TY - JOUR
T1 - Myc-associated zinc finger protein (MAZ) is regulated by miR-125b and mediates VEGF-induced angiogenesis in glioblastoma
AU - Smits, Michiel
AU - Wurdinger, Thomas
AU - Van Het Hof, Bert
AU - Drexhage, Joost A.R.
AU - Geerts, Dirk
AU - Wesseling, Pieter
AU - Noske, David P.
AU - Vandertop, W. Peter
AU - De Vries, Helga E.
AU - Reijerkerk, Arie
PY - 2012/6
Y1 - 2012/6
N2 - In patients with glioblastomas, vascular endothelial growth factor (VEGF) is a key mediator of tumor-associated angiogenesis. Glioblastomas are notorious for their capacity to induce neovascularization, driving continued tumor growth. Here we report that miR-125b is down-regulated in glioblastoma-associated endothelial cells, resulting in increased expression of its target, myc-associated zinc finger protein (MAZ), a transcription factor that regulates VEGF. The down-regulation of miR-125b was also observed on exposure of endothelial cells to glioblastoma-conditioned medium or VEGF, resulting in increased MAZ expression. Further analysis revealed that inhibition of MAZ accumulation by miR-125b, or by MAZ-specific shRNAs, attenuated primary human brain endothelial cell migration and tubule formation in vitro, phenomena considered to mimick angiogenic processes in vitro. Moreover, MAZ expression was elevated in brain blood vessels of glioblastoma patients. Altogether these results demonstrate a functional feed-forward loop in glioblastomarelated angiogenesis, in which VEGF inhibits the expression of miR-125b, resulting in increased expression of MAZ, which in its turn causes transcriptional activation of VEGF. This loop is functionally impeded by the VEGF receptor inhibitor vandetanib, and our results may contribute to the further development of inhibitors of tumor-angiogenesis.
AB - In patients with glioblastomas, vascular endothelial growth factor (VEGF) is a key mediator of tumor-associated angiogenesis. Glioblastomas are notorious for their capacity to induce neovascularization, driving continued tumor growth. Here we report that miR-125b is down-regulated in glioblastoma-associated endothelial cells, resulting in increased expression of its target, myc-associated zinc finger protein (MAZ), a transcription factor that regulates VEGF. The down-regulation of miR-125b was also observed on exposure of endothelial cells to glioblastoma-conditioned medium or VEGF, resulting in increased MAZ expression. Further analysis revealed that inhibition of MAZ accumulation by miR-125b, or by MAZ-specific shRNAs, attenuated primary human brain endothelial cell migration and tubule formation in vitro, phenomena considered to mimick angiogenic processes in vitro. Moreover, MAZ expression was elevated in brain blood vessels of glioblastoma patients. Altogether these results demonstrate a functional feed-forward loop in glioblastomarelated angiogenesis, in which VEGF inhibits the expression of miR-125b, resulting in increased expression of MAZ, which in its turn causes transcriptional activation of VEGF. This loop is functionally impeded by the VEGF receptor inhibitor vandetanib, and our results may contribute to the further development of inhibitors of tumor-angiogenesis.
KW - Brain cancer
KW - Brain endothelial cell
UR - http://www.scopus.com/inward/record.url?scp=84861789037&partnerID=8YFLogxK
U2 - 10.1096/fj.11-202820
DO - 10.1096/fj.11-202820
M3 - Article
C2 - 22415301
AN - SCOPUS:84861789037
SN - 0892-6638
VL - 26
SP - 2639
EP - 2647
JO - FASEB Journal
JF - FASEB Journal
IS - 6
ER -