AMPK-Dependent Phosphorylation of ULK1 Induces Autophagy

Zhao, Mantong; Klionsky, Daniel J.

doi:10.1016/j.cmet.2011.01.009

Cited by 128 publications

(96 citation statements)

References 11 publications

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“…35,36 Thus, under certain cellular settings, mTORC1 inhibition and AMPK activation may cooperate to trigger autophagy. [36][37][38] Although future research is needed to completely clarify this point, our data suggest that this could be the mechanism by which cannabinoids trigger autophagy in HCC cells. To note, it has been recently described that mTOR signaling has a critical role in the pathogenesis of HCC and that mTOR inhibitors have antineoplastic activity in experimental models of HCC.…”

Section: Discussionmentioning

confidence: 99%

Anti-tumoral action of cannabinoids on hepatocellular carcinoma: role of AMPK-dependent activation of autophagy

et al. 2011

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Hepatocellular carcinoma (HCC) is the third cause of cancer-related death worldwide. When these tumors are in advanced stages, few therapeutic options are available. Therefore, it is essential to search for new treatments to fight this disease. In this study, we investigated the effects of cannabinoids -a novel family of potential anticancer agents -on the growth of HCC. We found that D 9 -tetrahydrocannabinol (D 9 -THC, the main active component of Cannabis sativa) and JWH-015 (a cannabinoid receptor 2 (CB 2 ) cannabinoid receptor-selective agonist) reduced the viability of the human HCC cell lines HepG2 (human hepatocellular liver carcinoma cell line) and HuH-7 (hepatocellular carcinoma cells), an effect that relied on the stimulation of CB 2 receptor. We also found that D 9 -THC-and JWH-015-induced autophagy relies on tribbles homolog 3 (TRB3) upregulation, and subsequent inhibition of the serine-threonine kinase Akt/mammalian target of rapamycin C1 axis and adenosine monophosphate-activated kinase (AMPK) stimulation. Pharmacological and genetic inhibition of AMPK upstream kinases supported that calmodulin-activated kinase kinase b was responsible for cannabinoid-induced AMPK activation and autophagy. In vivo studies revealed that D 9 -THC and JWH-015 reduced the growth of HCC subcutaneous xenografts, an effect that was not evident when autophagy was genetically of pharmacologically inhibited in those tumors. Moreover, cannabinoids were also able to inhibit tumor growth and ascites in an orthotopic model of HCC xenograft. Our findings may contribute to the design of new therapeutic strategies for the management of HCC. Hepatocellular carcinoma (HCC) is one of the most common solid tumors and the third leading cause of cancer-related death worldwide. 1 Its prognosis remains reserved, with a 5-year survival rate of o5%. 2 It is the most common cause of death in patients with cirrhosis 3 and, according to the World Health Organization, the incidence of HCC is expected to increase until 2030. The overall survival of patients with HCC has not significantly improved in the past two decades. Current treatments are only applicable at early stages of tumor development and include tumor resection, liver transplantation, chemoembolization and sorafenib administration. 4 However, approximately half of the patients suffer tumor recurrence. The most important mechanism of liver cancer progression is cell proliferation. Although in recent years several clinical trials have tested the efficacy of agents that selectively target important signaling pathways involved in the control of this process, no relevant improvement in the prognostic/survival of patients with HCC has been achieved so far, 5 and, therefore, it is necessary to identify novel therapeutic strategies for the management of HCC.Cannabinoids are lipid mediators originally isolated from the hemp plant Cannabis sativa that produce their effects by activating primarily two G-protein-coupled receptors: cannabinoid receptor 1 (CB 1 ), which is highly abundant in the b...

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Section: Discussionmentioning

confidence: 99%

Anti-tumoral action of cannabinoids on hepatocellular carcinoma: role of AMPK-dependent activation of autophagy

et al. 2011

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“…However, this alone does not result in autophagy activation. For this to occur, ULK1 also requires direct activating phosphorylation by AMPK, emphasizing again the interplay between nutrient and energy-sensing pathways (Egan et al 2011;Zhao and Klionsky 2011). In starved cells, AMPK tightly binds ULK1, and this interaction is enhanced by rapamycin and disrupted by Rheb overexpression (Behrends et al 2010;.…”

