Author/Editor		Dolinar, Klemen; Jan, Vid; Pavlin, Mojca; Chibalin, Alexander V.; Pirkmajer, Sergej
Title		Nucleosides block AICAR-stimulated activation of AMPK in skeletal muscle and cancer cells
Type		članek
Publication year		2018
Volume		str. str.
ISSN		0363-6143 - American journal of physiology. Cell physiology
Language		eng
Abstract		AMP-activated kinase (AMPK) is a major regulator of energy metabolism and a promising target for development of new treatments for type 2 diabetes and cancer. 5-aminoimidazole-4-carboxamide-1-[beta]-D-ribofuranoside (AICAR), an adenosine analogue, is a standard positive control for AMPK activation in cell-based assays. Some broadly used cell culture media, such as MEM[alpha], contain high concentrations of adenosine and other nucleosides. We determined whether such media alter AICAR action in skeletal muscle and cancer cells. In nucleoside-free media, AICAR stimulated AMPK activation, increased glucose uptake and suppressed cell proliferation. Conversely, these effects were blunted or completely blocked in MEM[alpha] that contains nucleosides. Addition of adenosine or 2'-deoxyadenosine to nucleoside-free media also suppressed AICAR action. MEM[alpha] with nucleosides blocked AICAR-stimulated AMPK activation even in the presence of methotrexate, which normally markedly enhances AICAR action by reducing its intracellular clearance. Other common media components, such as vitamin B12, vitamin C and [alpha]-lipoic acid, had a minor modulatory effect on AICAR action. Our findings show that nucleoside-containing media, commonly used in AMPK research, block action of the most widely used pharmacological AMPK activator AICAR. Results of cell-based assays in which AICAR is used for AMPK activation therefore critically depend on media formulation. Furthermore, our findings highlight a role for extracellular nucleosides and nucleoside transporters in regulation of AMPK activation.
Keywords		nucleosides cell culture media AMP-activated kinase (AMPK) nukleozidi mediji celične kulture AMP-aktivirana kinaza (AMPK)