scholarly journals The Numb/p53 circuitry couples replicative self-renewal and tumor suppression in mammary epithelial cells

2015 ◽  
Vol 211 (4) ◽  
pp. 845-862 ◽  
Author(s):  
Daniela Tosoni ◽  
Silvia Zecchini ◽  
Marco Coazzoli ◽  
Ivan Colaluca ◽  
Giovanni Mazzarol ◽  
...  

The cell fate determinant Numb orchestrates tissue morphogenesis and patterning in developmental systems. In the human mammary gland, Numb is a tumor suppressor and regulates p53 levels. However, whether this function is linked to its role in fate determination remains unclear. Here, by exploiting an ex vivo system, we show that at mitosis of purified mammary stem cells (SCs), Numb ensures the asymmetric outcome of self-renewing divisions by partitioning into the progeny that retains the SC identity, where it sustains high p53 activity. Numb also controls progenitor maturation. At this level, Numb loss associates with the epithelial-to-mesenchymal transition and results in differentiation defects and reacquisition of stemness features. The mammary gland of Numb-knockout mice displays an expansion of the SC compartment, associated with morphological alterations and tumorigenicity in orthotopic transplants. This is because of low p53 levels and can be inhibited by restoration of Numb levels or p53 activity, which results in successful SC-targeted treatment.

Author(s):  
Deborah P. Lavin ◽  
Leila Abassi ◽  
Mohammed Inayatullah ◽  
Vijay K. Tiwari

The multi-step process of epithelial to mesenchymal transition (EMT), whereby static epithelial cells become migratory mesenchymal cells, plays a critical role during various developmental contexts, wound healing, and pathological conditions such as cancer metastasis. Despite the established function of basic helix-loop-helix (bHLH) transcription factors (TFs) in cell-fate determination, only a few have been examined for their role in EMT. Here, using transcriptome analysis of distinct stages during stepwise progression of TGFβ-induced EMT in mammary epithelial cells, we revealed distinct categories of bHLH TFs that show differential expression kinetics during EMT. Using a siRNA-mediated functional screen for bHLH TFs during EMT, we found Max network transcription repressor (MNT) to be essential for EMT in mammary epithelial cells. We show that the depletion of MNT blocks TGFβ-induced morphological changes during EMT, and this is accompanied by de-repression of a large number of epithelial genes. We show that MNT mediates the repression of epithelial identity genes during EMT by recruiting HDAC1 and mediating the loss of H3K27ac and chromatin accessibility. Lastly, we show that MNT is expressed at higher levels in EMT-High breast cancer cells and is required for their migration. Taken together, these findings establish MNT as a critical regulator of cell-fate changes during mammary EMT.


2019 ◽  
Vol 40 (10) ◽  
pp. 1179-1190 ◽  
Author(s):  
Anindita Chakrabarty ◽  
Sreeraj Surendran ◽  
Neil E Bhola ◽  
Vishnu S Mishra ◽  
Tasaduq Hussain Wani ◽  
...  

Abstract In pre-clinical models, co-existence of Human Epidermal Growth Factor Receptor-2 (HER2)-amplification and PI3K catalytic subunit (PIK3CA) mutations results in aggressive, anti-HER2 therapy-resistant breast tumors. This is not always reflected in clinical setting. We speculated that the complex interaction between the HER2 and PIK3CA oncogenes is responsible for such inconsistency. We performed series of biochemical, molecular and cellular assays on genetically engineered isogenic mammary epithelial cell lines and breast cancer cells expressing both oncogenes. In vitro observations were validated in xenografts models. We showed that H1047R, one of the most common PIK3CA mutations, is responsible for endowing a senescence-like state in mammary epithelial cells overexpressing HER2. Instead of imposing a permanent growth arrest characteristic of oncogene-induced senescence, the proteome secreted by the mutant cells promotes stem cell enrichment, angiogenesis, epithelial-to-mesenchymal transition, altered immune surveillance and acute vulnerability toward HSP90 inhibition. We inferred that the pleiotropism, as observed here, conferred by the mutated oncogene, depending on the host microenvironment, contributes to conflicting pre-clinical and clinical characteristics of HER2+, mutated PIK3CA-bearing tumor cells. We also came up with a plausible model for evolution of breast tumors from mammary epithelial cells harboring these two molecular lesions.


