TY  - JOUR
A1  - Zanucco, Emanuele
A1  - Götz, Rudolf
A1  - Potapenko, Tamara
A1  - Carraretto, Irene
A1  - Ceteci, Semra
A1  - Ceteci, Fatih
A1  - Seeger, Werner
A1  - Savai, Rajkumar
A1  - Rapp, Ulf R.
T1  - Expression of B-RAF V600E in Type II Pneumocytes Causes Abnormalities in Alveolar Formation, Airspace Enlargement and Tumor Formation in Mice
JF  - PLOS ONE
N2  - Growth factor induced signaling cascades are key regulatory elements in tissue development, maintenance and regeneration. Perturbations of these cascades have severe consequences, leading to developmental disorders and neoplastic diseases. As a major function in signal transduction, activating mutations in RAF family kinases are the cause of human tumorigenesis, where B-RAF V600E has been identified as the prevalent mutant. In order to address the oncogenic function of B-RAF V600E, we have generated transgenic mice expressing the activated oncogene specifically in lung alveolar epithelial type II cells. Constitutive expression of B-RAF V600E caused abnormalities in alveolar epithelium formation that led to airspace enlargements. These lung lesions showed signs of tissue remodeling and were often associated with chronic inflammation and low incidence of lung tumors. The inflammatory cell infiltration did not precede the formation of the lung lesions but was rather accompanied with late tumor development. These data support a model where the continuous regenerative process initiated by oncogenic B-RAF-driven alveolar disruption provides a tumor-promoting environment associated with chronic inflammation.
KW  - obstructive pulmonary-disease
KW  - lung-cancer
KW  - somatic mutations
KW  - epithelial-cells
KW  - mouse models
KW  - protein
KW  - kinase
KW  - inflammation
KW  - activation
KW  - pathway
Y1  - 2011
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-137061
VL  - 6
IS  - 12
ER  - 
TY  - JOUR
A1  - Ceteci, Fatih
A1  - Xu, Jiajia
A1  - Ceteci, Semra
A1  - Zanucco, Emanuele
A1  - Thakur, Chitra
A1  - Rapp, Ulf R.
T1  - Conditional Expression of Oncogenic C-RAF in Mouse Pulmonary Epithelial Cells Reveals Differential Tumorigenesis and Induction of Autophagy Leading to Tumor Regression
JF  - Neoplasia
N2  - Here we describe a novel conditional mouse lung tumor model for investigation of the pathogenesis of human lung cancer. On the basis of the frequent involvement of the Ras-RAF-MEK-ERK signaling pathway in human non-small cell lung carcinoma (NSCLC), we have explored the target cell availability, reversibility, and cell type specificity of transformation by oncogenic C-RAF. Targeting expression to alveolar type II cells or to Clara cells, the two likely precursors of human NSCLC, revealed differential tumorigenicity between these cells. Whereas expression of oncogenic C-RAF in alveolar type II cells readily induced multifocal macroscopic lung tumors independent of the developmental state, few tumors with type II pneumocytes features and incomplete penetrance were found when targeted to Clara cells. Induced tumors did not progress and were strictly dependent on the initiating oncogene. Deinduction of mice resulted in tumor regression due to autophagy rather than apoptosis. Induction of autophagic cell death in regressing lung tumors suggests the use of autophagy enhancers as a treatment choice for patients with NSCLC.
KW  - Human lung-cancer
KW  - K-RAS
KW  - Induced senescence
KW  - Gene-expression
KW  - In-vivo
KW  - Kinase pathway
KW  - P53
KW  - Activation
KW  - Model
KW  - Adenocarcinomas
Y1  - 2011
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-134347
VL  - 13
IS  - 11
ER  -