ABSTRACT
An increasing number of evidence indicates that static magnetic fields (SMFs) are capable of altering apoptosis, mainly through modulation of Ca(2+) influx. Here we present data that suggest apoptotic-related gene expression as an alternative pathway, through which exposure to 6milliTesla (mT) SMF can interfere with apoptosis. Exposure to 6mT SMF affects the apoptotic rate (spontaneous and drug-induced) and [Ca(2+)](i) in isolated human lymphocytes; the aged cells are more susceptible to exposure than fresh ones. The exposure to 6mT exerted a protective effect on chemical or physical-induced apoptosis, irrespective of the age of the cells. The investigation of the gene expression of bcl-2, bax, p53 and hsp70 in freshly isolated and in culture-aged human lymphocytes indicates that these genes are modulated by SMF exposure in the experimental conditions used, in a gene-, age- and time-dependent manner. The exposure of isolated lymphocytes to SMF for up to 24h modulated increased bax and p53 and decreased hsp70, and bcl-2. The amount of increment and/or decrement of the proteins varied for each gene examined and was independent of the apoptotic inducers. Finally, the same stress applied to freshly isolated or aged lymphocytes resulted in different modulation of bcl-2, bax and hsp70.
Subject(s)
Apoptosis Regulatory Proteins/radiation effects , Apoptosis/radiation effects , Cellular Senescence/radiation effects , Electromagnetic Fields , Lymphocytes/radiation effects , Adult , Apoptosis/physiology , Apoptosis Regulatory Proteins/genetics , Apoptosis Regulatory Proteins/metabolism , Cell Survival/genetics , Cell Survival/radiation effects , Cells, Cultured , Cellular Senescence/genetics , Cytoprotection/physiology , Cytoprotection/radiation effects , Down-Regulation/genetics , Down-Regulation/radiation effects , Gene Expression Regulation/genetics , Gene Expression Regulation/radiation effects , HSP72 Heat-Shock Proteins/genetics , HSP72 Heat-Shock Proteins/metabolism , HSP72 Heat-Shock Proteins/radiation effects , Humans , Lymphocytes/metabolism , Male , Middle Aged , Proto-Oncogene Proteins c-bcl-2/genetics , Proto-Oncogene Proteins c-bcl-2/metabolism , Proto-Oncogene Proteins c-bcl-2/radiation effects , Stress, Physiological/genetics , Time Factors , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism , Tumor Suppressor Protein p53/radiation effects , Up-Regulation/genetics , Up-Regulation/radiation effects , bcl-2-Associated X Protein/genetics , bcl-2-Associated X Protein/metabolism , bcl-2-Associated X Protein/radiation effectsABSTRACT
Augmented expression of members of the heat shock protein 70 (Hsp70) family are frequently observed in various human cancers. In this study, we examined applicability of laser scanning cytometer (LSC) to evaluate the level of Hsp72, which is the member constitutively expressed and significantly induced after heat shock, in human tumour cell lines. The relative nuclear content of Hsp72 measured by LSC correlated well with the relative intracellular content determined by Western blotting (R = 0.906). Furthermore, there was a close relationship between the relative nuclear content of Hsp72 measured by LSC and the colony-forming ability in soft agar, one of the malignant characteristics of tumour cells (R = 0.880). These results indicate that LSC measurement is useful for predicting the degree of malignancy of cancer cells, as it is reliable, faster than Western blotting and more objective and quantitative than visual measurements.
Subject(s)
HSP72 Heat-Shock Proteins/metabolism , HSP72 Heat-Shock Proteins/radiation effects , Hot Temperature , Neoplasms/metabolism , Phenotype , Blotting, Western , Cell Line, Tumor , Humans , Hyperthermia, Induced , Laser Scanning Cytometry , Predictive Value of TestsABSTRACT
The present work was undertaken in order to investigate the noradrenergic system and skeletal muscle heat shock protein 72 (HSP72) response to static magnetic field (MF) in male rats. At thermoneutrality (25 degrees C), the exposition of rats 1 hour/day for 5 consecutive days to MF of 128 mT (m tesla) induced an increase in norepinephrine content in gastrocnemius muscle (+25%, p < 0.05) but had no effect at 67 mT (+1%, p > 0.05), indicating a stimulatory effect of sub-acute MF exposure on the noradrenergic system activity. Moreover, exposed rats to MF displayed a non-significant increase of HSP72 levels in gastrocnemius muscles (+29%, p > 0.05). The results indicate that noradrenergic systems in rat's gastrocnemius muscles are affected by MF exposure. Interestingly, sub-acute exposure insufficiency increased HSP72 levels in gastrocnemius muscles.
