Derangements in apoptosis are common in cancer and confer resistance to cytotoxic therapy. However, the mechanisms that regulate cancer cell death are poorly understood. Dr. Cryns' laboratory has recently identified the heat shock protein alphaB-crystallin as a novel regulator of apoptosis. They have demonstrated that stable expression of alphaB-crystallin in cancer cells confers resistance to chemotherapy-induced apoptosis, at least in part, by a novel mechanism: alphaB-crystallin specifically binds to pro-caspase-3 in vitro and in vivo and inhibits its proteolytic activation by apical caspases. However, caspase-3 is not the only downstream target of alphaB-crystallin: alphaB-crystallin protects MCF-7 breast cancer cells (which lack caspase-3) from chemotherapy-induced apoptosis, although it confers greater protection to MCF-7 cells in which the pro-caspase-3 gene has been stably introduced. Preliminary studies from Dr. Cryns' laboratory also suggest that alphaB-crystallin is phosphorylated in response to chemotherapy and that phosphorylation of alphaB-crystallin may impair its anti-apoptotic function. The goal of the proposed experiments is to examine the hypothesis that alphaB-crystallin expression in cancer cells confers resistance to chemotherapy-induced apoptosis by inhibiting the activation of caspase-3 and other caspase(s).
The specific aims are: 1) To determine the molecular mechanisms by which alphaB-crystallin inhibits chemotherapy-induced apoptosis; 2) To delineate the functional domains of alphaB-crystallin that mediate its anti-apoptotic actions; 3) To assess the functional consequences of phosphorylation of alphaB-crystallin; and 4) To determine whether selective inhibition of alphaB-crystallin expression using a deoxyribozyme sensitized cancer cells to chemotherapy-induced caspase activation and apoptosis.
These aims will be accomplished using several techniques to quantitatively measure apoptosis (e.g., TUNEL staining and nuclear fragmentation assays) and caspase activation (e.g., pro-caspase proteolytic processing and cleavage of fluorogenic substrates). These studies, then, will provide novel insights into the mechanisms of chemoresistance in cancer and may lead to new therapies for cancer that specifically target alphaB-crystallin.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA097198-03
Application #
6856542
Study Section
Special Emphasis Panel (ZRG1-CAMP (01))
Program Officer
Forry, Suzanne L
Project Start
2003-03-03
Project End
2008-02-28
Budget Start
2005-03-01
Budget End
2006-02-28
Support Year
3
Fiscal Year
2005
Total Cost
$211,613
Indirect Cost
Name
Northwestern University at Chicago
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
005436803
City
Chicago
State
IL
Country
United States
Zip Code
60611
Malin, Dmitry; Petrovic, Vladimir; Strekalova, Elena et al. (2016) ?B-crystallin: Portrait of a malignant chaperone as a cancer therapeutic target. Pharmacol Ther 160:1-10
Oshita, Shayna E; Chen, Feng; Kwan, Toni et al. (2010) The small heat shock protein HspB2 is a novel anti-apoptotic protein that inhibits apical caspase activation in the extrinsic apoptotic pathway. Breast Cancer Res Treat 124:307-15
Evans, Joseph R; Bosman, Joshua D; Brown-Endres, Lauren et al. (2010) Induction of the small heat shock protein alphaB-crystallin by genotoxic stress is mediated by p53 and p73. Breast Cancer Res Treat 122:159-68
Bosman, Joshua D; Yehiely, Fruma; Evans, Joseph R et al. (2010) Regulation of alphaB-crystallin gene expression by the transcription factor Ets1 in breast cancer. Breast Cancer Res Treat 119:63-70
Ivanov, Olga; Chen, Feng; Wiley, Elizabeth L et al. (2008) alphaB-crystallin is a novel predictor of resistance to neoadjuvant chemotherapy in breast cancer. Breast Cancer Res Treat 111:411-7
Strohecker, Anne M; Yehiely, Fruma; Chen, Feng et al. (2008) Caspase cleavage of HER-2 releases a Bad-like cell death effector. J Biol Chem 283:18269-82
Lu, Meiling; Strohecker, Anne; Chen, Feng et al. (2008) Aspirin sensitizes cancer cells to TRAIL-induced apoptosis by reducing survivin levels. Clin Cancer Res 14:3168-76
Sitterding, Stephanie M; Wiseman, William R; Schiller, Carol L et al. (2008) AlphaB-crystallin: a novel marker of invasive basal-like and metaplastic breast carcinomas. Ann Diagn Pathol 12:33-40
Werner, Michael E; Chen, Feng; Moyano, Jose V et al. (2007) Caspase proteolysis of the integrin beta4 subunit disrupts hemidesmosome assembly, promotes apoptosis, and inhibits cell migration. J Biol Chem 282:5560-9
Moyano, Jose V; Evans, Joseph R; Chen, Feng et al. (2006) AlphaB-crystallin is a novel oncoprotein that predicts poor clinical outcome in breast cancer. J Clin Invest 116:261-70

Showing the most recent 10 out of 13 publications