Pax8-PPARgamma regulation of transcription and metabolism in thyroid cancer

Summary

Principal Investigator: RONALD JAY KOENIG
Abstract: DESCRIPTION (provided by applicant): The long term objective is to reveal the mechanisms underlying the transcriptional activity, metabolic effects and tumorigenicity of a unique nuclear receptor transcription factor, PAX8-PPARg Fusion Protein (PPFP) that is produced as a consequence of a chromosomal translocation in follicular thyroid carcinomas. PPFP contains nearly the full sequence of the transcription factor paired box 8 (PAX8) plus the entirety of the nuclear receptor peroxisome proliferator-activated receptor g1 (PPARg1). PPFP can activate the promoters of PPAR-responsive genes, although the activity of PPFP is clearly distinct from that of PPARg. Gene expression profiling of PPFP thyroid cancers (compared to all other benign and malignant thyroid neoplasms) resulted in the identification of a PPFP cancer gene signature. The metabolic pathway most enriched in PPFP signature genes is fatty acid 2 oxidation, which is physiologically regulated by PPARs. Stably transfected clones of the non-transformed thyroid cell line PCCL3 that express PPFP in a doxycycline-dependent manner (DoxyPPFP cells) will be used to understand the importance of fatty acid metabolism in the biology of PPFP cancers, the mechanism of oncogenesis, and potential approaches to therapy. In these cells, PPFP induces many genes that are induced in PPFP thyroid cancers, and these cells form xenograft tumors and lung metastases in NOD-SCID mice. In the first Specific Aim, chromatin immunoprecipitation - deep sequencing (ChIP-Seq) will be used to identify PPFP binding sites on a genome wide level. Additional studies will evaluate whether binding to specific DNA sites requires PPFP's PAX8 DNA binding domain, its PPARg DNA binding domain, or both. Affymetrix microarray gene expression profiling will be performed on DoxyPPFP cells to allow a comparison of gene expression with genome wide DNA binding. These data also will be compared with gene expression data already obtained from PPFP cancers. Coregulatory protein recruitment by PPFP to its target genes will be evaluated. The hypothesis is that the PAX8 portion of PPFP recruits inappropriate coregulators to PPAR responsive genes, and vice versa. These studies will rely primarily on chromatin immunoprecipitation - real time PCR. Specific Aim 2 will test the hypothesis that PPFP-expressing cells are highly dependent on fatty acid 2 oxidation for cell growth;i.e., that PPFP induction of 2 oxidation creates a growth advantage. A Seahorse XF24 bioanalyzer will be used to evaluate how much energy metabolism is via glycolysis versus the TCA cycle. The use of glucose versus fatty acids as energy sources will be evaluated. The effects of PPFP on de novo fatty acid synthesis, cell proliferation and apoptosis will be assessed, to better understand the putative growth advantage brought about by PPFP. In Specific Aim 3, the effects of PPARg ligands (thiazolidinediones) on xenograft tumor and metastasis formation will be evaluated in NOD-SCID mice. The importance of PPFP functional domains on xenograft tumor formation and metastases will be assessed with DoxyPPFP cell lines expressing mutant PPFPs (for example, mutation of either the PAX8 or PPARg DNA binding domain).
Funding Period: 2010-08-01 - 2015-06-30
more information: NIH RePORT

Top Publications

  1. pmc Pioglitazone induces a proadipogenic antitumor response in mice with PAX8-PPARgamma fusion protein thyroid carcinoma
    Melissa E Dobson
    Division of Metabolism, Endocrinology and Diabetes, Unit for Laboratory Animal Medicine, Department of Pathology, University of Michigan Medical School, 1150 West Medical Center Drive, 5560 MSRB2, Ann Arbor, Michigan 48109, USA
    Endocrinology 152:4455-65. 2011
  2. pmc Genetics and epigenetics of sporadic thyroid cancer
    Dang Vu-Phan
    Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, University of Michigan, Ann Arbor, MI, USA Electronic address
    Mol Cell Endocrinol 386:55-66. 2014
  3. pmc The thyroid cancer PAX8-PPARG fusion protein activates Wnt/TCF-responsive cells that have a transformed phenotype
    Dang Vu-Phan
    Cellular and Molecular Biology Graduate Program, Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, 48109, USA
    Endocr Relat Cancer 20:725-39. 2013

