Cisplatin-resistant derivatives of murine L1210 leukemia cells are not susceptible to growth-inhibiting and apoptosis-inducing actions of transforming growth factor-beta1.

Murine L1210 leukemia cells possessing an increased resistance to cisplatin were found to be refractory to transforming growth factor (TGF)-beta1-induced growth inhibition, while the parental L1210 cells were strongly inhibited by this cytokine. Growth inhibition was estimated on the basis of 3H]thymidine incorporation, cell counting and colony-forming assay. Cisplatin-resistant L1210 cells were also shown to be much more resistant than the parental cells to both cisplatin- and TGF-beta1-induced apoptosis. These results suggest the existence of cross-resistance to cisplatin and TGF-beta1 in the studied leukemia cells.