In Vitro Assessment of the Inflammatory Breast Cancer Cell Line SUM 149: Discovery of 2 Single Nucleotide Polymorphisms in the RNase L Gene

In vitro vascularized tumor platform for modeling tumor-vasculature interactions of inflammatory breast cancer

Inflammatory breast cancer (IBC), a rare form of breast cancer associated with increased angiogenesis and metastasis, is largely driven by tumor-stromal interactions with the vasculature and the extracellular matrix (ECM). However, there is currently a lack of understanding of the role these interactions play in initiation and progression of the disease. In this study, we developed the first three-dimensional, in vitro, vascularized, microfluidic IBC platform to quantify the spatial and temporal dynamics of tumor-vasculature and tumor-ECM interactions specific to IBC. Platforms consisting of collagen type 1 ECM with an endothelialized blood vessel were cultured with IBC cells, MDA-IBC3 (HER2+) or SUM149 (triple negative), and for comparison to non-IBC cells, MDA-MB-231 (triple negative). Acellular collagen platforms with endothelialized blood vessels served as controls. SUM149 and MDA-MB-231 platforms exhibited a significantly (p < .05) higher vessel permeability and decreased endothelial coverage of the vessel lumen compared to the control. Both IBC platforms, MDA-IBC3 and SUM149, expressed higher levels of vascular endothelial growth factor (p < .05) and increased collagen ECM porosity compared to non-IBCMDA-MB-231 (p < .05) and control (p < .01) platforms. Additionally, unique to the MDA-IBC3 platform, we observed progressive sprouting of the endothelium over time resulting in viable vessels with lumen. The newly sprouted vessels encircled clusters of MDA-IBC3 cells replicating a key feature of in vivo IBC. The IBC in vitro vascularized platforms introduced in this study model well-described in vivo and clinical IBC phenotypes and provide an adaptable, high throughput tool for systematically and quantitatively investigating tumor-stromal mechanisms and dynamics of tumor progression.

Inflammatory breast cancer biology: the tumour microenvironment is key

Inflammatory breast cancer (IBC) is a rare and aggressive disease that accounts for ~2-4% of all breast cancers. However, despite its low incidence rate, IBC is responsible for 7-10% of breast cancer-related mortality in Western countries. Thus, the discovery of robust biological targets and the development of more effective therapeutics in IBC are crucial. Despite major international efforts to understand IBC biology, genomic studies have not led to the discovery of distinct biological mechanisms in IBC that can be translated into novel therapeutic strategies. In this Review, we discuss these molecular profiling efforts and highlight other important aspects of IBC biology. We present the intrinsic characteristics of IBC, including stemness, metastatic potential and hormone receptor positivity; the extrinsic features of the IBC tumour microenvironment (TME), including various constituent cell types; and lastly, the communication between these intrinsic and extrinsic components. We summarize the latest perspectives on the key biological features of IBC, with particular emphasis on the TME as an important contributor to the aggressive nature of IBC. On the basis of the current understanding of IBC, we hope to develop the next generation of translational studies, which will lead to much-needed survival improvements in patients with this deadly disease.

Breast cancer in Morocco: a literature review

In Morocco, breast cancer is the most prevalent cancer in women and a major public health problem. Several Moroccan studies have focused on studying this disease, but more are needed, especially at the genetic and molecular levels. It is therefore interesting to establish the genetic and molecular profile of Moroccan patients with breast cancer. In this paper, we will highlight some pertinent hypotheses that may enhance breast cancer care in Moroccan patients. This review will give a precise description of breast cancer in Morocco and propose some new markers for detection and prediction of breast cancer prognosis.

