ABSTRACT
OBJECTIVE: To investigate the effect of ceramide monohexoside (CMH) on resistance to cisplatin and apoptosis in ovarian cell line COC1/DDP, and to provide new ideals and clues to seek new effective methods for studying the mechanism and reversing the resistance in ovarian cell line as well. METHODS: COC1 cells and COC1/DDP cells (before and after the treatment of mifepristone) were collected and neutral glycosphingolipids (N-GSLs) of the cells was isolated and purified, changes of CMH content were analyzed by high performance thin layer chromatography (HPTLC). The COC1/DDP cells were divided into three groups, one treated by cisplatin, one treated by mifepristone, the other treated by cisplatin and mifepristone. The survival rate of cells in three groups were evaluated by the methyl thiazolyl tetrazolium (MTT) assay, DNA ladders were presented by DNA gel electrophoresis, the forms of cells were observed by transmission electron microscope (TEM). RESULTS: The levels of CMH were (37.1 +/- 3.3)% in COC1/DDP, higher than that in COC1 (14.1 +/- 1.4)% (P < 0.001). After treating by 1.25, 5 micro mol/L mifepristone, the CMH were (26.6 +/- 2.6)% (P < 0.05) and (17.5 +/- 0.7)% (P < 0.001), respectively. Mifepristone had no effect on the viability of COC1/DDP cell below a concentration of 5 micro mol/L. But when mifepristone of 1.25 or 5 micro mol/L combined with cisplatin at a concentration of 0.1, 0.25, 0.5, 1.25, 2.5 micro g/ml, the inhibition rate of COC1/DDP cell is higher than that of COC1/DDP cells only treated by cisplatin at the concentration of 0.1 to 2.5 micro g/ml (P < 0.001). The combined treatment elicited DNA fragmentation, however, neither cisplatin of 1.25 micro g/ml nor mifepristone of 5 micro mol/L alone could potentiate DNA fragmentation. After the combined treatment, the COC1/DDP cells produced apoptosis body. CONCLUSIONS: CMH is related with resistance to cisplantin in ovarian cell line COC1/DDP. When CMH of COC1/DDP cells was inhibited by mifepristone, the cells were sensitive to cisplatin and apoptosis was elicited.
Subject(s)
Cerebrosides/physiology , Cisplatin/pharmacology , Ovarian Neoplasms/drug therapy , Cell Line, Tumor , Cell Survival/drug effects , Cerebrosides/analysis , Cerebrosides/antagonists & inhibitors , DNA, Neoplasm/analysis , Drug Resistance, Neoplasm , Female , Humans , Ovarian Neoplasms/pathology , Ovarian Neoplasms/ultrastructureABSTRACT
During the Evolution, effected by select pressure or nature mutation, the compositions of bacteria genomes is various. And many experiences prove that the genes between leading strand and lagging strand is distinctly in copy, transcription and repair. Some scholars presume that the bases distribution is difference between the two strand, to verify the guess, we using the technology of bioinformatics, compare the base usage between the DNA double strand in 17 species bacteria. The result show: 1. there is same bases usage frequency in coding sequence between leading strand and lagging strand 2. There also same bases usage frequency in first codon, second codon and third codon. It suggest that there is a equilibrium between the two strand by the effect of select pressure and nature mutation.
Subject(s)
Bacteria/genetics , Codon/genetics , DNA, Bacterial/genetics , Databases, Nucleic Acid , Evolution, Molecular , Genes, Bacterial/genetics , Genome, Bacterial , Mutation , Nucleotides/genetics , Selection, GeneticABSTRACT
OBJECTIVE: To observe the effect of mifepristone in enhancing chemosensitivity of drug-resistant ovarian cancer cell line to cisplatin and investigate its mechanism. METHODS: Human ovarian cancer cell lines COC1 (DDP-sensitive) and COC1/DDP (DDP-resistant) were incubated with or without mifepristone. The proliferation rate of the cells was determined by methyl thiazolyl tetrazolium (MTT) assay and positive expression of apoptosis-associated proteins Bcl-2 and Bax were observed by means of flow cytometry. RESULTS: It was observed that mifepristone at the dose of 1.25 micromol/L reversed the resistance of COC1/DDP cells to cisplatin, and Bcl-2 protein expression was deceased from (23.8067+/-0.4382)% to (19.3967+/-0.6866)% (P=0.000) while Bax protein expression increased from (12.75+/-0.2524)% to (25.5967+/-0.8834)% (P=0.000). CONCLUSION: Mifepristone may act to enhance the sensitivity of COC1/DDP cells to cisplatin, possibly through regulating Bcl-2 and Bax protein expressions.
