PMID: 9192817Jun 15, 1997Paper

Toxin-induced increase in survival factor receptors: modulation of the threshold for apoptosis

Cancer Research
C C Boyle, J A Hickman

Abstract

The threshold at which toxins induce cell death is thought to directly relate to the amount of injury sustained. We show that the threshold at which a cell initiates toxin-induced death may vary in response to changes in the trophic environment. Treatment of Rat-1 fibroblasts with 50-175 mM dimethylformamide (DMF) induced cell death by apoptosis. Addition of insulin-like growth factor 1 (IGF-1; 100 ng/ml) and/or overexpression of the IGF-1 receptor (IGF-1R) attenuated the cytotoxicity of DMF. Furthermore, 95-99% of cells were protected from DMF-induced apoptosis if cells were pretreated with platelet-derived growth factor (5 ng/ml) for 16 h before treatment with DMF in the presence of IGF-1. Platelet-derived growth factor induced the expression of IGF-1R mRNA. The ability of cells to proliferate and survive after a 24-h treatment with DMF was determined by colony formation; whereas treatment with concentrations of >130 mM DMF reduced cellular survival, exposure to concentrations of <130 mM unexpectedly increased the colony-forming ability of treated cells when compared to that of controls. Treatment of Rat-1 fibroblasts with 75 and 130 mM DMF induced IGF-1R mRNA as determined by reverse transcription-PCR analysis. Serum withdra...Continue Reading

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Apoptosis

Apoptosis is a specific process that leads to programmed cell death through the activation of an evolutionary conserved intracellular pathway leading to pathognomic cellular changes distinct from cellular necrosis