Cytotoxic manifestations of the interaction between hyperthermia and TNF: DNA fragmentation

Cytochemical study of role of alpha-d-mannose- and beta-d-galactose-containing glycoproteins in apoptosis

Recently, we found increased levels of alpha-d-mannose- and beta-d-galactose-containing glycoproteins in plasma membrane of the apoptotic murine leukemia L1210 cells (Bilyy & Stoika 2003). That indicator was suggested to be a novel marker of apoptosis in L1210 cells. The aim of our present work was to reveal if these changes in glycoprotein expression can be common for apoptotic cells of different origin and for various ways of apoptosis induction. It was demonstrated that an elevated expression of plasma membrane glycoproteins rich in alpha-d-mannose and beta-d-galactose did not depend on type of cell line and its tissue origin as well as on nature of apoptosis-inducing agent. We also found that an increase in membrane glycoprotein expression was dependent on concentration of apoptosis-inducing agent and was time-dependent. Changes in glycoproteins' expression were detected as early as 9-12 hours after apoptosis induction. Two hours pretreatment of cells with non-labeled lectin decreased plasma membrane staining with corresponding peroxidase-labeled lectin, probably because of lectin-induced internalization of specific membrane glycoproteins. PSL-lectin-affinity procedure was developed for isolation of apoptotic cells from their mixed population with normal cells. Lectin-dependent agglutination analysis showed that this process occurs at much lower lectin dilutions in the apoptotic cells than in the non-apoptotic cells. Thus, we found that alpha-d-mannose- and beta-d-galactose-containing glycoproteins can be used for lectinocytochemical detection, study and isolation of apoptotic cells.

Exposure to febrile temperature modifies endothelial cell response to tumor necrosis factor-alpha

Fever is an important regulator of inflammation that modifies expression and bioactivity of cytokines, including tumor necrosis factor (TNF)-alpha. Pulmonary vascular endothelium is an important target of TNF-alpha during the systemic inflammatory response. In this study, we analyzed the effect of a febrile range temperature (39.5 degrees C) on TNF-alpha-stimulated changes in endothelial barrier function, capacity for neutrophil binding and transendothelial migration (TEM), and cytokine secretion in human pulmonary artery endothelial cells (EC). Permeability for [(14)C]BSA tracer was increased by treatment with TNF-alpha, and this effect was augmented by incubating EC at 39.5 degrees C. Treating EC with 2. 5 U/ml TNF-alpha stimulated an increase in subsequent neutrophil adherence and TEM. Incubating EC at 39.5 degrees C caused a 30% increase in TEM but did not modify the enhancement of neutrophil adherence or TEM by TNF-alpha treatment. Analysis of cytokine expression in EC cultures exposed to TNF-alpha at either 37 degrees or 39.5 degrees C revealed three patterns of temperature and TNF-alpha responsiveness. Granulocyte-macrophage colony stimulating factor (GM-CSF) and interleukin (IL)-8 were not detectable in untreated EC but were increased after TNF-alpha exposure, and this increase was enhanced at 39.5 degrees C. IL-6 expression was also increased with TNF-alpha exposure, but IL-6 expression was lower in 39.5 degrees C EC cultures. Transforming growth factor-beta(1) was constitutively expressed, and its expression was not influenced either by TNF-alpha or exposure to 39.5 degrees C. These data demonstrate that clinically relevant shifts in body temperature might cause important changes in the effects of proinflammatory cytokines on the endothelium.

The role of fever in the infected host

Sepsis is a highly lethal clinical syndrome characterized by a systemic inflammatory response to infection. Fever, a non-specific acute-phase response, has been associated with improved survival and shortened disease duration in non-life-threatening infections. However, the influence of fever and the effects of antipyresis in patients with sepsis has not been prospectively studied in humans. This paper reviews the state of our knowledge concerning the biological effects of fever in infected hosts and the influence of fever and antipyretic therapy on survival during sepsis in experimental models and in man.

Antipyretic therapy in patients with sepsis

Sepsis is a clinical syndrome characterized by a systemic inflammatory response to infection. Mortality rates in sepsis have remained high, despite recent advances in our understanding of the immunological mechanisms that cause sepsis. Fever, a nonspecific acute-phase response, has been associated with improved survival and shortened disease duration in some infections. This article reviews the biological effects of fever and the influence of antipyretic therapy on the outcome in sepsis in experimental models and in humans and offers clinical recommendations for antipyretic therapy in early and late stages of the disorder.

Modes of L929 cell death induced by TNF-alpha and other cytotoxic agents

Recent studies have variably reported that tumour necrosis factor alpha (TNF-alpha) induces either necrosis or apoptosis in L929 cells. This study was undertaken to better characterize the mode of death induced in L929 cells by this agent. We determined the effects of exposure to TNF-alpha and other cytotoxic agents on cell size and morphology, cell membrane permeability, exposure of phosphatidylserine at the cell surface, nuclear morphology and fragmentation of DNA. Our results suggest that L929 cells treated with TNF-alpha alone show nuclear changes and a pattern of DNA fragmentation that are atypical of apoptosis. In contrast, our results demonstrate that, when augmented with actinomycin D, TNF-alpha induces classical apoptosis in L929 cells. We also provide the first report that, in L929 cells, staurosporine induces classical apoptosis and colchicine induces a form of apoptosis lacking internucleosomal DNA fragmentation. Previous studies of TNF-alpha-induced death in L929 cells relied on measurements of only one or two parameters to define the mode of death. Overall, our results suggest that in future cellular or biochemical studies of the effects of TNF-alpha on L929 cells it will be prudent to characterize the mode of death in each case using a multi-parameter approach, as done here.

