MULTIDRUG-RESISTANCE EVALUATION BY CONFOCAL MICROSCOPY IN PRIMARY UROTHELIAL CANCER EXPLANT COLONIES

Assessing functional multidrug resistance (MDR) status in clinical bio psy material using drug autofluorescence has potential applications to clinical management. The small size of many cystoscopy specimens has led us to develop, as an alternative to flow cytometry, a protocol for studying epirubicin accumulation in adherent colonies of primary blad der cancer cells viewed live and in situ by confocal microscopy. The l imitations to quantitation inherent in this technique are compensated for by preservation of cellular organisation and the elimination of no n-malignant cells. Biopsy material is disaggregated and explanted into culture-grade petri dishes. After incubation for three to seven days plaques of epithelial cells have developed. Classical patterns of sens itive and resistant drug distribution are observed. Cells of the rolle d edges of the colony accumulate more drug than those of the inner epi thelial monolayer. Some central areas of larger colonies give the appe arance of drug arrested at the intercellular junctions to give a fenes trated pattern. These observations contribute to the understanding of mechanisms in MDR as well as forming the basis for a clinical urologic al MDR evaluation protocol.