Novel role of Engrailed 1 as a prosurvival transcription factor in basal-like breast cancer and engineering of interference peptides block its oncogenic function

Basal-like breast tumors are aggressive cancers associated with high proliferation and metastasis. Chemotherapy is currently the only treatment option; however, resistance often occurs resulting in recurrence and patient death. Some extremely aggressive cancers are also associated with hypoxia, inflammation and high leukocyte infiltration. Herein, we discovered that the neural-specific transcription factor, Engrailed 1 (EN1), is exclusively overexpressed in these tumors. Short hairpin RNA (shRNA)-mediated knockdown of EN1 triggered potent and selective cell death. In contrast, ectopic overexpression of EN1 in normal cells activated survival pathways and conferred resistance to chemotherapeutic agents. Exogenous expression of EN1 cDNA reprogrammed the breast epithelial cells toward a long-lived, neural-like phenotype displaying dopaminergic markers. Gene expression microarrays demonstrated that the EN1 cDNA altered transcription of a high number of inflammatory molecules, notably chemokines and chemokine receptors, which could mediate prosurvival pathways. To block EN1 function, we engineered synthetic interference peptides (iPeps) comprising the EN1-specific sequences that mediate essential protein-protein interactions necessary for EN1 function and an N-terminal cell-penetrating peptide/nuclear localization sequence. These EN1-iPeps rapidly mediated a strong apoptotic response in tumor cells overexpressing EN1, with no toxicity to normal or non EN1-expressing cells. Delivery of EN1-iPeps into basal-like cancer cells significantly decreased the fifty percent inhibitory concentrations (IC50) of chemotherapeutic drugs routinely used to treat breast cancer. Lastly, matrix-assisted laser desorption/ionization-time of flight mass spectrometry and immunoprecipitation assays demonstrated that EN1-iPeps captured targets involved in transcriptional and post-transcriptional regulation. Importantly, the EN1-iPeps bound the glutamyl-prolyl tRNA synthetase (EPRS) target, which has been associated with the transcript-specific translational control of inflammatory proteins and activation of amino-acid stress pathways. This work unveils EN1 as an activator of intrinsic inflammatory pathways associated with prosurvival in basal-like breast cancer. We further build upon these results and describe the engineering of iPeps targeting EN1 (EN1-iPeps) as a novel and selective therapeutic strategy to combat these lethal forms of breast cancer.

Distinct splice variants and pathway enrichment in the cell-line models of aggressive human breast cancer subtypes

This study was conducted as a part of the Chromosome-Centric Human Proteome Project (C-HPP) of the Human Proteome Organization. The United States team of C-HPP is focused on characterizing the protein-coding genes in chromosome 17. Despite its small size, chromosome 17 is rich in protein-coding genes; it contains many cancer-associated genes, including BRCA1, ERBB2, (Her2/neu), and TP53. The goal of this study was to examine the splice variants expressed in three ERBB2 expressed breast cancer cell-line models of hormone-receptor-negative breast cancers by integrating RNA-Seq and proteomic mass spectrometry data. The cell lines represent distinct phenotypic variations subtype: SKBR3 (ERBB2+ (overexpression)/ER-/PR-; adenocarcinoma), SUM190 (ERBB2+ (overexpression)/ER-/PR-; inflammatory breast cancer), and SUM149 (ERBB2 (low expression) ER-/PR-; inflammatory breast cancer). We identified more than one splice variant for 1167 genes expressed in at least one of the three cancer cell lines. We found multiple variants of genes that are in the signaling pathways downstream of ERBB2 along with variants specific to one cancer cell line compared with the other two cancer cell lines and with normal mammary cells. The overall transcript profiles based on read counts indicated more similarities between SKBR3 and SUM190. The top-ranking Gene Ontology and BioCarta pathways for the cell-line specific variants pointed to distinct key mechanisms including: amino sugar metabolism, caspase activity, and endocytosis in SKBR3; different aspects of metabolism, especially of lipids in SUM190; cell-to-cell adhesion, integrin, and ERK1/ERK2 signaling; and translational control in SUM149. The analyses indicated an enrichment in the electron transport chain processes in the ERBB2 overexpressed cell line models and an association of nucleotide binding, RNA splicing, and translation processes with the IBC models, SUM190 and SUM149. Detailed experimental studies on the distinct variants identified from each of these three breast cancer cell line models that may open opportunities for drug target discovery and help unveil their specific roles in cancer progression and metastasis.