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Evidence for uptake of 8-methoxypsoralen and 5-methoxypsoralen by cellular nuclei
M Sasaki1, F Meguro, E Kumazawa
1Institute of Research and Development, Tokai University, Kanagawa-ken, Japan.
Abstract:
The fluorescent appearance of oral mucosa cells treated with 8-methoxypsoralen (8-MOP) and 5-methoxypsoralen (5-MOP) was observed by means of fluorescence microscopy. Fluorescence at the nuclei was weakened in 8-MOP-treated cells, while it was intensified in 5-MOP-treated cells. These findings were consistent with changes in the fluorescence intensities on association of the psoralen derivatives with DNA in aqueous solution. This intensity change of fluorescence and also the blue shift of the fluorescence maximum of the derivatives on association suggested that the environment around the psoralen molecules is as little polar as methanol. From the results of these fluorescence microscopic observations and spectroscopic analysis of fluorescence of derivatives interacting with DNA during equilibrium dialysis, we concluded that 8-MOP, as well as 5-MOP, is incorporated by nuclei of human cells.
Insights
This study observed how 8-methoxypsoralen (8-MOP) and 5-methoxypsoralen (5-MOP) affect oral cells. Findings indicate both psoralen derivatives are incorporated by human cell nuclei.
Area of Science:
- Photochemistry
- Molecular Biology
- Cell Biology
Background:
- Psoralens are photosensitizing compounds used in dermatology.
- Understanding psoralen interaction with cellular components is crucial for photochemotherapy.
Purpose of the Study:
- To investigate the cellular uptake and nuclear localization of 8-methoxypsoralen (8-MOP) and 5-methoxypsoralen (5-MOP).
- To analyze the fluorescence properties of psoralens upon interaction with DNA.
Main Methods:
- Fluorescence microscopy was used to observe oral mucosa cells treated with 8-MOP and 5-MOP.
- Spectroscopic analysis of psoralen-DNA interactions was performed using equilibrium dialysis.
Main Results:
- Fluorescence microscopy revealed distinct nuclear fluorescence changes: weakened with 8-MOP, intensified with 5-MOP.
- Spectroscopic data indicated a non-polar environment around psoralens bound to DNA, evidenced by fluorescence intensity changes and blue shifts.
- Consistent results from microscopy and spectroscopy support psoralen incorporation into cell nuclei.
Conclusions:
- Both 8-methoxypsoralen and 5-methoxypsoralen are incorporated into the nuclei of human cells.
- The observed fluorescence changes correlate with psoralen-DNA binding and suggest a non-polar microenvironment within the nucleus.