AbstractsBiology & Animal Science

Impact of growth factors, therapeutic inhibitors and cytostatic compounds on the response of non-small-cell lung carcinoma cell lines

by Ruth Merkle

Institution: Universität Heidelberg
Department: The Faculty of Bio Sciences
Degree: PhD
Year: 2015
Record ID: 1110440
Full text PDF: http://www.ub.uni-heidelberg.de/archiv/18741


Lung cancer with its most prevalent form non-small-cell lung carcinoma (NSCLC) is one of the leading causes of cancer-related deaths worldwide and is characterized by early metastatic spread. TGF-β is one of the growth factors that can be involved in the regulation of this process. Lung cancer is generally treated with chemotherapeutic drugs, e.g. with cisplatin, often in combination with different inhibitors, such as MEK inhibitors (MEKi). An important obstacle for lung cancer patients is the chemotherapy-induced anemia that can be treated with erythropoietin (Epo). Unfortunately, Epo was found to have tumor-stimulating effects. To establish reliable and reproducible experimental conditions, standard operating procedures for the NSCLC cell lines H1975 and H838 were developed. Cisplatin was shown to induce apoptosis in a dose-dependent manner in H838 cells. The MEKi U0126 was found to rescue H838 cells of cisplatin-induced apoptosis by arresting the cells in the cell cycle phase G1 and this effect could be reproduced with clinically relevant MEK inhibitors. Epo treatment of the cell line H838 resulted in decreased cisplatin sensitivity. To identify the differences in Epo-induced signaling in erythroid progenitor cells and the cell line H838, a dynamic pathway model was established that was able to describe the Epo-induced dynamics of the activation of the JAK2/STAT5 pathway in both cell types. The mathematical model predicted 8 cell type-specific parameters. Among these, the SOCS3 mRNA turnover rate was predicted to be slower in CFU-Es which was experimentally validated by qRT-PCR. Moreover, it was shown by genome wide expression profiling, that TGF-β treatment of NSCLC cells led to the upregulation of EMT genes and the downregulation of cell cycle genes. The TGF-β pseudoreceptor BAMBI was found to be downregulated in NSCLC. Its reconstitution resulted in a decreased TGF-β signaling in the cell line H1975. In conclusion, the study shows that MEKi treatment in combination with cisplatin-based chemotherapy poses a potential risk for lung cancer patients. Furthermore, the presence of EpoR in NSCLC cell lines results in response to Epo stimulation in a decreased sensitivity to cisplatin. Finally, TGF-β was verified to induce EMT in NSCLC and BAMBI was identified as a potential tumor suppressor in lung cancer. These studies show that molecular alterations can define responsiveness to therapeutic agents. Lungenkrebs mit seiner am weitesten verbreitete Form des nicht-kleinzelligen Lungenkarzinoms (NSCLC) ist weltweit eine der häufigsten Ursachen für Krebstodesfälle und ist durch eine frühe Metastasierung charakterisiert. Diese kann durch TGF-β reguliert sein. NSCLC wird im Allgemeinen mit dem Chemotherapeutikum Cisplatin behandelt, oft auch in Kombination mit einem MEK Signalweginhibitor (MEKi). Ein großes Problem für Lungenkrebspatienten ist die Chemotherapie induzierte Anämie, die aber mit Erythropoietin (Epo) behandelt werden kann. Leider wurde festgestellt, dass Epo auch eine stimulierende Wirkung auf den Tumor…