Neoalbaconol induces energy depletion and multiple cell death in cancer cells by targeting PDK1-PI3-K/Akt signaling pathway

Many natural compounds derived from plants or microbes show promising potential for anticancer treatment, but few have been found to target energy-relevant regulators. In this study, we report that neoalbaconol (NA), a novel small-molecular compound isolated from the fungus, Albatrellus confluens, could target 3-phosphoinositide-dependent protein kinase 1 (PDK1) and inhibit its downstream phosphoinositide-3 kinase (PI3-K)/Akt-hexokinase 2 (HK2) pathway, which eventually resulted in energy depletion. By targeting PDK1, NA reduced the consumption of glucose and ATP generation, activated autophagy and caused apoptotic and necroptotic death of cancer cells through independent pathway. Necroptosis was remarkably induced, which was confirmed by several necroptosis-specific markers: the activation of autophagy, presence of necrotic morphology, increase of receptor-interacting protein 1 (RIP1)/RIP3 colocalization and interaction and rescued by necroptosis inhibitor necrostatin-1. The possibility that Akt overexpression reversed the NA-induced energy crisis confirmed the importance of the PDK1-Akt-energy pathway in NA-mediated cell death. Moreover, NA shows the capability to inhibit PI3-K/Akt signaling and suppress tumor growth in the nasopharyngeal carcinoma (NPC) nude mouse model. These results supported the feasibility of NA in anticancer treatments.

[1]  N. Hay,et al.  Mitochondrial hexokinases, novel mediators of the antiapoptotic effects of growth factors and Akt , 2006, Oncogene.

[2]  R A Knight,et al.  Classification of cell death: recommendations of the Nomenclature Committee on Cell Death , 2005, Cell Death and Differentiation.

[3]  S. Pattingre,et al.  JNK1-mediated phosphorylation of Bcl-2 regulates starvation-induced autophagy. , 2008, Molecular cell.

[4]  W. N. Burnette,et al.  "Western blotting": electrophoretic transfer of proteins from sodium dodecyl sulfate--polyacrylamide gels to unmodified nitrocellulose and radiographic detection with antibody and radioiodinated protein A. , 1981, Analytical biochemistry.

[5]  A. Purvis,et al.  Getting the measure of biodiversity , 2000, Nature.

[6]  Kajia Cao,et al.  Potent obatoclax cytotoxicity and activation of triple death mode killing across infant acute lymphoblastic leukemia. , 2013, Blood.

[7]  R. Mittermeier,et al.  Biodiversity hotspots for conservation priorities , 2000, Nature.

[8]  Lucas N Joppa,et al.  Biodiversity hotspots house most undiscovered plant species , 2011, Proceedings of the National Academy of Sciences.

[9]  Chuan-Qi Zhong,et al.  Programmed necrosis: backup to and competitor with apoptosis in the immune system , 2011, Nature Immunology.

[10]  R A Knight,et al.  Molecular definitions of cell death subroutines: recommendations of the Nomenclature Committee on Cell Death 2012 , 2011, Cell Death and Differentiation.

[11]  Colin B. Reese,et al.  3-Phosphoinositide-dependent protein kinase-1 (PDK1): structural and functional homology with the Drosophila DSTPK61 kinase , 1997, Current Biology.

[12]  D. V. van Aalten,et al.  PDK1, the master regulator of AGC kinase signal transduction. , 2004, Seminars in cell & developmental biology.

[13]  Yong Li,et al.  A novel miR‐155/miR‐143 cascade controls glycolysis by regulating hexokinase 2 in breast cancer cells , 2012, The EMBO journal.

[14]  U. Lindequist,et al.  The Pharmacological Potential of Mushrooms , 2005, Evidence-based complementary and alternative medicine : eCAM.

[15]  J. Grandis,et al.  Antitumor Mechanisms of Targeting the PDK1 Pathway in Head and Neck Cancer , 2012, Molecular Cancer Therapeutics.

[16]  Raymond Sawaya,et al.  The role of autophagy in cancer development and response to therapy , 2005, Nature Reviews Cancer.

[17]  Small‐Molecule Inhibitors of PDK1 , 2008, ChemMedChem.

[18]  P. Cohen,et al.  Characterization of a 3-phosphoinositide-dependent protein kinase which phosphorylates and activates protein kinase Bα , 1997, Current Biology.

