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
1267 - Genetic landscape of KEAP1 and NFE2L2 mutated cancers from the AACR GENIE database
Presenter: Mark Zaki
Session: Poster Display session 1
Resources:
Abstract
878 - β-arrestin1 is involved in the Ras-induced malignant transformation
Presenter: Takashi Shibano
Session: Poster Display session 1
Resources:
Abstract
4143 - Incidence of second cancer among PLWHIV: retrospective observational study of a series of 601 patients in the French CANCERVIH network
Presenter: Jean-Philippe Spano
Session: Poster Display session 1
Resources:
Abstract
5145 - A challenging task – Identifying carcinoma of unknown primary (CUP) patients according to ESMO guidelines: the CUPISCO trial experience
Presenter: Chantal Pauli
Session: Poster Display session 1
Resources:
Abstract
1737 - Incidence and Outcome of chronic lymphocytic leukemia with Deletion 17p: An Indian experience; challenges and opportunities
Presenter: Ajay Gogia
Session: Poster Display session 1
Resources:
Abstract
2596 - Driving solo? Investigation into collaborating mutations in SDH-deficient neoplasia
Presenter: Jonathan Killian
Session: Poster Display session 1
Resources:
Abstract
1499 - The potential of a novel antiangiogenic VEGFR1-D2 binding peptide in oncology therapeutics
Presenter: Afsaneh Sadre Momtaz
Session: Poster Display session 1
Resources:
Abstract
1775 - First-in-human phase I study of TAS-117, an allosteric AKT inhibitor, in patients with advanced solid tumors
Presenter: Mayu Yunokawa
Session: Poster Display session 1
Resources:
Abstract
4584 - First-in-human study of ABBV-621 in patients (pts) with previously treated sold tumors: Dose-optimization cohorts
Presenter: Emiliano Calvo
Session: Poster Display session 1
Resources:
Abstract
3620 - Safety, efficacy, PK and PD biomarker results of the first-in-human study of mutant isocitrate dehydrogenase 1 (mIDH1) inhibitor BAY 1436032 in patients (pts) with mIDH1 advanced solid tumours
Presenter: Wolfgang Wick
Session: Poster Display session 1
Resources:
Abstract