Confocal Raman Microspectroscopy and Imaging Study of Theraphthal in Living Cancer Cells

Binary systems combining a transition metal complex and ascorbate have been proposed recently for catalytic therapy of malignant tumors. The killing effect on tumor cells is achieved by production of free radicals in the course of accelerated oxidation of ascorbate by dioxygen in the presence of tra...

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Bibliographic Details
Published in:	Biophysical journal Vol. 78; no. 1; pp. 499 - 512
Main Authors:	Feofanov, Alexei V., Grichine, Alexei I., Shitova, Larissa A., Karmakova, Tatyana A., Yakubovskaya, Raisa I., Egret-Charlier, Marguerite, Vigny, Paul
Format:	Journal Article
Language:	English
Published:	United States Elsevier Inc 2000 Biophysical Society
Subjects:	Adenocarcinoma Ascorbic Acid Cancer Cell Division Cell Survival Cellular biology Humans Indoles - analysis Indoles - pharmacokinetics Lung Neoplasms Microscopy, Confocal - methods Scientific imaging Spectrum Analysis, Raman - methods Tumor Cells, Cultured - pathology
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Summary:	Binary systems combining a transition metal complex and ascorbate have been proposed recently for catalytic therapy of malignant tumors. The killing effect on tumor cells is achieved by production of free radicals in the course of accelerated oxidation of ascorbate by dioxygen in the presence of transition metal complexes. Further progress in the development of binary catalytic systems (BCSs) requires a special method for their investigation in cells and tissues, because neither component of BCSs fluoresces. Here a resonance Raman confocal spectral imaging (RR CSI) technique was introduced as a unique approach to monitor quantitatively the transition metal complexes within living cells. Intracellular accumulation, localization, and retention of theraphthal (TP), a catalyst of the advanced TP/ascorbate BCS, were investigated in A549 cells with the RR CSI technique. The cellular analysis was complemented with the detailed study of molecular interactions of TP in solution and environmental factors affecting the RR spectrum of TP. TP does not penetrate into membranes, it binds very weakly to DNA and RNA, but it readily forms complexes with proteins. Binding with Ca 2+ cations and decreasing pH below 6 induce aggregation of TP. By analyzing RR spectra recorded from every point within a TP-treated cell, three states of the agent were discriminated, namely, monomeric TP in polar environment, TP bound to proteins, and aggregated TP. Their cytoplasmic and nuclear distributions were mapped at different stages of uptake and efflux. By introducing organelle-selective fluorescent probes into drug-treated cells and measuring intracellular localization of both the probe and the drug, compartmentation of TP was revealed. Cell growth suppression by the TP/ascorbate system was measured, and probable molecular and organelle targets of radical damage were characterized.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0006-3495 1542-0086
DOI:	10.1016/S0006-3495(00)76612-4