The precise control of gene transcription is of fundamental importance to prevent pathological disorders and carcinogenesis. Dysregulation of the transcription factor ER81 is involved in breast cancer, where ER81 is a downstream effector of HER2/Neu, and in those Ewing's sarcomas, where the ER81 gene is affected by a chromosomal translocation. They hypothesize that ER81 is activated by HER2/Neu via the mitogen-activated protein kinase signaling pathways. Activated ER81, in conjunction with the coactivators CBP and p300, leads to stimulation of target genes, similarly as in Ewing's sarcoma due to the presence of a constitutively active EWS-ER81 fusion protein. This dysregulation of ER81 target genes leads to pathological levels of certain proteins contributing to cell transformation.
Two specific aims are proposed to test these hypothesis. (1) They will study how mitogen-activated protein kinases stimulate ER81 upon HER2/Neu overexpression and how CBP/p300 support ER81-dependent transcription. Utilizing in vitro and in vivo phoyphorylation studies, they will determine the phosphoylation sites within ER81 and identify the protein kinases involved. Mutation of the phosphorylation sites will demonstrate how they affect ER81 and identify the protein kinases involved. Mutation of the phosphorylation sites will demonstrate how they affect ER81 function. Furthermore, it will be analyzed whether acetylation of ER81 by CBP/p300 regulates its transactivation function. Additionally, the impact of HER2/Neu on the interaction between ER81 and CBP/p300 will be investigated. (2) In order to identify ER81 target genes, human cells will be transfected with the constitutively active EWS-ER81 molecule. RNA from these cells and control cells will be employed to identify target genes utilizing DNA microarrays. Identified target genes will then be analyzed for their capacity to transform cells and contribute to metastasis. The analysis how the ER81-CBP/p300 complex is stimulated by HER2/Neu may point out novel strategies of interference with breast cancer development. The identification of ER81 target genes will shed light on how the pathological disorders in breast cancer and Ewing's sarcoma are elicited and how they could be cured.
|Janknecht, Ralf (2005) EWS-ETS oncoproteins: the linchpins of Ewing tumors. Gene 363:1-14|
|Dowdy, Sean C; Mariani, Andrea; Reinholz, Monica M et al. (2005) Overexpression of the TGF-beta antagonist Smad7 in endometrial cancer. Gynecol Oncol 96:368-73|
|Fuchs, Bruno; Inwards, Carrie Y; Janknecht, Ralf (2004) Vascular endothelial growth factor expression is up-regulated by EWS-ETS oncoproteins and Sp1 and may represent an independent predictor of survival in Ewing's sarcoma. Clin Cancer Res 10:1344-53|
|Goueli, Basem S; Janknecht, Ralf (2004) Upregulation of the Catalytic Telomerase Subunit by the Transcription Factor ER81 and Oncogenic HER2/Neu, Ras, or Raf. Mol Cell Biol 24:25-35|
|Goel, Apollina; Janknecht, Ralf (2004) Concerted activation of ETS protein ER81 by p160 coactivators, the acetyltransferase p300 and the receptor tyrosine kinase HER2/Neu. J Biol Chem 279:14909-16|
|Janknecht, Ralf (2004) On the road to immortality: hTERT upregulation in cancer cells. FEBS Lett 564:9-13|
|Goel, Apollina; Janknecht, Ralf (2003) Acetylation-mediated transcriptional activation of the ETS protein ER81 by p300, P/CAF, and HER2/Neu. Mol Cell Biol 23:6243-54|
|Janknecht, Ralf (2003) Regulation of the ER81 transcription factor and its coactivators by mitogen- and stress-activated protein kinase 1 (MSK1). Oncogene 22:746-55|
|Fuchs, Bruno; Inwards, Carrie Y; Janknecht, Ralf (2003) Upregulation of the matrix metalloproteinase-1 gene by the Ewing's sarcoma associated EWS-ER81 and EWS-Fli-1 oncoproteins, c-Jun and p300. FEBS Lett 553:104-8|
|Dowdy, Sean C; Mariani, Andrea; Janknecht, Ralf (2003) HER2/Neu- and TAK1-mediated up-regulation of the transforming growth factor beta inhibitor Smad7 via the ETS protein ER81. J Biol Chem 278:44377-84|
Showing the most recent 10 out of 14 publications