2017 ◽  
Vol 118 (9) ◽  
pp. 2983-2992 ◽  
Author(s):  
Alejandra Ordoñez-Moreno ◽  
Cecilia Rodriguez-Monterrosas ◽  
Pedro Cortes-Reynosa ◽  
Julio Isael Perez-Carreon ◽  
Eduardo Perez Salazar

2021 ◽  
Author(s):  
Indranil Paul ◽  
Dante Bolzan ◽  
Heather Hook ◽  
Ahmed Youssef ◽  
Gopal Karemore ◽  
...  

TGFβ mediated epithelial to mesenchymal transition (EMT) proceeds through hybrid "E/M" states. A deeper understanding of these states and events which regulate entry to and exit from the E/M states is needed for therapeutic exploitation. We quantified >60,000 molecules across ten time points and twelve omic layers in mammary epithelial cells. Proteomes of whole cells, phosphoproteins, nucleus, extracellular vesicles, secretome and membrane resolved major shifts, E→E/M and E/M→M during EMT, and defined state-specific signatures. Metabolomics identified early activation of arachidonic acid pathway and an enzyme-mediated switch from Cytochrome P450 to Cyclooxygenase / Lipoxygenase branches during E→E/M. Single-cell transcriptomics identified GLIS2 as an early modulator of EMT. Integrative modeling-predicted combinatorial inhibition of AURKB, PP2A and SRC exposed vulnerabilities at E→E/M juncture. Covariance analysis revealed remarkable discordance between proteins and transcripts, and between proteomic layers, implying insufficiency of current approaches. Overall, this dataset provides an unprecedented resource on TGFβ signaling, EMT and cancer.


2020 ◽  
Author(s):  
Mallory Genest ◽  
Franck Comunale ◽  
Damien Planchon ◽  
Pauline Govindin ◽  
Sophie Vacher ◽  
...  

AbstractAltered endocytosis and vesicular trafficking are major players during tumorigenesis. Flotillin overexpression, a feature observed in many invasive tumors, and identified as a marker of poor prognosis, induces a deregulated endocytic and trafficking pathway called Upregulated Flotillin-Induced Trafficking (UFIT). Here, we found that, in non tumoral mammary epithelial cells, induction of the UFIT pathway promotes epithelial-to-mesenchymal transition (EMT) and accelerates the endocytosis of several transmembrane receptors, including AXL, in flotillin-positive late endosomes. AXL overexpression, frequently observed in cancer cells, is linked to EMT and metastasis formation. In flotillin-overexpressing non-tumoral mammary epithelial cells and in invasive breast carcinoma cells, we found that the UFIT-mediated AXL endocytosis allows its stabilization and depends on sphingosine-kinase 2, a lipid kinase recruited in flotillin-rich plasma membrane-domains and endosomes.Thus, the deregulation of vesicular trafficking following flotillin upregulation, and through sphingosine kinase 2, emerges as a new mechanism of AXL overexpression and EMT-inducing signaling pathway activation.


Author(s):  
Victor K. Lin ◽  
Shih-Ya Wang ◽  
Lanxiao Wu ◽  
Smitha M. Rao ◽  
J. C. Chiao ◽  
...  

