Research Mentor Name

Ana C. deCarvalho

Research Mentor Email Address

adecarv1@hfhs.org

Institution / Department

Henry Ford Health Neurosurgery Department

Document Type

Research Abstract

Research Type

other

Other Type of Research

Translational Research

Graduate Level Research

no

Abstract

Background: Avapritinib, a selective inhibitor of mutated class III receptor tyrosine kinases (RTKs), shows promise in PDGFRA-altered pediatric glioma. We studied its efficacy in a glioblastoma (GBM) model (HF3253) containing two PDGFRA alterations: constitutive activation via an indel mutation and extrachromosomal DNA (ecDNA) amplification. We hypothesized that Avapritinib would preferentially improve survival in PDGFRA-amplified tumors.

Methods: Orthotopic xenografts derived from HF3253 PDGFRA ecDNA(+) (n=19) and ecDNA(-) (n=10) cells were treated with 40 mg/kg Avapritinib (5 days/week). To validate the role of PDGFRA expression, wild-type PDGFRA was overexpressed in ecDNA(-) cells, generating high PDGFRA levels with minimal ligand-independent activation in vivo. Bulk RNA sequencing was performed on ecDNA(-) and ecDNA(-) xenografts (n=6/group). Using FDR=0.05 and log2FC≥1.5, we identified 1,048 differentially expressed genes.

Results: Avapritinib significantly improved symptom-free survival in PDGFRA ecDNA(+) tumors (p< 0.0001) but had no improvement in ecDNA(-) tumors (p=0.93). Terminal tumor analyses showed no significant differences in PDGFRA expression or phosphorylation (Y754) after treatment. Overexpression of PDGFRA in ecDNA(-) tumors partially rescued their typically slower growth. RNA-seq revealed upregulation of tyrosine kinase adaptors (SHC1, HCK, SYK) and VEGFC/KDR and EFNA4/EPHA3 ligand-RTK pairs in PDGFRA-expressing tumors, suggesting non-canonical RTK crosstalk capable of transactivating PDGFRA and contributing to accelerated growth.

Conclusion: PDGFRA overexpression via ecDNA amplification or ectopic expression drives aggressive GBM growth and represents a promising therapeutic target for Avapritinib. Additionally, PDGFRA activity in GBM may be amplified through non-canonical interactions with other RTKs.

Disciplines

Medicine and Health Sciences

Comments

Thank you to my research mentor, Artem Berezovsky, for his knowledge and support. This work was funded by Demchik Fund for Avatar Models, Department of Defense grant CA180174 to A.C.D

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