[19]  M. Falasca,et al.  Targeting PDK1 in cancer. , 2011, Current medicinal chemistry.

[20]  Alexei Degterev,et al.  Chemical inhibitor of nonapoptotic cell death with therapeutic potential for ischemic brain injury , 2005, Nature chemical biology.

[21]  L. Cantley,et al.  PI3K pathway alterations in cancer: variations on a theme , 2008, Oncogene.

[22]  Xuetao Cao,et al.  Albaconol, a Plant-Derived Small Molecule, Inhibits Macrophage Function by Suppressing NF-κB Activation and Enhancing SOCS1 Expression , 2008, Cellular and Molecular Immunology.

[23]  R A Knight,et al.  Classification of cell death: recommendations of the Nomenclature Committee on Cell Death 2009 , 2005, Cell Death and Differentiation.

[24]  D. Hanahan,et al.  Hallmarks of Cancer: The Next Generation , 2011, Cell.

[25]  Russell G. Jones,et al.  Tumor suppressors and cell metabolism: a recipe for cancer growth. , 2009, Genes & development.

[26]  I. Kariv,et al.  Discovery of PDK1 Kinase Inhibitors with a Novel Mechanism of Action by Ultrahigh Throughput Screening , 2010, The Journal of Biological Chemistry.

[27]  Takeshi Noda,et al.  LC3, a mammalian homologue of yeast Apg8p, is localized in autophagosome membranes after processing , 2000, The EMBO journal.

[28]  E. Gottlieb,et al.  Targeting metabolic transformation for cancer therapy , 2010, Nature Reviews Cancer.

[29]  M. Jäättelä,et al.  Triggering caspase-independent cell death to combat cancer. , 2002, Trends in molecular medicine.

[30]  R. Davis,et al.  Signal Transduction by the JNK Group of MAP Kinases , 2000, Cell.

[31]  P. Vandenabeele,et al.  Molecular mechanisms of necroptosis: an ordered cellular explosion , 2010, Nature Reviews Molecular Cell Biology.

[32]  Ajjai Alva,et al.  Regulation of an ATG7-beclin 1 Program of Autophagic Cell Death by Caspase-8 , 2004, Science.

[33]  Junying Yuan,et al.  Alternative cell death mechanisms in development and beyond. , 2010, Genes & development.

[34]  T. Ueno,et al.  LC3 conjugation system in mammalian autophagy , 2004, The International Journal of Biochemistry & Cell Biology.

[35]  Saroj P. Mathupala,et al.  Hexokinase II: Cancer's double-edged sword acting as both facilitator and gatekeeper of malignancy when bound to mitochondria , 2006, Oncogene.

[36]  Joydeep Mukherjee,et al.  Hexokinase 2 is a key mediator of aerobic glycolysis and promotes tumor growth in human glioblastoma multiforme , 2011, The Journal of experimental medicine.

[37]  M. Stadler,et al.  Activities of Prenylphenol Derivatives from Fruitbodies of Albatrellus spp. on the Human and Rat Vanilloid Receptor 1 (VR1) and Characterisation of the Novel Natural Product, Confluentin , 2003, Archiv der Pharmazie.

[38]  Xin Yu,et al.  Grifolin, a potent antitumour natural product upregulates death-associated protein kinase 1 DAPK1 via p53 in nasopharyngeal carcinoma cells. , 2011, European journal of cancer.

[39]  A. Newton,et al.  Cellular Signaling Pivoting around PDK-1 , 2000, Cell.

[40]  A. Kimchi,et al.  Autophagy as a cell death and tumor suppressor mechanism , 2004, Oncogene.

[41]  Xiaofeng Zhu,et al.  c-Jun NH2-terminal kinase activation is essential for up-regulation of LC3 during ceramide-induced autophagy in human nasopharyngeal carcinoma cells , 2011, Journal of Translational Medicine.

[42]  M. Oshimura,et al.  PI3K-Akt pathway: Its functions and alterations in human cancer , 2004, Apoptosis.

[43]  J. Gutterman,et al.  A plant triterpenoid, avicin D, induces autophagy by activation of AMP-activated protein kinase , 2007, Cell Death and Differentiation.