Abstract 2641
Background
Glioblastoma (GB) are brain tumors with a poor prognosis despite multimodal treatment combining resection, chemotherapy (CT) and radiotherapy (RT). The rich vascularization of these tumors led to the introduction of anti-angiogenic therapy with most efforts focused on the vascular endothelial growth factor (VEGF). However, the angiopoietins (Ang) have emerged as alternative regulators of angiogenesis. In particular, in GB, Ang2 is up-regulated and stimulates tumor angiogenesis in concert with VEGF but also activates pro-angiogenic functions of macrophages. However, Ang2 functions are context-dependent. Therefore, we sought to elucidate the involvement of Ang2 in the interaction of glioma response to CT and RT, both therapeutic modalities known to alter tumor angiogenesis and inflammation.
Methods
To recapitulate high levels of Ang2 in GB patients, Ang2 was overexpressed in murine glioma cells (GL261-Ang2). Effects of Ang2 were studied on an orthotopic syngenic model of GB (GL261 cells) in response to combined CT/RT. C57bl/6 mice were co-treated with temozolomide (TMZ 10 mg/kg; i.p.) and brain tumors were irradiated with X-rays (4 Gy) at 7, 9 and 11 days post-cell injection. The tumor growth and its microenvironment were followed by MRI and immunohistology analyses.
Results
We showed that, in this model, the chronic overexpression of Ang2 does not modify tumor progression, but leads to a decrease in vessel density (-39±10%, p < 0.001) and to an increase in CD68+ inflammatory cells (+24±8%, p < 0.05), compared with the control tumor group (GL261). Interestingly, when combined with CT/RT, the overexpression of Ang2 in the tumor induces a robust delay in tumor recurrence (>3 months) compared with treated GL261 tumors (18±3 days). In vitro, no difference in the chemo-radiosensitivity of GL261 and GL261-Ang2 cells was noticed, suggesting a paracrine effect of Ang2 on the tumor microenvironment. Accordingly, we showed that Ang2 sensitizes the tumor vasculature to CT/RT and sustains inflammatory cells in the tumor microenvironment until 3 months post-treatment.
Conclusions
These results suggest that Ang2 might influence the therapeutic response of GB by acting on angiogenesis and inflammation.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
E. Petit.
Funding
This study was funded by the Région Normandie, the Centre National de la Recherche Scientifique (CNRS), the Université de Caen Normandie (UNICAEN), the European Union-Fonds Européen de Développement Régional (FEDER), ARCHADE, HABIONOR European project, la Fédération pour la Recherche sur le Cerveau par l’opération Rotary «Espoir en tête » (FRC), EdNBise 497 - Normandie Université.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
4925 - Prognostic role of CD73 in metastatic Non Small Cell Lung Cancer according to the presence of driver alterations
Presenter: Giulia Galli
Session: Poster Display session 1
Resources:
Abstract
785 - JAK-STAT inhibitor overcomes interferon γ-reduced, NK cell-mediated cytotoxicity in non-small-cell lung cancer cells
Presenter: Riki Okita
Session: Poster Display session 1
Resources:
Abstract
2326 - Low LATS2 expression is associated with poor prognosis in non small cell lung cancer
Presenter: Si-hyong Jang
Session: Poster Display session 1
Resources:
Abstract
5960 - Application of ESCAT and OncoKB scales in Liquid biopsy (LB) in Advanced NSCLC patients (pts): Is it feasible and reliable?
Presenter: Michael McCusker
Session: Poster Display session 1
Resources:
Abstract
4855 - IDH1R132H mutation induces a less aggressive phenotype of glioma cells and affects the radiosensitivity by interacting with Wnt/β-catenin signaling
Presenter: Xuetao Han
Session: Poster Display session 1
Resources:
Abstract
5743 - The Discovery of RNA-aptamers That Selectively Bind and Inhibit Glioblastoma Stem Cells by targeting EphA2
Presenter: Alessandra Affinito
Session: Poster Display session 1
Resources:
Abstract
4160 - Impact of tumor reoxygenation by nanoparticles on Tumor Associated Macrophages (TAMs)
Presenter: Aurélie Ferré
Session: Poster Display session 1
Resources:
Abstract
2474 - Prognostic significance of c-Rel/p50 heterodimer in the tumor microenvironment of uveal melanoma
Presenter: Seema Kashyap
Session: Poster Display session 1
Resources:
Abstract
1769 - Synergistic role of BAP1 and DNA damage response pathway in uveal melanoma and its prognostic significance.
Presenter: JAYANTI JHA
Session: Poster Display session 1
Resources:
Abstract
5037 - CXCR4, CCR2 and CCR5 expression in subsets of tumor cells with stem and/or EMT features
Presenter: Olga Savelieva
Session: Poster Display session 1
Resources:
Abstract