Induced thermotolerance to apoptosis in a human T lymphocyte cell line (original) (raw)
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Critical parameters influencing hyperthermia-induced apoptosis in human lymphoid cell lines
Apoptosis, 1998
Brief mild hyperthermia is sufficient to induce apoptosis (programmed cell death) in many cell lines. Here we describe the effects of a number of factors modulating heat shock induced apoptosis outcomes. We report the effects of cell type, heat load, recovery times, cellular growth phase, and protein synthesis on the levels of apoptoses seen in heat stressed cell populations. We observe that a number of cell lines are competent to undergo heat stress induced apoptosis using both the comet assay and cellular and nuclear morphologies. Of the cell lines tested we saw a wide spectrum of sensitivities, ranging from resistant (less than 1% apoptotic after 12 h) to exquisitely sensitive (>95%). By incrementally increasing the heat load from 37-49 • C, we observed a gradual increase in apoptosis with a significant change from apoptotic to necrotic death at temperatures beyond 45 • C. The kinetics of the apoptotic response to heat shock were also examined. A time dependent increase in apoptotic cell death was seen after initial hyperthermic treatment with most cell types reaching a 'plateau' at 18 h. In addition to these parameters we report that growth phase has a strong influence on the number of apoptoses induced as a result of heat stress. Cultured cells, grown to a plateau, undergo apoptosis at a much higher level than similarly treated cells taken during an exponential phase of growth. Finally, we determined the necessity of protein synthesis for apoptotic competency.
FEBS Letters, 1999
We tested the hypothesis that heat shock protein (Hsp) induction and cell death are mutually exclusive responses to stress. Despite activation of heat shock transcription factor 1 at temperatures ranging from 40 to 46 degrees C, Hsp72 and Hsp27 were not induced above 42 degrees C. Moreover, cells underwent apoptosis at 44 degrees C and necrosis at 46 degrees C, with mitochondrial cytochrome c release at both temperatures. However, only apoptosis was associated with caspase activation. Treatment of cells with z-VAD-fmk prior to heat shock at 44 degrees C failed to restore Hsp induction despite inhibition of heat-induced apoptosis. Furthermore, accumulation of Hsps after incubation at 42 degrees C rendered the cells resistant to apoptosis. These results suggest that lack of Hsp induction is the cause rather than the consequence of cell death.
Biochimica et biophysica acta, 2015
Hyperthermia (39-45°C) has emerged as an alternate prospect for cancer therapy in combination with radiation and chemotherapy. Despite promising progress in the clinic, molecular mechanisms involved in hyperthermia-induced cell death are not clear. Hyperthermia causes protein denaturation/aggregation, which results in cell death by apoptosis and/or necrosis. Hyperthermia also induces thermotolerance, which renders cells resistant to subsequent exposure to lethal heat shock. This study investigates the role of both lethal (42-43°C) and mild (40°C) hyperthermia in regulating ER stress and ER stress-induced apoptosis in HeLa cells. The ability of mild thermotolerance induced at 40°C to alleviate either or both of these processes is also determined. Hyperthermia (42-43°C) induced ER stress, revealed by phosphorylation of PERK, eIF2α and IRE1α, cleavage of ATF6 and increased expression of BiP and sXBP1. Real-time PCR revealed that mRNA levels of ATF6, ATF4, BiP, sXBP1 and CHOP increased ...
Journal of Pathology, 1991
Mild hyperthermia is known to enhance apoptosis in a range of normal and neoplastic cell populations. Studies of tumours previously shown to respond to heating in this manner might be expected to provide insights not only into the mechanism of hyperthermic cell killing, but also into the apoptotic process in general. In the present study, cell death induced by 43°C heating for 30 min in two human Burkitt's lymphoma lines, BM 13674 and WWl, and in murine mastocytoma P-8 15 x 2.1 was found to be exclusively apoptotic in type, identification being based on light and electron microscopic appearances and on the presence of internucleosomal cleavage of DNA into fragments that are multiples of 18G-200 base pairs, which was demonstrated by agarose gel electrophoresis, The heat-induced apoptosis was prevented by the presence of zinc sulphate, an inhibitor of the endonuclease considered to be responsible for the DNA cleavage, but was not suppressed by the protein synthesis inhibitor cycloheximide. The findings question the validity of the widely held view that active protein synthesis is an invariable prerequisite for the execution of apoptosis. It is suggested that an inositol triphosphate-mediated increase in cytosolic Ca2+, resulting from limited membrane damage, might be the critical event responsible for activation of apoptosis by mild hyperthermia.
