High Atlastin 2-2 (ATL2-2) Expression Associates with Worse Prognosis in Estrogen-Receptor-Positive Breast Cancer.

The disruption of endoplasmic reticulum (ER) homeostasis occurs in many human diseases. Atlastins (ATLs) maintain the branched network of the ER. The dysregulation of ATL2, located at ER network junctions, has been associated with cancer.

Cellular Plasticity and Heterotypic Interactions during Breast Morphogenesis and Cancer Initiation.

The human breast gland is a unique organ as most of its development occurs postnatally between menarche and menopause, a period ranging from 30 to 40 years. During this period, the monthly menstruation cycle drives the mammary gland through phases of cell proliferation, differentiation, and apoptosis, facilitated via a closely choreographed interaction between the epithelial cells and the surrounding stroma preparing the gland for pregnancy. If pregnancy occurs, maximal differentiation is reached to prepare for lactation.

Application of 3D Culture Assays to Study Breast Morphogenesis, Epithelial Plasticity, and Cellular Interactions in an Epithelial Progenitor Cell Line.

Capturing breast morphogenesis and cancer progression in 3D culture using cell lines with stem cell properties can greatly increase understanding of the underlying mechanisms involved in these processes, highlighting the importance of the culture method. D492 is a breast epithelial progenitor cell line that provides a model for branching morphogenesis when cultured in 3D reconstituted basement membrane matrix (rBM). Along with its derivate cell lines D492M and D492HER2, D492 also serves as a robust model for epithelial to mesenchymal transition (EMT) and tumorigenicity, respectively.

An Organotypic Assay to Study Epithelial-Fibroblast Interactions in Human Breast.

Epithelial-stromal interactions play an essential role in regulation of mammary gland development, homeostasis, and tumorigenesis. Fibroblasts constitute a substantial proportion of mammary gland stromal cells in human breast and have been recognized for their paracrine signaling and extracellular matrix production and remodeling roles during normal breast development as well as in breast cancer. However, our current knowledge on human breast fibroblast functions is incomplete.

Peroxidasin Enhances Basal Phenotype and Inhibits Branching Morphogenesis in Breast Epithelial Progenitor Cell Line D492.

The human breast is composed of terminal duct lobular units (TDLUs) that are surrounded by stroma. In the TDLUs, basement membrane separates the stroma from the epithelial compartment, which is divided into an inner layer of luminal epithelial cells and an outer layer of myoepithelial cells. Stem cells and progenitor cells also reside within the epithelium and drive a continuous cycle of gland remodelling that occurs throughout the reproductive period.

The Wittig bioconjugation of maleimide derived, water soluble phosphonium ylides to aldehyde-tagged proteins.

Herein we disclose the transformation of maleimides into water-soluble tris(2-carboxyethyl)phosphonium ylides and their subsequent application in the bioconjugation of protein- and peptide-linked aldehydes. The new entry into Wittig bioconjugate chemistry proceeds under mild conditions and relies on highly water soluble reagents, which are likely already part of most biochemists' inventory.

Twelfth Annual ENBDC Workshop: Methods in Mammary Gland Biology and Breast Cancer.

The twelfth annual workshop of the European Network for Breast Development and Cancer focused on methods in mammary gland biology and breast cancer, was scheduled to take place on March 26-28, 2020, in Weggis, Switzerland. Due to the COVID-19 pandemic, the meeting was rescheduled twice and eventually happened as a virtual meeting on April 22 and 23, 2021. The main topics of the meeting were branching and development of the mammary gland, tumor microenvironment, circulating tumor cells, tumor dormancy and breast cancer metastasis.

Unraveling the Breast: Advances in Mammary Biology and Cancer Methods.

The field of mammary gland biology and breast cancer research encompasses a wide range of topics and scientific questions, which span domains of molecular, cell and developmental biology, cancer research, and veterinary and human medicine, with interdisciplinary overlaps to non-biological domains. Accordingly, mammary gland and breast cancer researchers employ a wide range of molecular biology methods, in vitro techniques, in vivo approaches as well as in silico analyses. The list of techniques is ever-expanding; together with the refinement of established, staple techniques in the field, new technologies keep emerging thanks to technological advances and scientific creativity.

Mammary Organoids and 3D Cell Cultures: Old Dogs with New Tricks.

