Simulated Microgravity-Induced Alterations in PDAC Cells: A Potential Role for Trichostatin A in Restoring Cellular Phenotype.

Pancreatic ductal adenocarcinoma (PDAC) accounts for 90% of all pancreatic malignancies. Despite the remarkable improvement concerning treatment, late detection and resistance to clinically used chemotherapeutic agents remain major challenges. Trichostatin A (TSA), a histone deacetylase inhibitor, has been recognized as an effective therapeutic agent against PDAC by inhibiting proliferation, inducing apoptosis, and sensitizing PDAC cells to chemotherapeutic agents such as gemcitabine. Microgravity has become a useful tool in cancer research due to its effects on various cellular processes. This paper presents a deep molecular and proteomic analysis investigating cell growth, the modulation of cytokeratins, and proteins related to apoptosis, cellular metabolism, and protein synthesis after TSA treatment in simulated microgravity (SMG)-exposed PaCa44 3D cells. Our analysis concerns the effects of TSA treatment on cell proliferation: the impairment of the cell cycle with the downregulation of proteins involved in Cdc42 signaling and G1/G2- and G2/M-phase transitions. Thus, we observed modification of survival pathways and proteins related to autophagy and apoptosis. We also observed changes in proteins involved in the regulation of transcription and the repair of damaged DNA. TSA treatment promotes the downregulation of some markers involved in the maintenance of the potency of stem cells, while it upregulates proteins involved in the induction and modulation of the differentiation process. Our data suggest that TSA treatment restores the cell phenotype prior to simulated microgravity exposure, and exerts an intriguing activity on PDAC cells by reducing proliferation and inducing cell death via multiple pathways.