TY  - JOUR
A1  - Meder, Lydia
A1  - König, Katharina
A1  - Ozretić, Luka
A1  - Schultheis, Anne M.
A1  - Ueckeroth, Frank
A1  - Ade, Carsten P.
A1  - Albus, Kerstin
A1  - Boehm, Diana
A1  - Rommerscheidt-Fuss, Ursula
A1  - Florin, Alexandra
A1  - Buhl, Theresa
A1  - Hartmann, Wolfgang
A1  - Wolf, Jürgen
A1  - Merkelbach-Bruse, Sabine
A1  - Eilers, Martin
A1  - Perner, Sven
A1  - Heukamp, Lukas C.
A1  - Buettner, Reinhard
T1  - NOTCH, ASCL1, p53 and RB alterations define an alternative pathway driving neuroendocrine and small cell lung carcinomas
JF  - International Journal of Cancer
N2  - Small cell lung cancers (SCLCs) and extrapulmonary small cell cancers (SCCs) are very aggressive tumors arising de novo as primary small cell cancer with characteristic genetic lesions in RB1 and TP53. Based on murine models, neuroendocrine stem cells of the terminal bronchioli have been postulated as the cellular origin of primary SCLC. However, both in lung and many other organs, combined small cell/non-small cell tumors and secondary transitions from non-small cell carcinomas upon cancer therapy to neuroendocrine and small cell tumors occur. We define features of "small cell-ness" based on neuroendocrine markers, characteristic RB1 and TP53 mutations and small cell morphology. Furthermore, here we identify a pathway driving the pathogenesis of secondary SCLC involving inactivating NOTCH mutations, activation of the NOTCH target ASCL1 and canonical WNT-signaling in the context of mutual bi-allelic RB1 and TP53 lesions. Additionaly, we explored ASCL1 dependent RB inactivation by phosphorylation, which is reversible by CDK5 inhibition. We experimentally verify the NOTCH-ASCL1-RB-p53 signaling axis in vitro and validate its activation by genetic alterations in vivo. We analyzed clinical tumor samples including SCLC, SCC and pulmonary large cell neuroendocrine carcinomas and adenocarcinomas using amplicon-based Next Generation Sequencing, immunohistochemistry and fluorescence in situ hybridization. In conclusion, we identified a novel pathway underlying rare secondary SCLC which may drive small cell carcinomas in organs other than lung, as well.
KW  - lung cancer
KW  - small cell lung cancer
KW  - achaete-scute homolog 1
KW  - neurogenic locus notch homolog
KW  - retinoblastoma protein
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-190853
VL  - 138
IS  - 4
ER  - 
TY  - JOUR
A1  - Lorenzin, Francesca
A1  - Benary, Uwe
A1  - Baluapuri, Apoorva
A1  - Walz, Susanne
A1  - Jung, Lisa Anna
A1  - von Eyss, Björn
A1  - Kisker, Caroline
A1  - Wolf, Jana
A1  - Eilers, Martin
A1  - Wolf, Elmar
T1  - Different promoter affinities account for specificity in MYC-dependent gene regulation
JF  - eLife
N2  - Enhanced expression of the MYC transcription factor is observed in the majority of tumors. Two seemingly conflicting models have been proposed for its function: one proposes that MYC enhances expression of all genes, while the other model suggests gene-specific regulation. Here, we have explored the hypothesis that specific gene expression profiles arise since promoters differ in affinity for MYC and high-affinity promoters are fully occupied by physiological levels of MYC. We determined cellular MYC levels and used RNA- and ChIP-sequencing to correlate promoter occupancy with gene expression at different concentrations of MYC. Mathematical modeling showed that binding affinities for interactions of MYC with DNA and with core promoter-bound factors, such as WDR5, are sufficient to explain promoter occupancies observed in vivo. Importantly, promoter affinity stratifies different biological processes that are regulated by MYC, explaining why tumor-specific MYC levels induce specific gene expression programs and alter defined biological properties of cells.
KW  - MYC
KW  - promoter affinity
KW  - human
KW  - mathematical modeling
KW  - mouse
KW  - ChIP-sequencing
KW  - MIZ1
KW  - cancer biology
KW  - cell biology
KW  - WDR5
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-162913
VL  - 5
ER  -