Dariusz Leszczynski responds to comments of Maël Dieudonné on Leszczynski's review of the scientific evidence on the individual sensitivity to electromagnetic fields (EHS)

While Dieudonné has praised thoroughness of Leszczynski's review of EHS studies, he was critical of the final conclusions. Leszczynski strongly disagrees with argumentation of Dieudonné that EHS issue is settled and that biomarker research is unnecessary because it is expensive and might produce false positives. Leszczynski's opinion is that his review has demonstrated how very poor scientifically and inadequate statistically is the to-date executed research on EHS. Dieudonné's approach of using such poor science to justify claim that EHS issue is settled and there is no causality link between EHS and EMF exposures, is completely unjustified and simply false.

The lack of international and national health policies to protect persons with self-declared electromagnetic hypersensitivity

Electromagnetic hypersensitivity (EHS), known also as an idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF) or a microwave sickness, is not considered by the World Health Organization (WHO) as being caused by the exposures to electromagnetic fields (EMF). EHS is not recognized as a disease anywhere in the world. Some studies have roughly estimated that 1-10% of the population might experience some form of EHS. However, because of the lack of diagnostic criteria for EHS, these estimates might be either under- or over-estimates. Because the vast majority of human population is exposed to EMF, the possibility of developing EHS from the EMF is a substantial public health issue that should be dealt with globally, even if the individual risk of developing EHS might be small. The WHO recognizes that the symptoms experienced by the EHS persons might be severe and might significantly hamper everyday life. However, after a broad analysis of international and national documents, there seems to be currently no effort to develop health policies for the dealing with EHS, no matter what causes it. National governments, follow the opinions of the WHO and the EMF safety standards setting organizations, the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and the Institute of Electrical and Electronics Engineers - International Committee on Electromagnetic Safety (IEEE-ICES), are not developing any practical health policy advisories for self-declared EHS sufferers. However, symptoms experienced by the self-declared EHS persons affect their well-being and, according to the Constitution of the WHO, are a health problem. Hence, independently of what causes EHS symptoms, this admitted well-being-impairment should be dealt with globally by developing an uniform health policy. Furthermore, WHO, ICNIRP and IEEE-ICES should be advocating and supporting research that would generate a reliable scientific evidence on what are the possible cause(s) of EHS. Without such research there is not possible to develop diagnostic methods as well as any possible mitigation approaches. There is an urgent need for the WHO to advocate for the national governments to urgently develop a comprehensive and common EHS health policy.

Review of the scientific evidence on the individual sensitivity to electromagnetic fields (EHS)

Part of the population considers themselves as sensitive to the man-made electromagnetic radiation (EMF) emitted by powerlines, electric wiring, electric home appliance and the wireless communication devices and networks. Sensitivity is characterized by a broad variety of non-specific symptoms that the sensitive people claim to experience when exposed to EMF. While the experienced symptoms are currently considered as a real life impairment, the factor causing these symptoms remains unclear. So far, scientists were unable to find causality link between symptoms experienced by sensitive persons and the exposures to EMF. However, as presented in this review, the executed to-date scientific studies, examining sensitivity to EMF, are of poor quality to find the link between EMF exposures and sensitivity symptoms of some people. It is logical to consider that the sensitivity to EMF exists but the scientific methodology used to find it is of insufficient quality. It is time to drop out psychology driven provocation studies that ask about feelings-based non-specific symptoms experienced by volunteers under EMF exposure. Such research approach produces only subjective and therefore highly unreliable data that is insufficient to prove, or to disprove, causality link between EHS and EMF. There is a need for a new direction in studying sensitivity to EMF. The basis for it is the notion of a commonly known phenomenon of individual sensitivity, where individuals' responses to EMF depend on the genetic and epigenetic properties of the individual. It is proposed here that new studies, combining provocation approach, where volunteers are exposed to EMF, and high-throughput technologies of transcriptomics and proteomics are used to generate objective data, detecting molecular level biochemical responses of human body to EMF.

