Blockade of Wnt signaling inhibits angiogenesis and tumor growth in hepatocellular carcinoma.
Aberrant activation of Wnt signaling plays an important role in hepatocarcinogenesis. In addition to direct effects on tumor cells, Wnt signaling might be involved in the organization of tumor microenvironment. In this study, we have explored whether Wnt signaling blockade by exogenous expression of Wnt antagonists could inhibit tumor angiogenesis and control tumor growth. Human Wnt inhibitory factor 1 (WIF1) and secreted frizzled-related protein 1 (sFRP1) were each fused with Fc fragment of human IgG1 to construct fusion proteins WIF1-Fc and sFRP1-Fc. The recombinant adenoviral vectors carrying WIF1-Fc and sFRP1-Fc driven by cytomegalovirus promoter were constructed. Ad-WIF1-Fc or Ad-sFRP1-Fc induced the expression and correct conformation of WIF1-Fc and sFRP1-Fc fusion proteins. These molecules caused down-regulation of E2F1, cyclin D1, and c-myc and promoted cell apoptosis in hepatocellular carcinoma cells. Treatment of established hepatocellular carcinoma tumors with Ad-WIF1-Fc and/or Ad-sFRP1-Fc resulted in significant inhibition of tumor growth and prolonged animal survival. The antineoplastic effect was associated with increased apoptosis of tumor cells, reduced microvessel density, and decreased expression of vascular endothelial growth factor and stromal cell-derived factor-1. Tube formation and migration of human microvascular endothelial cells and mouse endothelial progenitor cells (EPC) were significantly inhibited by both WIF1-Fc and sFRP1-Fc. In addition, these molecules blocked EPC differentiation and caused EPC apoptosis. Our data indicate that Wnt antagonists WIF1-Fc and sFRP1-Fc inhibit Wnt signaling and exert potent antitumor activity by increasing the apoptosis rate in tumor cells and by impairing tumor vascularization.
Hu
Jie
J
Division of Gene Therapy and Hepatology, Center for Applied Medical Research, University of Navarra, Pamplona, Spain.
Dong
Aiwen
A
Fernandez-Ruiz
Veronica
V
Shan
Juanjuan
J
Kawa
Milosz
M
Martínez-Ansó
Eduardo
E
Prieto
Jesus
J
Qian
Cheng
C
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics; D000256:Adenoviridae; D000818:Animals; D017209:Apoptosis / Q000235:genetics; D006528:Carcinoma, Hepatocellular / Q000098:blood supply / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D045744:Cell Line, Tumor; D003587:Cytomegalovirus; D015536:Down-Regulation; D015972:Gene Expression Regulation, Neoplastic; D015316:Genetic Therapy; D005822:Genetic Vectors; D006801:Humans; D007141:Immunoglobulin Fc Fragments / Q000235:genetics; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics; D008114:Liver Neoplasms, Experimental / Q000098:blood supply / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D008565:Membrane Proteins / Q000235:genetics; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D009389:Neovascularization, Pathologic / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics; D014162:Transfection; D051153:Wnt Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics; D000094742:Secreted Frizzled-Related Proteins
D048868:Adaptor Proteins, Signal Transducing; D007141:Immunoglobulin Fc Fragments; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D051153:Wnt Proteins; C117636:SFRP1 protein, human; D000094742:Secreted Frizzled-Related Proteins; C485569:WIF1 protein, human