Establishment of @entity1891 -resistant and XXXX -resistant lines of murine lymphoblasts in vitro and characterisation of their patterns of cross-resistance and drug sensitivities.

@entity632 @entity7324 @entity2663 @entity1259 @entity4316 @entity2879 @entity1487 @entity1891 @entity1499 @entity71262 @entity5713
Clinical evidence suggests some lack of cross resistance between @entity1891 (VCR) and @entity7324 (VDS). To investigate this phenomenon experimentally, drug-resistant L5178Y lymphoblast cell lines have been derived in vitro. These lines, under conditions of continuous drug exposure, exhibit a 50-fold order of resistance. Resistance appears due, at least in part, to impaired cellular drug accumulation and retention. Exposure of these resistant cells to VCR or VDS for 24 h showed that the presence or absence of cross resistance was dose-dependent, being most noticeable at low concentrations (less than 0.5 ng/ml) and absent at higher drug levels. Cross resistance also showed some dose-dependency for @entity5713 and @entity71262 , but this was not seen with other drugs. Marked and complete cross resistance at all concentrations tested was noted with @entity632 and @entity1259 in both resistant lines, which, however, retained the same sensitivities as the parent line to @entity2663 , @entity2879 , @entity1487 , and @entity1499 . Responses to @entity4316 and mAMSA differed in these two resistant lines. VDS-resistant cells exhibited cross resistance to both drugs, whilst VCR-resistant cells showed only slight resistance to @entity4316 whilst retaining full sensitivity mAMSA. This observation that cross resistance between VCR and VDS is not invariable in vitro appears to reflect clinical experience.
