ASSOCIATION OF DOCETAXEL PACLITAXEL WITH IRRADIATION IN OVARIAN-CARCINOMA CELL-LINES IN BIDIMENSIONAL (SULFORHODAMINE-B ASSAY) AND TRIDIMENSIONAL (SPHEROIDS) CULTURES/

The association of taxoid derivatives (paclitaxel and docetaxel) with irradiation was evaluated in ovarian carcinoma cell lines (A2780 and C AVEOC-2) using the multicellular tumor spheroids (MTS) tridimensional model and compared to the conventional bidimensional model. The radios ensitivity parameters were the surviving fraction at 2 Gy, and alpha c alculated using the linear-quadratic model for monolayer culture, the residual/control volume ratios at 2 Gy (RSV(2)) acid doses inducing 50 % decrease in MTS number (SCD50) calculated for spheroids. In A2780 mo nolayer culture, the combination was synergistic for paclitaxel and ad ditive for docetaxel. In spheroids, both compounds induced a decrease in RSV(2) and SCD50 in the two cell lines, and their combination with radiation was additive. Therefore, the radiosensitizing effect of taxo id derivatives was not constant in ovarian cell lines. The different r esults achieved in monolayer culture and in spheroids may suggest high er drug incorporation and fixation through the multiple cell layers of the spheroids than in monolayers.