Cross-resistance of cultured murine leukemia vincristine-resistant P388 cells to vinblastine, vindesine, and bis (N-ethylidene vindesine) disulfide, disulfate.

Cultured P388 leukemia cells derived from vincristine (VCR)-resistant cell populations developed in vivo in (C57BL X DBA/2)F1 mice (P388/VCR) were cross-resistant to vinblastine (VLB), vindesine (VDS), and bis(N-ethylidene vindesine)disulfide, disulfate (bis-VDS). Cross-resistance was a function of concentration and time of exposure. Cultured P388/VCR cells were more sensitive to 6.1x10-5Mbis- VDS than to 6.1x10-5MVDS or to 6.1x10-5MVLB. Cultured P388 cells derived from VCR-sensitive P388 leukemia passaged in vivo (P388/0)were significantly more sensitive to VDS and bis-VDS than to VLB. This degree of difference in sensitivity was also a function of concentration and time of exposure.