Research On The Molecular Mechanisms Of Mycoepoxydiene Inhibits The Growth Of Cervical Cancer HeLa Cells

Natural products are an important resource of antitumor drugs for their wealthful source,complex and diverse structures,and rich biological activities.Mycoepoxydiene(MED)possesses novel chemical structure and potently suppresses the growth of HeLa cells(IC50 is 20μM),but the mechanisms is far from understood.In this study,we used two dimensional gel eletrophoresis(2-DE)and other technologies to research the mechanisms which meditate the inhibition of MED to the growth of HeLa cells,laid foundations for devoloping MED as antitumor drugs,especially the the therapy of cervical cancer.The differential proteins in HeLa cells treated by MED involve glycolysis,pentose phosphate pathway,fatty acid synthesis,nuleotides metablosim,cell cycle,cell skeleton,cell apopotosis,transcriptional process,protein translation and degradation.What’s more,most of them were downregulated,which showed by the results of 2-DE.The enzymes related to glucose,lipid metabolism were choosed for further research.We found that the decrease of this proteins were closely associated with the suppression of MED to the growth of HeLa cells.Triosephosphate isomerase identified by 2-DE was conformed by western blot(WB).Meanwhile,several other glycolytic enzymes,such as,hexokinase 2,phosphofructokinase 1,aldolase A,enolase 1 and lactate dehydrogenase A(LDHA)were also downregulated,which manifested by WB.Lactate,the end product of glycolysis,was reduced in MED dose-dependent manner.The enzymatic activity of LDHA is inhibited by MED indirectly.Overexpressing these downregulated glycolytic enzymes significantly lowers the inhibition of MED to the growth of HeLa cells.6-phosphogluconolactonase(PGLS)was lowered by MED,which was showed by 2-DE and WB.WB indicates G6PD was also downregulated by MED.NADPH decreased in MED dose-dependent manner.What’s more,MED suppressed G6PD activity indirectyly.Overexpression of G6PD and PGLS both reducd ROS produced by MED,and alleviated the inhibition of MED to the growth of HeLa cells.Adipose triglyceride lipase(ATGL),carnitine palmitoyltransferase 1 A(CPT1-A),fumarate hydratase and succinate dehydrogenase complex subunit A were all upregulated by MED.Knocking down CPT1-A by shRNA reduced the rise of ATP and ROS induced by MED,and antagonizes the inhibition of MED to HeLa cells.In contrast to promoting fatty acid β-oxidation,MED inhibited fatty acid synthesis via reducing the protein level of FASN.In summary,we can conclude that the mechansims of MED inhibiting the growth of HeLa cells involves multiaspects:inhibiting glycolysis,PPP,fatty acid de novo synthesis,and accelerating triglyceride hydrolysis,fatty acid β-oxidation and oxdative phosphorylation.This work explained the mechanisms of MED acts on glycometabolism and lipid metabolism,laid a good foundation for further developing MED into antitumor drugs directing at cervical cancer.