The anticancer agent, di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT), up-regulates the AMPK-dependent energy homeostasis pathway in cancer cells

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Krishan, Sukriti
Richardson, Des R
Sahni, Sumit
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2016
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Abstract

Adenosine monophosphate-activated protein kinase (AMPK) is a cellular energy sensor that monitors ATP levels. There is also evidence that AMPK has onco-suppressive properties. Iron plays a crucial role in cellular energy transducing pathways and tumor cell proliferation. Therefore, metals (e.g., iron) could play an important role in the regulation of AMPK-dependent pathways. Hence, this investigation examined the effect of the iron and copper chelator and potent anti-cancer agent, di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT), on the AMPK-mediated pathway. These studies demonstrated that Dp44mT, which forms intracellular redox-active complexes with iron and copper, significantly activated AMPK (i.e., p-AMPK/AMPK ratio) in 5 different tumor cell-types. Furthermore, examination of the Dp44mT-metal complexes demonstrated that the effect of Dp44mT on AMPK was due to a dual mechanism: (1) its ability to chelate metal ions; and (2) the generation of reactive oxygen species (ROS). The activation of the AMPK-pathway by Dp44mT was mediated by the upstream kinase, liver kinase B1 (LKB1) that is a known tumor suppressor. Moreover, using AMPKα1-selective silencing, we demonstrated that Dp44mT activated AMPK, resulting in inhibition of acetyl CoA carboxylase 1 (ACC1) and raptor, and activation of Unc-51 like kinase (ULK1). These effects are vital for inhibition of fatty acid synthesis, suppression of protein synthesis and autophagic activation, respectively. Together, this AMPK-mediated repair response aims to rescue the loss of metal ions via chelation and the induction of cytotoxic damage mediated by redox cycling of the Dp44mT-metal ion complex. In conclusion, this study demonstrates for the first time that chelators target the AMPK-dependent pathway.

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Biochimica et Biophysica Acta (BBA) - Molecular Cell Research

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1863

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12

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Biochemistry and cell biology

Medical microbiology

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Life Sciences & Biomedicine

Biochemistry & Molecular Biology

Cell Biology

Dp44mT

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Krishan, S; Richardson, DR; Sahni, S, The anticancer agent, di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT), up-regulates the AMPK-dependent energy homeostasis pathway in cancer cells, Biochimica et Biophysica Acta (BBA) - Molecular Cell Research, 2016, 1863 (12), pp. 2916-2933

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