Enhanced cytotoxicity and suppression of glucose transport rate by combined treatment of recombinant human tumour necrosis factor-alpha and hyperthermia on L929 cells

Combined treatment with human recombinant TNF-alpha (rhTNF-alpha) and hyperthermia at 43 degrees C arrested the growth of mouse fibrosarcoma L929 cells in vitro. The cytotoxic effect was enhanced in combined treatment compared with that following administration of rhTNF-alpha or hyperthermia alone. When the cells were subjected to hyperthermia at 43 degrees C for 3 hours and then incubated with 0.4 ng/ml rhTNF-alpha at 37 degrees C for 24 hours, a statistically significant 65% decrease in the rate of cellular glucose uptake was observed. This suppressive effect was synergistic in terms of effect achieved by rhTNF-alpha or hyperthermia individually. Since the growth of tumour cells depends mainly on catabolism of glucose, our findings indicate that one manner by which combined rhTNF-alpha and hyperthermia treatment inhibits L929 cell growth may be by reducing the supply of glucose to the cells.

Analysis of histological therapeutic effect, apoptosis rate and p53 status after combined treatment with radiation, hyperthermia and 5-fluorouracil suppositories for advanced rectal cancers

The tumour-suppressor gene p53 encodes a transcription factor that plays a critical role in the induction of G1 cell cycle arrest and apoptosis after DNA damage. To clarify the role of the p53 gene and apoptosis in combined hyperthermia, chemotherapy and radiation (hyperthermochemoradiotherapy, HCR therapy) for rectal cancer, we examined the histological response, rate of apoptosis, DNA fragmentation and p53 status in tumours from 28 patients undergoing HCR therapy before surgery and from 22 patients who did not have preoperative treatment. The therapeutic effect of HCR therapy was closely correlated with the rate of apoptosis; the correlation was statistically significant, suggesting that this effect occurs through apoptosis. The incidence of p53 mutations in the treated group were as follows: in tumours resistant to HCR therapy, four of seven (57.1%); intermediately sensitive, 7 of 13 (53.9%); or sensitive, three of eight (37.5%), suggesting that the therapeutic effect and apoptosis rate were related to the p53 status of the tumours to some extent, but the relation was not statistically significant. In the 22 control tumours (non-treated group), the apoptosis rate was 2.0 +/- 1.1%, and there was no significant difference in p53 status compared with the HCR group. Our study indicates that the pathological response to HCR therapy correlates with the rate of apoptosis with statistical significance and that it induces the therapeutic effect more significantly in rectal cancer cells with wild-type p53, although HCR therapy-induced apoptosis also occurs in some rectal cancers with mutated p53. Therefore, this combination therapy can induce an additive or synergistic anti-tumour effect in rectal cancers with wild-type p53 as well as in those with mutated p53 through apoptosis, offering new therapeutic opportunities and a better prognosis.

The in vivo interaction between flavone acetic acid and hyperthermia

The in vivo interaction between flavone acetic acid (FAA) and hyperthermia was studied in a C3H mammary carcinoma grown in the feet of female CDF1 mice and in normal foot skin. FAA was intraperitoneally injected prior to local tissue heating in restrained non-anaesthetized animals. Alone, FAA at doses of 100 mg/kg and above, inhibited tumour growth in a dose-dependent fashion. FAA also enhanced the tumour response to heat, the effect being dependent on both the time interval between the two modalities and the FAA dose, the greatest effect occurring when FAA doses of > or = 150 mg/kg preceeded heat by 3-48 h. These effects of FAA correlated with the drug's ability to decrease tumour blood perfusion measured using the RbCl extraction procedure. Injecting 150 mg/kg FAA 3 h before heating (42.7 degrees C) resulted in a 2.2-fold increase in tumour heat damage, but had little effect on the response of normal foot skin in non-tumour-bearing mice. However, this treatment gave a 2.0-fold increase in normal tissue damage when the skin experiments were repeated in tumour-bearing animals. These effects in skin occurred in the absence of any blood perfusion changes, but appeared to be associated with FAA-induced TNF-alpha production.

Small stress proteins as novel regulators of apoptosis. Heat shock protein 27 blocks Fas/APO-1- and staurosporine-induced cell death

Small stress protein expression enhances the survival of mammalian cells exposed to numerous injuries that induce necrotic cell death. The cell surface receptor Fas/APO-1 and its ligand have been recently identified as important mediators of apoptosis. Here, we show that constitutive expression of human heat shock protein (hsp)27 in murine L929 cells blocks Fas/APO-1-mediated cell death. Expression of human hsp27 prevented anti-APO-1-induced DNA fragmentation and morphological changes. These results strongly suggest that human hsp27 acts as a cellular inhibitor of Fas/APO-1-induced apoptosis. We also report that the expression of small stress proteins from different species, such as human hsp27, Drosophila Dhsp27, or human alphaB-crystallin, confers resistance to apoptotic cell death induced by staurosporine, a protein kinase C inhibitor. Hence, small stress proteins are novel regulators that are able to block apoptosis induced by different pathways.