Functional Myc-Max heterodimer is required for activation-induced apoptosis in T cell hybridomas.
01 Dec 1994-Journal of Experimental Medicine (Rockefeller University Press)-Vol. 180, Iss: 6, pp 2413-2418
TL;DR: It is shown that coexpression of a reciprocally mutant Myc protein capable of forming functional heterodimers with the mutant Max can compensate for the dominant negative activity and restore activation-induced apoptosis.
Abstract: T cell hybridomas respond to activation signals by undergoing apoptotic cell death, and this is likely to represent comparable events related to tolerance induction in immature and mature T cells in vivo. Previous studies using antisense oligonucleotides implicated the c-Myc protein in the phenomenon of activation-induced apoptosis. This role for c-Myc in apoptosis is now confirmed in studies using a dominant negative form of its heterodimeric binding partner, Max, which we show here inhibits activation-induced apoptosis. Further, coexpression of a reciprocally mutant Myc protein capable of forming functional heterodimers with the mutant Max can compensate for the dominant negative activity and restore activation-induced apoptosis. These results imply that Myc promotes activation-induced apoptosis by obligatory heterodimerization with Max, and therefore, by regulating gene transcription.
Citations
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TL;DR: A precise physiological role is identified in the induction of apoptosis as a transcriptional regulator of the FasL gene through a non-canonical binding site for c-Myc-Max heterodimers in the Fas L promoter.
49 citations
Cites background from "Functional Myc-Max heterodimer is r..."
...We recently reported that transforming growth factor-β (TGF-β) suppresses the transcriptional activation of FasL and AICD by the direct inhibition of c-Myc expression [16]....
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...Previous observations had indicated a potential role for Max in the activity of c-Myc in regulating FasL transcription and induction of AICD [9,10]....
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...Notably, one of our earlier studies described the requirement for Myc–Max heterodimers in AICD [10]....
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...Activated T lymphocytes are eliminated by an apoptotic process known as activation-induced cell death (AICD), which requires the transcriptional induction of FasL expression [5–7] and sustained levels of c-Myc [8]....
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...We have previously shown that c-Myc is required for AICD and FasL expression in T cells and T-cell hybridomas [8–10]....
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TL;DR: This work shows for the first time that VK(3)-induced apoptosis requires the Fas/FasL system, and induced apoptosis in Jurkat cells, coincident with an increase in both Fas and FasL expression.
46 citations
TL;DR: The results indicate that s-Myc does not require the JNK signaling unlike c- myc during UV-triggered apoptosis, but the MKK6/p38MAPK pathway might regulate common apoptotic machinery for both s-myc and c-MyC upstream of caspase.
44 citations
01 Jan 1999
TL;DR: In this article, the authors showed that menadione-induced cell death requires the Fas/FasL system and showed that the activation of the system after oxidative stress apparently acted through a p53-independent pathway.
Abstract: Menadione, or vitamin K(3) (VK(3)), a potent oxidative stress inducer, has been recently used as an effective and remarkably safe cytotoxic drug for treatment of several human tumors. VK(3) induces apoptotic cell death through a poorly understood mechanism. Here we show for the first time that VK(3)-induced apoptosis requires the Fas/FasL system. Spleen cells from both Fas- and FasL-deficient mice (C57BL/6-lpr and C57BL/6-gld, respectively) had much lower levels of VK(3) apoptosis in vitro compared to cells from control C57BL/6 mice. VK(3) cytotoxicity toward mouse splenocytes was also blocked with a Fas-Fc fusion protein. VK(3) induced apoptosis in Jurkat cells, coincident with an increase in both Fas and FasL expression. A FasL-resistant variant of these Jurkat cells was also resistant to VK(3)-induced apoptosis. Furthermore, because VK(3) effects were inhibited by glutathione, a potent antioxidant, oxidative stress was linked to the Fas/FasL system. Moreover, since the Jurkat cell lines were p53 null, the activation of Fas/FasL system after oxidative stress apparently acted through a p53-independent pathway. The therapeutic relevance of the K vitamins has been growing in recent years; our findings offer new insight for improving and expanding their applications.
43 citations
TL;DR: It is suggested that proteasome inhibitors cause the accumulation of c‐Myc protein which induces transiently FasL message to stimulate the Fas receptor–ligand apoptotic signaling pathway.
40 citations
References
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Journal Article•
TL;DR: This highly reproducible, quantitative assay for T cell growth factor (TCGF), based upon the tritiated-thymidine incorporation of continuous murine tumor-specific cytotoxic T cell lines (CTLL), has revealed that T lymphocytes are required for its production.
