenesis as well as tumor growth. Our findings demonstrate the processing of proVEGF-C by PCs and highlight the potential use of PC inhibitors as agents for inhibiting malignancies induced by VEGF-C.
Siegfried
Geraldine
G
Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, Montreal, Quebec, Canada.
Basak
Ajoy
A
Cromlish
James A
JA
Benjannet
Suzanne
S
Marcinkiewicz
Jadwiga
J
Chrétien
Michel
M
Seidah
Nabil G
NG
Khatib
Abdel-Majid
AM
D020816:Amino Acid Motifs; D000818:Animals; D001665:Binding Sites; D015153:Blotting, Western; D016466:CHO Cells; D002219:Carbamates / Q000378:metabolism*; D002471:Cell Transformation, Neoplastic; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D016228:Endothelial Growth Factors / Q000378:metabolism*; D045683:Furin; D006801:Humans; D007150:Immunohistochemistry; D007700:Kinetics; D009154:Mutation; D009369:Neoplasms / Q000378:metabolism*; D009842:Oligopeptides / Q000378:metabolism*; D010452:Peptide Biosynthesis; D011233:Precipitin Tests; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013381:Subtilisins / Q000378:metabolism*; D013997:Time Factors; D014162:Transfection; D014407:Tumor Cells, Cultured; D042582:Vascular Endothelial Growth Factor C
D002219:Carbamates; D016228:Endothelial Growth Factors; D009842:Oligopeptides; D012333:RNA, Messenger; D011994:Recombinant Proteins; D042582:Vascular Endothelial Growth Factor C; C075359:tetrapeptide carbamate; C099101:PCSK7 protein, human; C490930:Pcsk7 protein, mouse; D013381:Subtilisins; D045683:Furin