A Functional Landscape of Resistance to MEK1/2 and CDK4/6 Inhibition in NRAS-Mutant Melanoma.

Cancer Res
Authors
Keywords
Abstract

Combinatorial inhibition of MEK1/2 and CDK4/6 is currently undergoing clinical investigation in NRAS-mutant melanoma. To prospectively map the landscape of resistance to this investigational regimen, we utilized a series of gain- and loss-of-function forward genetic screens to identify modulators of resistance to clinical inhibitors of MEK1/2 and CDK4/6 alone and in combination. First, we identified NRAS-mutant melanoma cell lines that were dependent on NRAS for proliferation and sensitive to MEK1/2 and CDK4/6 combination treatment. We then used a genome-scale ORF overexpression screen and a CRISPR knockout screen to identify modulators of resistance to each inhibitor alone or in combination. These orthogonal screening approaches revealed concordant means of achieving resistance to this therapeutic modality, including tyrosine kinases, RAF, RAS, AKT, and PI3K signaling. Activated KRAS was sufficient to cause resistance to combined MEK/CDK inhibition and to replace genetic depletion of oncogenic NRAS. In summary, our comprehensive functional genetic screening approach revealed modulation of resistance to the inhibition of MEK1/2, CDK4/6, or their combination in NRAS-mutant melanoma. SIGNIFICANCE: These findings reveal that NRAS-mutant melanomas can acquire resistance to genetic ablation of or combination MEK1/2 and CDK4/6 inhibition by upregulating activity of the RTK-RAS-RAF and RTK-PI3K-AKT signaling cascade.

Year of Publication
2019
Journal
Cancer Res
Volume
79
Issue
9
Pages
2352-2366
Date Published
2019 05 01
ISSN
1538-7445
DOI
10.1158/0008-5472.CAN-18-2711
PubMed ID
30819666
PubMed Central ID
PMC7227487
Links
Grant list
R35 CA197568 / CA / NCI NIH HHS / United States
R35 CA197737 / CA / NCI NIH HHS / United States