EMT Alters Interstitial Fluid Flow-induced Signaling in ERBB2-positive Breast Cancer
ABSTRACT: A variety of mechanotransduction forces are altered in the tumor microenvironment (TME) and these biophysical forces can influence cancer progression. One such force is interstitial fluid flow (IFF) - the movement of fluid through the tissue matrix. IFF was previously shown to induce invasion of cancer cells, but the activated signaling cascades remain poorly understood. Here, it is demonstrated that IFF induces invasion of ERBB2/HER2 expressing breast cancer cells via activation of phosphoinositide-3-kinase (PI3K). In constitutively activate ERBB2 expressing cells that have undergone epithelial-to-mesenchymal transition (EMT), IFF-mediated invasion requires the chemokine receptor CXCR4, a gradient of its ligand CXCL12, and activity of the PI3K catalytic subunits p110a and β. In wild-type ERBB2 expressing cells, IFF-mediated invasion is chemokine receptor-independent and requires only p110a activation. To test whether cells undergoing EMT alter their signaling response to IFF, TGFb1 was used to induce EMT in wild-type ERBB2-expressing cells resulting in IFF-induced invasion dependent on CXCR4 and p110β. 2 cell lines (NeuN, NeuT), 2 conditions (flow, static), 3 replicates each, 12 samples total
Project description:A variety of mechanotransduction forces are altered in the tumor microenvironment (TME) and these biophysical forces can influence cancer progression. One such force is interstitial fluid flow (IFF) - the movement of fluid through the tissue matrix. IFF was previously shown to induce invasion of cancer cells, but the activated signaling cascades remain poorly understood. Here, it is demonstrated that IFF induces invasion of ERBB2/HER2 expressing breast cancer cells via activation of phosphoinositide-3-kinase (PI3K). In constitutively activate ERBB2 expressing cells that have undergone epithelial-to-mesenchymal transition (EMT), IFF-mediated invasion requires the chemokine receptor CXCR4, a gradient of its ligand CXCL12, and activity of the PI3K catalytic subunits p110a and β. In wild-type ERBB2 expressing cells, IFF-mediated invasion is chemokine receptor-independent and requires only p110a activation. To test whether cells undergoing EMT alter their signaling response to IFF, TGFb1 was used to induce EMT in wild-type ERBB2-expressing cells resulting in IFF-induced invasion dependent on CXCR4 and p110β. Overall design: 2 cell lines (NeuN, NeuT), 2 conditions (flow, static), 3 replicates each, 12 samples total
Project description:PI3K signaling and FOXO transcription factors play opposing roles at several B cell developmental stages. We show here abundant nuclear FOXO1 expression in the proliferative compartment of the germinal center (GC), its dark zone (DZ), and PI3K activity, downregulating FOXO1, in the GC light zone (LZ), where cells are selected for further differentiation. However, here FOXO1 is expressed in c-Myc+ cells destined for DZ reentry. Upon FOXO1 ablation by genetic means or induction of PI3K activity GCs become devoid of their DZ, due at least partly to the downregulation of the chemokine receptor CXCR4. While this is known to prevent proper cyclic selection of cells expressing high-affinity antibodies, the initiation of immunoglobulin switching is essentially dependent on FOXO1 activity. All samples were obtained from mouse germinal center (GC) B cells (Cgamma1-cre; YFP, P110*, FOXO1 f/f or PTEN f/f animals). Cells used for microarray analysis were FACS sorted cells.