Section: Mtorc1 Directly Regulates Autophagymentioning

confidence: 99%

mTOR-Dependent Cell Survival Mechanisms

Hung

García-Haro

Sparks

et al. 2012

Cold Spring Harbor Perspectives in Biology

163

135

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The mechanistic target of rapamycin (mTOR) kinase is a conserved regulator of cell growth, proliferation, and survival. In cells, mTOR is the catalytic subunit of two complexes called mTORC1 and mTORC2, which have distinct upstream regulatory signals and downstream substrates. mTORC1 directly senses cellular nutrient availability while indirectly sensing circulating nutrients through growth factor signaling pathways. Cellular stresses that restrict growth also impinge on mTORC1 activity. mTORC2 is less well understood and appears only to sense growth factors. As an integrator of diverse growth regulatory signals, mTOR evolved to be a central signaling hub for controlling cellular metabolism and energy homoeostasis, and defects in mTOR signaling are important in the pathologies of cancer, diabetes, and aging. Here we discuss mechanisms by which each mTOR complex might regulate cell survival in response to metabolic and other stresses.

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“…14,25 Therefore, we investigated whether ULK1 was involved in autophagy induction and monocyte differentiation mediated by CSF1. To this aim, we used pharmacological and siRNA approaches.…”

Section: Plcg2 Downstream Of the Csf1 Receptor Is Required For Monocymentioning

confidence: 99%

The PRKAA1/AMPKα1 pathway triggers autophagy during CSF1-induced human monocyte differentiation and is a potential target in CMML

Obba

Hizir²,

Boyer

et al. 2015

Autophagy

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These authors contributed equally to this work.Keywords: autophagy, CMML, CSF1, differentiation, primary monocyte, PRKAA1/AMPKa1, P2RY6Abbreviations: ACTB actin, b; CAMKK2, calcium/calmodulin-dependent protein kinase kinase 2, b; CASP8, caspase 8; apoptosisrelated cysteine peptidase; CFLAR CASP8 and FADD-like apoptosis regulator; CMML chronic myelomonocytic leukemia; CSF1 colony stimulating factor 1 (macrophage); CSF1R colony stimulating factor 1 receptor; DEFA1 defensin a 1; DEFA3 defensin a 3 neutrophil-specific; DRS; dorsomorphin; EMR1 EGF-like module-containing mucin-like hormone receptor-like 1; FADD Fas (TNFRSF6)-associated via death domain; ITGAM integrin a M; MAP1LC3B/LC3B microtubule-associated protein 1 light chain 3 b; P2RY6 pyrimidinergic receptor P2Y; G-protein coupled 6; PLCB3 phospholipase C; b 3 (phosphatidylinositol-specific); PLC phospholipase; PLCG2 phospholipase C gamma 2 (phosphatidylinositol-specific); PRKAA protein kinase AMP-activated; PRKAA1 protein kinase AMP-activated a 1 catalytic subunit; PRKAA2 protein kinase AMP-activated a 2 catalytic subunit; PRKAG1 protein kinase AMP-activated gamma 1 noncatalytic subunit; RIPK1 receptor (TNFRSF)-interacting serine-threonine kinase 1; STK11 serine/ threonine kinase 11; TFRC transferrin receptor; UDP uridine diphosphate; ULK1 unc-51 like autophagy activating kinase 1; WT wild-type.Autophagy is induced during differentiation of human monocytes into macrophages that is mediated by CSF1/CSF-1/M-CSF (colony stimulating factor 1 [macrophage]). However, little is known about the molecular mechanisms that link CSF1 receptor engagement to the induction of autophagy. Here we show that the CAMKK2-PRKAA1-ULK1 pathway is required for CSF1-induced autophagy and human monocyte differentiation. We reveal that this pathway links P2RY6 to the induction of autophagy, and we decipher the signaling network that links the CSF1 receptor to P2RY6-mediated autophagy and monocyte differentiation. In addition, we show that the physiological P2RY6 ligand UDP and the specific P2RY6 agonist MRS2693 can restore normal monocyte differentiation through reinduction of autophagy in primary myeloid cells from some but not all chronic myelomonocytic leukemia (CMML) patients. Collectively, our findings highlight an essential role for PRKAA1-mediated autophagy during differentiation of human monocytes and pave the way for future therapeutic interventions for CMML.

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AMPK-Dependent Phosphorylation of ULK1 Induces Autophagy

Cited by 128 publications

References 11 publications

Anti-tumoral action of cannabinoids on hepatocellular carcinoma: role of AMPK-dependent activation of autophagy

Anti-tumoral action of cannabinoids on hepatocellular carcinoma: role of AMPK-dependent activation of autophagy

mTOR-Dependent Cell Survival Mechanisms

The PRKAA1/AMPKα1 pathway triggers autophagy during CSF1-induced human monocyte differentiation and is a potential target in CMML

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