The relationship between tumorigenicity and in vitro differentiation was studied in four Friend erythroleukemia cell lines The cell lines were isolated by repeated subcloning of an unmutagenized population (sib selection) The cell lines differed in their ability to form tumors when 10(3) cells were injected subcutaneously into syngeneic mice (8 to 56% animals with tumors) The ability of cell lines to form tumors was not proportional to their ability to be induced to differentiate by dimethylsulfoxide The cell lines had indistinguishable chromosome numbers, plating efficiencies, number of cycling cells, population doubling times and spontaneous mutation rates to drug resistance However, the cell lines had different spontaneous differentiation rates in the absence of dimethylsulfoxide (087 to 160 X 10(-4) per cell per generation) The ability of cell lines to form tumors was inversely proportional to their spontaneous differentiation rate Apparently cells which are most efficiently blocked in differentiation have the highest probability of forming tumors

Tumorigenicity of Friend murine erythroleukemia cell lines differing in spontaneous differentiation rates.

Dimethyl sulphoxide has a variety of biological effects that have made it the subject of numerous pharmacological studies. The first dimethyl sulphoxide therapeutic indication approved by the United States Food and Drug Administration (FDA) in 1978 was for intravesical instillation in cases of interstitial cystitis. Since then, due to its distinctive properties, it has been the subject of studies in several areas. This review describes indications, adverse effects and contraindications, as takes a critical approach to the main articles addressing the clinical use of dimethyl sulphoxide.

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Comparative use of dimethyl sulphoxide (DMSO) in different animal species

Modification of membrane physical properties, biological response and insulin binding in Friend cells by low serum concentration

Log-phase-cultured Friend erythroleukemia cells of the FLC-745 line of DBA/2J origin administered either sc or ip in DBA/2J mice produced survival characteristics that were independent of the route of implantation The survival time of host animals, however, was dependent on their immunological status The effects of treatment of cells in culture with a series of glycerol and dihydroxyacetone analogs or of exposure to medium enriched in deuterium oxide on cell proliferation and differentiation in culture and on the tumorigenicity of treated cells transplanted into DBA/2J mice were examined Animals surviving implantation of a single dose of altered cells were tested for their ability to reject a lethal rechallenge with 106 untreated Friend erythroleukemia cells given 10 to 14 weeks after primary implantation of treated cells

Only a small proportion of animals survived primary challenge with cells exposed to 1-chloro-3-hydroxyacetone benzoate (CIHAB) and related α-halocarbonyl derivatives at concentrations of 10 or 20 µm Similarly, only a small proportion of animals survived primary challenge with cells attenuated by growth in medium enriched up to 80% in deuterium oxide or by exposure to 3000 rads of X-irradiation In these cases, where a small proportion of animals survived primary challenge with a single injection of potentially tumorigenic cells, the survivors were completely resistant to rechallenge A single injection of sonically disrupted Friend cells or of virus harvested from cultured cells had no effect on the survival time of animals subsequently rechallenged with intact Friend erythroleukemia cells Animals given injections of cells killed by exposure to 50 µm CIHAB in culture exhibited increased survival times upon rechallenge, but only 12% of the animals were completely resistant In contrast, however, although Friend erythroleukemia cells treated for 3 hr in culture with 30 µm CIHAB were nonproliferative in subculture and completely nontumorigenic when implanted either ip or sc into DBA/2J hosts, animals receiving a single injection of 106 cells altered in this way were fully protected against rechallenge Thus, carefully controlled modification of Friend erythroleukemia cells by exposure to a relatively low but sharply defined concentration of CIHAB abrogated tumorigenicity of the treated cells without altering their ability to confer protection to subsequent rechallenge with unaltered cells

Immunogenicity of Friend erythroleukemia cells altered in culture by chemical or physical agents.

The characteristics of cellular and molecular mechanisms associated with cell proliferation and differentiation is important to understand malignancy. In this report we characterise a leukemic model, D5A1, to study the action of differentiation agent, cellular events and gene expression of the selected transcription factors. Cells induced with 4 mM hexamethylene bisacetamide (HMBA) caused signs of erythroid differentiation (changes in morphology and size, haemoglobinisation) and cessation of proliferation including accumulation of cells in G 0/G1. Treatment with HMBA caused a timerelated decrease of tumorigenicity detectable by 48 hour. Northern-blotting showed induction of d amino levulinic acid synthase-erythroid (ALAS-E) mRNA at 48 hours and appeared in a strong level subsequently. C-myc (myelocytomatosis) and c-myb (myeloblastoma) mRNA levels decreased transiently in early hours returning to control values by 24 hour and decreased again. Stem cell leukaemia (SCL) and GATA-1 mRNA were markedly down regulated in early hours and then returned back. A later time point, upregulation of GATA-1 and SCL was relevant to maturation phenotype. These data provide a useful model to study the cellular and m olecular events in leukomogenesis and action of differentiation therapy in leukaemia. Iran. Biomed. J. 6 (4): 97-103, 2002

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Paul Pavelic

Papers

Friend leukemia cells: Relationship between differentiation, clonogenicity and malignancy