Physiological effects of millimeter-waves on skin and skin cells: an overview of the to-date published studies

The currently ongoing deployment if the fifth generation of the wireless communication technology, the 5G technology, has reignited the health debate around the new kind of radiation that will be used/emitted by the 5G devices and networks - the millimeter-waves. The new aspect of the 5G technology, that is of concern to some of the future users, is that both, antennas and devices will be continuously in a very close proximity of the users' bodies. Skin is the only organ of the human body, besides the eyes, that will be directly exposed to the mm-waves of the 5G technology. However, the whole scientific evidence on the possible effects of millimeter-waves on skin and skin cells, currently consists of only some 99 studies. This clearly indicates that the scientific evidence concerning the possible effects of millimeter-waves on humans is insufficient to devise science-based exposure limits and to develop science-based human health policies. The sufficient research has not been done and, therefore, precautionary measures should be considered for the deployment of the 5G, before the sufficient number of quality research studies will be executed and health risk, or lack of it, scientifically established.

Integrative proteomic and microRNA analysis of primary human coronary artery endothelial cells exposed to low-dose gamma radiation

High doses of ionising radiation significantly increase the risk of cardiovascular disease (CVD), the vascular endothelium representing one of the main targets. Whether radiation doses lower than 500 mGy induce cardiovascular damage is controversial. The aim of this study was to investigate radiation-induced expression changes on protein and microRNA (miRNA) level in primary human coronary artery endothelial cells after a single 200 mGy radiation dose (Co-60). Using a multiplex gel-based proteomics technology (2D-DIGE), we identified 28 deregulated proteins showing more than ±1.5-fold expression change in comparison with non-exposed cells. A great majority of the proteins showed up-regulation. Bioinformatics analysis indicated "cellular assembly and organisation, cellular function and maintenance and molecular transport" as the most significant radiation-responsive network. Caspase-3, a central regulator of this network, was confirmed to be up-regulated using immunoblotting. We also analysed radiation-induced alterations in the level of six miRNAs known to play a role either in CVD or in radiation response. The expression of miR-21 and miR-146b showed significant radiation-induced deregulation. Using miRNA target prediction, three proteins found differentially expressed in this study were identified as putative candidates for miR-21 regulation. A negative correlation was observed between miR-21 levels and the predicted target proteins, desmoglein 1, phosphoglucomutase and target of Myb protein. This study shows for the first time that a low-dose exposure has a significant impact on miRNA expression that is directly related to protein expression alterations. The data presented here may facilitate the discovery of low-dose biomarkers of radiation-induced cardiovascular damage.

Effects of radiofrequency-modulated electromagnetic fields on proteome

Proteomics, the science that examines the repertoire of proteins present in an organism using both high-throughput and low-throughput techniques, might give a better understanding of the functional processes ongoing in cells than genomics or transcriptomics, because proteins are the molecules that directly regulate physiological processes. Not all changes in gene expression are necessarily reflected in the proteome. Therefore, using proteomics approaches to study the effects of RF-EMF might provide information about potential biological and health effects. Especially that the RF-EMF used in wireless communication devices has very low energy and is unable to directly induce gene mutations.

Five years later: the current status of the use of proteomics and transcriptomics in EMF research

The World Health Organization's and Radiation and Nuclear Safety Authority's "Workshop on Application of Proteomics and Transcriptomics in Electromagnetic Fields Research" was held in Helsinki in the October/November 2005. As a consequence of this meeting, Proteomics journal published in 2006 a special issue "Application of Proteomics and Transcriptomics in EMF Research" (Vol. 6 No. 17; Guest Editor: D. Leszczynski). This Proteomics issue presented the status of research, of the effects of electromagnetic fields (EMF) using proteomics and transcriptomics methods, present in 2005. The current overview/opinion article presents the status of research in this area by reviewing all studies that were published by the end of 2010. The review work was a part of the European Cooperation in the Field of Scientific and Technical Research (COST) Action BM0704 that created a structure in which researchers in the field of EMF and health shared knowledge and information. The review was prepared by the members of the COST Action BM0704 task group on the high-throughput screening techniques and electromagnetic fields (TG-HTST-EMF).

