The overall goal of this proposal is to characterize the normal regulation of the p27 kip1 protein, and how loss of this regulation contributes to multi-step tumorigenesis. p27kip1 is a member of the Cip/Kip family of cyclin-dependent kinase (CDK) inhibitors, which bind to an inhibit CDKs in response to anti-proliferative signals. P27 expression is regulated by physiologic stimuli such as mitogen. Conversely, loss of p27 expression is associated with increased cell division and tumorigenesis. Low p27 expression is associated with increased cell division and tumorigenesis. Low p27 expression correlates with poor outcome in many human cancers, and p27 function as a tumor suppressor in mice. The mechanism of p27 loss in tumors and how this participates in neoplastic transformation is largely unknown. The experiments described in this proposal address both of these issues. P27 abundance is controlled at many levels, including proteolysis, translation, phosphorylation, and subcellular localization. In this proposal, we will define the nuclear transport mechanisms of p27, and how they are integrated with other modes of p27 control to globally regulate p27 abundance and function. We have identified a novel nuclear pore protein, termed PASSTA, that interacts with p27 and created a targeted deletion of PASSTA in mice that causes embryonic lethality, neural tube defects, and dwarfism. We will now test the hypothesis that PASSTA mediates interactions between p27 and the nuclear pore, and determine the mechanisms and physiologic consequences of these interactions in normal and tumor cells. The mechanism of tumor suppression by p27 is not clearly understood. We have established a mouse model to identify genes that cooperate with p27 loss in multi-step transformations by using insertional mutagenesis to induce lymphomas in p27 null and wild type mice. P27 null animals exhibit greatly accelerated lymphogenesis. We will now identify the activated genes in these lymphomas, determine how they synergize with p27 loss, and examine if they are similarly involved with human cancer associated with low p27 expression. Ultimately, understanding the mechanisms underlying p27 regulation in normal and neoplastic cells may lead to the identification of novel therapeutic targets for the treatment of cancer and other diseases.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA084069-05
Application #
6697038
Study Section
Cell Development and Function Integrated Review Group (CDF)
Program Officer
Spalholz, Barbara A
Project Start
2000-02-16
Project End
2005-01-31
Budget Start
2004-02-01
Budget End
2005-01-31
Support Year
5
Fiscal Year
2004
Total Cost
$334,264
Indirect Cost
Name
Fred Hutchinson Cancer Research Center
Department
Type
DUNS #
078200995
City
Seattle
State
WA
Country
United States
Zip Code
98109
Toledo, Chad M; Ding, Yu; Hoellerbauer, Pia et al. (2015) Genome-wide CRISPR-Cas9 Screens Reveal Loss of Redundancy between PKMYT1 and WEE1 in Glioblastoma Stem-like Cells. Cell Rep 13:2425-2439
Davis, Ryan J; Welcker, Markus; Clurman, Bruce E (2014) Tumor suppression by the Fbw7 ubiquitin ligase: mechanisms and opportunities. Cancer Cell 26:455-64
Welcker, Markus; Clurman, Bruce E (2014) Oncoprotein ubiquitylation: dimers, degrons, and degradation. Cell Cycle 13:1829-30
Hughes, Bridget T; Sidorova, Julia; Swanger, Jherek et al. (2013) Essential role for Cdk2 inhibitory phosphorylation during replication stress revealed by a human Cdk2 knockin mutation. Proc Natl Acad Sci U S A 110:8954-9
Pierce, Nathan W; Lee, J Eugene; Liu, Xing et al. (2013) Cand1 promotes assembly of new SCF complexes through dynamic exchange of F box proteins. Cell 153:206-15
Davis, Michael A; Larimore, Elizabeth A; Fissel, Brian M et al. (2013) The SCF-Fbw7 ubiquitin ligase degrades MED13 and MED13L and regulates CDK8 module association with Mediator. Genes Dev 27:151-6
Sancho, Rocio; Blake, Sophia M; Tendeng, Christian et al. (2013) Fbw7 repression by hes5 creates a feedback loop that modulates Notch-mediated intestinal and neural stem cell fate decisions. PLoS Biol 11:e1001586
Hizli, Asli A; Chi, Yong; Swanger, Jherek et al. (2013) Phosphorylation of eukaryotic elongation factor 2 (eEF2) by cyclin A-cyclin-dependent kinase 2 regulates its inhibition by eEF2 kinase. Mol Cell Biol 33:596-604
Welcker, Markus; Larimore, Elizabeth A; Swanger, Jherek et al. (2013) Fbw7 dimerization determines the specificity and robustness of substrate degradation. Genes Dev 27:2531-6
Grim, Jonathan E; Knoblaugh, Sue E; Guthrie, Katherine A et al. (2012) Fbw7 and p53 cooperatively suppress advanced and chromosomally unstable intestinal cancer. Mol Cell Biol 32:2160-7

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