Evidence for Phenotypic Plasticity in Aggressive Triple-Negative Breast Cancer: Human Biology Is Recapitulated by a Novel Model System

Abstract

Breast cancers with a basal-like gene signature are primarily triple-negative, frequently metastatic, and carry a poor prognosis. Basal-like breast cancers are enriched for markers of breast cancer stem cells as well as markers of epithelial-mesenchymal transition (EMT). While EMT is generally thought to be important in the process of metastasis, in vivo evidence of EMT in human disease remains rare. Here we report a novel model of human triple-negative breast cancer, the DKAT cell line, which was isolated from an aggressive, treatment-resistant triple-negative breast cancer that demonstrated morphological and biochemical evidence suggestive of phenotypic plasticity in the patient. The DKAT cell line displays a basal-like phenotype in vitro when cultured in serum-free media, and undergoes phenotypic changes consistent with EMT/MET in response to serum-containing media, a unique property among the breast cancer cell lines we tested. This EMT is marked by increased expression of the transcription factor Zeb1, and Zeb1 is required for the enhanced migratory ability of DKAT cells in the mesenchymal state. DKAT cells also express progenitor-cell markers, and single DKAT cells are able to generate tumorspheres containing both epithelial and mesenchymal cell types. In vivo, as few as ten DKAT cells are capable of forming xenograft tumors which display a range of epithelial and mesenchymal phenotypes. The DKAT model provides a novel model to study the molecular mechanisms regulating phenotypic plasticity and the aggressive biology of triple-negative breast cancers.

c-Jun N-terminal kinase promotes stem cell phenotype in triple-negative breast cancer through upregulation of Notch1 via activation of c-Jun

“…A human stem cell RT 2 Profiler PCR array (Qiagen Inc., Valencia, CA, USA) was used to evaluate the expression of 84 specific genes. Cells were treated with JNK-IN-8 (2.5 μM) for 48 h, and then total RNA was extracted from the cells using the miRNeasy mini kit (Qiagen Inc.) according to the manufacturer’s instructions.…”

“…Compared to other types of breast cancer, TNBC is more aggressive and has a worse prognosis because of its tendency to metastasize and recur 1 . The major cause of death of patients with TNBC is recurrence (30–40% of cases), which might be due to the cancer stem-like cell (CSC) phenotype of TNBC cells 2, 3 . CSCs, a subpopulation of cancer cells, possess the capacity to self-renew and give rise to heterogeneous lineages that make up a tumor 4, 5 .…”

FAS Death Receptor: A Breast Cancer Subtype-Specific Radiation Response Biomarker and Potential Therapeutic Target

“…Cell lines were obtained from the American Type Culture Collection (ATCC®, Gaithersburg, MD) with the exception of DKAT, ZR751, MCF10A and the SUM lines, which were a gift from Drs. Victoria Seewaldt and Gayathri Devi (15, 16). For full details of culture conditions, please see the Supplementary Information (http://dx.doi.org/10.1667/RR14089.1.S1).…”

Comprehensive Functional Annotation of Seventy-One Breast Cancer Risk Loci

“…We compared gene expression levels between HMEC and MDAMB231 cells by using the affymetrix HG-U133 plus2 microarrays obtained from the accession number [GSE33167] [93]. RAD51L1 gene expression values for both cells were processed and its bar plots were graphed by using the GEO2R [94] (Fig.…”

“…RAD51L1 gene expression value for HMEC and MDAMB231 were obtained from accession number [GSE33167]. Three replicates for each cell type were generated by using the affymetrix HG-U133 plus2 arrays [93]. Expression bar plots were graphed by using the GEO2R [94] …”