The effect of pulsed 900-MHz GSM mobile phone radiation on the acrosome reaction, head morphometry and zona binding of human spermatozoa

Several recent studies have indicated that radiofrequency electromagnetic fields (RF-EMF) have an adverse effect on human sperm quality, which could translate into an effect on fertilization potential. This study evaluated the effect of RF-EMF on sperm-specific characteristics to assess the fertilizing competence of sperm. Highly motile human spermatozoa were exposed for 1 h to 900-MHz mobile phone radiation at a specific absorption rate of 2.0 W/kg and examined at various times after exposure. The acrosome reaction was evaluated using flow cytometry. The radiation did not affect sperm propensity for the acrosome reaction. Morphometric parameters were assessed using computer-assisted sperm analysis. Significant reduction in sperm head area (9.2 ± 0.7 μm² vs. 18.8 ± 1.4 μm²) and acrosome percentage of the head area (21.5 ± 4% vs. 35.5 ± 11.4%) was reported among exposed sperm compared with unexposed controls. Sperm-zona binding was assessed directly after exposure using the hemizona assay. The mean number of zona-bound sperm of the test hemizona and controls was 22.8 ± 12.4 and 31.8 ± 12.8 (p < 0.05), respectively. This study concludes that although RF-EMF exposure did not adversely affect the acrosome reaction, it had a significant effect on sperm morphometry. In addition, a significant decrease in sperm binding to the hemizona was observed. These results could indicate a significant effect of RF-EMF on sperm fertilization potential.

In vivo UVA irradiation of mouse is more efficient in promoting pulmonary melanoma metastasis than in vitro

BACKGROUND

We have previously shown in vitro that UVA increases the adhesiveness of mouse B16-F1 melanoma cells to endothelium.We have also shown in vivo that UVA exposure of C57BL/6 mice, i.v. injected with B16-F1 cells, increases formation of pulmonary colonies of melanoma. The aim of the present animal study was to confirm the previously observed in vivo UVA effect and to determine whether in vitro UVA-exposure of melanoma cells, prior the i.v. injection, will have an enhancing effect on the pulmonary colonization capacity of melanoma cells. As a second aim, UVA-derived immunosuppression was determined.

METHODS

Mice were i.v. injected with B16-F1 cells into the tail vein and then immediately exposed to UVA. Alternatively, to study the effect of UVA-induced adhesiveness on the colonization capacity of B16-F1 melanoma, cells were in vitro exposed prior to i.v. injection. Fourteen days after injection, lungs were collected and the number of pulmonary nodules was determined under dissecting microscope. The UVA-derived immunosuppression was measured by standard contact hypersensitivity assay.

RESULTS AND DISCUSSION

Obtained results have confirmed that mice, i.v. injected with B16-F1 cells and thereafter exposed to UVA, developed 4-times more of melanoma colonies in lungs as compared with the UVA non-exposed group (p < 0.01). The in vitro exposure of melanoma cells prior to their injection into mice, led only to induction of 1.5-times more of pulmonary tumor nodules, being however a statistically non-significant change. The obtained results postulate that the UVA-induced changes in the adhesive properties of melanoma cells do not alone account for the 4-fold increase in the pulmonary tumor formation. Instead, it suggests that some systemic effect in a mouse might be responsible for the increased metastasis formation. Indeed, UVA was found to induce moderate systemic immunosuppression, which effect might contribute to the UVA-induced melanoma metastasis in mice lungs.

Low-dose irradiation causes rapid alterations to the proteome of the human endothelial cell line EA.hy926

