| dc.description.abstract | Cancer cell metabolism have long been thought to rely on glycolysis more than mitochondrial oxidative phosphorylation regardless of the availability of oxygen, which normally regulates the switch between anaerobic to aerobic metabolism in normal cells. This phenomenon has been termed the Warburg effect, named after its discoverer Otto Warburg. This phenomenon has, however, been better understood over the years and it has been shown that the role of mitochondria respiration is indeed important for tumorigenesis. The flexibility of cancer cells to exploit glycolysis versus oxidative phosphorylation for energy needs has opened the door for more potential therapies. In pancreatic cancer metabolic drug such as metformin has been tested and found to be effective in reducing the mortality rate. Metformin together with another biguanide; phenformin are well known anti diabetic drugs that used to treat type II diabetes. These drugs are found to act on cancer metabolism, most likely through inhibiting mitochondrial metabolism, and this thesis focus on the effect of these drugs in different Pancreatic Ductal Adenocarcinoma (PDA) cell lines using a range of methods to detect mitochondrial changes.
Pancreatic cancer cell lines (MIA PaCa-2, PANC-1, AsPC, and HPAF-II) derived from different patients with different medical backgrounds were investigated. The inhibitory effect of metformin and phenformin drugs on the PDA cell lines was demonstrated via toxicity assay, metabolic profiling, and mitochondrial content assay. This work has also introduced the use of Confocal Raman Microscope as label-free and non-invasion techniques for mitochondrial biomarkers (cytochrome c) in cancer cells. All experiment with AsPC, and HPAF-II cell lines were done in two different growth media using low (5mM) and high (25 mM) glucose concentration.
The results indicate that metformin and phenformin are potent inhibitors of mitochondrial metabolism in our PDA models. PDA cell lines were found to be more affected by phenformin than metformin, which required a higher dose to induce cell death. Glucose concentration in culture medium influence the effect of these drugs on the PDA cell lines, where cells grown in physiological glucose conditions are more affected by drug treatment. The mitochondrial inhibition detected by metabolic flux analysis corresponded to that found when using Confocal Raman microscope analysis of Cytochrome C in treated and non-treated fixated cell lines. This makes this an interesting analysis to further explore to determine mitochondrial defects in fixated patient cancer tissue slides which can be related to potential susceptibility to metabolic drugs for future treatment. | |