title: Structure-activity relationships of antineoplastic agents in multidrug resistance.
abstract: Clinical resistance to many antineoplastic agents is a major cause of treatment failure. The well-documented phenomenon addressed as multidrug resistance (MDR) allows cells to withstand exposure to lethal doses of drugs with dissimilar chemical structures, modes of action, and physicochemical properties. In one of the earliest studies on MDR, Biedler and Riehm in an attempt to explain the cross-resistance profile of actinomycin D resistant Chinese hamster cells suggested that molecular weight was an important determinant. Our statistical analysis of their data validates their claim and indeed strongly demonstrates that cross resistance is enhanced by the increased size and hydrophobicity of the antitumor agent. Our preliminary studies with methotrexate-resistant L1210 cells indicates that cross resistance is increased in the case of moderate-sized, hydrophilic drugs. These two studies and others suggest that current chemotherapy regimens may be improved by treating resistant cells with antineoplastic agents displaying physicochemical characteristics opposite to that of the original inducing agent.
authors.affiliation: Department of Chemistry, Pomona College, Claremont, California 91711.
authors.forename: C D
authors.initials: CD
authors.lastname: Selassie
authors.forename: C
authors.initials: C
authors.lastname: Hansch
authors.forename: T A
authors.initials: TA
authors.lastname: Khwaja
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D006224:Cricetinae; D003609:Dactinomycin / Q000494:pharmacology; D004351:Drug Resistance; D007939:Leukemia L1210; D051379:Mice; D012044:Regression Analysis; D013329:Structure-Activity Relationship; D014407:Tumor Cells, Cultured / Q000166:cytology / Q000187:drug effects
chemical_list: D000970:Antineoplastic Agents; D003609:Dactinomycin