Mtiochondrial DNA Mutation In Glioma Cells And The Suppressed Effect Of Idebenone On The Proliferation Of U251 And C6 Cells

ObjectMitochondrion is not only the power station of the cell, but also takes part in many other cellular activities, including protein synthesis, cellular duplication, and apoptosis. Mitochondrion has its idios DNA system, which is independent of nuclear DNA and has own cycle of duplication and transcription. Different from normal cell, structure and function of mitochondrion in tumorous cells have changed very much and they become the biological marker in the tumor research and treatment now. These differences include mitochondrial DNA mutation, disturbance of electron transport chain, upgrading of mitochondrial membrane potential and suppressing of mitochondrion-dependent apoptosis in tumorous cells. Additionally, energy production in the term of acrobic glycolysis is also the main difference between tumorous cell and normal cell. Energy produced by acrobic glycolysis is more in the maligent tumor commonly. To explore the new way of glioma therapy and observe the influence of Idebenone, which can activate mitochondrial oxidative phosphorylation and upgrading cellular ATP production in normal cells, on the glioma cells, we did this study.Materials and methods1. Extracting the mitochondrial DNA from U251 cells and amplified the gene ATP6ase and ND6 sequence by PCR, then sequencing the products and comparing them to normal human ATP6ase and ND6 sequences.2. U251 and C6 glioma cells were cultivated by normal ways. We observed the effects of Idebenone of 20, 30, and 40μM on their growing curve, mitochondrial membrane potential by observing the intensity of rhodamine and JC-1 fluorescence , reactive oxygen spaces (ROS) by observing the intensity of DCFH-AD flourescence, peroxiredoxin 3 (PRDX3) expression by immunochemistry, and cellular ATP and ATP from mitochondrial exact by observing the intensity of firefly luciferase.Results1. There was a point mutation in U251 ATP6ase (A8860G) and no changes of U251 ND6 sequence. Some anmino sequence of U251 ATP6ase is depleted.2. We found out that Idebenone could suppress the growth of glioma cells (P<0.05), lower the mitochondrial membrane potential (P<0.05), upgrade the cellular ROS (P<0.05), degrade the expression of PRDX3 (P<0.05), decrease the cellular ATP (P<0.05) and have no effect on ATP content from mitochondrial exact (P>0.05).Conclusion1. The changed base of U251 is a rare polymorphasms site and this change prompts that A8860G is associated with this entity. The depletion of the anmino sequence hints that the functional changes of ATP6ase and the disturbance of mitochondrial ATP production.2. Idebenoen can suppress the glioma growth in vitro. Its function was partly attributed to upgrading ROS, decreasing expression of PRDX3, lowering mitochondrial membrane potential and degrading the cellular ATP content.