EFFECTS OF TGF-b1, FLUOROURACIL AND CYTOTOXIC LECTINS ON HT-29 AND SW-480 HUMAN COLON CANCER CELLS
Human colon cancer cells of HT-29 line and of SW-480 line (defective in Smad 4 protein function necessary for transforming growth factor b1 (TGF-b1) signalling) were subjected to the action of TGF-b1, anti-cancer drug fluorouracil and some cytotoxic plant lectins. It was found that SW-480 cells were more sensitive than HT-29 cells to growth-inhibiting and cell-killing effects of the cytotoxic mistletoe agglutinins 1 and 2, while the difference in the cytotoxic action of wheat germ agglutinin was not so distinct. TGF-b1 (10 ng/ml) did not affect significantly 3H-thymidine incorporation into DNA of both studied cell lines. These cell lines were similarly inhibited by fluorouracil. The cytotoxic actions of the lectins and fluorouracil were accompanied by strong DNA fragmentation in both cancer cell lines. Potential mechanisms responsible for the appearance of different sensitivity to the cytotoxic lectins in the studied cell lines are discussed.
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