Abstract 5144: Oligonucleotide-based inhibition of the pro-angiogenic activity of Hepatoma-derived growth factor related protein 3 in neuroblastoma

Abstract

Abstract Hepatoma-derived growth factor related protein 3 (HDGFRP3) belongs to the HDGF polypeptide family. Expression of HDGF is a prognostic factor for NSCLC, pancreatic and gastrointestinal tumors, and silencing of HDGF suppressed cell proliferation, migration and invasion of squamous lung cancer cells. Here we investigated the expression of HDGFRP3 in various tumor cell lines by quantitative PCR and western blot analysis. HDGFRP3 is highly expressed and secreted from neuroblastoma (NB) cell lines. The presence of high levels of HDGFRP3 was confirmed in two animal models of human NB. Since HDGFRP3 shares a conserved Pro-Trp-Trp-Pro motif (PWWP) domain with its family members, we assessed whether it could promote proliferation, migration and angiogenesis in analogy to HDGF. Recombinant HDGFRP3 inhibited migration of endothelial cells in a modified Boyden chamber experiment, while cell survival was not affected. Nevertheless, the protein promoted angiogenesis in vitro, as assessed through vascular sprouting and tubulogenesis assays. Starting from the structural insight of the PWWP domain, an oligonucleotide-based inhibitor was designed and tested to block the pro-angiogenic effect of HDGFRP3. A single stranded DNA inhibited the pro-angiogenic properties of HDGFRP3 in vitro. After modifications to improve its serum stability, the cytotoxicity of the designed oligonucleotide-based molecule (BN210) was tested by an MTT cell viability assay on various NB cell lines. BN210 slightly reduced NB cells proliferation. To determine if BN210 could be used both as single anti-angiogenic agent and in combination with chemotherapy in vivo, orthotopic NB tumor-bearing mice were randomly divided in different groups of treatment: 1 mg/kg of vincristine (VCR), once a week for 4 weeks; 7-21 mg/kg of BN210, either i.p. (5 days/week) or i.v (every 2 days). Other mice were treated with a combination of VCR and BN210. NB-bearing mice treated with BN210 alone showed a partial increase in life span, compared to control mice. However, mice treated with the combination of VCR plus BN210 had statistically significant increased life span, compared to both the control and the single treatment groups, with long term survivors obtained with the combined schedule when BN210 was injected i.v. Thus, the oligonucleotide-based inhibition of the pro-angiogenic activity of HDGFRP3 can be considered as a novel strategy for combined anti-tumor therapy in NB. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5144. doi:10.1158/1538-7445.AM2011-5144