The effect of 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) on fatty acid oxidation in hepatocytes isolated from neonatal piglets

In the present study, the effect of 5-aminoimidazole-4-carboxamide ribonucleoside （AICAR） on long-chain fatty acid oxidation by hepatocytes isolated from suckled neonatal pig liver （a low ketogenic and lipogenic tissue） was tested Incubation of hepatocytes with AICAR （0.5 raM） in the presence of ] mM of carnitine and 10 mM of glucose for 1 hour at 37℃ had no significant effect on total [1-14C]-palrnitate （0.5 mM） oxidation （14CO2 and 14C-Acid soluble products （ASP））. Consistent with the fatty acid oxidation, carnitine palmitoyltransferase I activity and inhibition of its activity by malonyI-CoA （10 MM） assayed in cell homogenate also remained constant. However, addition of AICAR to the hepatocytes decreased 14CO2 production by 18% compared to control （p 〈 0.06）. The reduction of labeled carboxylic carbon accumulated in C02 caused a significant difference in distribution of oxidative products between 14C02 and 14C-ASP （p 〈 0.03） compared with the control. It was also noticed that acetyI-CoA carboxylase （ACC） was increased by AICAR （p 〈 0.03）, indicating that ACC might drive acetyI-CoA toward fatty acid synthesis pathway and induce an increase in distribution of fatty acid carbon to 14C-ASP. Addition of insulin to hepatocyte incubations with AICAR did not change the oxidative product distribution between CO2 and ASP, but further promoted ACC activity. The increased ACC activity was 70% higher than in the control group when citrate was absent in the reaction medium and was 30% higher when citrate was present in the medium. Our results suggest that AICAR may affect the distribution of metabolic products from fatty acid oxidation by changing ACC activity in hepatocyte isolated from suckled neonatal piglets; however, the basis for the increase in ACC activity elicited by AICAR is not apparent.

AIC AR and Decitabine Enhance the Sensitivity of K562 Cells to Imatinib by Promoting Mitochondrial Activity

Although the advent of tyrosine kinase inhibitors(TKIs)has dramatically improved the survival of patients with chronic myeloid leukaemia(CML),acquired drug resistance and TKI-insensitive leukaemic stem cells(LSCs)remain major obstacles to a CML cure.In recent years,the reprogramming of mitochondrial metabolism has emerged as a hallmark of cancers,including CML,and in turn may be exploited for therapeutic purposes.Here,we investigated the effects of several drugs on the mitochondrial function of the CML cell line K562 and found that 5-aminoimidazole-4-carboxamide ribotide(AICAR)and decitabine could effectively increase the ATP content and mitochondrial biogenesis.In addition,these two drugs induced cell cycle arrest and a decrease in colony-forming capacity and promoted K562 cell differentiation.Moreover,we demonstrated that treatment with AICAR or decitabine enhanced the sensitivity o f K562 cells to imatinib,as evidenced by a combination treatment assay.Altogether,our findings indicate that TKIs combined with mitochondrial regulation may provide a therapeutic strategy for the treatment of CML.