In this project we are investigating the fundamental mechanisms of photodynamic therapy (PDT) action on tumor microstructure. Specifically, the subcellular localization and subcellular phototoxicity of PDT drugs are being investigated. Initially, CPAE endothelial and PTK2 epithelial cells were studied by visualizing the subcellular organelle fluorescence when the cells were exposed to 5-aminolaevulinic acid (ALA). Both cell types showed a large amount of fluorescence in the perinuclear cytoplasm, where the photosensitizer selectively localized in the mitochondria. To investigate the subcellular phototoxicity of ALA, the subcellular regions of the cells were irradiated with a 630 nm laser microbeam. The results demonstrated that the nucleus followed by the perinuclear cytoplasm are the most sensitive areas of the cell. Particularly intriguing was the finding that the nucleus was the most sensitive region since 1) no fluorescence was observed in the nucleus and 2) th e generally accepted mechanism for PDT damage involve singlet oxygen targeting of cytoplasmic elements. Based upon these findings we will further investigate the subcellular localization and phototoxicity of ALA and other PDT drugs using 2-photon excitation. Activation of PDT drugs through multiphoton absorption provides greater selectivity than single photon absorption. in addition, the 2-photon fluorescence will allow improved visualization of drug distribution within the cell, especially along the optical axis.

Agency
National Institute of Health (NIH)
Institute
National Center for Research Resources (NCRR)
Type
Biotechnology Resource Grants (P41)
Project #
5P41RR001192-20
Application #
6119306
Study Section
Project Start
1999-04-01
Project End
2000-03-31
Budget Start
1998-10-01
Budget End
1999-09-30
Support Year
20
Fiscal Year
1999
Total Cost
Indirect Cost
Name
University of California Irvine
Department
Type
DUNS #
161202122
City
Irvine
State
CA
Country
United States
Zip Code
92697
Paugh, Jerry R; Alfonso-Garcia, Alba; Nguyen, Andrew Loc et al. (2018) Characterization of expressed human meibum using hyperspectral stimulated Raman scattering microscopy. Ocul Surf :
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Friedman, Jacob E; Dobrinskikh, Evgenia; Alfonso-Garcia, Alba et al. (2018) Pyrroloquinoline quinone prevents developmental programming of microbial dysbiosis and macrophage polarization to attenuate liver fibrosis in offspring of obese mice. Hepatol Commun 2:313-328
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Alfonso-García, Alba; Paugh, Jerry; Farid, Marjan et al. (2017) A machine learning framework to analyze hyperspectral stimulated Raman scattering microscopy images of expressed human meibum. J Raman Spectrosc 48:803-812
Takesh, Thair; Sargsyan, Anik; Anbarani, Afarin et al. (2017) Effects of a Novel Whitening Formulation on Dental Enamel. Dentistry (Sunnyvale) 7:
Malacrida, Leonel; Astrada, Soledad; Briva, Arturo et al. (2016) Spectral phasor analysis of LAURDAN fluorescence in live A549 lung cells to study the hydration and time evolution of intracellular lamellar body-like structures. Biochim Biophys Acta 1858:2625-2635
Choi, Bernard; Tan, Wenbin; Jia, Wangcun et al. (2016) The Role of Laser Speckle Imaging in Port-Wine Stain Research: Recent Advances and Opportunities. IEEE J Sel Top Quantum Electron 2016:

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