High doses of ionising radiation damage the heart by an as yet unknown mechanism. A concern for radiological protection is the recent epidemiological data indicating that doses as low as 100-500 mGy may induce cardiac damage. The aim of this study was to identify potential molecular targets and/or mechanisms involved in the pathogenesis of low-dose radiation-induced cardiovascular disease. The vascular endothelium plays a pivotal role in the regulation of cardiac function and is therefore a potential target tissue. We report here that low-dose radiation induced rapid and time-dependent changes in the cytoplasmic proteome of the human endothelial cell line EA.hy926. The proteomes were investigated at 4 and 24 h after irradiation at two different dose rates (Co-60 gamma ray total dose 200 mGy; 20 mGy/min and 190 mGy/min) using 2D-DIGE technology. Differentially expressed proteins were identified, after in-gel trypsin digestion, by MALDI-TOF/TOF tandem mass spectrometry, and peptide mass fingerprint analyses. We identified 15 significantly differentially expressed proteins, of which 10 were up-regulated and 5 down-regulated, with more than ±1.5-fold difference compared with unexposed cells. Pathways influenced by the low-dose exposures included the Ran and RhoA pathways, fatty acid metabolism and stress response.

Mobile phone radiation does not induce pro-apoptosis effects in human spermatozoa

Abstract Recent reports suggest that mobile phone radiation may diminish male fertility. However, the effects of this radiation on human spermatozoa are largely unknown. The present study examined effects of the radiation on induction of apoptosis-related properties in human spermatozoa. Ejaculated, density-purified, highly motile human spermatozoa were exposed to mobile phone radiation at specific absorption rates (SARs) of 2.0 and 5.7 W/kg. At various times after exposure, flow cytometry was used to examine caspase 3 activity, externalization of phosphatidylserine (PS), induction of DNA strand breaks, and generation of reactive oxygen species. Mobile phone radiation had no statistically significant effect on any of the parameters studied. This suggests that the impairment of fertility reported in some studies was not caused by the induction of apoptosis in spermatozoa.

Analysis of proteome response to the mobile phone radiation in two types of human primary endothelial cells

BACKGROUND

Use of mobile phones has widely increased over the past decade. However, in spite of the extensive research, the question of potential health effects of the mobile phone radiation remains unanswered. We have earlier proposed, and applied, proteomics as a tool to study biological effects of the mobile phone radiation, using as a model human endothelial cell line EA.hy926. Exposure of EA.hy926 cells to 900 MHz GSM radiation has caused statistically significant changes in expression of numerous proteins. However, exposure of EA.hy926 cells to 1800 MHz GSM signal had only very small effect on cell proteome, as compared with 900 MHz GSM exposure. In the present study, using as model human primary endothelial cells, we have examined whether exposure to 1800 MHz GSM mobile phone radiation can affect cell proteome.

RESULTS

Primary human umbilical vein endothelial cells and primary human brain microvascular endothelial cells were exposed for 1 hour to 1800 MHz GSM mobile phone radiation at an average specific absorption rate of 2.0 W/kg. The cells were harvested immediately after the exposure and the protein expression patterns of the sham-exposed and radiation-exposed cells were examined using two dimensional difference gel electrophoresis-based proteomics (2DE-DIGE). There were observed numerous differences between the proteomes of human umbilical vein endothelial cells and human brain microvascular endothelial cells (both sham-exposed). These differences are most likely representing physiological differences between endothelia in different vascular beds. However, the exposure of both types of primary endothelial cells to mobile phone radiation did not cause any statistically significant changes in protein expression.

CONCLUSIONS

Exposure of primary human endothelial cells to the mobile phone radiation, 1800 MHz GSM signal for 1 hour at an average specific absorption rate of 2.0 W/kg, does not affect protein expression, when the proteomes were examined immediately after the end of the exposure and when the false discovery rate correction was applied to analysis. This observation agrees with our earlier study showing that the 1800 MHz GSM radiation exposure had only very limited effect on the proteome of human endothelial cell line EA.hy926, as compared with the effect of 900 MHz GSM radiation.

