Tumor angiogenesis is regulated by a dynamic crosstalk between tumor cells and the host microenvironment. Because membrane vesicles shed by tumor cells are known to mediate several tumor–host interactions, we determined whether vesicles might also stimulate angiogenesis. Vesicles shed by human ovarian carcinoma cell linesCABAI and A2780 stimulated the motility and invasiveness of endothelial cells in vitro. Enzymelinked immunosorbent assay and Western blot analysis revealed relevant amounts of vascular endothelial growth factor (VEGF) and the two matrix metalloproteinases MMP-2 and MMP-9, but not fibroblast growth factor-2, contained in shed vesicles. An A2780 cell– derived clone transfected to overexpress VEGF shed the same amount of vesicles as did a control clone, but contained significantly more VEGF within the vesicles. Despite a greater amount of VEGF in vesicles of the overexpressing clone, vesicles of both clones stimulated endothelial cell motility to comparable levels, suggesting that VEGF was stored within the vesicle and was unavailable. Only following vesicle burst induced by acidic pH (a characteristic of the tumormicroenvironment) was VEGF released, leading to significantly higher stimulation of cell motility. Thus, tumor-shed membrane vesicles carry VEGF and release it in a bioactive form in conditions typical of the tumor microenvironment.

Biovailability of VEGF in tumor shed vesicles depends on vesicle burst induced by acidic pH

GIUSTI I;DOLO, VINCENZA
2006

Abstract

Tumor angiogenesis is regulated by a dynamic crosstalk between tumor cells and the host microenvironment. Because membrane vesicles shed by tumor cells are known to mediate several tumor–host interactions, we determined whether vesicles might also stimulate angiogenesis. Vesicles shed by human ovarian carcinoma cell linesCABAI and A2780 stimulated the motility and invasiveness of endothelial cells in vitro. Enzymelinked immunosorbent assay and Western blot analysis revealed relevant amounts of vascular endothelial growth factor (VEGF) and the two matrix metalloproteinases MMP-2 and MMP-9, but not fibroblast growth factor-2, contained in shed vesicles. An A2780 cell– derived clone transfected to overexpress VEGF shed the same amount of vesicles as did a control clone, but contained significantly more VEGF within the vesicles. Despite a greater amount of VEGF in vesicles of the overexpressing clone, vesicles of both clones stimulated endothelial cell motility to comparable levels, suggesting that VEGF was stored within the vesicle and was unavailable. Only following vesicle burst induced by acidic pH (a characteristic of the tumormicroenvironment) was VEGF released, leading to significantly higher stimulation of cell motility. Thus, tumor-shed membrane vesicles carry VEGF and release it in a bioactive form in conditions typical of the tumor microenvironment.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11697/13571
Citazioni
  • ???jsp.display-item.citation.pmc??? 89
  • Scopus 153
  • ???jsp.display-item.citation.isi??? 146
social impact