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Matthew W Wilson, Zachary Goldsmith, William Coppess, Bradley Gao, Matthew McEwen, Andrew Irvine, Rachel C Brennan, Vanessa Marie Morales; PDGF-PDGFR Signaling Sustain Angiogenesis in an Autocrine and Paracrine Fashion in Retinoblastoma. Invest. Ophthalmol. Vis. Sci. 201657(12):.
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© 2017 Association for Research in Vision and Ophthalmology.
Purpose: The presence of vitreous seeding is considered a poor prognostic factor for ocular survival in Retinoblastoma (Rb) patients. External beam radiotherapy and chemotherapy have failed to increase ocular survival rates beyond 70% for eyes with vitreous seeding at the time of diagnosis, in part due to the presence of dormant tumor cells. Platelet derived growth factor is highly abundant in the vitreous microenvironment, especially in patients suffering from proliferative retinal disorders. We hypothesize reduction of the PDGF-PDGFR signaling may control vitreous seeds in Rb.
Methods: We used the Rb cell lines Y79 and Weri-1 as they represent the metastatic and non-metastatic forms of the disease. Cells were cultured with or without PDGF-AB as primary stimulus and evaluated for the expression of angiogenesis-related genes, production of angiogenic factors, and morphological changes by qPCR, Multiplex assays and confocal microscopy. Next, we evaluated how PDGF regulates Rb tumor proliferation and angiogenesis via autocrine and paracrine signaling by modulation of the PDGFR-b by imatinib mesylate (IM) and a neutralization antibody against the PDGF-BB isoform.
Results: We found high expression of the PDGFA and PDGFB isoforms in Rb cells by qPCR analysis. Western blot, Multiplex and flow cytometry analyses revealed a reduction in the PDGF-AB/BB isoforms (p=0.04), FLT-3L (p=0.02), and VEGF (p=0.08) after concomitant incubation of IM and recombinant human PDGF-AB (rhPDGF-AB), when compared to untreated and rhPDGF-AB stimulation. We observe striking differences in cellular migration both in 2D and 3D culture models when Rb cells were treated with IM. Additional studies utilizing the neutralizing antibody increased the magnitude of the angiogenic reduction.
Conclusions: Our work suggests PDGF-PDGFR signaling sustain angiogenesis in an autocrine and paracrine fashion. These studies are a step in the pursuit of our goal of development of identifying targets of immunotherapy that will control the factors sustaining Rb.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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