Although hyperthermia is a promising modality in cancer therapy, the underlying molecular mechanisms of heat-induced cell killing and thermotolerance are still speculative. This proposal aims at studying the molecular mechanisms of thermal-inactivation of Ca-transport functions of intracellular Ca-pumping ATPase and ligand-regulated Ca-channel proteins. The intracellular Ca- pumping ATPase and Ca-channel proteins will be isolated from the fractionated sarcoplasmic reticulum membranes of rabbit muscles. Using the membrane protein reconstitution and the lipid-exchange protein-mediated lipid modification techniques, the above membrane Ca-transport proteins in native, lipid- modified, and reconstituted membranes will be studied. The thermal-inactivation kinetics of the Ca-transport functions for the above membranes at different lipid compositions will be measured in the presence or absence of different Ca-regulating factors (Ca2+, pH, calmodulin, glutathione, and IP3) as well as exogenous hyperthermic sensitizing and protective chemicals (sugars, polyols, local anesthetics, alcohols, and antibiotics). The thermal-induced structural alteration of the specific functional site and the overall conformational change of the protein will be determined by studying the fluorescence intensity of the covalently attached fluorescent probes and the native protein fluorescence, respectively. These structural alterations will then be related to the corresponding functional-inactivation of the protein. The physical state of lipids in modulating the structural and functional impairment of the Ca-transport proteins will also be examined using lipophilic probe molecules. This study, which employs a well-defined model system, will advance our present knowledge of the heat-induced inactivation of cell membrane Ca- transport proteins, and provide insight toward understanding the mechanisms of the alteration of Ca-homeostasis within the cell which will lead to cell death or thermotolerance.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
7R29CA047610-03
Application #
3458983
Study Section
Radiation Study Section (RAD)
Project Start
1987-09-01
Project End
1992-05-31
Budget Start
1988-09-22
Budget End
1989-05-31
Support Year
3
Fiscal Year
1988
Total Cost
Indirect Cost
Name
Texas Tech University
Department
Type
Schools of Arts and Sciences
DUNS #
City
Lubbock
State
TX
Country
United States
Zip Code
79409
Vetrova, Elena V; Kudryasheva, Nadezhda S; Cheng, Kwan H (2009) Effect of quinone on the fluorescence decay dynamics of endogenous flavin bound to bacterial luciferase. Biophys Chem 141:59-65
Chen, S Y; Cheng, K H (1996) Detection of membrane packing defects by time-resolved fluorescence depolarization. Biophys J 71:878-84
Cheng, K H; Somerharju, P (1996) Effects of unsaturation and curvature on the transverse distribution of intramolecular dynamics of dipyrenyl lipids. Biophys J 70:2287-98
Cheng, K H (1994) In vivo tissue characterization of human brain by chisquares parameter maps: multiparameter proton T2-relaxation analysis. Magn Reson Imaging 12:1099-109
Cheng, K H; Somerharju, P; Sugar, I (1994) Detection and characterization of the onset of bilayer packing defects by nanosecond-resolved intramolecular excimer fluorescence spectroscopy. Chem Phys Lipids 74:49-64
Cheng, K H; Ruymgaart, L; Liu, L I et al. (1994) Intramolecular excimer kinetics of fluorescent dipyrenyl lipids: 1. DMPC/cholesterol membranes. Biophys J 67:902-13
Cheng, K H; Ruymgaart, L; Liu, L I et al. (1994) Intramolecular excimer kinetics of fluorescent dipyrenyl lipids: 2. DOPE/DOPC membranes. Biophys J 67:914-21
Cheng, K H (1993) Quantitation of non-Einstein diffusion behavior of water in biological tissues by proton MR diffusion imaging: synthetic image calculations. Magn Reson Imaging 11:569-83
Cheng, K H; Hernandez, M (1992) Magnetic resonance diffusion imaging detects structural damage in biological tissues upon hyperthermia. Cancer Res 52:6066-73
Chen, S Y; Cheng, K H; Van der Meer, B W (1992) Quantitation of lateral stress in lipid layer containing nonbilayer phase preferring lipids by frequency-domain fluorescence spectroscopy. Biochemistry 31:3759-68

Showing the most recent 10 out of 21 publications