title: Sequential cytotoxicity: a theory examined using a series of 3,5-bis(benzylidene)-1-diethylphosphono-4-oxopiperidines and related phosphonic acids.
abstract: The concept of sequential cytotoxicity, which states that successive chemical attacks on cellular constituents can be more deleterious to neoplasms than normal cells, was evaluated using a series of 3,5-bis(benzylidene)-1-diethylphosphono-4-oxopiperidines 1 and related phosphonic acids 2, which were screened against a panel of malignant and normal cell lines. The compounds proved to be not only potent cytotoxins (71% of the CC(50) figures are submicromolar) but to display greater cytotoxicity to the neoplastic cells. QSAR revealed that both cytotoxic potencies and selective toxicity were increased by a rise in the electron-withdrawing properties and a decrease in the hydrophobicity of the aryl substituents. Utilisation of the PL10 concept and evaluation of druglike properties revealed 1c as the lead tumour-specific cytotoxin. This molecule activated caspase-3 in HL-60 cells but not in the HSC-2 cell line. While 1c caused internucleosomal DNA fragmentation in HL-60 cells, it did not elicit this effect in either HSC-2 and HSC-4 cells. Clearly 1c exerts its cytotoxic potencies by different mechanisms and such pleiotropy is likely the principal reason for the remarkable display of preferential toxicity towards malignant cells of the compounds in series 1 and 2.
authors.affiliation: Drug Design and Discovery Research Group, College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5C9.
authors.forename: Swagatika
authors.initials: S
authors.lastname: Das
authors.forename: Umashankar
authors.initials: U
authors.lastname: Das
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sakagami
authors.forename: Ken
authors.initials: K
authors.lastname: Hashimoto
authors.forename: Masami
authors.initials: M
authors.lastname: Kawase
authors.forename: Dennis K J
authors.initials: DK
authors.lastname: Gorecki
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Dimmock
mesh_terms: D045744:Cell Line, Tumor; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D063065:Organophosphonates / Q000737:chemistry* / Q000494:pharmacology*; D010880:Piperidines / Q000737:chemistry* / Q000494:pharmacology*
chemical_list: D063065:Organophosphonates; D010880:Piperidines