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Dillon, Deborah

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Dillon

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Deborah

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Dillon, Deborah

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Now showing 1 - 3 of 3
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    Publication
    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.
  • Publication
    Recurrent EML4–NTRK3 fusions in infantile fibrosarcoma and congenital mesoblastic nephroma suggest a revised testing strategy
    (Springer Science and Business Media LLC, 2017-11-03) Church, Alanna; Calicchio, Monica; Nardi, Valentina; Skálová, Alena; Pinto, Andre; Dillon, Deborah; Gomez-Fernandez, Carmen; Manoj, Namitha; Haimes, Josh; Stahl, Joshua; Dela Cruz, Filemon; Tannenbaum-Dvir, Sarah; Glade-Bender, Julia; Kung, Andrew; DuBois, Steven; Kozakewich, Harry; Janeway, Katherine; Perez-Atayde, Antonio; Harris, Marian
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    Publication
    Response and resistance to BET bromodomain inhibitors in triple negative breast cancer
    (2015) Shu, Shaokun; Lin, Charles Y.; He, Housheng Hansen; Witwicki, Robert; Tabassum, Doris P.; Roberts, Justin M.; Janiszewska, Michalina; Huh, Sung Jin; Liang, Yi; Ryan, Jeremy; Doherty, Ernest; Mohammed, Hisham; Guo, Hao; Stover, Daniel G.; Ekram, Muhammad B.; Brown, Jonathan; D'Santos, Clive; Krop, Ian; Dillon, Deborah; McKeown, Michael; Ott, Christopher; Qi, Jun; Ni, Min; Rao, Prakash K.; Duarte, Melissa; Wu, Shwu-Yuan; Chiang, Cheng-Ming; Anders, Lars; Young, Richard A.; Winer, Eric; Letai, Antony; Barry, William T.; Carroll, Jason S.; Long, Henry; Brown, Myles; Liu, X. Shirley; Meyer, Clifford; Bradner, James E; Polyak, Kornelia
    Triple negative breast cancer (TNBC) is a heterogeneous and clinically aggressive disease for which there is no targeted therapy1-3. BET bromodomain inhibitors, which have shown efficacy in several models of cancer4-6, have not been evaluated in TNBC. These inhibitors displace BET bromodomain proteins such as BRD4 from chromatin by competing with their acetyllysine recognition modules, leading to inhibition of oncogenic transcriptional programs7-9. Here we report the preferential sensitivity of TNBCs to BET bromodomain inhibition in vitro and in vivo, establishing a rationale for clinical investigation and further motivation to understand mechanisms of resistance. In paired cell lines selected for acquired resistance to BET inhibition from previously sensitive TNBCs, we failed to identify gatekeeper mutations, new driver events or drug pump activation. BET-resistant TNBC cells remain dependent on wild-type BRD4, which supports transcription and cell proliferation in a bromodomain-independent manner. Proteomic studies of resistant TNBC identify strong association with MED1 and hyper-phosphorylation of BRD4 attributable to decreased activity of PP2A, identified here as a principal BRD4 serine phosphatase. Together, these studies provide a rationale for BET inhibition in TNBC and present mechanism-based combination strategies to anticipate clinical drug resistance.