3D cell culture methods have been an integral part of and an essential tool for mammary gland and breast cancer research for half a century. In fact, mammary gland researchers, who discovered and deciphered the instructive role of extracellular matrix (ECM) in mammary epithelial cell functional differentiation and morphogenesis, were the pioneers of the 3D cell culture techniques, including organoid cultures. The last decade has brought a tremendous increase in the 3D cell culture techniques, including modifications and innovations of the existing techniques, novel biomaterials and matrices, new technological approaches, and increase in 3D culture complexity, accompanied by several redefinitions of the terms "3D cell culture" and "organoid".

Melflufen, a peptide-conjugated alkylator, is an efficient anti-neo-plastic drug in breast cancer cell lines.

Melphalan flufenamide (hereinafter referred to as "melflufen") is a peptide-conjugated drug currently in phase 3 trials for the treatment of relapsed or refractory multiple myeloma. Due to its lipophilic nature, it readily enters cells, where it is converted to the known alkylator melphalan leading to enrichment of hydrophilic alkylator payloads. Here, we have analysed in vitro and in vivo the efficacy of melflufen on normal and cancerous breast epithelial lines.

Expression of ncRNAs on the DLK1-DIO3 Locus Is Associated With Basal and Mesenchymal Phenotype in Breast Epithelial Progenitor Cells.

Epithelial-to-mesenchymal transition (EMT) and its reversed process mesenchymal-to-epithelial transition (MET) play a critical role in epithelial plasticity during development and cancer progression. Among important regulators of these cellular processes are non-coding RNAs (ncRNAs). The imprinted DLK1-DIO3 locus, containing numerous maternally expressed ncRNAs including the lncRNA maternally expressed gene 3 () and a cluster of over 50 miRNAs, has been shown to be a modulator of stemness in embryonic stem cells and in cancer progression, potentially through the tumor suppressor role of .

The BLIMP1-EZH2 nexus in a non-Hodgkin lymphoma.

Waldenström's macroglobulinemia (WM) is a non-Hodgkin lymphoma, resulting in antibody-secreting lymphoplasmacytic cells in the bone marrow and pathologies resulting from high levels of monoclonal immunoglobulin M (IgM) in the blood. Despite the key role for BLIMP1 in plasma cell maturation and antibody secretion, its potential effect on WM cell biology has not yet been explored. Here we provide evidence of a crucial role for BLIMP1 in the survival of cells from WM cell line models and further demonstrate that BLIMP1 is necessary for the expression of the histone methyltransferase EZH2 in both WM and multiple myeloma cell lines.

ECM1 secreted by HER2-overexpressing breast cancer cells promotes formation of a vascular niche accelerating cancer cell migration and invasion.

The tumor microenvironment is increasingly recognized as key player in cancer progression. Investigating heterotypic interactions between cancer cells and their microenvironment is important for understanding how specific cell types support cancer. Forming the vasculature, endothelial cells (ECs) are a prominent cell type in the microenvironment of both normal and neoplastic breast gland.

YKL-40/CHI3L1 facilitates migration and invasion in HER2 overexpressing breast epithelial progenitor cells and generates a niche for capillary-like network formation.

Epithelial to mesenchymal transition (EMT) is a developmental event that is hijacked in some diseases such as fibrosis and cancer. In cancer, EMT has been linked to increased invasion and metastasis and is generally associated with a poor prognosis. In this study, we have compared phenotypic and functional differences between two isogenic cell lines with an EMT profile: D492M and D492HER2 that are both derived from D492, a breast epithelial cell line with stem cell properties.

The imprinted gene Delta like non-canonical Notch ligand 1 (Dlk1) is conserved in mammals, and serves a growth modulatory role during tissue development and regeneration through Notch dependent and independent mechanisms.

Delta like non-canonical Notch ligand 1 (Dlk1) is an imprinted gene, mainly known for its involvement in adipogenesis, although it has been associated with many other stem cells/progenitors and is known to be widely expressed during organism development and tissue regeneration. In a systematic manner, we have outlined the overall expression pattern of Dlk1 in both man and mouse, and found Dlk1 to be expressed in tissues from all three germ layers. Yet, Dlk1 expression decreases along with increased differentiation as gestation proceeds and in most tissues Dlk1 is absent around birth.

Application of the D492 Cell Lines to Explore Breast Morphogenesis, EMT and Cancer Progression in 3D Culture.

The human female breast gland is composed of branching epithelial ducts that extend from the nipple towards the terminal duct lobular units (TDLUs), which are the functional, milk-producing units of the gland and the site of origin of most breast cancers. The epithelium of ducts and TDLUs is composed of an inner layer of polarized luminal epithelial cells and an outer layer of contractile myoepithelial cells, separated from the vascular-rich stroma by a basement membrane. The luminal- and myoepithelial cells share an origin and in recent years, there has been increasing understanding of how these cell types interact and how they contribute to breast cancer.

