Kinase inhibition sensitizes pancreatic cancer cells towards radiation

ABSTRACT: Pancreatic ductal adenocarcinoma is one of the most aggressive cancer types and is well-known for its general low intrinsic radiosensitivity. In order to resolve mechanisms of how PDAC cells carry out radioresistance, a combination of proteomics and phosphoproteomics of two radiosensitive as well as radioresistant murine PDAC cell lines upon exposition to radiation was performed. A high depth of (phospho)proteomic identifications with > 13000 confidently identified phosphorylation sites and > 7800 proteins was achieved. Measuring the response of the phosphoproteome upon radiation revealed >700 phosphorylation sites on >400 proteins which were regulated in all four cell lines independently of the sensitivity status. This analysis validated already known radiomarkers but also uncovered novel members of the radiation-dependent signaling network in PDAC cells that were shown to be exclusively based on protein phosphorylation but not protein expression. Among those radioresponsive phosphoproteins were ten novel ATM substrates, which were validated by in vitro kinase assays. Comparison of radiosensitive and -resistant cells revealed a complex regulation of apoptotic processes, while changes in expression of DNA repair proteins seemed to not play a pivotal role. Especially increased expression of NQO1 was found to be a potential mechanism enabling resistance by clearing harmful reactive oxygen species from the PDAC cells. Further analysis of the radioresistance-associated-phosphoproteome, which was especially enriched in phosphoproteins with cytoskeleton organizational function, uncovered increased Actin dynamics and FAK activity in radioresistant cells. Both likely lead to increased survival, migrational capacity and perturbations in chromatin condensation which could oppose radiation. Based on the displayed adaptions in cellular protein expression and signaling in resistant PDAC cells, pharmacological inhibition of NQO1 and FAK could be suggested to sensitize towards radiation.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Mus Musculus (mouse)

DISEASE(S): Pancreatic Ductal Adenocarcinoma

SUBMITTER: Svenja Wiechmann  

LAB HEAD: Bernhard Kuster

PROVIDER: PXD015284 | Pride | 2020-07-13

REPOSITORIES: Pride