Biology subjects

Timelthaler, G.

Publications and source records attributed to Timelthaler, G..

3 recordsLinked to original sources

bioRxiv2025

Small Particles, Big Problems: Polystyrene nanoparticles induce DNA damage, oxidative stress, migration, and mitogenic pathways predominantly in non-malignant lung cells

Polystyrene micro-and nanoplastics (PS-MNPs) are emerging environmental pollutants with potential implications for human health. In this study, we used two different sizes of PS-MNPs (0.25 {micro}m and 1 {micro}m) on non-small cell lung cancer (A549, H460), small cell lung cancer (DMS53, H372), and normal lung epithelial (BEAS-2B) cells, as well as on human-derived lung organoids, to investigate the cytotoxic effects of PS particles. At lower concentrations (< 30 {micro}g/cm2, equivalent to 50 {micro}g/ml), neither PS-MPs nor PS-NPs did not interfere with cell viability or proliferation. Intracellular kinetic assays revealed that non-malignant (BEAS-2B) lung cells showed the strongest turnover of PS-NPs compared to malignant cells. Since PS-NPs exhibited more pronounced cellular effects, we focused further analyses on their impact. Furthermore, we observed significantly increased migration, prolonged S-phase arrest along with induced DNA damage, and oxidative stress in non-malignant (BEAS-2B) lung cells. Thus, our data suggest that BEAS-2B cells exhibit the highest sensitivity to PS-NPs. We also demonstrate that after PS-NP treatment, these cells displayed decreased base excision repair capacity and increased activation of survival pathways, including AKT and ERK phosphorylation. PS-NP internalization and increase of signal pathways were validated in a more physiological lung organoid setting. Altogether, our findings suggest that PS-NPs do not significantly affect the malignant behavior of cancer cells. However, they could promote tumor-like features in normal lung cells by inducing survival pathways, migration, and alterations in stress response mechanisms. Environmental ImplicationsThis study investigates the effects of polystyrene micro-and nanoplastics (PS-MNPs) at environmentally relevant concentrations. The tested concentrations of PS-MNPs (0, 15, 30, and 60 {micro}g/cm2, equivalent to 0, 25, 50, and 100 {micro}g/ml) are commonly studied in the literature in lung cells. While these findings provide insights into cellular responses, the overall environmental impact of PS-MNPs remains limited at realistic exposure levels. HighlightsO_LIPS-MNPs are internalized into lung cells, with higher uptake in non-malignant cells. C_LIO_LIPS-NPs lead to increased migration, DNA damage, oxidative stress, and disturbed cell cycle progression. C_LIO_LIPS-NPs promote activation of survival pathways in non-malignant cells and lung organoids. C_LIO_LIExposure of PS-NPs may cause potential implications for lung cancer development and progression. C_LI

molecular biology↗

bioRxiv2020

PIDDosome-induced p53-activation for ploidy restriction facilitates hepatocarcinogenesis

Polyploidization frequently precedes tumorigenesis but also occurs during normal development in several tissues. Hepatocyte ploidy is controlled by the PIDDosome during development and regeneration. The PIDDosome multi-protein complex is activated by supernumerary centrosomes to induce p53 and restrict proliferation of polyploid cells, otherwise prone for chromosomal instability. PIDDosome-deficiency in the liver results in drastically increased polyploidy. To investigate PIDDosome-induced p53-activation in the pathogenesis of liver cancer, we chemically induced hepatocellular carcinoma (HCC) in mice. Strikingly, PIDDosome-deficiency reduced tumor number and burden, despite the inability to activate p53 in polyploid cells. Liver tumors arise primarily from cells with low ploidy, indicating an intrinsic pro-tumorigenic effect of PIDDosome-mediated ploidy restriction. These data suggest that hyperpolyploidization caused by PIDDosome-deficiency protects from HCC. Moreover, high tumor cell density, as a surrogate marker of low ploidy, predicts of survival of HCC patients receiving liver transplantation. Together, we show that the PIDDosome is a potential therapeutic target to manipulate hepatocyte polyploidization for HCC prevention and tumor cell density serves as a novel prognostic marker for recurrence free survival in HCC patients.

cancer biology↗

bioRxiv2020

Requirement of DNMT1 to orchestrate epigenomic reprogramming during NPM-ALK driven T cell lymphomagenesis

Malignant transformation depends on genetic and epigenetic events that result in a burst of deregulated gene expression and chromatin changes. To dissect the sequence of events in this process, we used a T cell-specific lymphoma model based on the human oncogenic NPM-ALK translocation. We find that transformation of T cells shifts thymic cell populations to an undifferentiated immunophenotype, which occurs only after a period of latency, accompanied by induction of the MYC-NOTCH1 axis and deregulation of key epigenetic enzymes. We discover aberrant DNA methylation patterns, overlapping with regulatory regions, plus a high degree of epigenetic heterogeneity between individual tumors. In addition, ALK positive tumors show a loss of collaborative methylation patterns of neighboring CpG sites. Notably, deletion of the maintenance DNA methyltransferase DNMT1 completely abrogates lymphomagenesis in this model, despite oncogenic signaling through NPM-ALK, suggesting that faithful maintenance of tumor-specific methylation through DNMT1 is essential for sustained proliferation and tumorigenesis. STATEMENT OF SIGNIFICANCEEpigenetic alterations are causally involved in tumorigenesis. Here we show that induction of a single human oncogene in murine T cells induces specific deregulation of epigenetic enzymes resulting in epigenomic alterations similar to human tumors. Our findings are of broader implication to understand how epigenomic processes are shaped by oncogene induced transformation.

cancer biology↗