Time dependence of the potentiation of 1,3-bis(2-chloroethyl)-1-nitrosourea cytotoxicity caused by alpha-difluoromethylornithine-induced polyamine depletion in 9L rat brain tumor cells. 1984

L Alhonen-Hongisto, and D F Deen, and L J Marton

Treatment of 9L rat brain tumor cells with 1.0 mM alpha-difluoromethylornithine (DFMO) produced a time-dependent depletion of cellular putrescine and spermidine. An increase in the potentiation of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) cytotoxicity, measured with a colony-forming efficiency assay, followed the time course of polyamine depletion, reaching its maximum at 48 hr, the time at which maximum polyamine depletion was achieved. Treatment with DFMO at concentrations as low as 0.05 mM for 48 hr effectively depleted putrescine and spermidine and potentiated BCNU cytotoxicity. Treatment for 96 hr with 0.01 mM DFMO produced a partial decrease in putrescine and spermidine levels and a moderate potentiation of BCNU cytotoxicity. The amount of polyamine depletion in 9L cells treated with 0.05, 0.1, and 0.5 mM DFMO was identical at both 48 and 96 hr, but potentiation of BCNU cytotoxicity was greater at 96 hr than at 48 hr. When 9L cells were treated for 48 hr with 1 mM DFMO and DFMO was then removed from the cultures, polyamine levels did not reach control levels by 96 hr after change of medium. The potentiation of BCNU cytotoxicity during this 96-hr period correlated with the extent of polyamine depletion. When 100 microM putrescine was added to the culture medium after DFMO pretreatment (1 mM), polyamine levels approached those of control cells by 24 hr, and the amount of potentiation of DFMO cytotoxicity decreased. These results show that potentiation of BCNU cytotoxicity correlates closely with the amount of DFMO-induced polyamine depletion in 9L cells.

UI MeSH Term Description Entries
D007700 Kinetics The rate dynamics in chemical or physical systems.
D009952 Ornithine An amino acid produced in the urea cycle by the splitting off of urea from arginine. 2,5-Diaminopentanoic Acid,Ornithine Dihydrochloride, (L)-Isomer,Ornithine Hydrochloride, (D)-Isomer,Ornithine Hydrochloride, (DL)-Isomer,Ornithine Hydrochloride, (L)-Isomer,Ornithine Monoacetate, (L)-Isomer,Ornithine Monohydrobromide, (L)-Isomer,Ornithine Monohydrochloride, (D)-Isomer,Ornithine Monohydrochloride, (DL)-Isomer,Ornithine Phosphate (1:1), (L)-Isomer,Ornithine Sulfate (1:1), (L)-Isomer,Ornithine, (D)-Isomer,Ornithine, (DL)-Isomer,Ornithine, (L)-Isomer,2,5 Diaminopentanoic Acid
D011700 Putrescine A toxic diamine formed by putrefaction from the decarboxylation of arginine and ornithine. 1,4-Butanediamine,1,4-Diaminobutane,Tetramethylenediamine,1,4 Butanediamine,1,4 Diaminobutane
D001932 Brain Neoplasms Neoplasms of the intracranial components of the central nervous system, including the cerebral hemispheres, basal ganglia, hypothalamus, thalamus, brain stem, and cerebellum. Brain neoplasms are subdivided into primary (originating from brain tissue) and secondary (i.e., metastatic) forms. Primary neoplasms are subdivided into benign and malignant forms. In general, brain tumors may also be classified by age of onset, histologic type, or presenting location in the brain. Brain Cancer,Brain Metastases,Brain Tumors,Cancer of Brain,Malignant Primary Brain Tumors,Neoplasms, Intracranial,Benign Neoplasms, Brain,Brain Neoplasm, Primary,Brain Neoplasms, Benign,Brain Neoplasms, Malignant,Brain Neoplasms, Malignant, Primary,Brain Neoplasms, Primary Malignant,Brain Tumor, Primary,Brain Tumor, Recurrent,Cancer of the Brain,Intracranial Neoplasms,Malignant Neoplasms, Brain,Malignant Primary Brain Neoplasms,Neoplasms, Brain,Neoplasms, Brain, Benign,Neoplasms, Brain, Malignant,Neoplasms, Brain, Primary,Primary Brain Neoplasms,Primary Malignant Brain Neoplasms,Primary Malignant Brain Tumors,Benign Brain Neoplasm,Benign Brain Neoplasms,Benign Neoplasm, Brain,Brain Benign Neoplasm,Brain Benign Neoplasms,Brain Cancers,Brain Malignant Neoplasm,Brain Malignant Neoplasms,Brain Metastase,Brain Neoplasm,Brain Neoplasm, Benign,Brain Neoplasm, Malignant,Brain Neoplasms, Primary,Brain Tumor,Brain Tumors, Recurrent,Cancer, Brain,Intracranial Neoplasm,Malignant Brain Neoplasm,Malignant Brain Neoplasms,Malignant Neoplasm, Brain,Neoplasm, Brain,Neoplasm, Intracranial,Primary Brain Neoplasm,Primary Brain Tumor,Primary Brain Tumors,Recurrent Brain Tumor,Recurrent Brain Tumors,Tumor, Brain
D002330 Carmustine A cell-cycle phase nonspecific alkylating antineoplastic agent. It is used in the treatment of brain tumors and various other malignant neoplasms. (From Martindale, The Extra Pharmacopoeia, 30th ed, p462) This substance may reasonably be anticipated to be a carcinogen according to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985). (From Merck Index, 11th ed) BCNU,1,3-Bis(2-Chloroethyl)-1-Nitrosourea,BiCNU,FIVB,N,N'-Bis(2-Chloroethyl)-N-Nitrosourea,Nitrumon
D002460 Cell Line Established cell cultures that have the potential to propagate indefinitely. Cell Lines,Line, Cell,Lines, Cell
D004357 Drug Synergism The action of a drug in promoting or enhancing the effectiveness of another drug. Drug Potentiation,Drug Augmentation,Augmentation, Drug,Augmentations, Drug,Drug Augmentations,Drug Potentiations,Drug Synergisms,Potentiation, Drug,Potentiations, Drug,Synergism, Drug,Synergisms, Drug
D000518 Eflornithine An inhibitor of ORNITHINE DECARBOXYLASE, the rate limiting enzyme of the polyamine biosynthetic pathway. Difluoromethylornithine,alpha-Difluoromethylornithine,DL-alpha-Difluoromethylornithine,Eflornithine Hydrochloride,Eflornithine Monohydrochloride, Monohydrate,MDL-71,782 A,Ornidyl,RMI 71782,Vaniqa,alpha-Difluoromethyl Ornithine,DL alpha Difluoromethylornithine,MDL 71,782 A,MDL71,782 A,Ornithine, alpha-Difluoromethyl,alpha Difluoromethyl Ornithine,alpha Difluoromethylornithine
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D013095 Spermidine A polyamine formed from putrescine. It is found in almost all tissues in association with nucleic acids. It is found as a cation at all pH values, and is thought to help stabilize some membranes and nucleic acid structures. It is a precursor of spermine.

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