The central hypothesis of this research proposal is that new targets and compounds for cancer therapy can be coordinately revealed by a high throughput screen for genes and small molecules that mimic the effects of the molecular scaffold Kinase Suppressor of Ras 1 (KSR1). KSR1-/- mice and cells derived from those mice grow and develop normally but are resistant to tumorigenesis and transformation by oncogenic Ras. These observations suggest that KSR1, gene products downstream of KSR1, or gene products with functional characteristics similar to KSR1, may serve as targets for therapeutic manipulation in tumors bearing oncogenic Ras, but with reduced or minimal toxicity to normal tissue. We developed a Gene Expression High Throughput Screen (GE-HTS) that can coordinately identify effectors mimicking KSR1 function and small molecule inhibitors of those targets that selectively inhibit tumor cell growth, but not growth of normal colonic epithelium. Subsequent analysis demonstrated that human colon tumor cell lines expressing mutated, activated Ras exhibit KSR1-dependent expression of transcriptional regulators essential for maintenance of the transformed phenotype. Immortalized normal human colonic epithelial cells did not express these regulators. These data identify a previously unrecognized signaling network that promotes colon tumor cell survival. RNAi based GE- HTS will be used to define that network and test its potential as a therapeutic target by characterizing the role of transcriptional regulators and the identification of additional network effectors regulating KSR1-dependent tumorigenic potential. GE-HTS using a natural products library will be used to identify small molecule inhibitors of network effectors. These effectors and small molecules will be tested in vitro and in in vivo orthotopic tumor models to validate their ability to regulate tumor development and maintenance.

Public Health Relevance

When mutated and activated, the protein product of the Ras gene contributes to 30% of human cancer including 50% of colon cancers. We previously identified a scaffold protein that is critical to the complete formation of tumors by activated Ras protein, but seemingly dispensable to normal cells. We used this observation to develop an assay that would detect similarly acting proteins and chemical compounds that might inhibit their function. The goal of this research is to identify and validate those proteins and compounds as targets and potential therapeutics, respectively, for the treatment of cancer.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
1R01CA157774-01A1
Application #
8238634
Study Section
Cancer Genetics Study Section (CG)
Program Officer
Forry, Suzanne L
Project Start
2012-04-12
Project End
2017-03-31
Budget Start
2012-04-12
Budget End
2013-03-31
Support Year
1
Fiscal Year
2012
Total Cost
$319,933
Indirect Cost
$104,490
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
McCall, Jamie L; Gehring, Drew; Clymer, Beth K et al. (2016) KSR1 and EPHB4 Regulate Myc and PGC1β To Promote Survival of Human Colon Tumors. Mol Cell Biol 36:2246-61
Guo, Lili; Costanzo-Garvey, Diane L; Smith, Deandra R et al. (2016) Cell non-autonomous regulation of hepatic IGF-1 and neonatal growth by Kinase Suppressor of Ras 2 (KSR2). Sci Rep 6:32093
Bohovych, Iryna; Fernandez, Mario R; Rahn, Jennifer J et al. (2015) Metalloprotease OMA1 Fine-tunes Mitochondrial Bioenergetic Function and Respiratory Supercomplex Stability. Sci Rep 5:13989
Fisher, Kurt W; Das, Binita; Kim, Hyun Seok et al. (2015) AMPK Promotes Aberrant PGC1β Expression To Support Human Colon Tumor Cell Survival. Mol Cell Biol 35:3866-79
Kortum, Robert L; Fernandez, Mario R; Costanzo-Garvey, Diane L et al. (2014) Caveolin-1 is required for kinase suppressor of Ras 1 (KSR1)-mediated extracellular signal-regulated kinase 1/2 activation, H-RasV12-induced senescence, and transformation. Mol Cell Biol 34:3461-72
Henry, MaLinda D; Costanzo-Garvey, Diane L; Klutho, Paula J et al. (2014) Obesity-dependent dysregulation of glucose homeostasis in kinase suppressor of ras 2-/- mice. Physiol Rep 2:
Guo, Lili; Volle, Deanna J; Lewis, Robert E (2014) Identification of a truncated kinase suppressor of Ras 2 mRNA in sperm. FEBS Open Bio 4:420-5
Peters, Staci L; Hlady, Ryan A; Opavska, Jana et al. (2013) Essential role for Dnmt1 in the prevention and maintenance of MYC-induced T-cell lymphomas. Mol Cell Biol 33:4321-33
Potts, Malia B; Kim, Hyun Seok; Fisher, Kurt W et al. (2013) Using functional signature ontology (FUSION) to identify mechanisms of action for natural products. Sci Signal 6:ra90
Fernandez, Mario R; Henry, MaLinda D; Lewis, Robert E (2012) Kinase suppressor of Ras 2 (KSR2) regulates tumor cell transformation via AMPK. Mol Cell Biol 32:3718-31

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