MiR-203a is differentially expressed during branching morphogenesis and EMT in breast progenitor cells and is a repressor of peroxidasin.

MicroRNAs regulate developmental events such as branching morphogenesis, epithelial to mesenchymal transition (EMT) and its reverse process mesenchymal to epithelial transition (MET). In this study, we performed small RNA sequencing of a breast epithelial progenitor cell line (D492), and its mesenchymal derivative (D492M) cultured in three-dimensional microenvironment. Among the most downregulated miRNAs in D492M was miR-203a, a miRNA that plays an important role in epithelial differentiation.

The non-canonical NOTCH1 ligand Delta-like 1 homolog (DLK1) self interacts in mammals.

Delta-like 1 homolog (DLK1) is an imprinted gene, which is widely expressed during mammalian development and plays a pivotal role in differentiation of various tissue types. Most recently, we have shown that DLK1 interacts with NOTCH1, yet several Notch independent mechanisms have previously been suggested as well, but only poorly confirmed in a mammalian context. In the present study, we employed the mammalian two-hybrid (MTH) system, a genetic in vivo protein-protein interaction system, to show robust DLK1-DLK1, DLK1-FnI (Fibronectin) and DLK1-CFR (cysteine-rich FGF receptor) interactions, whereas the proposed DLK1-IGFBP1 interaction was not supported by MTH.

Neonatal epicardial-derived progenitors aquire myogenic traits in skeletal muscle, but not cardiac muscle.

Background/objectives: Epicardium-derived progenitor cells (EPDCs) differentiate into all heart cell types in the embryonic heart, yet their differentiation into cardiomyocytes in the adult heart is limited and poorly described. This may be due to EPDCs lacking myogenic potential or the inert adult heart missing regenerative signals essential for directed differentiation of EPDCs. Herein, we aimed to evaluate the myogenic potential of neonatal EPDCs in adult and neonatal mouse myocardium, as well as in skeletal muscle.

Evidence of non-canonical NOTCH signaling: Delta-like 1 homolog (DLK1) directly interacts with the NOTCH1 receptor in mammals.

Canonical NOTCH signaling, known to be essential for tissue development, requires the Delta-Serrate-LAG2 (DSL) domain for NOTCH to interact with its ligand. However, despite lacking DSL, Delta-like 1 homolog (DLK1), a protein that plays a significant role in mammalian development, has been suggested to interact with NOTCH1 and act as an antagonist. This non-canonical interaction is, however controversial, and evidence for a direct interaction, still lacking in mammals.

Preadipocytes proliferate and differentiate under the guidance of Delta-like 1 homolog (DLK1).

Obesity occurs when an excessive dietary fat intake leads to expansion of adipose tissue, which mainly consists of adipocytes that arise from proliferating and differentiating adipose stem cells, the preadipocytes. Obesity is a consequence of both adipocyte hypertrophy and hyperplasia. Knowledge about preadipocyte differentiation is relatively well established, whereas the mechanism responsible for preadipocyte proliferation is incompletely understood and only in the early stage of comprehension.

DLK1 is a novel regulator of bone mass that mediates estrogen deficiency-induced bone loss in mice.

Delta-like 1/fetal antigen 1 (DLK1/FA-1) is a transmembrane protein belonging to the Notch/Delta family that acts as a membrane-associated or a soluble protein to regulate regeneration of a number of adult tissues. Here we examined the role of DLK1/FA-1 in bone biology using osteoblast-specific Dlk1-overexpressing mice (Col1-Dlk1). Col1-Dlk1 mice displayed growth retardation and significantly reduced total body weight and bone mineral density (BMD).

dlk1/FA1 regulates the function of human bone marrow mesenchymal stem cells by modulating gene expression of pro-inflammatory cytokines and immune response-related factors.

dlk1/FA1 (delta-like 1/fetal antigen-1) is a member of the epidermal growth factor-like homeotic protein family whose expression is known to modulate the differentiation signals of mesenchymal and hematopoietic stem cells in bone marrow. We have demonstrated previously that Dlk1 can maintain the human bone marrow mesenchymal stem cells (hMSC) in an undifferentiated state. To identify the molecular mechanisms underlying these effects, we compared the basal gene expression pattern in Dlk1-overexpressing hMSC cells (hMSC-dlk1) versus control hMSC (negative for Dlk1 expression) by using Affymetrix HG-U133A microarrays.