Implications of endocrine gland-derived vascular endothelial growth factor/prokineticin-1 signaling in human neuroblastoma progression

  • Clin Cancer Res. 2007 Feb 1;13(3):868-75. doi: 10.1158/1078-0432.CCR-06-2176.
Elly S W Ngan  1 ,  Francesco Y L Sit ,  KingLiu Lee ,  Xiaoping Miao ,  Zhengwei Yuan ,  Weilin Wang ,  John M Nicholls ,  Kenneth K Y Wong ,  Mercè Garcia-Barcelo ,  Vincent C H Lui ,  Paul K H Tam
Affiliations
  • 1. 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. [email protected]
PMID: 17289879 DOI: 10.1158/1078-0432.CCR-06-2176
Abstract

Purpose: 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.

Experimental design: 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.