miRNA-Signaturen in Blutzellen von Lungentumorpatienten unter besonderer Berücksichtigung verschiedener Blutzellfraktionen

• Applicant: Dr. Petra Leidinger
• Subject Area: Human Genetics
• Term: from 2010 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 192523625

During my first DFG grant I was able to show for lung cancer that cells with common progenitors (myeloide or lymphoide progenitors) and cells of the inate and the adaptive immune system show similarities in their miRNA expression. The miRNA expression pattern of five investigated leukocyte subpopulations (T cells, B cells, NK cells, eosinophile and neutrophile granulocytes, monocytes) were different compared to those of whole blood. Thus, it was not possible to trace the whole blood pattern back to one of the leukocyte subpopulations. This suggests that additional constituents in the blood, mainly exosomes, have an impact on the whole blood miRNA expression pattern. Evidence for this was already shown in recent publications. Based on my previous work, in the proposed study I will analyze miRNA pattern in exosomes of lung cancer patients and healthy controls. The exosomal miRNA pattern will be related to the miRNA pattern of the five leukocyte subpopulations mentioned above. To this end I will apply microarray analysis, as already done in my first DFG grant. With the miRNA microarray data I will try to deduce which differences in the miRNA pattern of patients and controls result from exosomes or one of the leukocyte subpopulations. In addition, in a more functional assay I will examine the influence of tumor exosomes and exosomal miRNAs on the miRNA pattern of leukocytes. To this end, leukocytes of a healthy donor will be cultivated with different lung cancer cell lines or exosomes isolated from those cell lines and with microarrays it will be determined if and to what extend miRNAs of the tumor exosomes have an effect on the miRNome of leukocytes. Additionally it will be determined to what extend exosomal miRNAs isolated from lung canecr patient serum have any influence on the miRNome of leukocytes of a healthy donor. To this end, i will isolate exosomes from serum of lung cancer patients and incubate these with leukocytes of a healthy donor. Then the miRNA expression profiles of exosomes and leukocytes will be compared. To determine if and to what extend exosomes or exosomal miRNAs have any direct impact on the tumorigenesis I will apply an endothelial tube formation assay. Here, exosomes of serum of lung cancer patients and of healthy donors will be incubated with endothelial cells to determine the number of new blood vessels. The results of the endothelial tube formation assay will be related to the exosomal miRNome microarray data to identfy miRNAs that contribute most to the fromation of new blood vessels. With the proposed project I will contribute to the understanding of the role of exosomal miRNAs in lung cancer.

• DFG Programme: Research Grants