Digital Commons Network^™

Accurate Molecular Classification Of Cancer Using Simple Rules., Xiaosheng Wang, Osamu Gotoh

Journal Articles: Genetics, Cell Biology & Anatomy

BACKGROUND: One intractable problem with using microarray data analysis for cancer classification is how to reduce the extremely high-dimensionality gene feature data to remove the effects of noise. Feature selection is often used to address this problem by selecting informative genes from among thousands or tens of thousands of genes. However, most of the existing methods of microarray-based cancer classification utilize too many genes to achieve accurate classification, which often hampers the interpretability of the models. For a better understanding of the classification results, it is desirable to develop simpler rule-based models with as few marker genes as possible.

METHODS: …

Role Of Mammalian Ecdysoneless In Cell Cycle Regulation., Jun Hyun Kim, Channabasavaiah B. Gurumurthy, Mayumi Naramura, Ying Zhang, Andrew T. Dudley, Lynn Doglio, Hamid Band, Vimla Band

Journal Articles: Genetics, Cell Biology & Anatomy

The Ecdysoneless (Ecd) protein is required for cell-autonomous roles in development and oogenesis in Drosophila, but the function of its evolutionarily conserved mammalian orthologs is not clear. To study the cellular function of Ecd in mammalian cells, we generated Ecd(lox/lox) mouse embryonic fibroblast cells from Ecd floxed mouse embryos. Cre-mediated deletion of Ecd in Ecd(lox/lox) mouse embryonic fibroblasts led to a proliferative block due to a delay in G(1)-S cell cycle progression; this defect was reversed by the introduction of human Ecd. Loss of Ecd led to marked down-regulation of E2F target gene expression. Furthermore, Ecd directly bound to Rb …

N-Glycosylation Status Of E-Cadherin Controls Cytoskeletal Dynamics Through The Organization Of Distinct Β-Catenin- And Γ-Catenin-Containing Ajs., Basem T Jamal, Mihai Nita-Lazar, Zhennan Gao, Bakr Amin, Janice Walker, Maria A Kukuruzinska

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

N-glycosylation of E-cadherin has been shown to inhibit cell-cell adhesion. Specifically, our recent studies have provided evidence that the reduction of E-cadherin N-glycosylation promoted the recruitment of stabilizing components, vinculin and serine/threonine protein phosphatase 2A (PP2A), to adherens junctions (AJs) and enhanced the association of AJs with the actin cytoskeleton. Here, we examined the details of how N-glycosylation of E-cadherin affected the molecular organization of AJs and their cytoskeletal interactions. Using the hypoglycosylated E-cadherin variant, V13, we show that V13/β-catenin complexes preferentially interacted with PP2A and with the microtubule motor protein dynein. This correlated with dephosphorylation of the microtubule-associated protein …

Intra-Tumor Heterogeneity Of Mlh1 Promoter Methylation Revealed By Deep Single Molecule Bisulfite Sequencing., Katherine E Varley, David G Mutch, Tina B Edmonston, Paul J Goodfellow, Robi D Mitra

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

A single tumor may contain cells with different somatic mutations. By characterizing this genetic heterogeneity within tumors, advances have been made in the prognosis, treatment and understanding of tumorigenesis. In contrast, the extent of epigenetic intra-tumor heterogeneity and how it influences tumor biology is under-explored. We have characterized epigenetic heterogeneity within individual tumors using next-generation sequencing. We used deep single molecule bisulfite sequencing and sample-specific DNA barcodes to determine the spectrum of MLH1 promoter methylation across an average of 1000 molecules in each of 33 individual samples in parallel, including endometrial cancer, matched blood and normal endometrium. This first glimpse, …

Interaction With Lc8 Is Required For Pak1 Nuclear Import And Is Indispensable For Zebrafish Development., Christine M Lightcap, Gabor Kari, Luis E Arias-Romero, Jonathan Chernoff, Ulrich Rodeck, John C Williams

Department of Biochemistry and Molecular Biology Faculty Papers

Pak1 (p21 activated kinase 1) is a serine/threonine kinase implicated in regulation of cell motility and survival and in malignant transformation of mammary epithelial cells. In addition, the dynein light chain, LC8, has been described to cooperate with Pak1 in malignant transformation of breast cancer cells. Pak1 itself may aid breast cancer development by phosphorylating nuclear proteins, including estrogen receptor alpha. Recently, we showed that the LC8 binding site on Pak1 is adjacent to the nuclear localization sequence (NLS) required for Pak1 nuclear import. Here, we demonstrate that the LC8-Pak1 interaction is necessary for epidermal growth factor (EGF)-induced nuclear import …

