title: Coordinated activation of AMP-activated protein kinase, extracellular signal-regulated kinase, and autophagy regulates phorbol myristate acetate-induced differentiation of SH-SY5Y neuroblastoma cells.
abstract: We explored the interplay between the intracellular energy sensor AMP-activated protein kinase (AMPK), extracellular signal-regulated kinase (ERK), and autophagy in phorbol myristate acetate (PMA)-induced neuronal differentiation of SH-SY5Y human neuroblastoma cells. PMA-triggered expression of neuronal markers (dopamine transporter, microtubule-associated protein 2, β-tubulin) was associated with an autophagic response, measured by the conversion of microtubule-associated protein light chain 3 (LC3)-I to autophagosome-bound LC3-II, increase in autophagic flux, and expression of autophagy-related (Atg) proteins Atg7 and beclin-1. This coincided with the transient activation of AMPK and sustained activation of ERK. Pharmacological inhibition or RNA interference-mediated silencing of AMPK suppressed PMA-induced expression of neuronal markers, as well as ERK activation and autophagy. A selective pharmacological blockade of ERK prevented PMA-induced neuronal differentiation and autophagy induction without affecting AMPK phosphorylation. Conversely, the inhibition of autophagy downstream of AMPK/ERK, either by pharmacological agents or LC3 knockdown, promoted the expression of neuronal markers, thus indicating a role of autophagy in the suppression of PMA-induced differentiation of SH-SY5Y cells. Therefore, PMA-induced neuronal differentiation of SH-SY5Y cells depends on a complex interplay between AMPK, ERK, and autophagy, in which the stimulatory effects of AMPK/ERK signaling are counteracted by the coinciding autophagic response. Phorbol myristate acetate (PMA) induces the expression of dopamine transporter, microtubule-associated protein 2, and β-tubulin, and subsequent neuronal differentiation of SH-SY5Y neuroblastoma cells through AMP-activated protein kinase (AMPK)-dependent activation of extracellular signal-regulated kinase (ERK). The activation of AMPK/ERK axis also induces the expression of beclin-1 and Atg7, and increases LC3 conversion, thereby triggering the autophagic response that counteracts differentiation process.
authors.affiliation: Institute for Biological Research "Sinisa Stankovic", University of Belgrade, Belgrade, Serbia.
authors.forename: Nevena
authors.initials: N
authors.lastname: Zogovic
authors.forename: Gordana
authors.initials: G
authors.lastname: Tovilovic-Kovacevic
authors.forename: Maja
authors.initials: M
authors.lastname: Misirkic-Marjanovic
authors.forename: Ljubica
authors.initials: L
authors.lastname: Vucicevic
authors.forename: Kristina
authors.initials: K
authors.lastname: Janjetovic
authors.forename: Ljubica
authors.initials: L
authors.lastname: Harhaji-Trajkovic
authors.forename: Vladimir
authors.initials: V
authors.lastname: Trajkovic
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000378:metabolism*; D001343:Autophagy / Q000187:drug effects*; D000071193:Autophagy-Related Protein 7; D000071189:Autophagy-Related Protein-1 Homolog; D002454:Cell Differentiation / Q000187:drug effects*; D045744:Cell Line, Tumor; D050483:Dopamine Plasma Membrane Transport Proteins / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009447:Neuroblastoma / Q000473:pathology; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D034622:RNA Interference / Q000502:physiology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D044764:Ubiquitin-Activating Enzymes / Q000378:metabolism
chemical_list: D050483:Dopamine Plasma Membrane Transport Proteins; D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; C477012:MAP1LC3A protein, human; C489788:MAP2 protein, human; D008869:Microtubule-Associated Proteins; D000071189:Autophagy-Related Protein-1 Homolog; D017346:Protein Serine-Threonine Kinases; C484754:ULK1 protein, human; D048049:Extracellular Signal-Regulated MAP Kinases; D055372:AMP-Activated Protein Kinases; C509349:ATG7 protein, human; D000071193:Autophagy-Related Protein 7; D044764:Ubiquitin-Activating Enzymes; D013755:Tetradecanoylphorbol Acetate
keywords: AMP-activated protein kinase; autophagy; extracellular signal-regulated kinase; neuronal differentiation; phorbol myristate acetate