The development of cancer involves genetic changes leading to alterations in the control of tissue development and homeostatic maintenance, which is tightly regulated by the cellular suicide program, apoptosis. Many tumor cells are resistant to intrinsic and extrinsic apoptotic stimuli, probably due to impaired apoptotic pathways in these cells. Bcl-2 family proteins are major regulators of the cellular response to apoptotic signals. Among them, anti-apoptotic Bcl-XLand pro-apoptotic Bak and Bax have-been shown to play an essential role during apoptosis. Initial studies suggest that in addition to their functions at mitochondria, Bcl-2 proteins also localize on the endoplasmic reticulum (ER) and function to regulate a parallel pathway of apoptosis. Experiments in this proposal are designed to elucidate the detailed molecular mechanisms of Bcl-2 proteins regulating apoptosis. The following specific aims are proposed: 1) Investigate the electrophysiological properties of Bcl-XL, Bak and Bax on the ER membrane and their contribution to the induction of membrane permeabilization during apoptosis. A novel patch-clamp approach to record single ion channel activity will be used to characterize Bcl-2 proteins on the ER membrane. The electrophysiological properties of purified recombinant as well as reexpressed Bcl-XL, Bak and Bax proteins on the ER membrane will be studied. The hypothesis that Bak and Bax form lipidic pores on membranes during apoptosis will also be examined; 2) Study the distinct apoptotic pathways mediated by Bcl-2 family proteins localized on different organelles. Efforts will be made to better characterize caspase pathways mediated by Bak or Bcl-XL localized on the ER or mitochondria using a RNAi approach. The importance of intracellular localizations of pro- and anti-apoptotic Bcl-2 proteins for the regulation of apoptosis will be studied by selectively targeting these proteins to specific organelles. The possible role of Ca2+ in the regulation of distinct apoptotic pathways will be investigated; and 3) Determine whether the expression of Bak and Bax affects cellular physiology and thus cellular response to death signals. Oligonucleotide-based microarray analysis will be performed to examine the changes in gene expression patterns in response to Bak or Bax expression. Genes whose expression may be involved in apoptosis regulation will be further studied.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Scientist Development Award - Research & Training (K01)
Project #
7K01CA106599-02
Application #
7177394
Study Section
Subcommittee G - Education (NCI)
Program Officer
Eckstein, David J
Project Start
2005-07-01
Project End
2010-06-30
Budget Start
2006-02-01
Budget End
2006-06-30
Support Year
2
Fiscal Year
2005
Total Cost
$86,608
Indirect Cost
Name
University of Louisville
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
057588857
City
Louisville
State
KY
Country
United States
Zip Code
40292
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Yaddanapudi, Kavitha; Li, Chi; Eaton, John W (2018) Vaccination with induced pluripotent stem cells confers protection against cancer. Stem Cell Investig 5:23
Zhao, Guoping; Neely, Aaron M; Schwarzer, Christian et al. (2016) N-(3-oxo-acyl) homoserine lactone inhibits tumor growth independent of Bcl-2 proteins. Oncotarget 7:5924-42
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Schwarzer, Christian; Fu, Zhu; Morita, Takeshi et al. (2015) Paraoxonase 2 serves a proapopotic function in mouse and human cells in response to the Pseudomonas aeruginosa quorum-sensing molecule N-(3-Oxododecanoyl)-homoserine lactone. J Biol Chem 290:7247-58
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Zhao, Guoping; Zhu, Yanglong; Eno, Colins O et al. (2014) Activation of the proapoptotic Bcl-2 protein Bax by a small molecule induces tumor cell apoptosis. Mol Cell Biol 34:1198-207
Schwarzer, Christian; Fu, Zhu; Shuai, Stacey et al. (2014) Pseudomonas aeruginosa homoserine lactone triggers apoptosis and Bak/Bax-independent release of mitochondrial cytochrome C in fibroblasts. Cell Microbiol 16:1094-104

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