Comparative study on the cytotoxic effect of viscotoxin and mistletoe lectin on tumour cells in culture

Abstract

AbstractA comparative study was carried out on the effect of viscotoxin and mistletoe lectin I, two mistletoe proteins known to be toxic to mammals, on three tumour cell lines in culture (Yoshida sarcoma cells, T‐cell leukaemia cells Molt4, and myeloid cells K562). Both viscotoxin and mistletoe lectin were cytotoxic for the three cell lines tested, although the cell sensitivity was dependent on the type of cells used. Yoshida cells were the most sensitive to viscotoxin (ED50 = 0.7 μg/mL) and less sensitive to mistletoe lectin (ED50 = 12.8 μg/mL). K562 cells were more sensitive to mistletoe lectin (ED50 = 75 pg/mL) than Molt4 cells (ED50 = 1.3 ng/mL), whose high sensitivity to mistletoe lectin is well known. Data are also reported showing that this cell line dependent sensitivity can be exploited to demonstrate and/or to discriminate the toxic activities of either substances in crude mistletoe extracts. In particular the Yoshida cell line can represent a suitable system for a bioassay of viscotoxin in these extracts.