Cell death by apoptosis results in the removal of individual cells from the midst of a living tissue without damage to surrounding tissue. In recent years, it has been recognized that resistance to apoptosis is a hallmark of cancers and that resistance to chemotherapy can stem from a failure in apoptotic signal transmission. We have found that high levels of glucose metabolism, as is typically seen in cancer cells, can potently suppress apoptosis. In particular, we have found that the initiator caspase, caspase 2 (C2), activated in response to a number of chemotherapeutic agents, is suppressed when pentose phosphate pathway (PPP) activity is high. We have found that abundant NADPH, produced by the PPP, promotes activation of the kinase CaMKII to phosphorylate and suppress C2. Binding of phosphorylated C2 by the small acidic protein 14-3-3? prevents C2 dephosphorylation, dimerization, and activation. Conversely, when glucose or other nutrients are scarce, 14-3-3 ? is released from C2 to allow dephosphorylation and activation. We have recently found that 14- 3-3 ? binding to C2 is impeded by acetylation when nutrients are depleted (so that the PPP cannot operate) and that 14-3-3 ? deacetylation, catalyzed by the sirtuin, Sirt1, is stimulated under nutrient replete conditions.
The aims of this grant are 1) to delineate the molecular pathways linking NADPH and CaMKII, 2) to determine how Sirt1 is regulated to control 14-3-3 ?-C2 interactions and 3) to determine whether chemoresponsiveness of breast cancer cells can be altered by manipulating the pathways linking metabolism and C2.

Public Health Relevance

The goal of this grant is to determine how metabolism regulates the apoptotic protease, caspase 2 and to determine how metabolic manipulation might be used to enhance caspase-2 activation. As caspase 2 has been implicated in the response to some chemotherapeutic agents, this work may provide avenues for enhancing the response to cancer chemotherapy.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM080333-07
Application #
8618906
Study Section
Cancer Molecular Pathobiology Study Section (CAMP)
Program Officer
Maas, Stefan
Project Start
2007-09-21
Project End
2016-02-29
Budget Start
2014-03-01
Budget End
2015-02-28
Support Year
7
Fiscal Year
2014
Total Cost
$320,891
Indirect Cost
$116,502
Name
Duke University
Department
Pharmacology
Type
Schools of Medicine
DUNS #
044387793
City
Durham
State
NC
Country
United States
Zip Code
27705
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Andersen, Joshua L; Thompson, J Will; Lindblom, Kelly R et al. (2011) A biotin switch-based proteomics approach identifies 14-3-3? as a target of Sirt1 in the metabolic regulation of caspase-2. Mol Cell 43:834-42
Thomenius, M; Freel, C D; Horn, S et al. (2011) Mitochondrial fusion is regulated by Reaper to modulate Drosophila programmed cell death. Cell Death Differ 18:1640-50
Horn, Sarah R; Thomenius, Michael J; Johnson, Erika Segear et al. (2011) Regulation of mitochondrial morphology by APC/CCdh1-mediated control of Drp1 stability. Mol Biol Cell 22:1207-16
Johnson, C E; Freel, C D; Kornbluth, S (2010) Features of programmed cell death in intact Xenopus oocytes and early embryos revealed by near-infrared fluorescence and real-time monitoring. Cell Death Differ 17:170-9

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