Oncogenic signaling in idiopathic pulmonary fibrosis

Ulke, Henrik Marcel (2023): Oncogenic signaling in idiopathic pulmonary fibrosis. Dissertation, LMU München: Medizinische Fakultät

Abstract

Idiopathic pulmonary fibrosis (IPF) and non-small cell lung cancer (NSCLC) are two devastating pulmonary disorders, which are marked by excessive tissue production, irreversible damage to lung structure, and eventually loss of pulmonary function. The natural history of both diseases is characterized by chronic progression and represents a fatal prognosis for the affected patients. Treatments are able to slow down the diseases’ progression, but to date no approved, curative treatment option exists. IPF is frequently associated with lung cancer and both diseases’ pathogenesis share common hallmarks, such as altered cellular phenotypes, misregulated biological pathways and mediators, and similar genetic changes. We aimed to establish a link between the pathomechanisms of IPF and NSCLC by analyzing patterns of gene expression alterations and to further characterize the role of candidate genes in the pathogenesis of IPF. NSCLC microarray datasets (GSE44077, GSE43458, GSE18842) from Gene Expression Omnibus (GEO) were analyzed and differentially expressed genes (DEGs) were extracted. Gene set enrichment analysis (GSEA) was used to determine the enrichment of DEGs from NSCLC in an IPF microarray dataset (GSE47460) and to describe the subsequent list of candidate genes. Further characterization of these genes of interest was achieved by annotation enrichment analysis, protein-protein interaction networks, BioGPS, and principal component analysis. The final candidate genes were verified by quantitative real-time polymerase chain reaction (qRT-PCR) as well as western blot analysis in human and mouse lung tissue samples, human bronchial epithelial cells, and primary murine alveolar epithelial type II (pmATII) cells. Finally, treatment of bronchial epithelial cells with pro-fibrotic transforming growth factor beta 1 (TGF-beta) was performed and the expression of the candidate genes was analyzed. IPF and NSCLC showed a significant pattern of shared gene expression alterations in the GSEA. Further analysis revealed a common set of 92 equally misregulated genes in IPF and NSCLC (log2 fold change > 1; adjusted p-value < 0.05), which demonstrated an IPF-specific signature in the principal component analysis. Annotation enrichment analysis of this gene set highlighted common themes, such as P53 regulation, extracellular matrix (ECM) organization, cell cycle, and proliferation. Western blot and qRT-PCR validated a significantly increased expression of the two candidate genes G protein-coupled receptor 87 (GPR87) and phosphoserine aminotransferase 1 (PSAT1) in NSCLC, IPF, and bleomycin-induced lung fibrosis in mice. TGF-beta treatment of bronchial epithelial cells resulted in a significant upregulation of GPR87 in vitro. In summary, we demonstrated a pathogenic link between IPF and NSCLC, which resulted in a subset of potential novel therapeutic targets. Further analysis of GPR87 and the other candidate genes might improve our understanding of IPF and enable novel therapeutic strategies.

• Dokumententyp: Dissertationen (Dissertation, LMU München)
• Keywords: IPF, NSCLC, differentially expressed genes, GPR87, PSAT1
• Themengebiete: 600 Technik, Medizin, angewandte Wissenschaften ; 600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin und Gesundheit
• Fakultäten: Medizinische Fakultät
• Sprache der Hochschulschrift: Englisch
• Datum der mündlichen Prüfung: 20. Juli 2023
• 1. Bericht­erstatter:in: Königshoff, Melanie