Regulation of VEGF-A in uveal melanoma.
OBJECTIVE
Blood vessels are important constituents of intraocular uveal melanoma (UM), but whether angiogenesis is regulated by environmental factors such as ischemia or by genetic mechanisms is not known. This study was undertaken to examine the regulation of the proangiogenic factor vascular endothelial growth factor (VEGF-A).


METHODS
Cell lines and primary tumors were tested for expression of VEGF-A, under normoxic and hypoxic conditions, using quantitative PCR, ELISA, WST-1 viability, and in-cell Western experiments. VEGF-A serum levels were determined by ELISA.


RESULTS
Hypoxia induced expression of HIF-1alpha and VEGF-A in UM cell lines and primary tumor cultures, but it did not influence proliferation. VEGF-A expression in primary tumors was variable, demonstrating no correlation with specific histologic markers or prognosis. However, VEGF-A levels were significantly raised in UM patients with metastases compared with those without metastases (P < 0.001).


CONCLUSIONS
VEGF-A expression by UM cells is mainly controlled by hypoxia and involves the HIF-1alpha pathway, thus indicating an important role for the tumor cell environment. Metastases led to increased serum VEGF-A levels, indicating that VEGF-A may be involved in the growth of metastases.
el Filali
Mariam
M
Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands.
Missotten
Guy S O A
GS
Maat
Willem
W
Ly
Long V
LV
Luyten
Gregorius P M
GP
van der Velden
Pieter A
PA
Jager
Martine J
MJ
D000368:Aged; D015153:Blotting, Western; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D004797:Enzyme-Linked Immunosorbent Assay; D015353:Eye Enucleation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology*; D006801:Humans; D000860:Hypoxia / Q000097:blood / Q000235:genetics; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism; D008297:Male; D008545:Melanoma / Q000097:blood / Q000235:genetics* / Q000556:secondary; D008875:Middle Aged; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014604:Uveal Neoplasms / Q000097:blood / Q000235:genetics* / Q000473:pathology; D042461:Vascular Endothelial Growth Factor A / Q000097:blood / Q000235:genetics*
C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D012333:RNA, Messenger; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A