Project description:HER2 (ERBB2) gene amplification and PIK3CA mutations often co-occur in breast cancer, and aberrant activation of the PI3K pathway has been implicated in resistance to HER2-directed therapies. We have created a mouse model of HER2-overexpressing (HER2+), PIK3CAH1047R-mutant breast cancer. Mice expressing both human HER2 and mutant PIK3CA in their mammary glands developed tumors with a significantly shorter latency compared to mice expressing either oncogene alone. By microarray analysis, HER2-driven tumors clustered with the luminal subtype, whereas HER2+PIK3CA and PIK3CA-driven tumors were associated with the claudin-low breast cancer subtype. In accordance, PIK3CA and HER2+PIK3CA tumors expressed elevated levels of EMT and stem cell markers, and cells from HER2+PIK3CA tumors more efficiently formed mammospheres, providing further evidence that activated PIK3CA may enrich for cancer stem cells. Finally, HER2+PIK3CA tumors are resistant to the HER2 antibody trastuzumab; resistance is partially reversed by the addition of a PI3K inhibitor. Taken together, these studies suggest that the co-expression of HER2 and PI3KH1047R in the mouse mammary gland accelerates the formation of aggressive, trastuzumab-resistant tumors. referenceXsample
Project description:To gain insight into EMT-independent biological processes through which PI3K promotes invasion, RNA samples from 344SQ_p110α shRNA cells and 344SQ_scr cells were subjected to global transcriptional profiling. Two groups, control and PIK3CA shRNA, in 344SQ lung cancer cell line Two group comparison
Project description:The loss of E-cadherin causes dysfunction of the cell-cell junction machinery, which is an initial step in epithelial-to-mesenchymal transition (EMT), facilitating cancer cell invasion and the formation of metastases. A set of transcriptional repressors of E-cadherin (CDH1) gene expression, including Snail1, Snail2 and Zeb2 mediate E-cadherin down-regulation in breast cancer. However, the molecular mechanisms underlying the control of E-cadherin expression in breast cancer progression remain largely unknown. Here, by using global gene expression approaches, we uncover a novel function for Cdc42 GTPase-activating protein (CdGAP) in the regulation of expression of genes involved in EMT. We found that CdGAP used its proline-rich domain to form a functional complex with Zeb2 to mediate the repression of E-cadherin expression in ErbB2-transformed breast cancer cells. Conversely, knockdown of CdGAP expression led to a decrease of the transcriptional repressors Snail1 and Zeb2, and this correlated with an increase in E-cadherin levels, restoration of cell-cell junctions, and epithelial-like morphological changes. In vivo, loss of CdGAP in ErbB2-transformed breast cancer cells impaired tumor growth and suppressed metastasis to lungs. Finally, CdGAP was highly expressed in basal-type breast cancer cells, and its strong expression correlated with poor prognosis in breast cancer patients. Together, these data support a previously unknown nuclear function for CdGAP where it cooperates in a GAP-independent manner with transcriptional repressors to function as a critical modulator of breast cancer through repression of E-cadherin transcription. Targeting Zeb2-CdGAP interactions may represent novel therapeutic opportunities for breast cancer treatment. Overall design: Total RNA profiles of ErbB2-expressing control mammary tumor explants cells (shCON) and CdGAP-depleted cells (shCdGAP) were generated by deep sequencing, in triplicate, using Illumina HiSEq2000.
Project description:In colorectal cancer, increased expression of the CXC chemokine receptor 4 (CXCR4) has been shown to provoke metastatic disease due to the interaction with its ligand stromal cell-derived factor 1 (SDF-1). Recently, a second SDF-1 receptor, CXCR7, was found to enhance tumor growth in solid tumors. Albeit signaling cascades via SDF-1/CXCR4 have been intensively studied, the significance of the SDF-1/CXCR7-induced intracellular communication triggering malignancy is still only marginally understood. In tumor tissue of 52 colorectal cancer (CRC) patients, we observed that expression of CXCR7 and CXCR4 increased with tumor stage, tumor size, and lymph node infiltration. Asking whether activation of CXCR4 or CXCR7 might result in a similar expression pattern, we performed microarray expression analyses using lentivirally CXCR4- and/or CXCR7-overexpressing SW480 colon cancer cell lines with and without stimulation by SDF-1α. Gene regulation via SDF-1α/CXCR4 and SDF-1α/CXCR7 was completely different and partly antidromic. Expressions of the differentially expressed genes AKR1C3, AXL, EGFR, IGFBP7, IL24, TNNC1, TRIP6 were confirmed by qPCR. Differentially regulated genes were assigned by GO to migration and lipid metabolic processes. Furthermore, using the in silico gene set enrichment analysis we showed for the first time that expressions of miR-217 and miR-218 were increased in CXCR4 and reduced in CXCR7 cells after stimulation with SDF-1α. As expected, their putative target mRNAs were inversely expressed. Functional assays exerted that exposure to SDF-1α resulted in strongly amplified invasiveness and chemosensitivity of CXCR4-expressing cells. CXCR7 overexpression led to reduced invasiveness which could only be marginally increased by SDF-1α. The CXCR4 antagonist plerixafor significantly reduced invasiveness of CXCR4-overexpressing cells only. Similarly, compared to control cells, CXCR4 cells showed increased sensitivity against 5-FU, while CXCR7 cells were more chemoresistant. These opposing results for CXCR4- or CXCR7-overexpressing colon carcinoma cells demand an unexpected attention in the clinical application of chemokine receptor antagonists like Plerixafor. 24 samples
