ID2-VEGF-related pathways in the pathogenesis of Kaposi's sarcoma: a link disrupted by rapamycin.
The Id-proteins are a family of four related proteins implicated in the control of differentiation and cell-cycle progression. Down-regulation of Id-gene expression is essential for the differentiation of several cell types. In addition, deregulated Id2 activity inhibits the Rb tumor suppressor pathway and promotes the expression of vascular endothelial growth factor (VEGF). Several members of VEGF family could be involved in Kaposi's sarcoma (KS) development and progression. Lymphatic vascular endothelial hyaluronan receptor-1 (LYVE-1) is the first marker of lymphatic endothelial competence during development in the mature vasculature, and is also expressed on KS spindle cells. Rapamycin (RAPA), an immunosuppressive drug, has been shown to reverse KS growth and to reduce tumor angiogenesis. We evaluate, in transplantation-associated KS and in cultured KS-cells the RAPA effect on Id2 and on de novo lymphangiogenesis. Markers of lymphatic-endothelial-cells (VEGFR-3, LYVE-1) and Id2, expressed at low levels within the normal skin, were up-regulated in KS and returned to normal levels after RAPA introduction. The association between Id2 and lymphangiogenesis is suggested by co-localization of Id2, VEGFR-3 and LYVE-1. RAPA inhibition on Id2 expression was confirmed in vitro in KS-cells, both in basal conditions and upon stimulation with VEGF. In conclusion, our data would suggest a novel molecular mechanism for the antineoplastic effects of RAPA in posttransplant KS.
Stallone
G
G
Department of Biomedical Sciences, Section of Nephrology, University of Foggia, Italy. g.stallone@unifg.it
Infante
B
B
Pontrelli
P
P
Ranieri
E
E
Loverre
A
A
Schena
A
A
Cormio
L
L
Carrieri
G
G
Schena
F P
FP
Grandaliano
G
G
Gesualdo
L
L
D045744:Cell Line, Tumor; D018450:Disease Progression; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D051797:Inhibitor of Differentiation Protein 2 / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D012514:Sarcoma, Kaposi / Q000209:etiology* / Q000378:metabolism* / Q000601:surgery; D015398:Signal Transduction / Q000187:drug effects*; D020123:Sirolimus / Q000494:pharmacology*; D016038:Skin Transplantation; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism*; D040321:Vascular Endothelial Growth Factor Receptor-3 / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000378:metabolism
C497450:ID2 protein, human; D051797:Inhibitor of Differentiation Protein 2; C119248:LYVE1 protein, human; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D033921:Vesicular Transport Proteins; D040321:Vascular Endothelial Growth Factor Receptor-3; D020123:Sirolimus