INTEREST OF RHODAMINE-123 IN DETECTION OF SMALL NUMBER OF MULTIDRUG-RESISTANT CELLS

The neoplasias resistance to chemotherapy is mainly due to multidrug r esistance phenomenon (MDR) mediated by an ATP-dependent efflux pump ca lled P-glycoprotein. This function can be reversed by many multidrug r eversing agents so numerous chemotherapy regimens have been initiated in malignancies. To make sure the success of these protocols it is nec essary to detect as soon and as certain as possible the presence of re sistant cells among malignant population. We have chosen to evaluate f unctional test using rhodamine 123 in this aim in view. We have made v arious mixtures of resistant ans sensitive cells of three cell lines. Rhodamine 123 allows to detect 1% of resistant cells among sensitive c ells. Influence of dead cells on the interpretation is discussed.