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Breast Cancer Res Treat. 2017 Jun;163(3):475-484. doi: 10.1007/s10549-017-4216-6. Epub 2017 Mar 27.

ΔNp63 activates EGFR signaling to induce loss of adhesion in triple-negative basal-like breast cancer cells.

Author information

1
RECAMO, Masaryk Memorial Cancer Centre, Zluty kopec 7, 65633, Brno, Czech Republic.
2
Clinic of Comprehensive Cancer Care, Zluty kopec 7, 65633, Brno, Czech Republic.
3
RECAMO, Masaryk Memorial Cancer Centre, Zluty kopec 7, 65633, Brno, Czech Republic. vojtesek@mou.cz.
4
RECAMO, Masaryk Memorial Cancer Centre, Zluty kopec 7, 65633, Brno, Czech Republic. philip.coates@mou.cz.

Abstract

PURPOSE:

The basal-A subtype of triple-negative breast cancer is characterized by high levels of ΔNp63. Various functions have been proposed for p63 in breast cancer initiation and growth, and p63 mediates chemotherapeutic response in a subset of triple-negative breast cancers. We investigated the signaling pathways that are controlled by ΔNp63 in basal-A triple-negative breast cancer.

METHODS:

Human basal-A triple-negative breast cancer cell lines with ΔNp63α induction or inhibition were studied, along with primary human triple-negative breast cancer tissues. Proteomic, phospho-kinase array, mRNA measurements, and immunohistochemistry were employed.

RESULTS:

Global phosphoproteomics identified increased EGFR phosphorylation in MDA-MB-468 cells expressing ΔNp63α. ΔNp63α expression increased EGFR mRNA, total EGFR protein, and phospho-EGFR(Y1086), whereas silencing endogenous ΔNp63 in HCC1806 cells reduced both total and phospho-EGFR levels and inhibited the ability of EGF to activate EGFR. EGFR pathway gene expression analysis indicated that ΔNp63 alters EGFR-regulated genes involved in cell adhesion, migration, and angiogenesis. Addition of EGF or neutralizing EGFR antibodies demonstrated that EGFR activation is responsible for ΔNp63-mediated loss of cellular adhesion. Finally, immunohistochemical staining showed that p63-positive triple-negative breast cancers were more likely to express high levels of EGFR than p63-negative cancers, corroborated by in silico analysis of gene expression profiling data.

CONCLUSIONS:

These data identify EGFR as a major target for ΔNp63 regulation that influences cancer cell adhesion in basal-like triple-negative breast cancer.

KEYWORDS:

Adhesion; Breast cancer; EGFR; Invasion; Metastasis; p63

PMID:
28349272
DOI:
10.1007/s10549-017-4216-6
[Indexed for MEDLINE]

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