Epithelial to mesenchymal transition (EMT) has been believed to play a critical role in cancer metastasis. TGFβ has been described as an inducer of EMT in normal mammary epithelial cells by signaling through receptor serine/threonine kinase pathways to regulate epithelial cell plasticity and invasion. In this study, we investigated the EMT cellular responses, including morphologic changes, phenotype switches, invasiveness enhancement, and cellular contraction alteration, in TGFβ stimulated human prostate normal epithelial cells (PZ-HPV-7). Migration of TGFβ treated PZ-HPV-7 cells across matrigel was measured in invasion chambers (8 μm pore size). The cells were treated with or without TGFβ (2 ng/ml) in PrEGM media for 3 days. Immunoblot assay was conducted and it was demonstrated that the induction of vimentin when stimulated by TGFβ was accompanied by a downregulation of E-cadherin, though p-cadherin level was not altered. It was also observed that there was a decrease in cytokaretin 5/6 expression associated with the downregulation of E-cadherin during the induction of EMT. In order to study the cell contraction, three-dimensional collage lattice assay was performed. It was demonstrated that TGFβ-stimulated PZ-HPV-7 cells gained contractility. Our results showed that TGFβ stimulation induced PZ-HPV-7 cells to undergo epithelial to mesenchymal transition. EMT characteristics such as acquisition of mesenchymal markers and loss of epithelial markers were evident in the induction of vimentin and downregulation of E-cadherin and cytokeratins, as well as phenotypic alterations including increased contraction and enhanced mobility were detected.


Oncogene ◽  
2004 ◽  
Vol 23 (9) ◽  
pp. 1766-1779 ◽  
Author(s):  
Pepper J Schedin ◽  
Kristin L Eckel-Mahan ◽  
Shauntae M McDaniel ◽  
Jason D Prescott ◽  
Kelley S Brodsky ◽  
...  

2000 ◽  
pp. 199-226 ◽  
Author(s):  
D S Saloman ◽  
C Bianco ◽  
A D Ebert ◽  
N I Khan ◽  
M De Santis ◽  
...  

The EGF-CFC gene family encodes a group of structurally related proteins that serve as important competence factors during early embryogenesis in Xenopus, zebrafish, mice and humans. This multigene family consists of Xenopus FRL-1, zebrafish one-eyed-pinhead (oep), mouse cripto (Cr-1) and cryptic, and human cripto (CR-1) and criptin. FRL-1, oep and mouse cripto are essential for the formation of mesoderm and endoderm and for correct establishment of the anterior/posterior axis. In addition, oep and cryptic are important for the establishment of left-right (L/R) asymmetry. In zebrafish, there is strong genetic evidence that oep functions as an obligatory co-factor for the correct signaling of a transforming growth factor-beta (TGFbeta)-related gene, nodal, during gastrulation and during L/R asymmetry development. Expression of Cr-1 and cryptic is extinguished in the embryo after day 8 of gestation except for the developing heart where Cr-1 expression is necessary for myocardial development. In the mouse, cryptic is not expressed in adult tissues whereas Cr-1 is expressed at a low level in several different tissues including the mammary gland. In the mammary gland, expression of Cr-1 in the ductal epithelial cells increases during pregnancy and lactation and immunoreactive and biologically active Cr-1 protein can be detected in human milk. Overexpression of Cr-1 in mouse mammary epithelial cells can facilitate their in vitro transformation and in vivo these Cr-1-transduced cells produce ductal hyperplasias in the mammary gland. Recombinant mouse or human cripto can enhance cell motility and branching morphogenesis in mammary epithelial cells and in some human tumor cells. These effects are accompanied by an epithelial-mesenchymal transition which is associated with a decrease in beta-catenin function and an increase in vimentin expression. Expression of cripto is increased several-fold in human colon, gastric, pancreatic and lung carcinomas and in a variety of different types of mouse and human breast carcinomas. More importantly, this increase can first be detected in premalignant lesions in some of these tissues. Although a specific receptor for the EGF-CFC proteins has not yet been identified, oep depends upon an activin-type RIIB and RIB receptor system that functions through Smad-2. Mouse and human cripto have been shown to activate a ras/raf/MAP kinase signaling pathway in mammary epithelial cells. Activation of phosphatidylinositol 3-kinase and Akt are also important for the ability of CR-1 to stimulate cell migration and to block lactogenic hormone-induced expression of beta-casein and whey acidic protein. In mammary epithelial cells, part of these responses may depend on the ability of CR-1 to transactivate erb B-4 and/or fibroblast growth factor receptor 1 through an src-like tyrosine kinase.


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