2 O 2 -Removal, and Cellular Bioenergetics in the Human Pancreatic Cancer Cell Lines MIA PaCa-2 and Panc-1: Impact on Susceptibilities to Ascorbate/H 2 O 2

摘要

We have been using quantitative approaches to better understand how externally/internally generated reactive species, metabolism, cell signaling and death pathways lead to differential sensitivities to cancer treatment. Studying aspects of cell biology in more quantitative and absolute terms allows direct comparisons to be made and unknown relationships to be discovered that may be therapeutically actionable to enhance treatment efficacy, prevent treatment-limiting complications or therapy/cross resistance. We have focused primarily on using quantitative approaches on a set of human pancreatic cancer cell lines, MIA PaCa-2 and Panc-1, which are differentially sensitive to high concentrations of ascorbate. High-dose ascorbate acts as a pro-drug that generates extracellular H 2 O 2 in vivo and in vitro . We have identified cell size (volume), catalase levels, changes in GSH, and quantitative differences in cellular bioenergetics (ATP) as major contributors to the differential toxicity seen in this pair of cell lines. For example, Panc-1 has a much higher rate of ATP-linked oxygen consumption compared to MIA PaCa-2 as determined using a Seahorse XF96 extracellular flux analyzer. Using our quantitative approaches along with the new proton efflux rate (PER) developed by Agilent/Seahorse, we are able to quantitatively estimate the basal and maximal ATP generation rate from respiration and glycolysis on a per cell basis for this cell line pair. These quantitative approaches to cellular bioenergetics allows a direct comparison of the rates of ATP generation in these two cell lines and the role that bioenergetics may play in cell susceptibility to ascorbate/ H 2 O 2 .