Targeting the RhoGEF ?PIX/COOL-1 in Glioblastoma: Proof of Concept Studies.
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ABSTRACT: Glioblastoma (GBM), a highly invasive and vascular malignancy is shown to rapidly develop resistance and evolve to a more invasive phenotype following bevacizumab (Bev) therapy. Rho Guanine Nucleotide Exchange Factor proteins (RhoGEFs) are mediators of key components in Bev resistance pathways, GBM and Bev-induced invasion. To identify GEFs with enhanced mRNA expression in the leading edge of GBM tumours, a cohort of GEFs was assessed using a clinical dataset. The GEF ?Pix/COOL-1 was identified, and the functional effect of gene depletion assessed using 3D-boyden chamber, proliferation, and colony formation assays in GBM cells. Anti-angiogenic effects were assessed in endothelial cells using tube formation and wound healing assays. In vivo effects of ?Pix/COOL-1-siRNA delivered via RGD-Nanoparticle in combination with Bev was studied in an invasive model of GBM. We found that siRNA-mediated knockdown of ?Pix/COOL-1 in vitro decreased cell invasion, proliferation and increased apoptosis in GBM cell lines. Moreover ?Pix/COOL-1 mediated endothelial cell migration in vitro. Mice treated with ?Pix/COOL-1 siRNA-loaded RGD-Nanoparticle and Bev demonstrated a trend towards improved median survival compared with Bev monotherapy. Our hypothesis generating study suggests that the RhoGEF ?Pix/COOL-1 may represent a target of vulnerability in GBM, in particular to improve Bev efficacy.
SUBMITTER: Connor K
PROVIDER: S-EPMC7761123 | biostudies-literature | 2020 Nov
REPOSITORIES: biostudies-literature
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