6th ESACP Congress, Heidelberg, April 7-11, 1999

A029
RAMAN SPECTRAL IMAGING ON SINGLE LIVING CELL: A PROMISING TOOL TOWARDS CANCER DIAGNOSIS
Beljebbar A , Morjani H, Sockalingum GD, Manfait M

Unité Médian, IFR53, UFR de Pharmacie, Université de Reims Champagne-Ardenne, Reims CEDEX, France

Despite the advance of cancer chemotherapy, major difficulties still need to be overcome such as the phenomenon of cross-resistance to a variety of natural product drugs and their synthetic derivatives. Among the different types of drug resistance, researchers have been interested in the so-called multidrug resistance (MDR) where P-glycoprotein (P-gp) protein is responsible for the active efflux of the drug, out of the cell. Several cancer cell lines have been investigated by Raman spectral imaging using red excitation. This technique has been used to determine and quantify the intracellular distribution of the proteins and lipids in single living sensitive and resistant cells. Spectral images have been recorded on the 3 different single living sensitive and resistant cells without any treatment with the drug in the same spectral conditions. The comparison between Raman spectra in each point, between sensitive and resistant cells, displays some changes in the amide I intensity corresponding to the changes in the intracellular proteins content of the cells. The spectral analysis of the sensitive and resistant cell lines has allowed to identify the differences proper to the MDR and non-MDR-phenotype. Cells exhibiting MDR-phenotype and obtained both by drug selection and transfection with mdr gene, are included. Our data show that it can be possible to identify the spectral characteristics associated with this resistance mechanism (profile, percentage of proteins and lipids). Resolution enhancement methods (deconvolution, derivatives, and curve fitting) have also been used to characterise the conformational changes in the secondary structure of cell constituents that accompany the MDR phenotype.