EGFR Activates a TAZ-Driven Oncogenic Program in Glioblastoma

Area of Science:

• Oncology
• Molecular Biology
• Cancer Signaling

Background:

• Hyperactivated Epidermal Growth Factor Receptor (EGFR) signaling is a known driver in human cancers, including glioblastoma (GBM).
• Understanding key signaling hubs that amplify EGFR signaling is critical for developing effective targeted therapies.
• The transcription factor TAZ is investigated as a potential signaling hub within the EGFR network.

Purpose of the Study:

• To elucidate the role of the transcription factor TAZ in EGFR signaling pathways in glioblastoma.
• To investigate the mechanism by which EGFR signaling influences TAZ activation.
• To evaluate the efficacy of EGFR inhibitors, specifically osimertinib, in targeting the EGFR-TAZ axis in GBM.

Main Methods:

• Analysis of TAZ and EGFR expression in clinical GBM specimens.
• Investigating EGF-induced TAZ activation via EGFR-ERK and EGFR-STAT3 signaling in GBM neurospheres.
• Genome-wide analysis to identify downstream targets of the EGFR-TAZ axis.
• Screening of brain-penetrating EGFR inhibitors and in vivo xenograft studies.

Main Results:

• TAZ expression positively correlates with EGFR expression in GBM.
• EGFR signaling (ERK, STAT3) and EGFRvIII mutation induce TAZ activation.
• The EGFR-TAZ axis upregulates oncogenic genes, including HIF1α, and promotes GBM stem-like cell growth, invasion, radioresistance, and tumorigenicity.
• Osimertinib potently inhibits the EGFR-TAZ signaling axis and reduces in vivo GBM xenograft growth.

Conclusions:

• TAZ is a critical mediator of EGFR signaling in glioblastoma, driving key oncogenic processes.
• The therapeutic efficacy of osimertinib in GBM is dependent on its ability to inhibit the EGFR-TAZ axis.
• TAZ serves as a potential biomarker for osimertinib sensitivity and a therapeutic target in EGFR-driven cancers.