Correlation of cytotoxicity and mitotic spindle dissolution by vinblastine in mammalian cells

In two hamster cell lines that differed 100-fold in their vinblastine sensitivity, dissolution of the mitotic spindle by vinblastine in living cells correlated with cytotoxicity from vinblastine expressed as suppression of colony formation. The effect on the spindle apparatus occurred in 30 sec or less and thus provides a rapid assay for determining the cytotoxic effects of the Vinca alkaloids, as well as the potential for quantitative assay of solutions of Vinca derivatives.