PEST domain mutations in Notch receptors comprise an oncogenic driver segment in triple-negative breast cancer sensitive to a γ-secretase inhibitor.

Abstract

PURPOSE:

To identify and characterize novel, activating mutations in Notch receptors in breast cancer and to determine response to the gamma secretase inhibitor (GSI) PF-03084014.

EXPERIMENTAL DESIGN:

We used several computational approaches, including novel algorithms, to analyze next-generation sequencing data and related omic datasets from The Cancer Genome Atlas (TCGA) breast cancer cohort. Patient-derived xenograft (PDX) models were sequenced, and Notch-mutant models were treated with PF-03084014. Gene-expression and functional analyses were performed to study the mechanism of activation through mutation and inhibition by PF-03084014.

RESULTS:

We identified mutations within and upstream of the PEST domains of NOTCH1, NOTCH2, and NOTCH3 in the TCGA dataset. Mutations occurred via several genetic mechanisms and compromised the function of the PEST domain, a negative regulatory domain commonly mutated in other cancers. Focal amplifications of NOTCH2 and NOTCH3 were also observed, as were heterodimerization or extracellular domain mutations at lower incidence. Mutations and amplifications often activated the Notch pathway as evidenced by increased expression of canonical Notch target genes, and functional mutations were significantly enriched in the triple-negative breast cancer subtype (TNBC). PDX models were also identified that harbored PEST domain mutations, and these models were highly sensitive to PF-03084014.

CONCLUSIONS:

This work suggests that Notch-altered breast cancer constitutes a bona fide oncogenic driver segment with the most common alteration being PEST domain mutations present in multiple Notch receptors. Importantly, functional studies suggest that this newly identified class can be targeted with Notch inhibitors, including GSIs.

• Authors: Kai Wang, Qin Zhang, Danan Li, Keith Ching, Cathy Zhang, Xianxian Zheng, Mark Ozeck, Stephanie Shi, Xiaorong Li, Hui Wang, Paul Rejto, James Christensen, Peter Olson
• Journal: Clinical cancer research : an official journal of the American Association for Cancer Research (Clin Cancer Res) Vol. 21 Issue 6 Pg. 1487-96 (Mar 15 2015) ISSN: 1557-3265 [Electronic] United States
• PMID: 25564152 (Publication Type: Journal Article)
• Copyright: ©2015 American Association for Cancer Research.

Chemical References

• NOTCH1 protein, human
• NOTCH2 protein, human
• NOTCH3 protein, human
• Receptor, Notch1
• Receptor, Notch2
• Receptor, Notch3
• Receptors, Notch
• Tetrahydronaphthalenes
• Amyloid Precursor Protein Secretases
• Valine
• nirogacestat

Topics

• Algorithms
• Amyloid Precursor Protein Secretases (antagonists & inhibitors)
• Animals
• Base Sequence
• Cell Line, Tumor
• Cell Proliferation
• Computational Biology (methods)
• DNA Copy Number Variations (genetics)
• Female
• Gene Dosage (genetics)
• Humans
• Mice
• Mice, SCID
• Protein Structure, Tertiary (genetics)
• Receptor, Notch1 (genetics)
• Receptor, Notch2 (genetics)
• Receptor, Notch3
• Receptors, Notch (genetics)
• Sequence Analysis, DNA
• Signal Transduction (genetics)
• Tetrahydronaphthalenes (pharmacology)
• Triple Negative Breast Neoplasms (drug therapy, genetics)
• Valine (analogs & derivatives, pharmacology)
• Xenograft Model Antitumor Assays