EGF receptor, a member of the ErbB family of receptor tyrosine kinases, plays essential physiological roles in development and mainatenance of epithelial tissues by genrating cell proliferation, survival, differentiation and migration signals in response to specific ligands. Activation of ErbB receptors is linked to etiology of human cancer, including tumor initiation and progression. ErbB receptors also mediate cytoprotection from chemotherapy and radiation, and represent targets for radio- and chemo-sentization of tumors. Elucidating molecular mechanisms that control signaling potency of ErbB receptos is therefore a major goal in cancer biology. Ligand-induced downregulation, representing a balance between lysosomal degradation and recycling to cell sureface, constitutes a major determinant of signaling potency of ErbB receptors. We and others have established that Cbl-family ubiquitin ligase proteins play a crucial role in EGFR down-regulation by faciliatating receptor ubiquitination. The latter is recognized by endosomal ESCRT protein complexes as a signal for lysosomal sorting of the receptor. The precise endocytic step(s) and mechanisms by which Cbl and its closely related, functionally reducndant, family member Cbl-b physiologically operate remain to be established. The biological consequence of negative regulation by Cbl proteins on physiological and oncogenic roles of EGFR also remain to be uncovered. This proposal will utilize unique Cbl/Cbl-b null murine MEF and mammary epithelial cells as wel as Cbl/Cbl-b knockdown human mammary epithelial cells to address whether Cbl proteins selectively control lysosomal sorting of EGFR or if they are also required for initial internalization;reconstitiution of Cbl/Cbl-b deficient cells will provide structural basis for negative regulation of EGFR by Cbl proteins. By using proteomic and gene expression analyses, we will investigate if Cbl proteins provide global or selective regulation of certain signaling modules and link these to biological outputs of EGFR signaling. Finally, we will use mammary gland targeted Cbl/Cbl-b knockout in mice to address the functional consequences of EGFR regulation by Cbl proteins during physiological mammary galnd development and in EGFR-mediated mammary oncogenesis. Insights gained from these studies should further our understanding of receptor tyrosine kinase down-regulation, and may identify newer targets to rationally design anti-cancer agents and to potentiate existing chemotherapeutic and radiation-based cancer cell killing, by countering receptor tyrosine kinase-mediated cytoprotection.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA099163-10
Application #
7800449
Study Section
Molecular Oncogenesis Study Section (MONC)
Program Officer
Salnikow, Konstantin
Project Start
2002-12-01
Project End
2013-04-30
Budget Start
2010-05-01
Budget End
2011-04-30
Support Year
10
Fiscal Year
2010
Total Cost
$338,884
Indirect Cost
Name
University of Nebraska Medical Center
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
168559177
City
Omaha
State
NE
Country
United States
Zip Code
68198
Mohapatra, Bhopal; Zutshi, Neha; An, Wei et al. (2017) An essential role of CBL and CBL-B ubiquitin ligases in mammary stem cell maintenance. Development 144:1072-1086
Nadeau, Scott A; An, Wei; Mohapatra, Bhopal C et al. (2017) Structural Determinants of the Gain-of-Function Phenotype of Human Leukemia-associated Mutant CBL Oncogene. J Biol Chem 292:3666-3682
Cypher, Luke R; Bielecki, Timothy Alan; Huang, Lu et al. (2016) CSF-1 receptor signalling is governed by pre-requisite EHD1 mediated receptor display on the macrophage cell surface. Cell Signal 28:1325-35
Cypher, Luke R; Bielecki, Timothy Alan; Huang, Lu et al. (2016) Corrigendum to CSF-1 receptor signalling is governed by pre-requisite EHD1 mediated receptor display on the macrophage cell surface [Cell Signalling 2016 Sep.; 28(9): 1325-35]. Cell Signal 28:1933
An, Wei; Mohapatra, Bhopal C; Zutshi, Neha et al. (2016) VAV1-Cre mediated hematopoietic deletion of CBL and CBL-B leads to JMML-like aggressive early-neonatal myeloproliferative disease. Oncotarget 7:59006-59016
William, Basem M; An, Wei; Feng, Dan et al. (2016) Fasudil, a clinically safe ROCK inhibitor, decreases disease burden in a Cbl/Cbl-b deficiency-driven murine model of myeloproliferative disorders. Hematology 21:218-24
Bhattacharyya, Sohinee; Rainey, Mark A; Arya, Priyanka et al. (2016) Endocytic recycling protein EHD1 regulates primary cilia morphogenesis and SHH signaling during neural tube development. Sci Rep 6:20727
Raja, Srikumar M; Desale, Swapnil S; Mohapatra, Bhopal et al. (2016) Marked enhancement of lysosomal targeting and efficacy of ErbB2-targeted drug delivery by HSP90 inhibition. Oncotarget 7:10522-35
Goetz, Benjamin; An, Wei; Mohapatra, Bhopal et al. (2016) A novel CBL-Bflox/flox mouse model allows tissue-selective fully conditional CBL/CBL-B double-knockout: CD4-Cre mediated CBL/CBL-B deletion occurs in both T-cells and hematopoietic stem cells. Oncotarget 7:51107-51123
Mir, Riyaz A; Lovelace, Jeff; Schafer, Nicholas P et al. (2016) Biophysical characterization and modeling of human Ecdysoneless (ECD) protein supports a scaffolding function. AIMS Biophys 3:195-208

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