Department of Molecular, Cell and Cancer Biology; Program in Molecular Medicine; UMass Metabolic Network
Cancer Biology | Cell Biology | Molecular Biology
Autocrine VEGF signaling is critical for sustaining prostate and other cancer stem cells (CSCs), and it is a potential therapeutic target, but we observed that CSCs isolated from prostate tumors are resistant to anti-VEGF (bevacizumab) and anti-VEGFR (sunitinib) therapy. Intriguingly, resistance is mediated by VEGF/neuropilin signaling, which is not inhibited by bevacizumab and sunitinib, and it involves the induction of P-Rex1, a Rac GEF, and consequent Rac1-mediated ERK activation. This induction of P-Rex1 is dependent on Myc. CSCs isolated from the PTEN(pc-/-) transgenic model of prostate cancer exhibit Rac1-dependent resistance to bevacizumab. Rac1 inhibition or P-Rex1 downregulation increases the sensitivity of prostate tumors to bevacizumab. These data reveal that prostate tumors harbor cells with stem cell properties that are resistant to inhibitors of VEGF/VEGFR signaling. Combining the use of available VEGF/VEGFR-targeted therapies with P-Rex1 or Rac1 inhibition should improve the efficacy of these therapies significantly.
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Citation: Cell Rep. 2016 Mar 8;14(9):2193-208. doi: 10.1016/j.celrep.2016.02.016. Epub 2016 Feb 25.
This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Goel, Hira Lal; Pursell, Bryan M.; Shultz, Leonard D.; Greiner, Dale L.; Brekken, Rolf A.; Vander Kooi, Craig W.; and Mercurio, Arthur M., "P-Rex1 Promotes Resistance to VEGF/VEGFR-Targeted Therapy in Prostate Cancer" (2016). Molecular, Cell and Cancer Biology Publications. 59.
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