Detail Information

Publications3

  1. pmc Pioglitazone induces a proadipogenic antitumor response in mice with PAX8-PPARgamma fusion protein thyroid carcinoma
    Melissa E Dobson
    Division of Metabolism, Endocrinology and Diabetes, Unit for Laboratory Animal Medicine, Department of Pathology, University of Michigan Medical School, 1150 West Medical Center Drive, 5560 MSRB2, Ann Arbor, Michigan 48109, USA
    Endocrinology 152:4455-65. 2011
    ..Furthermore, the data predict that pioglitazone will be therapeutic in patients with PPFP-positive carcinomas...
  2. pmc Genetics and epigenetics of sporadic thyroid cancer
    Dang Vu-Phan
    Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, University of Michigan, Ann Arbor, MI, USA Electronic address
    Mol Cell Endocrinol 386:55-66. 2014
    ..Anaplastic carcinomas may contain some of the above changes as well as additional mutations. Therapies that are targeted to these mutations are being used in patient care and clinical trials. ..
  3. pmc The thyroid cancer PAX8-PPARG fusion protein activates Wnt/TCF-responsive cells that have a transformed phenotype
    Dang Vu-Phan
    Cellular and Molecular Biology Graduate Program, Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, 48109, USA
    Endocr Relat Cancer 20:725-39. 2013
    ....

Research Grants30

  1. Role of the Y-Located TSPY Gene in Human Oncogenesis
    Yun Fai Chris Lau; Fiscal Year: 2013
    ..This project will shed important insights on how the Y-oncogene and X-tumor suppressor operate and how one can interfere or boost their actions respectively to treat prostate cancer. ..
  2. Regulation of Tumorigenesis and therapeutic resistance by Nrf2 in lung cancer
    Shyam Biswal; Fiscal Year: 2013
    ..Successful completion of this project will develop a new therapeutic strategy for lung cancer treatment. ..
  3. HORMONAL REGULATION OF BLOOD PRESSURE
    Michal Laniado Schwartzman; Fiscal Year: 2013
    ..ular tone, in the pathophysiology of hypertension and cardiovascular disease. ..
  4. Inflammatory responses of vascular cells
    Paul L Fox; Fiscal Year: 2013
    ..abstract_text> ..
  5. HORMONAL REGULATION OF MAMMALIAN GENE EXPRESSION
    Ronald M Evans; Fiscal Year: 2013
    ....
  6. In vivo therapy and mechanisms of PAX8-PPARgamma thyroid cancer
    RONALD JAY KOENIG; Fiscal Year: 2013
    ..Overall, these studies will help elucidate mechanisms through which PPFP contributes to thyroid cancer and will help identify novel therapies both in the transgenic mouse model and in patients. ..
  7. Role of 11q23 Chromosome Abnormalities in the Causation of Acute Leukemia
    Carlo M Croce; Fiscal Year: 2013
    ..abstract_text> ..
  8. Interrogating Epigenetic Changes in Cancer Genomes
    Tim H M Huang; Fiscal Year: 2013
    ..abstract_text> ..
  9. Mechanistic Pharmacology of Anti-Mitotics and Apoptosis Regulation
    Timothy J Mitchison; Fiscal Year: 2013
    ..In aim 4 we will pursue several approaches towards translating mechanistic understanding from aims 1-3 into improved patient care. ..
  10. UNMC EPPLEY CANCER CENTER SUPPORT GRANT
    Kenneth H Cowan; Fiscal Year: 2013
    ....