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Montréal, Canada

Amplification and overexpression of erbB2/neu proto-oncogene is observed in 20–30% human breast cancer and is inversely correlated with the survival of the patient. Despite this, somatic activating mutations within erbB2 in human breast cancers are rare. However, we have previously reported that a splice isoform of erbB2, containing an in-frame deletion of exon 16 (herein referred to as ErbB2ΔEx16), results in oncogenic activation of erbB2 because of constitutive dimerization of the ErbB2 receptor. Here, we demonstrate that the ErbB2ΔEx16 is a major oncogenic driver in breast cancer that constitutively signals from the cell surface. We further show that inducible expression of the ErbB2ΔEx16 variant in mammary gland of transgenic mice results in the rapid development of metastatic multifocal mammary tumors. Genetic and biochemical characterization of the ErbB2ΔEx16-derived mammary tumors exhibit several unique features that distinguish this model from the conventional ErbB2 ones expressing the erbB2 proto-oncogene in mammary epithelium. Unlike the wild-type ErbB2-derived tumors that express luminal keratins, ErbB2ΔEx16-derived tumors exhibit high degree of intratumoral heterogeneity co-expressing both basal and luminal keratins. Consistent with these distinct pathological features, the ErbB2ΔEx16 tumors exhibit distinct signaling and gene expression profiles that correlate with activation of number of key transcription factors implicated in breast cancer metastasis and cancer stem cell renewal.Oncogene advance online publication, 9 May 2016; doi:10.1038/onc.2016.129. © 2016 Macmillan Publishers Limited Source

Kurley S.J.,Vanderbilt University | Bierie B.,Whitehead Institute For Biomedical Research | Carnahan R.H.,Vanderbilt University | Carnahan R.H.,Vanderbilt Ingram Cancer Center | And 9 more authors.

Although p120-catenin (p120) is crucial for E-cadherin function, ablation experiments in epithelial tissues from different organ systems reveal markedly different effects. Here, we examine for the first time the consequences of p120 knockout during mouse mammary gland development. An MMTV-Cre driver was used to target knockout to the epithelium at the onset of puberty. p120 ablation was detected in approximately one-quarter of the nascent epithelium at the forth week post-partum. However, p120 null cells were essentially nonadherent, excluded from the process of terminal end bud (TEB) morphogenesis and lost altogether by week six. This elimination process caused a delay in TEB outgrowth, after which the gland developed normally from cells that had retained p120. Mechanistic studies in vitro indicate that TEB dysfunction is likely to stem from striking E-cadherin loss, failure of cell-cell adhesion and near total exclusion from the collective migration process. Our findings reveal an essential role for p120 in mammary morphogenesis. © 2012. Published by The Company of Biologists Ltd. Source

Lu S.X.,Sloan Kettering Cancer Center | Kappel L.W.,Sloan Kettering Cancer Center | Kappel L.W.,The New School | Charbonneau-Allard A.-M.,Goodman Cancer Center | And 27 more authors.

Background: Allogeneic bone marrow transplantation (allo-BMT) is a potentially curative therapy for a variety of hematologic diseases, but benefits, including graft-versus-tumor (GVT) activity are limited by graft-versus-host-disease (GVHD). Carcinoembryonic antigen related cell adhesion molecule 1 (Ceacam1) is a transmembrane glycoprotein found on epithelium, T cells, and many tumors. It regulates a variety of physiologic and pathological processes such as tumor biology, leukocyte activation, and energy homeostasis. Previous studies suggest that Ceacam1 negatively regulates inflammation in inflammatory bowel disease models. Methods: We studied Ceacam1 as a regulator of GVHD and GVT after allogeneic bone marrow transplantation (allo-BMT) in mouse models. In vivo, Ceacam1-/- T cells caused increased GVHD mortality and GVHD of the colon, and greater numbers of donor T cells were positive for activation markers (CD25hi, CD62Llo). Additionally, Ceacam1-/- CD8 T cells had greater expression of the gut-trafficking integrin α4β7, though both CD4 and CD8 T cells were found increased numbers in the gut post-transplant. Ceacam1-/- recipients also experienced increased GVHD mortality and GVHD of the colon, and alloreactive T cells displayed increased activation. Additionally, Ceacam1-/- mice had increased mortality and decreased numbers of regenerating small intestinal crypts upon radiation exposure. Conversely, Ceacam1-overexpressing T cells caused attenuated target-organ and systemic GVHD, which correlated with decreased donor T cell numbers in target tissues, and mortality. Finally, graft-versus-tumor survival in a Ceacam1+ lymphoma model was improved in animals receiving Ceacam1-/- vs. control T cells. Conclusions: We conclude that Ceacam1 regulates T cell activation, GVHD target organ damage, and numbers of donor T cells in lymphoid organs and GVHD target tissues. In recipients of allo-BMT, Ceacam1 may also regulate tissue radiosensitivity. Because of its expression on both the donor graft and host tissues, this suggests that targeting Ceacam1 may represent a potent strategy for the regulation of GVHD and GVT after allogeneic transplantation. © 2011 Lu et al. Source

Rampakakis E.,Goodman Cancer Center | Gkogkas C.,Goodman Cancer Center | Di Paola D.,Goodman Cancer Center | Zannis-Hadjopoulos M.,Goodman Cancer Center
Journal of Cellular Biochemistry

Genomic propagation in both prokaryotes and eukaryotes is tightly regulated at the level of initiation, ensuring that the genome is accurately replicated and equally segregated to the daughter cells. Even though replication origins and the proteins that bind onto them (initiator proteins) have diverged throughout the course of evolution, the mechanism of initiation has been conserved, consisting of origin recognition, multi-protein complex assembly, helicase activation and loading of the replicative machinery. Recruitment of the multiprotein initiation complexes onto the replication origins is constrained by the dense packing of the DNA within the nucleus and unusual structures such as knots and supercoils. In this review, we focus on the DNA topological barriers that the multi-protein complexes have to overcome in order to access the replication origins and how the topological state of the origins changes during origin firing. Recent advances in the available methodologies to study DNA topology and their clinical significance are also discussed. © 2010 Wiley-Liss, Inc. Source

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