On the cellular role of the intermediate filaments keratin 5 and keratin 14 as well as vimentin in oral keratinocytes of varying degrees of transformation

• Applicant: Professor Dr. Pascal Tomakidi
• Subject Area: Anatomy and Physiology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 565406973

The cell-functional role of the intermediate filaments (IFs) keratin (K) 5 and K14 as well as vimentin in epithelial keratinocytes of the oral cavity, which are at different stages of cell transformation, is not yet known. This is mainly due to the fact that there are hardly any cell systems available today that adequately reflect a continuous progression of the cell transformation of oral epithelial cells. Therefore, we have developed a cell system that can be used to differentiate between two different morphological phenotypes as a result of ethanol treatment, starting from an immortalized human gingival keratinocyte cell line (HGK) that has all the molecular characteristics of the original tissue and has not shown any tumorigenicity in animal experiments. Alcohol treatment was chosen as an agent for further transformation of the HGK because it is causatively involved in oral carcinogenesis, among other triggers. One of the two phenotypes exhibited an epithelium-like keratinocyte morphology, which is why it is referred as EPI, and the other a spindle-shaped morphology analogous to connective tissue fibroblasts, which is why this phenotype is referred to below as FIB. This spindle-shaped morphology of FIB shows parallels to the phenotype that occurs during the epithelial-mesenchymal transition (EMT). In addition to molecular changes, the EMT-associated phenotype of FIB cells, which is more advanced in transformation than HGK and EPI, is also supported by cell growth changes that we were able to demonstrate in studies conducted after the morphological clones had been established. As already mentioned, the cell-functional role of the IFs keratin (K) 5 and K14 as well as vimentin in epithelial keratinocytes of the oral cavity, which are at different stages of cell transformation, is not yet known. In this context, the aim of the proposal is to test the hypothesis that interventional RNAi-based downregulation of the IFs K5 and K14 as well as Vimentin in the three phenotypes HGK, EPI and FIB, which are at different stages of cell transformation, causes molecular and thus cell-functional changes. The insights gained from this project are of great use in characterizing the functional role of the IFs K5 and K14 as well as vimentin, i.e. their significance for cell functions, in oral keratinocytes at different stages of transformation. Since all three phenotypes are not yet tumorigenic, but the FIB phenotype already shows numerous EMT-innate characteristics, molecular changes identified in the project can be assigned to biomarkers of very early stages of alcohol-induced oral carcinogenesis. Such an assignment can prospectively contribute to the establishment of diagnostic markers in the context of cancer screening.

• DFG Programme: Research Grants