Decorin Is A Novel Antagonistic Ligand Of The Met Receptor., Silvia Goldoni, Ashley Humphries, Alexander Nyström, Sampurna Sattar, Rick T Owens, David J Mcquillan, Keith Ireton, Renato V Iozzo

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Decorin, a member of the small leucine-rich proteoglycan gene family, impedes tumor cell growth by down-regulating the epidermal growth factor receptor. Decorin has a complex binding repertoire, thus, we predicted that decorin would modulate the bioactivity of other tyrosine kinase receptors. We discovered that decorin binds directly and with high affinity (K(d) = approximately 1.5 nM) to Met, the receptor for hepatocyte growth factor (HGF). Binding of decorin to Met is efficiently displaced by HGF and less efficiently by internalin B, a bacterial Met ligand. Interaction of decorin with Met induces transient receptor activation, recruitment of the E3 ubiquitin ligase …

U2os Cells Lacking Chk1 Undergo Aberrant Mitosis And Fail To Activate The Spindle Checkpoint, Laura Carrassa, Yolanda Sanchez, Eugenio Erba, Giovanna Damia

Dartmouth Scholarship

Chk1 is a conserved protein kinase originally identified in fission yeast, required to delay entry of cells with damaged or unreplicated DNA into mitosis. The requirement of Chk1 for both S and G2/M checkpoints has been elucidated while only few studies have connected Chk1 to the mitotic spindle checkpoint. We used a small interference RNA strategy to investigate the role of Chk1 in unstressed conditions. Chk1 depletion in U2OS human osteosarcoma cells inhibited cell proliferation and raised the percentage of cells with a 4N DNA content, which correlated with accumulation of giant polynucleated cells morphologically distinct from apoptotic cells, while …

The Significance Of Gata3 Expression In Breast Cancer: A 10-Year Follow-Up Study., Vincenzo Ciocca, Constantine Daskalakis, Robin M. Ciocca, Alejandra Ruiz-Orrico, Juan P. Palazzo

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

GATA3 is a transcription factor closely associated with estrogen receptor alpha in breast carcinoma, with a potential prognostic utility. This study investigated the immunohistochemical expression of GATA3 in estrogen receptor alpha-positive and estrogen receptor alpha-negative breast carcinomas. One hundred sixty-six cases of invasive breast carcinomas with 10-year follow-up information were analyzed. Positive GATA3 and estrogen receptor alpha cases were defined as greater than 20% of cells staining. Time to cancer recurrence and time to death were analyzed with survival methods. Of 166 patients, 40 were estrogen receptor alpha negative and 121 estrogen receptor alpha positive. Thirty-eight (23%) recurrences and 51 …

Stat5 Regulation Of Bcl10 Parallels Constitutive Nfkappab Activation In Lymphoid Tumor Cells., Zsuzsanna S Nagy, Matthew J Lebaron, Jeremy A Ross, Abhisek Mitra, Hallgeir Rui, Robert A Kirken

Department of Cancer Biology Faculty Papers

BACKGROUND: Signal Transducer and Activator of Transcription 5 A and B (STAT5) are key survival factors in cells of the lymphoid lineage. Identification of novel, tissue-specific STAT5 regulated genes would advance the ability to combat diseases due to aberrant STAT5 signaling. In the present work a library of human STAT5 bound genomic elements was created and validated. RESULTS: Of several STAT5 responsive genomic regulatory elements identified, one was located within the first intron of the human BCL10 gene. Chromatin immuno-precipitation reactions confirmed constitutive in vivo STAT5 binding to this intronic fragment in various human lymphoid tumor cell lines. Interestingly, non-phosphorylated …

The Interaction Of Hab18g/Cd147 With Integrin Alpha6beta1 And Its Implications For The Invasion Potential Of Human Hepatoma Cells., Jing-Yao Dai, Ke-Feng Dou, Cong-Hua Wang, Pu Zhao, Wayne Bond Lau, Ling Tao, Ya-Mei Wu, Juan Tang, Jian-Li Jiang, Zhi-Nan Chen

Department of Emergency Medicine Faculty Papers

BACKGROUND: HAb18G/CD147 plays pivotal roles in invasion by hepatoma cells, but the underlying mechanism remains unclear. Our previous study demonstrated that overexpression of HAb18G/CD147 promotes invasion by interacting with integrin alpha3beta1. However, it has never been investigated whether alpha3beta1 is solely responsible for this process or if other integrin family members also interact with HAb18G/CD147 in human hepatoma cells. METHODS: Human SMMC-7721 and FHCC98 cells were cultured and transfected with siRNA fragments against HAb18G/CD147. The expression levels of HAb18G/CD147 and integrin alpha6beta1 were determined by immunofluorescent double-staining and confocal imaging analysis. Co-immunoprecipitation and Western blot analyses were performed to examine …