Project description:Understanding transcriptional changes during cancer progression is of crucial importance to develop new and more efficacious diagnostic and therapeutic approaches. It is well known that ErbB2 is overexpressed in about 25% of human invasive breast cancers. We have previously demonstrated that p130Cas overexpression synergizes with ErbB2 in mammary cell transformation and promotes ErbB2-dependent invasion in three-dimensional (3D) cultures of human mammary epithelial cells. Here, by comparing coding and non-coding gene expression profiles, we define the invasive signatures associated with concomitant p130Cas overexpression and ErbB2 activation in 3D cultures of mammary epithelial cells. Specifically, we have found that genes involved in amino acids synthesis (CBS, PHGDH), cell motility, migration (ITPKA, PRDM1), and angiogenesis (HEY1) are upregulated, while genes involved in inflammatory response (SAA1, S100A7) are downregulated. In parallel, we have shown that the expression of specific miRNAs is altered. Among these, miR-200b, miR-222, miR-221, miR-R210, and miR-424 are upregulated, while miR-27a, miR-27b, and miR-23b are downregulated. Overall, this study presents, for the first time, the gene expression changes underlying the invasive behavior following p130Cas overexpression in an ErbB2 transformed mammary cell model. To identify transcriptional changes occurring during invasion we have performed a comparative microarray analysis of non coding RNA (miRNA) between MCF10A.B2 acini over-expressing p130Cas with activation of ErbB2 and control cells.
Project description:Cardiomyocyte (CM) loss after injury results in adverse remodelling and fibrosis, which inevitably lead to heart failure. Neuregulin-ErbB2 and Hippo-Yap signaling pathways are key mediators of CM proliferation and regeneration although the crosstalk between these pathways is unclear. Here, we demonstrate in mice that temporal over-expression (OE) of activated ErbB2 in CMs promotes cardiac regeneration in a heart failure model. Cellularly, OE CMs present an EMT-like regenerative response involving cytoskeletal reprograming, migration, ECM turnover, and displacement. Molecularly, we identified Yap as a critical mediator of ErbB2 signaling. In OE CMs, Yap interacts with nuclear envelope and cytoskeletal components, reflective of the altered mechanic state elicited by ErbB2. Hippo-independent activating phosphorylation on Yap at S352 and S274 were enriched in OE CMs, peaking during metaphase. Viral overexpression of Yap phospho-mutants dampened the proliferative competence of OE CMs. Taken together, we demonstrate a potent ErbB2-mediated Yap mechanosensory signaling involving EMT-like characteristics, resulting in heart regeneration.
Project description:Chemokine receptors CXCR4 and CCR5 regulate white blood cell trafficking, and are engaged by the HIV-1 envelope glycoprotein gp120 during infection. We combine directed evolution of CXCR4 and CCR5 libraries comprising nearly all ~7,000 single amino acid substitutions with deep sequencing to define sequence-fitness landscapes for surface expression and ligand interactions. Functional interaction sites are mapped based on conservation; for example, extracellular residues are conserved for binding HIV-1-blocking antibodies, as expected. Chemokine CXCL12 interacts with residues extending asymmetrically into the CXCR4 ligand-binding cavity, and distal mutations within allosteric and G protein coupling sites are identified that enhance chemokine binding. CCR5 residues conserved for gp120 interactions partially overlap with the chemokine-binding site, and gp120 binding is increased by acidic substitutions in the CCR5 N-terminus and extracellular loops. Furthermore, general features are apparent from sequence patterns, including membrane regions that are intolerant to polar mutations, and deleterious cysteine substitutions within extracellular loops. Overall design: Single-site saturation mutagenesis libraries were constructed of human CXCR4 and CCR5, and expressed in human Expi293F cells (a HEK293 derivative). Cells were evolved by FACS for surface expression and binding to protein ligands. Frequencies of variants in the sorted population (measured from RNA transcripts) were compared to frequencies in the DNA libraries to calculate log(base2) enrichment ratios for all amino acid substitutions. All evolution experiments were in duplicate.