The FGFR2c/PKCε Axis Controls MCL-1-Mediated Invasion in Pancreatic Ductal Adenocarcinoma Cells: Perspectives for Innovative Target Therapies

Polyethylene Micro/Nanoplastics Exposure Induces Epithelial-Mesenchymal Transition in Human Bronchial and Alveolar Epithelial Cells

Micro/nanoplastics (MNPs), which are widely spread in the environment, have gained attention because of their ability to enter the human body mainly through ingestion, inhalation, and skin contact, thus representing a serious health threat. Several studies have reported the presence of MNPs in lung tissue and the potential role of MNP inhalation in triggering lung fibrosis and tumorigenesis. However, there is a paucity of knowledge regarding the cellular response to MNPs composed of polyethylene (PE), one of the most common plastic pollutants in the biosphere. In this study, we investigated the effects of low/high concentrations of PE MNPs on respiratory epithelial cell viability and migration/invasion abilities, using MTT, scratch, and transwell assays. Morphological and molecular changes were assessed via immunofluorescence, Western blot, and qRT-PCR. We demonstrated that acute exposure to PE MNPs does not induce cellular toxicity. Instead, cells displayed visible morphological changes also involving actin cytoskeleton reorganization. Our data underlined the role of epithelial-mesenchymal transition (EMT) in triggering this process. Moreover, a remarkable increase in migration potential was noticed, in absence of a significant alteration of the cell's invasive capacity. The present study highlights the potential impact of PE MNPs inhalation on the human respiratory epithelium, suggesting a possible role in carcinogenesis.

TRPA1 Contributes to FGFR2c Signaling and to Its Oncogenic Outcomes in Pancreatic Ductal Adenocarcinoma-Derived Cell Lines

Fibroblast growth factor receptor (FGFR) signaling is a key modulator of cellular processes dysregulated in cancer. We recently found that the high expression of the mesenchymal FGFR2c variant in human pancreatic ductal adenocarcinoma (PDAC)-derived cells triggers the PKCε-mediated improvement of EMT and of MCL-1/SRC-dependent cell invasion. Since other membrane proteins can affect the receptor tyrosine kinase signaling, including transient receptor potential channels (TRPs), in this work, we investigated the role of TRPs in the FGFR2c/PKCε oncogenic axis. Our results highlighted that either the FGFR2c/PKCε axis shut-off obtained by shRNA or its sustained activation via ligand stimulation induces TRPA1 downregulation, suggesting a channel/receptor dependence. Indeed, biochemical molecular and immunofluorescence approaches demonstrated that the transient depletion of TRPA1 by siRNA was sufficient to attenuate FGFR2c downstream signaling pathways, as well as the consequent enhancement of EMT. Moreover, the biochemical check of MCL1/SRC signaling and the in vitro assay of cellular motility suggested that TRPA1 also contributes to the FGFR2c-induced enhancement of PDAC cell invasiveness. Finally, the use of a selective channel antagonist indicated that the contribution of TRPA1 to the FGFR2c oncogenic potential is independent of its pore function. Thus, TRPA1 could represent a putative candidate for future target therapies in PDAC.