TY  - JOUR
A1  - Wiegering, Armin
A1  - Pfann, Christina
A1  - Uthe, Friedrich Wilhelm
A1  - Otto, Christoph
A1  - Rycak, Lukas
A1  - Mäder, Uwe
A1  - Gasser, Martin
A1  - Waaga-Gasser, Anna-Maria
A1  - Eilers, Martin
A1  - Germer, Christoph-Thomas
T1  - CIP2A Influences Survival in Colon Cancer and Is Critical for Maintaining Myc Expression
JF  - PLoS ONE
N2  - The cancerous inhibitor of protein phosphatase 2A (CIP2A) is an oncogenic factor that stabilises the c-Myc protein. CIP2A is overexpressed in several tumours, and expression levels are an independent marker for long-term outcome. To determine whether CIP2A expression is elevated in colon cancer and whether it might serve as a prognostic marker for survival, we analysed CIP2A mRNA expression by real-time PCR in 104 colon cancer samples. CIP2A mRNA was overexpressed in colon cancer samples and CIP2A expression levels correlated significantly with tumour stage. We found that CIP2A serves as an independent prognostic marker for disease-free and overall survival. Further, we investigated CIP2A-dependent effects on levels of c-Myc, Akt and on cell proliferation in three colon cancer cell lines by silencing CIP2A using small interfering (si) and short hairpin (sh) RNAs. Depletion of CIP2A substantially inhibited growth of colon cell lines and reduced c-Myc levels without affecting expression or function of the upstream regulatory kinase, Akt. Expression of CIP2A was found to be dependent on MAPK activity, linking elevated c-Myc expression to deregulated signal transduction in colon cancer.
KW  - caco-2 cells
KW  - carcinomas
KW  - colon
KW  - colorectal cancer
KW  - MAPK signaling cascades
KW  - metastasis
KW  - protein expression
KW  - small interferring RNA
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-97252
ER  - 
TY  - JOUR
A1  - Peter, Stefanie
A1  - Bultinck, Jennyfer
A1  - Myant, Kevin
A1  - Jaenicke, Laura A.
A1  - Walz, Susanne
A1  - Müller, Judith
A1  - Gmachl, Michael
A1  - Treu, Matthias
A1  - Boehmelt, Guido
A1  - Ade, Casten P.
A1  - Schmitz, Werner
A1  - Wiegering, Armin
A1  - Otto, Christoph
A1  - Popov, Nikita
A1  - Sansom, Owen
A1  - Kraut, Norbert
A1  - Eilers, Martin
T1  - H Tumor cell-specific inhibition of MYC function using small molecule inhibitors of the HUWE1 ubiquitin ligase
JF  - EMBO Molecular Medicine
N2  - Deregulated expression of MYC is a driver of colorectal carcinogenesis, necessitating novel strategies to inhibit MYC function. The ubiquitin ligase HUWE1 (HECTH9, ARF-BP1, MULE) associates with both MYC and the MYC-associated protein MIZ1. We show here that HUWE1 is required for growth of colorectal cancer cells in culture and in orthotopic xenograft models. Using high-throughput screening, we identify small molecule inhibitors of HUWE1, which inhibit MYC-dependent transactivation in colorectal cancer cells, but not in stem and normal colon epithelial cells. Inhibition of HUWE1 stabilizes MIZ1. MIZ1 globally accumulates on MYC target genes and contributes to repression of MYC-activated target genes upon HUWE1 inhibition. Our data show that transcriptional activation by MYC in colon cancer cells requires the continuous degradation of MIZ1 and identify a novel principle that allows for inhibition of MYC function in tumor cells.
KW  - colorectal cancer
KW  - HUWE1
KW  - MIZ1
KW  - MYC
KW  - ubiquitination
KW  - cancer
KW  - digestive system
KW  - pharmacology
KW  - drug discovery
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-118132
SN  - 1757-4684
VL  - 6
IS  - 12
ER  -