Differential Expression of Cellular Proteins in Pancreatic Cancer Cells Treated with Transketolase Inhibitor Oxythiamine

摘要

In previous studies, we demonstrated that oxythiamine (OT), an inhibitor of transketolase enzyme, specifically inhibited phosphoprotein expression and pancreatic cancer cell proliferation through down-regulation of cycle activity. To examine whether oxythiamine (OT) can interfere cellular proteome profile in MIA PaCa-2 cancer cells, we analyzed the effect of OT treatment on the cellular proteome in MIA pancreatic cancer cells using the established quantitative proteomics method. MIA cells were cultured in 50percent 15N labeled amino acid mixture for 72 hrs. Twenty-seven proteins differentially expressed in OT-treated MIA cells were identified by using two dimensional gel electrophoresis (2-DE) and matrix assisted laser desorption and ionization (MALDI) time-of-flight and time-of-flight (TOF/TOF) mass spectrometry. The protein turnover rates of these proteins were calculated by using our newly developed quantitative proteomics methodology. As an example, glyceraldehyde-3- phosphate dehydrogenase (GAPDH) with a turnover rate of 65percent was validated by using a case-control pancreatic cancer specimens.