Molecular effects of Taxol and Caffeine on pancreatic cancer cells

Pancreatic cancer is the fifth leading cause of cancer related deaths in th e United States. Despite many recent advances in the treatment modalities, the mortality rate still remains very high. Paclitaxel (Taxol) and Caffeine have been used for the treatment of this disease, however the molecular me chanisms of these agents are not fully understood, which may be partly resp onsible for the failure of these agents in the treatment of pancreatic canc er. Human pancreatic adenocarcinoma cell lines, HPAC and PANC-1 containing wild-type and mutant p53 respectively, were used to investigate the effects of Taxol and Caffeine on cell growth, and their effects on the modulation of cell cycle and apoptosis related genes. Protein extracts from these cell s treated with 100 nM of Taxol or 4 mM of Caffeine were subjected to Wester n blot analysis for this study. Drug treated cells were also analyzed to ca lculate the number of cells undergoing apoptosis. Dose and time dependent g rowth inhibition was observed in both PANC-1 and HPAC cells when treated wi th either Taxol or Caffeine. Western blot analysis showed an up-regulation of p21(WAF1) it, both cell lines treated with either Taxol or Caffeine. Fur thermore, down-regulation of cyclin B and cdk1 was observed in Taxol and Ca ffeine treated HPAC cells. However, the results were drastically different in PANC-1 cells where cyclin B was down regulated only by Caffeine treatmen t and the level of cdk1 protein was undetectable in this cell line. Moreove r, up-regulation of p53 and down-regulation of Bcl-2 was observed only in H PAC cells treated with Taxol. Apoptotic cell death analysis showed increasi ng number of cells undergoing apoptosis between 24 and 48 h of Caffeine tre atment, however only Taxol showed greater than 50% cells undergoing apoptos is only in HPAC cells. The up-regulation of p21(WAF1) and down-regulation o f cyclin B and cdk1 suggest their possible roles in G(2)/M cell cycle arres t caused by both Taxol and Caffeine as reported earlier. From these results ale conclude that the differential molecular changes observed in this stud y may determine the cellular effects of these agents on pancreatic adenocar cinoma cells and that the effects of chemotherapeutic agents may be determi ned by the endogenous status of p53 mutation and, in turn, may determine th e therapeutic effects of these agents in the treatment of pancreatic cancer .