Heat Shock Proteins Increase Resistance to Apoptosis
Experimental Cell Research, 1996
Heat shock treatment of cells increases their survival and resistance to apoptosis. The kinetics of development of this resistance correlates with the kinetics of synthesis of heat shock proteins (hsps). U937 and Wehi-s cells were cultured for 1 h at 42 degrees C, conditions which induced the synthesis of heat shock proteins 27, 70, and 90. The cells were subsequently permitted to recover for a 2-h period, prior to exposure to the apoptosis inducing agents actinomycin-D (5 micrograms/ml), camptothecin (5 micrograms/ml), and etoposide (25 micrograms/ml). Apoptosis was determined by both DNA fragmentation and flow cytometric analysis. Heat-shocked cultures had a smaller number of apoptotic compared to control cultures when both were exposed to apoptosis inducing stimuli. Transfected Wehi-s cells constitutively overexpressing human hsp 70 or 27 were then examined for their resistance to apoptosis inducing by these drugs. Using the MTT assay, hsp 27 and 70 overexpressing cells exhibited an increased resistance to cell death when compared to the parental line. The parental line demonstrated features of apoptosis, that is, cell shrinkage and single- and double-strand DNA breaks. Taken together these results demonstrate that an increase in cellular levels of hsp 27 or 70, either by a mild heat shock treatment or by stable transfection, increases the resistance of U937 and Wehi-s cells to apoptotic cell death.
2013
ABT-737 Abott laboratories inhibitor of Bcl-2, Bcl-xL, Bcl-w AIF Apoptosis-inducing factor APAF-1 Apoptotic protease-activating factor-1 AP20187 FKBP ligand (homodimerizer) ASK1 Apoptosis signal-regulating kinase 1 ATP Adenosine triphosphate BAD Bcl-2 associated death promoter BAK Bcl-2 antagonist / killer BAX Bcl-2-associated X protein BCL-2 B-cell leukemia/lymphoma-2 BCL-x L B-cell lymphoma extra-large BFL1/A1 Bcl-2 related protein A1 BH Bcl-2 homology BH3 Bcl-2 homology domain 3 BID BH3 interacting domain death agonist BiFC Bi-molecular fluorescence complementation BIK Bcl-2-interacting killer BIM Bcl-2-interacting mediator of cell death BIR Baculovirus IAP repeat BMF Bcl-2-modifying factor BRAF v-raf murine sarcoma viral oncogene homolog B b-VAD-fmk Biotinylated-valine-alanine-aspartate-fluoromethylketone CARD Caspase activation and recruitment domain Caspases Cysteinyl aspartate-specific proteases CED Cell death abnormal c-FLIP Cellular-FLICE-like inhibitory protein CH11 Agonistic human CD95 antibody cIAP1/2 Cellular inhibitor of apoptosis-1/2 c-neu verb -B2 erythroblastic leukemia viral oncogene homolog 2, neuro/glioblastoma derived oncogene homolog cyt. c Cytochrome c dATP Deoxyadenosine triphosphate DD Death domain DDR DNA damage response DED Death effector domain DISC Death-inducing signaling complex DKO Double knockout xiv plasma membrane DD
Role of tumor necrosis factor alpha in hyperthermia-induced apoptosis of human leukemia cells
PubMed, 1999
We used the human myelomonoblastic leukemia cell line PLB-985 to study the effects of temperatures ranging from 37 degrees C to 43 degrees C for 1 h on the induction of apoptosis and cell cycle distribution in leukemia cells. The threshold temperature for the onset of apoptosis was 42 degrees C. Whereas hyperthermia exerted no effect on the expression of Bcl-2 and Bax, heat induced a >30-fold increase of tumor necrosis factor (TNF) alpha mRNA expression and a significant increase in TNF-alpha protein secretion. This endogenous production of TNF-alpha correlated directly with the temperature-induced apoptode effect. Blocking TNF-alpha expression via treatment with pyrrolidinedithiocarbamate or blocking TNF-alpha activity with neutralizing antibodies abrogated heat-provoked apoptosis. In addition, exposure of cell culture supernatant of heat-treated PLB-985 cells to untreated cells induced an apoptotic effect. These data indicate a TNF-a-mediated self eradication of the leukemia cells after heat exposure. Inducing apoptosis with wild-type TNF-alpha or p55 and p75 protein muteins demonstrated that this effect was mediated by the p55 receptor. Interestingly, the autocrine suicidal loop found in immature leukemia cells was lost after granulocytic differentiation with 0.5% N,N-dimethylformamide. These data should be of critical importance for the understanding of the biological impact of fever as well as for developing therapeutic approaches to malignant diseases