Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Robinson, I.
Differential expression of miRNAs in A549 cells and plasma samplesfrom lung adenocarcinoma patients and healthy donors
Doktoratsstudium der Medizinischen Wissenschaft; Humanmedizin; [ Dissertation ] Medizinische Universität Graz; 2024. pp. 89
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- Autor*innen der Med Uni Graz:
- Betreuer*innen:
- Hrzenjak Andelko
- Leithner Katharina
- Olschewski Horst
- Altmetrics:
- Abstract:
- MicroRNAs (miRNAs) are small non-coding RNA molecules, which take part in gene regulation on the post-transcriptional level. They are involved in different biological processes, but also in tumorigenesis. In this thesis, we wanted to extend our knowledge about miRNA expression and its role in lung cancer, to find out a potential circulating miRNA that could be promising as a diagnostic biomarker for early lung cancer detection. In the first part of the thesis, we aimed to analyze the global expression of 752 miRNAs in vitro in A549 lung adenocarcinoma (LUAD) cells and primary, non-malignant bronchial epithelial (BE) cells from healthy donors, and to identify the most prominently deregulated miRNAs. Expression of 752 miRNAs in LUAD and BE cells was assessed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) with the mean-centering restricted (MCR) normalization. Out of 752 miRNAs, 37 miRNAs were significantly deregulated in A549 cells compared to BE cells. After setting ΔΔCt ≥ 2.5, eighteen significantly deregulated miRNAs were chosen, 8 were up- and 10 down-regulated in A549 cells compared to BEC cells. Based on those in vitro data, the second part of this thesis aimed to analyze miRNAs expression in plasma samples from patients with histologically diagnosed lung adenocarcinoma and healthy donors (n = 18 for each group, total n = 36). We also aimed to identify stably expressed miRNAs in plasma. We found four significant deregulation miRNAs in plasma samples (miR-15b-3p, miR-148a-3p, miR-193b-3p, and miR-195-5p) in LUAD patients compared to donors’ samples. One miRNA (miR-195- 5p) was up-regulated and three miRNAs (miR-15b-3p, miR148a-3p, and miR-193b-3p) were down-regulated in plasma sample of LUAD patients compared to healthy donors. Two miRNAs were used for normalization (miR-16-5p and miR-191-5p), because of their known and proven stability. Finally, by different in silico tools, we identified the target genes influenced by deregulated circulating miRNAs and determine their assignments to specific pathways relevant to the biology of lung adenocarcinoma. Based on the literature, 107 validated genes are regulated by these four miRNAs. Out of 107 validated target genes, five (PTEN, CXCR4, IGF1R, FGF2, and PD-L1) were described to be regulated with more than one of four deregulated miRNAs. Concerning their molecular function, 107 direct target genes were annotated to five main functional groups: binding, catalytic activity, molecular function regulator, molecular transducer activity, and transporter activity. In conclusion, we could demonstrate the relevant differences between cancer and control miRNA expression in vitro and plasma samples of LUAD patients compared to healthy donors. These four dysregulated miRNAs are promising as diagnostic biomarkers for lung adenocarcinoma.