title: High throughput kinase inhibitor screens reveal TRB3 and MAPK-ERK/TGFβ pathways as fundamental Notch regulators in breast cancer.
abstract: Expression of the Notch ligand Jagged 1 (JAG1) and Notch activation promote poor-prognosis in breast cancer. We used high throughput screens to identify elements responsible for Notch activation in this context. Chemical kinase inhibitor and kinase-specific small interfering RNA libraries were screened in a breast cancer cell line engineered to report Notch. Pathway analyses revealed MAPK-ERK signaling to be the predominant JAG1/Notch regulator and this was supported by gene set enrichment analyses in 51 breast cancer cell lines. In accordance with the chemical screen, kinome small interfering RNA high throughput screens identified Tribbles homolog 3 (TRB3), a known regulator of MAPK-ERK, among the most significant hits. We demonstrate that TRB3 is a master regulator of Notch through the MAPK-ERK and TGFβ pathways. Complementary in vitro and in vivo studies underscore the importance of TRB3 for tumor growth. These data demonstrate a dominant role for TRB3 and MAPK-ERK/TGFβ pathways as Notch regulators in breast cancer, establishing TRB3 as a potential therapeutic target.
authors: Campbell Family Institute for Breast Cancer Research,  Ontario Cancer Institute, Toronto, ON,  Canada M5G 2M9.
authors: Julia
authors: J
authors: Izrailit
authors: Hal K
authors: HK
authors: Berman
authors: Alessandro
authors: A
authors: Datti
authors: Jeffrey L
authors: JL
authors: Wrana
authors: Michael
authors: M
authors: Reedijk
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D045744:Cell Line, Tumor; D005260:Female; D056945:Hep G2 Cells; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D053631:Interleukin Receptor Common gamma Subunit / Q000172:deficiency / Q000235:genetics; D000072100:Jagged-1 Protein; D020935:MAP Kinase Signaling System; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D016688:Mice, Inbred NOD; D018345:Mice, Knockout; D016513:Mice, SCID; D047428:Protein Kinase Inhibitors / Q000302:isolation & purification / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D051881:Receptor, Notch1 / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000072099:Serrate-Jagged Proteins; D015398:Signal Transduction / Q000187:drug effects; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*; D023041:Xenograft Model Antitumor Assays
chemical_list: D002135:Calcium-Binding Proteins; D018797:Cell Cycle Proteins; C507942:Il2rg protein, mouse; D036341:Intercellular Signaling Peptides and Proteins; D053631:Interleukin Receptor Common gamma Subunit; C000606273:JAG1 protein, human; C000606274:Jag1 protein, mouse; D000072100:Jagged-1 Protein; D008565:Membrane Proteins; D047428:Protein Kinase Inhibitors; D051881:Receptor, Notch1; D012097:Repressor Proteins; D000072099:Serrate-Jagged Proteins; C474831:TRIB3 protein, human; D016212:Transforming Growth Factor beta; D017346:Protein Serine-Threonine Kinases