B193
VEGF autocrine signalling maybe involved in proliferation of tumour initiating cells
Emma Kenney-Herbert, Siolian Ball, Colin Watts
Brain Repair Centre, Cambridge, UK
Introduction
PDGFRα, VEGFR2 and their respective endogenous agonists PDGFA and VEGF are over expressed in glioblastoma WHO grade IV (GBM), suggesting the importance of autocrine signalling in tumourigenesis. We have derived tumorigenic cell lines, under serum free conditions, from GBM samples and used them to investigate the contribution of putative PDGFA and VEGF autocrine signalling in tumour initiating cell (TIC) proliferation.
Methods
Semi-quantitive RT-PCR was used to determine the presence of PDGFA, PDGFRα, VEGF and VEGFR2 transcripts and translation of PDGFA and VEGF was confirmed by ELISA. Inhibitory antibodies to PDGFA and VEGF were applied to our cell lines and their effects on cell proliferation assessed by MTS assay.
Results
PDGFRα mRNA was confirmed in all cell lines, whereas, PDGFA transcripts were present in 6/7 lines. Inhibitory antibodies to PDGFA did not significantly affect cell proliferation in any line analysed. VEGF mRNA was detected in all lines, and showed a relationship with the amount of VEGF secreted. VEGFR2 mRNA was present in 5/7 lines only. Inhibitory antibodies to VEGF could significantly inhibit proliferation of cell lines, but only where VEGFR2 mRNA was present.
Conclusion
The results suggest that anti- PDGFA therapy would have little or no significant effect on GBM TICs in vitro and is consistent with evidence from a proportion of clinical trials. Also our data suggests that targeting VEGF may be a more efficacious strategy in management of these tumours and confirms the potential usefulness of our model lines for future drug screening.
