The differential effect of AICAR on c-Myc expression and proliferation in specific tumor cell lines / 中国药理学通报

Aim To investigate the effect of AICAR on the expression of the proto-oncogene c-Myc and cell proliferation rates in specific cancer cell lines. Methods The mRNA levels of c-Myc were evaluated using fluorescence-based qRT-PCR to examine the effect of AICAR treatment on c-Myc mRNA expression levels. Western blot was used to evaluate the protein levels of c-Myc following AICAR treatment. RNA interference was employed to determine whether the regulatory effect of AICAR on c-Myc was dependent on AMPK and the downstream metabolic enzymes relating to AICAR. Actinomycin D and cycloheximide were used to assess the effect of AICAR on the stability of cMyc mR-NA and protein. Western blot was used to examine the regulatory effect of AICAR on c-Myc in various cancer cell lines. The MTT assay was used to determine the effect of AICAR on cell viability in these cell lines. Results AICAR significantly up-regulated c-Myc at both mRNA and protein levels. The protein level of c-Myc reached a plateau 12 h after the AICAR treatment. The up-regulatory effect of c-Myc induced by AICAR was not dependent on either the AMPK signaling pathway or the downstream metabolites of AICAR. AICAR could significantly enhance the mRNA stability of c-Myc but did not affect the protein stability. The up-regulation of c-Myc induced by AICAR was cell-type specific. AICAR up-regulated c-Myc in SW1990, 786-0, and A549, while down-regulated c-Myc in HepG2, MCF7, and U20S. In HepG2 cells, AICAR treatment decreased cell viability. However, in SW1990 and A549 cells, AICAR treatment did not lead to any significant difference in cell viability. AICAR decreased the cell viability only when c-Myc was knocked down in SW1990 and A549 cells. Conclusions AICAR directly up-regulates c-Myc expression in an AMPK-independent manner. The up-regulation effect is cell-type dependent. The regulation of c-Myc expression by AICAR is linked to the inhibitory effect of AICAR on tumor cell proliferation.

Mitochondrial uncoupler BAM15 inhibits artery constriction and potently activates AMPK in vascular smooth muscle cells

Our previous studies found that mitochondrial uncouplers CCCP and niclosamide inhibited artery constriction and the mechanism involved AMPK activation in vascular smooth muscle cells. BAM15 is a novel type of mitochondrial uncoupler. The aim of the present study is to identify the vasoactivity of BAM15 and characterize the BAM15-induced AMPK activation in vascular smooth muscle cells (A10 cells). BAM15 relaxed phenylephrine (PE)-induced constricted rat mesenteric arteries with intact and denuded endothelium. Pretreatment with BAM15 inhibited PE-induced constriction of rat mesenteric arteries with intact and denuded endothelium. BAM15, CCCP, and niclosamide had the comparable IC value of vasorelaxation in PE-induced constriction of rat mesenteric arteries. BAM15 was less cytotoxic in A10 cells compared with CCCP and niclosamide. BAM15 depolarized mitochondrial membrane potential, induced mitochondrial fission, increased mitochondrial ROS production, and increased mitochondrial oxygen consumption rate in A10 cells. BAM15 potently activated AMPK in A10 cells and the efficacy of BAM15 was stronger than that of CCCP, niclosamide, and AMPK positive activators metformin and AICAR. In conclusion, BAM15 activates AMPK in vascular smooth muscle cells with higher potency than that of CCCP, niclosamide and the known AMPK activators metformin and AICAR. The present work indicates that BAM15 is a potent AMPK activator.

AICAR promotes the wound healing in diabetic ulcers by improving the survival rate of MSC in biomaterials transplantation / 局解手术学杂志

Objective To investigate the mechanism of AICAR in improving the survival of mesenchymal stem cells (MSCs) in biomaterials and the therapeutic effect on diabetic ulcer.Methods Totally 40 male C57BL/6J mice were equally divided into 4 groups:control group,MSCs group,AICAR group and AICAR-MSCs group.The effects of AICAR on the apoptosis and migration of MSCs were observed by flow cytometry and transwell migration assay.The expression of VEGF in conditioned medium was detected.Prepared diabetic foot ulcer model and AICAR-stimulated MSCs-covered wounds.The wound neovascularization was observe by CD31 staining 2 weeks later.Results Compared with the control group and MSCs group,the results of the cell experiments showed that the AICAR-MSCs group had lower MSCs apoptosis rate,better MSCs migration ability and higher VEGF secretion.Animal experiments showed that AICAR-stimulated MSCs covered diabetic foot ulcer wounds had good angiogenesis and rapid ulcer healing processes.Conclusion AICAR promotes the survival and paracrine effect of MSCs by inhibiting the high glucose effect on MSCs apoptosis,so as to promote the angiogenesis and accelerate the healing of ulcer.

The effect of AICAR on rat uterine smooth muscle / 中国药学杂志

OBJECTIVE: To study the effect of AICAR on uterine smooth muscle of pregnant and nonpregnant rats. METHODS: The action of AICAR and dibutyryl-cAMP on the contractile function of isolated myometrium of pregnant and nonpregnant Sprague-Dawley rats was investigated. AICAR or dibutyryl-cAMP was used at cumulative doses from 10-9 to 10-4 mol · L-1 for myometrium of pregnant rats, and at 10-5 mol · L for myometrium of nonpregnant rats. The amplitude of the contractility of myometruim was recorded. RESULTS: For the myometrium of pregnant or nonpregnant rats, AICAR and dibutyryl-cAMP exerted strong inhibitory action on the contractile function in dose-dependent manners. For the myometrium of pregnant rats, AICAR or dibutyryl-cAMP showed inhibitory effect at a low concentration of 10-7 mol · L-1. AICAR and dibutyryl-cAMP also caused significant inhibition in myometrium from nonpregnant rats. CONCLUSION: AICAR exerted strong inhibitory action on the contractile function of myometrium from pregnant or nonpregnant rats, suggesting that AICAR may have inhibitory effect on spontaneous activity of myometrium of human.