Abstract

The KLF4 transcription factor is important in cell fate and differentiation of epithelial cells. KLF4 rapidly initiates cutaneous squamous cell carcinoma (SCC) in mice, and is deregulated at an early step in human skin tumor progression. Using a conditional KLF4-ER fusion protein, we identified the cell fate determinant Notch 1 as a transcriptional target of KLF4. In cultured cells, in transgenic mice and in human tumors, KLF4 expression is associated with expression of Notchl, Notchl ligands, and Notchl effectors such as Cyclin D1. Transformation of RK3E epithelial cells requires Notchl. These studies identify a KLF4-Notch1 pathway that appears important in cell fate specification of normal epithelial cells and tumor cells. Mutagenesis of KLF4 identified dominant negative (DN) alleles that block transformation in vitro by KLF4. KLF4-DNs identify a role of KLF4 in growth of specific human cell types in vitro, and in transformation by specific transforming oncogenes such as ErbB2 and c-MYC. To study the role of Klf4 in cutaneous SCC we developed a novel highly penetrant model of SCC by administering carcinogens to genetically-engineered mice. Tumors were histologically similar to human SCC, and expressed SCC markers such as p53, keratin 14, and Notch! SCCs that developed in this model included KLF4-positive tumors and some tumors that were KLF4-negative. To understand the mechanisms that normally regulate KLF4, we will study the role of posttranslational modifications in the DN activity of mutant KLF4 proteins (Aim 1). The role of endogenous Klf4 in tumor initiation and maintenance will be studied in the new SCC mouse model using conditional, Cre-mediated deletion of Klf4/LoxP alleles, and by tetracycline-inducible expression of siRNA or KLF4-DN in transgenic mice (Aim 2). Using similar loss- and gain-of-function strategies, the role of Klf4 in mammary epithelial development and in transformation by ErbB2 will be determined (Aim 3).
In Aim 4, a posttranslational control that appears responsible for upregulation of Klf4 transcripts in mouse and human SCC will be analyzed by identifying RNA destabilizing elements in the KLF4 cDNA. These studies may provide support of a role for KLF4 and Notchl in pathogenesis of common human cancers such as SCC and breast cancer. Thus, completion of the studies would identify this pathway as a target for prevention and treatment, and provide new animal models in which to assess such therapies.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA127405-05
Application #
7998180
Study Section
Tumor Cell Biology Study Section (TCB)
Program Officer
Watson, Joanna M
Project Start
2007-03-01
Project End
2011-12-31
Budget Start
2011-01-01
Budget End
2011-12-31
Support Year
5
Fiscal Year
2011
Total Cost
$270,000
Indirect Cost

  Institution

Name
West Virginia University
Department
Biochemistry
Type
Schools of Medicine
DUNS #
191510239
City
Morgantown
State
WV
Country
United States
Zip Code
26506

  Publications

Farrugia, Mark K; Vanderbilt, Daniel B; Salkeni, Mohamad A et al. (2016) Kruppel-like Pluripotency Factors as Modulators of Cancer Cell Therapeutic Responses. Cancer Res 76:1677-82
Lin, C-C; Sharma, S B; Farrugia, M K et al. (2015) Kruppel-like factor 4 signals through microRNA-206 to promote tumor initiation and cell survival. Oncogenesis 4:e155
Sharma, Sriganesh B; Ruppert, John Michael (2015) MicroRNA-Based Therapeutic Strategies for Targeting Mutant and Wild Type RAS in Cancer. Drug Dev Res 76:328-42
Deng, Wentao; Vanderbilt, Daniel B; Lin, Chen-Chung et al. (2015) SOX9 inhibits ?-TrCP-mediated protein degradation to promote nuclear GLI1 expression and cancer stem cell properties. J Cell Sci 128:1123-38
Farrugia, M K; Sharma, S B; Lin, C-C et al. (2015) Regulation of anti-apoptotic signaling by Kruppel-like factors 4 and 5 mediates lapatinib resistance in breast cancer. Cell Death Dis 6:e1699
Sharma, Sriganesh B; Lin, Chen-Chung; Farrugia, Mark K et al. (2014) MicroRNAs 206 and 21 cooperate to promote RAS-extracellular signal-regulated kinase signaling by suppressing the translation of RASA1 and SPRED1. Mol Cell Biol 34:4143-64
Lin, Chen-Chung; Liu, Ling-Zhi; Addison, Joseph B et al. (2011) A KLF4-miRNA-206 autoregulatory feedback loop can promote or inhibit protein translation depending upon cell context. Mol Cell Biol 31:2513-27
Liu, Zhaoli; Teng, Lihong; Bailey, Sarah K et al. (2009) Epithelial transformation by KLF4 requires Notch1 but not canonical Notch1 signaling. Cancer Biol Ther 8:1840-51
Jiang, Wen; Deng, Wentao; Bailey, Sarah K et al. (2009) Prevention of KLF4-mediated tumor initiation and malignant transformation by UAB30 rexinoid. Cancer Biol Ther 8:289-98
Lubet, Ronald A; Boring, Daniel; Steele, Vernon E et al. (2009) Lack of efficacy of the statins atorvastatin and lovastatin in rodent mammary carcinogenesis. Cancer Prev Res (Phila Pa) 2:161-7

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