Implications of endocrine gland-derived vascular endothelial growth factor/prokineticin-1 signaling in human neuroblastoma progression.
OBJECTIVE
Neuroblastoma is a common pediatric tumor that is derived from improperly differentiated neural crest cells (NCC). We recently revealed that endocrine gland-derived vascular endothelial growth factor/prokineticin-1 (EG-VEGF/Prok-1) is a key factor mediating the growth and differentiation of enteric NCCs during development. In this report, we further elucidate its role in neuroblastoma progression.


METHODS
We studied the expression and copy number of EG-VEGF/Prok-1 receptors (PK-R1 and PK-R2) in 26 neuroblastoma tumors by real-time reverse transcription-PCR and immunohistochemical analysis. Implication of EG-VEGF/Prok-1 signaling in neuroblastoma progression was further shown in a neuroblastoma cell line (SK-N-SH).


RESULTS
We found that all neuroblastoma samples from stages II to IV expressed both PK-R1 and PK-R2. Kruskall-Wallis signed rank tests revealed that the expression level of PK-R1 transcript is associated with the stages and metastasis of the neuroblastoma (P<0.05), and PK-R2 is persistently higher in advanced-stage neuroblastoma samples. About 38% of the neuroblastoma tumors (10:26) possessed MYCN amplification, whereas no PK-R1 and PK-R2 amplifications were detected, suggesting that the overexpression of the receptors was not due to gene amplification. Subsequent functional studies showed that EG-VEGF/Prok-1 activates the Akt pathway to induce the proliferation of neuroblastoma cells. Targeted down-regulation studies revealed that EG-VEGF/Prok-1-mediated proliferation requires the presence of these two receptors, and that PK-R2 is essential for inhibiting apoptosis. In vitro migration and invasion assays also indicated that EG-VEGF/Prok-1 significantly enhances the cell migration/invasion of SK-N-SH.


CONCLUSIONS
Our study has shown for the first time that aberrant EG-VEGF/Prok-1 signaling favors neuroblastoma progression and could be a potential target for future neuroblastoma treatment.
Ngan
Elly S W
ES
Department of Surgery, University of Hong Kong, Pokfulam, Hong Kong, SAR, China, and Department of Pediatric Surgery, The Second Affiliated Hospital of China Medical University, Shenyang, China. engan@hkucc.hku.hk
Sit
Francesco Y L
FY
Lee
KingLiu
K
Miao
Xiaoping
X
Yuan
Zhengwei
Z
Wang
Weilin
W
Nicholls
John M
JM
Wong
Kenneth K Y
KK
Garcia-Barcelo
Mercè
M
Lui
Vincent C H
VC
Tam
Paul K H
PK
D002465:Cell Movement; D049109:Cell Proliferation; D002648:Child; D002675:Child, Preschool; D018450:Disease Progression; D004702:Endocrine Glands / Q000378:metabolism*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007223:Infant; D008297:Male; D009361:Neoplasm Invasiveness; D009447:Neuroblastoma / Q000378:metabolism* / Q000473:pathology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D042662:Vascular Endothelial Growth Factor, Endocrine-Gland-Derived / Q000378:metabolism*
D042662:Vascular Endothelial Growth Factor, Endocrine-Gland-Derived