ABSTRACT
OBJECTIVES@#Radiotherapy is one of the main therapies for colorectal cancer, but radioresistance often leads to radiotherapy failure. To improve the radioresistance, we explore the effect of oligomycin A, the H@*METHODS@#The effects of different concentrations of oligomycin A on the survival rate and glycolysis of HT29 colorectal cancer cells at different time points were investigated via MTT and glycolysis assay. siRNA-PFK1 was synthesized in vitro and transfected into HT29 cells. The effects of oligomycin A on radiosensitivity of HT29 colorectal cancer cells were measured via MTT and colony formation assay. Western blotting was used to detect the effect of oligomycin A on the expression of glycolytic enzyme PFK1. We compared difference between the effects of siRNA-PFK1 group and oligomycin A combined with siRNA-PFK1 group on cell survival and glycolysis. After 4 Gy X-ray irradiation, the effects of cell survival and glycolysis between the siRNA-PFK1 group and the oligomycin A combined with siRNA-PFK1 group were compared.@*RESULTS@#Compared with the 0 μmol/L oligomycin A group, the cell survival rate of HT29 cells treated with 4 μmol/L oligomycin A was significantly increased (@*CONCLUSIONS@#Oligomycin A can promote the radioresistance of HT29 colorectal cancer cells, which may be related to up-regulation of the PFK1 expression and increase of cell glycolysis.
Subject(s)
Humans , Cell Line, Tumor , Colorectal Neoplasms/genetics , HT29 Cells , Oligomycins/pharmacology , Radiation ToleranceABSTRACT
Rotenone is a specific inhibitor of the NADH dehydrogenase complex. In mitochondria, rotenone inhibitsthe oxidation of NADH to NAD, thereby blocking the oxidation of NAD and the substrates such asglutamate, alpha-ketoglutarate, and pyruvate. Rotenone also inhibits the mitochondrial respiratory chainbetween diphosphopyridine nucleotide and flavine.2, 4-Dinitrophenol – (DNP) is lipophilic weak acids that pick up a proton, transport across the mitochondrialinner membrane into the matrix, deprotonate, then exit as anions before repeating the catalytic cycle,and dissipating the proton gradient. In this situation, electrons continue to pass through the electrontransport system, reduce oxygen to water and metabolic rate, heat are increased, but ATP is lesssynthesized in this process.The macrolide antibiotic - oligomycin binds to the surface of the c8-10 ring of the Fo domain of ATPsynthase, making contact with two neighboring molecules and blocking proton flow, which explains theinhibitory effect on ATP synthesis. Intraperitoneal injection of oligomycin into the rat (0.5 mg per kg)reduces the oxygen consumption by about 50%; decreases ATP production by the aerobic pathway andincreases formation of lactate in blood serum. These changes may cause a decelerated metabolism andan increased formation of free radicals or ROS in membranes.