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Wang, Hongfang

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Wang

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Hongfang

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Wang, Hongfang

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2011 - 20154

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Author's Publications: search.filters.isAuthorOfPublication.edb1c567-f33e-48bf-bcc9-07d288bca9e1

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Now showing 1 - 4 of 4
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    Network analysis of gene essentiality in functional genomics experiments
    (BioMed Central, 2015) Jiang, Peng; Wang, Hongfang; Li, Wei; Zang, Chongzhi; Li, Bo; Wong, Yinling J.; Meyer, Cliff; Liu, Jun; Aster, Jon; Liu, X. Shirley
    Many genomic techniques have been developed to study gene essentiality genome-wide, such as CRISPR and shRNA screens. Our analyses of public CRISPR screens suggest protein interaction networks, when integrated with gene expression or histone marks, are highly predictive of gene essentiality. Meanwhile, the quality of CRISPR and shRNA screen results can be significantly enhanced through network neighbor information. We also found network neighbor information to be very informative on prioritizing ChIP-seq target genes and survival indicator genes from tumor profiling. Thus, our study provides a general method for gene essentiality analysis in functional genomic experiments (http://nest.dfci.harvard.edu). Electronic supplementary material The online version of this article (doi:10.1186/s13059-015-0808-9) contains supplementary material, which is available to authorized users.
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    PKCθ Regulates T-Cell Leukemia-Initiating Activity via Reactive Oxygen Species
    (2013) Giambra, Vincenzo; Jenkins, Christopher R.; Wang, Hongfang; Lam, Sonya H.; Shevchuk, Olena O.; Nemirovsky, Oksana; Wai, Carol; Gusscott, Sam; Chiang, Mark Y.; Aster, Jon; Humphries, R. Keith; Eaves, Connie; Weng, Andrew P.
    Reactive oxygen species (ROS), a by-product of cellular metabolism, damage intracellular macromolecules and, in excess, can promote normal hematopoietic stem cell differentiation and exhaustion1–3. However, mechanisms that regulate ROS levels in leukemia-initiating cells (LICs) and the biological role of ROS in these cells remain largely unknown. We show here the ROSlow subset of CD44+ cells in T-cell acute lymphoblastic leukemia (T-ALL), a malignancy of immature T-cell progenitors, to be highly enriched in the most aggressive LICs, and that ROS are maintained at low levels by downregulation of protein kinase C theta (PKCθ). Strikingly, primary mouse T-ALLs lacking PKCθ show improved LIC activity whereas enforced PKCθ expression in both mouse and human primary T-ALLs compromised LIC activity. We also demonstrate that PKCθ is positively regulated by RUNX1, and that NOTCH1, which is frequently activated by mutation in T-ALL4–6 and required for LIC activity in both mouse and human models7,8, downregulates PKCθ and ROS via a novel pathway involving induction of RUNX3 and subsequent repression of RUNX1. These results reveal key functional roles for PKCθ and ROS in T-ALL and suggest that aggressive biological behavior in vivo could be limited by therapeutic strategies that promote PKCθ expression/activity or ROS accumulation.
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    Gauging NOTCH1 Activation in Cancer Using Immunohistochemistry
    (Public Library of Science, 2013) Kluk, Michael J.; Ashworth, Todd; Wang, Hongfang; Knoechel, Birgit; Mason, Emily F.; Morgan, Elizabeth; Dorfman, David; Pinkus, Geraldine; Weigert, Oliver; Hornick, Jason; Chirieac, Lucian; Hirsch, Michelle; Oh, David J.; South, Andrew P.; Leigh, Irene M.; Pourreyron, Celine; Cassidy, Andrew J.; DeAngelo, Daniel J.; Weinstock, David M.; Krop, Ian E.; Dillon, Deborah; Brock, Jane; Lazar, Alexander J. F.; Peto, Myron; Cho, Raymond J.; Stoeck, Alexander; Haines, Brian B.; Sathayanrayanan, Sriram; Rodig, Scott; Aster, Jon
    Fixed, paraffin-embedded (FPE) tissues are a potentially rich resource for studying the role of NOTCH1 in cancer and other pathologies, but tests that reliably detect activated NOTCH1 (NICD1) in FPE samples have been lacking. Here, we bridge this gap by developing an immunohistochemical (IHC) stain that detects a neoepitope created by the proteolytic cleavage event that activates NOTCH1. Following validation using xenografted cancers and normal tissues with known patterns of NOTCH1 activation, we applied this test to tumors linked to dysregulated Notch signaling by mutational studies. As expected, frequent NICD1 staining was observed in T lymphoblastic leukemia/lymphoma, a tumor in which activating NOTCH1 mutations are common. However, when IHC was used to gauge NOTCH1 activation in other human cancers, several unexpected findings emerged. Among B cell tumors, NICD1 staining was much more frequent in chronic lymphocytic leukemia than would be predicted based on the frequency of NOTCH1 mutations, while mantle cell lymphoma and diffuse large B cell lymphoma showed no evidence of NOTCH1 activation. NICD1 was also detected in 38% of peripheral T cell lymphomas. Of interest, NICD1 staining in chronic lymphocytic leukemia cells and in angioimmunoblastic lymphoma was consistently more pronounced in lymph nodes than in surrounding soft tissues, implicating factors in the nodal microenvironment in NOTCH1 activation in these diseases. Among carcinomas, diffuse strong NICD1 staining was observed in 3.8% of cases of triple negative breast cancer (3 of 78 tumors), but was absent from 151 non-small cell lung carcinomas and 147 ovarian carcinomas. Frequent staining of normal endothelium was also observed; in line with this observation, strong NICD1 staining was also seen in 77% of angiosarcomas. These findings complement insights from genomic sequencing studies and suggest that IHC staining is a valuable experimental tool that may be useful in selection of patients for clinical trials.
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    High-Level IGF1R Expression is Required for Leukemia-Initiating Cell Activity in T-ALL and is Supported by Notch Signaling
    (Rockefeller University Press, 2011) Medyouf, Hind; Gusscott, Samuel; Wai, Carol; Nemirovsky, Oksana; Trumpp, Andreas; Pflumio, Francoise; Carboni, Joan; Gottardis, Marco; Pollak, Michael; Holzenberger, Martin; Weng, Andrew P.; Wang, Hongfang; Tseng, Jen-Chieh; Kung, Andrew; Aster, Jon
    T cell acute lymphoblastic leukemia (T-ALL) is an aggressive cancer of immature T cells that often shows aberrant activation of Notch1 and PI3K–Akt pathways. Although mutations that activate PI3K–Akt signaling have previously been identified, the relative contribution of growth factor-dependent activation is unclear. We show here that pharmacologic inhibition or genetic deletion of insulin-like growth factor 1 receptor (IGF1R) blocks the growth and viability of T-ALL cells, whereas moderate diminution of IGF1R signaling compromises leukemia-initiating cell (LIC) activity as defined by transplantability in syngeneic/congenic secondary recipients. Furthermore, IGF1R is a Notch1 target, and Notch1 signaling is required to maintain IGF1R expression at high levels in T-ALL cells. These findings suggest effects of Notch on LIC activity may be mediated in part by enhancing the responsiveness of T-ALL cells to ambient growth factors, and provide strong rationale for use of IGF1R inhibitors to improve initial response to therapy and to achieve long-term cure of patients with T-ALL.