Abstract: Several soluble factors have recently been associated with the proliferation and differentiation of thymus-derived lymphocytes. One of these factors present in medium conditioned by T cell mitogen-stimulated lymphocytes has the ability to promote the long-term culture of normal and antigen-specific cytotoxic T cells. We report a method to test for this proliferative stimulus in the form of a sensitive microassay based upon the tritiated thymidine incorporation of continuous murine tumorspecific cytotoxic T cell lines (CTLL). The microassay requires microliter quantities of sample fluid and is amenable to quantitative analysis. This highly reproducible, quantitative assay for T cell growth factor (TCGF) has allowed investigation as to the kinetics of TCGF generation and has revealed that T lymphocytes are required for its production. Further investigation has supported the notion that this nonspecies-specific factor is actively removed from tissue culture medium by the proliferation of either T cell mitogen-activated lymphocytes or CTLL.
3,106 citations
TL;DR: It is demonstrated that deregulated c-myc expression induces apoptosis in cells growth arrested by a variety of means and at various points in the cell cycle.
3,047 citations
TL;DR: The present review describes several methods to characterize and differentiate between two different mechanisms of cell death, apoptosis and necrosis, applied to studies of apoptosis triggered in the human leukemic HL-60 cell line by DNA topoisomerase I or II inhibitors, and in rat thymocytes by either topoisomersase inhibitors or prednisolone.
Abstract: The present review describes several methods to characterize and differentiate between two different mechanisms of cell death, apoptosis and necrosis. Most of these methods were applied to studies of apoptosis triggered in the human leukemic HL-60 cell line by DNA topoisomerase I or II inhibitors, and in rat thymocytes by either topoisomerase inhibitors or prednisolone. In most cases, apoptosis was selective to cells in a particular phase of the cell cycle: only S-phase HL-60 cells and G0 thymocytes were mainly affected. Necrosis was induced by excessively high concentrations of these drugs. The following cell features were found useful to characterize the mode of cell death: a) Activation of an endonuclease in apoptocic cells resulted in extraction of the low molecular weight DNA following cell permeabilization, which, in turn, led to their decreased stainability with DNA-specific fluorochromes. Measurements of DNA content made it possible to identify apoptotic cells and to recognize the cell cycle phase specificity of the apoptotic process. b) Plasma membrane integrity, which is lost in necrotic but not apoptotic cells, was probed by the exclusion of propidium iodide (PI). The combination of PI followed by Hoechst 33342 proved to be an excellent probe to distinguish live, necrotic, early- and late-apoptotic cells. c) Mitochondrial transmembrane potential, assayed by retention of rhodamine 123 was preserved in apoptotic but not necrotic cells. d) The ATP-dependent lysosomal proton pump, tested by the supravital uptake of acridine orange (AO) was also preserved in apoptotic but not necrotic cells. e) Bivariate analysis of cells stained for DNA and protein revealed markedly diminished protein content in apoptotic cells, most likely due to activation of endogenous proteases. Necrotic cells, having leaky membranes, had minimal protein content. f) Staining of RNA allowed for the discrimination of G0 from G1 cells and thus made it possible to reveal that apoptosis was selective to G0 thymocytes. g) The decrease in forward light scatter, paralleled either by no change (HL-60 cells) or an increase (thymocytes) of right angle scatter, were early changes during apoptosis. h) The sensitivity of DNA in situ to denaturation, was increased in apoptotic and necrotic cells. This feature, probed by staining with AO at low pH, provided a sensitive and early assay to discriminate between live, apoptotic and necrotic cells, and to evaluate the cell cycle phase specificity of these processes. i) The in situ nick translation assay employing labeled triphosphonucleotides can be used to reveal DNA strand breaks, to detect the very early stages of apoptosis.(ABSTRACT TRUNCATED AT 400 WORDS)
1,953 citations
TL;DR: In this paper, the Max polypeptide when associated with the Myc or Mad polyPEptide is capable of binding to nucleotide sequences containing CACGTG.
Abstract: Nucleic acid molecules capable of hybridizing under stringent conditions to the nucleotide sequence residing between positions 1 and 453 of the max cDNAs shown in Figure 2, or to the nucleotide sequence reisiding between positions 148 and 810 of the mad cDNAs shown in Figure 14. The Max polypeptide when associated with the Myc or Mad polypeptide is capable of binding to nucleotide sequences containing CACGTG.
1,602 citations
TL;DR: Results identify T3-epsilon as a cell surface protein involved in the transduction of activation signals and can both activate and inhibit T-cell function.
Abstract: A monoclonal antibody (145-2C11) specific for the murine T3 complex was derived by immunizing Armenian hamsters with a murine cytolytic T-cell clone. The antibody is specific for a 25-kDa protein component (T3-epsilon) of the antigen-specific T-cell receptor. It reacts with all mature T cells and can both activate and inhibit T-cell function. These results identify T3-epsilon as a cell surface protein involved in the transduction of activation signals.
1,509 citations