gms | German Medical Science

70. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC)
Joint Meeting mit der Skandinavischen Gesellschaft für Neurochirurgie

Deutsche Gesellschaft für Neurochirurgie (DGNC) e. V.

12.05. - 15.05.2019, Würzburg

The synthetic ligand Apelin-F13A binds and activates glioblastoma APLNR reducing the pro-invasive side effect of anti-angiogenic therapy

Die Bindung und Aktivierung des APLNR Rezeptors mittels synthetischem Liganden Apelin-F13A führt zur Reduktion des pro-invasiven Nebeneffektes der anti-angiogenen Glioblastom-Therapie

Meeting Abstract

  • presenting/speaker Roland Kälin - Klinikum der Universität München, Neurochirurgische Klinik, München, Deutschland
  • Veit Stöcklein - Klinikum der Universität München, Neurochirurgische Klinik, München, Deutschland
  • Min Li - Klinikum der Universität München, Neurochirurgische Klinik, München, Deutschland
  • Sören Reinhard - Ludwig-Maximilians-Universität München, Department Pharmazie, München, Deutschland
  • Giorgia Mastrella - Klinikum der Universität München, Neurochirurgische Klinik, München, Deutschland
  • Ernst Wagner - Ludwig-Maximilians-Universität München, Department Pharmazie, München, Deutschland
  • Jörg-Christian Tonn - Klinikum der Universität München, Neurochirurgische Klinik, München, Deutschland
  • Rainer Glass - Klinikum der Universität München, Neurochirurgische Klinik, München, Deutschland

Deutsche Gesellschaft für Neurochirurgie. 70. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit der Skandinavischen Gesellschaft für Neurochirurgie. Würzburg, 12.-15.05.2019. Düsseldorf: German Medical Science GMS Publishing House; 2019. DocP074

doi: 10.3205/19dgnc412, urn:nbn:de:0183-19dgnc4127

Veröffentlicht: 8. Mai 2019

© 2019 Kälin et al.
Dieser Artikel ist ein Open-Access-Artikel und steht unter den Lizenzbedingungen der Creative Commons Attribution 4.0 License (Namensnennung). Lizenz-Angaben siehe http://creativecommons.org/licenses/by/4.0/.


Gliederung

Text

Objective: Anti-angiogenic therapy of glioblastoma (GBM) blocking vascular endothelial growth factor-A (VEGFA) often resulted in accelerated tumor-cell invasion and upregulation of alternative angiogenic pathways. Here, we studied the impact of different apelin peptides acting on the G-protein coupled receptor APLNR to mediate tumor angiogenesis and glioblastoma cell invasion.

Methods: Towards this aim, we applied the smallest bioactive peptide apelin-13 and its C-terminally mutated alternative apelin-F13A in in vitro migration/invasion assays. Next, we established its mechanistic differences in two different in vitro internalization assays. For functional studies we performed orthotopic implantation of human patient-derived and mouse subtype-specific GBM stem cell cultures and employed pharmacological blockade for apelin / APLNR and VEGFA / VEGFR2-signaling.

Results: Apelin/APLNR are broadly expressed in human GBM and modulating apelin-levels reduced GBM vascularization but also strongly accelerated GBM cell-invasion. Thus we performed two migration assays, a wound healing and a Boyden chamber chemotaxis assay, and confirmed that the depletion of apelin in glioblastoma cells lead to significantly increased invasive behavior of GBM cells. In contrast, application of apelin-13 or apelin-F13A attenuated this increased invasive phenotype. To investigate if both ligands can activate APLNR on GBM cells, we performed two in vitro receptor internalization assays. We found that apelin-13 and apelin-F13A caused the internalization of the APLNR to cytoplasmic and perinuclear regions. Most interestingly, apelin-13 lead to an increase of APLNR localization in the cytoplasm and a massive decrease in the nucleus, apelin-F13A caused exactly the opposite outcome. In a second internalization assay we administered GFP-linked apelin peptides. We found that both, apelin-13 and apelin-F13A were internalized by GBM cells in a sequence specific and dose dependent manner.

Conclusion: Together, these findings imply that the synthetic APLNR ligand apelin-F13A efficiently binds to and activates glioblastoma APLNR to function as a competitive agonist for other APLNR ligands. Our receptor internalization assay revealed that apelin-F13A induces a distinct pattern of intracellular APLNR localization which may explain why only apelin-F13A (but not apelin-13) was able to block the angiogenic effect of intratumoral apelin in addition to its anti-invasive role.