In:
Clinical Cancer Research, American Association for Cancer Research (AACR), Vol. 28, No. 11 ( 2022-06-01), p. 2425-2439
Abstract:
Molecular targeted therapy using BRAF and/or MEK inhibitors has been applied to BRAFV600E-mutant high-grade gliomas (HGG); however, the therapeutic effect is limited by the emergence of drug resistance. Experimental Design: We established multiple paired BRAFV600E-mutant HGG patient-derived xenograft models based on tissues collected prior to and at relapse after molecular targeted therapy. Using these models, we dissected treatment-resistant mechanisms for molecular targeted therapy and explored therapeutic targets to overcome resistance in BRAFV600E HGG models in vitro and in vivo. Results: We found that, despite causing no major genetic and epigenetic changes, BRAF and/or MEK inhibitor treatment deregulated multiple negative feedback mechanisms, which led to the reactivation of the MAPK pathway through c-Raf and AKT signaling. This altered oncogenic signaling primarily mediated resistance to molecular targeted therapy in BRAFV600E-mutant HGG. To overcome this resistance mechanism, we performed a high-throughput drug screening to identify therapeutic agents that potently induce additive cytotoxicity with BRAF and MEK inhibitors. We discovered that HSP90 inhibition combined with BRAF/MEK inhibition coordinately deactivated the MAPK and AKT/mTOR pathways, and subsequently induced apoptosis via dephosphorylation of GSK3β (Ser9) and inhibition of Bcl-2 family proteins. This mediated potent cytotoxicity in vitro and in vivo in refractory models with acquired resistance to molecular targeted therapy. Conclusions: The combination of an HSP90 inhibitor with BRAF or MEK inhibitors can overcome the limitations of the current therapeutic strategies for BRAFV600E-mutant HGG.
Type of Medium:
Online Resource
ISSN:
1078-0432
,
1557-3265
DOI:
10.1158/1078-0432.CCR-21-3622
Language:
English
Publisher:
American Association for Cancer Research (AACR)
Publication Date:
2022
detail.hit.zdb_id:
1225457-5
detail.hit.zdb_id:
2036787-9
Permalink
