Intracellular dynamics of topoisomerase I inhibitor, CPT-11, by slit-scanning confocal Raman microscopy
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Most molecular imaging technologies require exogenous probes and may have some influence on the intracellular dynamics of target molecules. In contrast, Raman scattering light measurement can identify biomolecules in their innate state without application of staining methods. Our aim was to analyze intracellular dynamics of topoisomerase I inhibitor, CPT-11, by using slit-scanning confocal Raman microscopy, which can take Raman images with high temporal and spatial resolution. We could acquire images of the intracellular distribution of CPT-11 and its metabolite SN-38 within several minutes without use of any exogenous tags. Change of subcellular drug localization after treatment could be assessed by Raman imaging. We also showed intracellular conversion from CPT-11 to SN-38 using Raman spectra. The study shows the feasibility of using slit-scanning confocal Raman microscopy for the non-labeling evaluation of the intracellular dynamics of CPT-11 with high temporal and spatial resolution. We conclude that Raman spectromicroscopic imaging is useful for pharmacokinetic studies of anticancer drugs in living cells.
KeywordsSlit-scanning Raman microscopy Molecular imaging Non-labeling method Anticancer-drug
We thank Dr. Katsumasa Fujita and Dr. Keisaku Hamada of Osaka University for their helpful discussion, and Dr. Taisuke Ota and Dr. Minoru Kobayashi of Nanophoton Corporation for their useful advice. Grant-in-Aid (C-20500396) from the Ministry of Education, Culture, Sports, Science, and Technology of Japan.
Conflict of interest statement
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