The Research Of EGF Signaling Pathways On PKM2 O-GlcNAc Modification In MCF-7 Cell

In order to satisfy the requirement of malignant proliferation,tumor cells still go on glycolysis,absorbing more glucose,producing more lactate in a well-oxygenized environment.The process is known as aerobic glycolysis or the Warburg effect,which is first noted by Otto Warburg.The Warburg effect is a feature of tumor,but its mechanism is unclear.As the key enzyme of Warburg effect,M2 pyruvate kinase(PKM2)is exclusively expressed in tumor cells.A variety of posttranslational modifications adjust the activity and function of PKM2 to Warburg effect.Recent literatures suggest the activity and function of PKM2 is regulated by O-GlcNAc modification.This modification is a relatively new modification type,able to perceive the changes of cell metabolism,positively associated with the degree of deterioration of tumor cells.PKM2 O-GlcNAc modification plays an important role in the development of tumor,but which signaling pathways mediating its occurrence do not know currently.In recent years,studies have shown the phosphorylation and acetylation of PKM2 have been controlled by EGF signaling pathways.To detect whether EGF signaling pathways mediate PKM2 O-GlcNAc modification,we use exogenous epidermal growth factor(EGF)to stimulate MCF-7cells in this study.The experimental results show that the level of PKM2O-GlcNAc modification is increased with EGF stimulation.By adding multiple protein inhibitors of EGF downstream signaling pathways,we demonstrate PKM2 O-GlcNAc modification is mediated by MEK-ERK signaling pathway in case of EGF stimulation.In order to further determine the signaling pathways mediating PKM2 O-GlcNAc modification,MEK1Q56 P the active form of MEK is transfected in MCF-7 cells.With the expression of MEK1Q56 P,the level of O-GlcNAc modification of PKM2 is increased.Above two kinds of methods suggest MEK-ERK signaling pathway mediates the level of PKM2 O-GlcNAc modification in MCF-7 cells.we further find the MEK-ERK signaling pathway promotes the phosphorylation of OGT,which could regulate the activity of OGT and adjust the level of O-GlcNAc modification.Finding the signaling pathways mediating PKM2 O-GlcNAc modification,will provide more drug targets for cancer treatment.