Concentration changes in gemcitabine and its metabolites after hyperthermia in pancreatic cancer cells assessed using RP-HPLC

BackgroundGemcitabine (2,2-difluoro-2-deoxycytidine;dFdC) is a first-line chemotherapy drug for pancreatic cancer. Recently, a synergistic anti-tumor treatment of dFdC and hyperthermia has achieved good clinical results, but there are few reports on the molecular mechanism influenced by hyperthermia. This study is an initial exploration of the effects of hyperthermia on changes in the concentration of dFdC and its metabolites in pancreatic cancer cells. The aim is to provide a theoretical basis for clinical detection and pharmacokinetic research.MethodsPANC-1 cells at logarithmic growth phase were used as the experimental object. The MTT assay was performed to determine the half maximal inhibitory concentration (IC50) of dFdC. After PANC-1 cells were cultured in DMEM medium containing IC(50)dFdC and treated with hyperthermia at 41 degrees C or 43 degrees C, changes in the concentration of dFdC, 2,2-difluorodeoxyuridine (dFdU) and difluorodeoxycytidine triphosphate (dFdCTP) in the cells were tested using an optimized reverse phase high-performance liquid chromatography (RP-HPLC) protocol.ResultsWe found that 41 degrees C and 43 degrees Chyperthermia gave rise to a decrease in dFdC and dFdU content. At 41 degrees C, the levels respectively fell to 9.28 and 30.93% of the baseline, and at 43 degrees C, to 24.76 and 57.80%, respectively. The dFdCTP content increased by 21.82% at 41 degrees C and 42.42% at 43 degrees C.ConclusionThe two heat treatments could alter the mechanism of dFdC metabolism in PANC-1 cells. The effect of 43 degrees C hyperthermia is more significant. Our observations may be instrumental to explaining the higher anti-tumor efficacy of this combination therapy.