Mobile phone radiation health risk controversy: the reliability and sufficiency of science behind the safety standards

There is ongoing discussion whether the mobile phone radiation causes any health effects. The International Commission on Non-Ionizing Radiation Protection, the International Committee on Electromagnetic Safety and the World Health Organization are assuring that there is no proven health risk and that the present safety limits protect all mobile phone users. However, based on the available scientific evidence, the situation is not as clear. The majority of the evidence comes from in vitro laboratory studies and is of very limited use for determining health risk. Animal toxicology studies are inadequate because it is not possible to "overdose" microwave radiation, as it is done with chemical agents, due to simultaneous induction of heating side-effects. There is a lack of human volunteer studies that would, in unbiased way, demonstrate whether human body responds at all to mobile phone radiation. Finally, the epidemiological evidence is insufficient due to, among others, selection and misclassification bias and the low sensitivity of this approach in detection of health risk within the population. This indicates that the presently available scientific evidence is insufficient to prove reliability of the current safety standards. Therefore, we recommend to use precaution when dealing with mobile phones and, whenever possible and feasible, to limit body exposure to this radiation. Continuation of the research on mobile phone radiation effects is needed in order to improve the basis and the reliability of the safety standards.

In vitro effect of pulsed 900 MHz GSM radiation on mitochondrial membrane potential and motility of human spermatozoa

Ejaculated, density purified, human spermatozoa were exposed to pulsed 900 MHz GSM mobile phone radiation at two specific absorption rate levels (SAR 2.0 and 5.7 W/kg) and compared with controls over time. Change in sperm mitochondrial membrane potential was analysed using flow cytometry. Sperm motility was determined by computer assisted sperm analysis (CASA). There was no effect of pulsed 900 MHz GSM radiation on mitochondrial membrane potential. This was also the case for all kinematic parameters assessed at a SAR of 2.0 W/kg. However, over time, the two kinematic parameters straight line velocity (VSL) and beat-cross frequency (BCF) were significantly impaired (P < 0.05) after the exposure at SAR 5.7 W/kg and no exposure by time interaction was present. This result should not be ascribed to thermal effects, due to the cooling methods employed in the RF chamber and temperature control within the incubator.

Mobile phone radiation might alter protein expression in human skin

Background

Earlier we have shown that the mobile phone radiation (radiofrequency modulated electromagnetic fields; RF-EMF) alters protein expression in human endothelial cell line. This does not mean that similar response will take place in human body exposed to this radiation. Therefore, in this pilot human volunteer study, using proteomics approach, we have examined whether a local exposure of human skin to RF-EMF will cause changes in protein expression in living people.

Results

Small area of forearm's skin in 10 female volunteers was exposed to RF-EMF (specific absorption rate SAR = 1.3 W/kg) and punch biopsies were collected from exposed and non-exposed areas of skin. Proteins extracted from biopsies were separated using 2-DE and protein expression changes were analyzed using PDQuest software. Analysis has identified 8 proteins that were statistically significantly affected (Anova and Wilcoxon tests). Two of the proteins were present in all 10 volunteers. This suggests that protein expression in human skin might be affected by the exposure to RF-EMF. The number of affected proteins was similar to the number of affected proteins observed in our earlier in vitro studies.

Conclusion

This is the first study showing that molecular level changes might take place in human volunteers in response to exposure to RF-EMF. Our study confirms that proteomics screening approach can identify protein targets of RF-EMF in human volunteers.

Continuous wave and simulated GSM exposure at 1.8 W/kg and 1.8 GHz do not inducehsp16-1 heat-shock gene expression inCaenorhabditis elegans

Recent data suggest that there might be a subtle thermal explanation for the apparent induction by radiofrequency (RF) radiation of transgene expression from a small heat-shock protein (hsp16-1) promoter in the nematode, Caenorhabditis elegans. The RF fields used in the C. elegans study were much weaker (SAR 5-40 mW kg(-1)) than those routinely tested in many other published studies (SAR approximately 2 W kg(-1)). To resolve this disparity, we have exposed the same transgenic hsp16-1::lacZ strain of C. elegans (PC72) to higher intensity RF fields (1.8 GHz; SAR approximately 1.8 W kg(-1)). For both continuous wave (CW) and Talk-pulsed RF exposures (2.5 h at 25 degrees C), there was no indication that RF exposure could induce reporter expression above sham control levels. Thus, at much higher induced RF field strength (close to the maximum permitted exposure from a mobile telephone handset), this particular nematode heat-shock gene is not up-regulated. However, under conditions where background reporter expression was moderately elevated in the sham controls (perhaps as a result of some unknown co-stressor), we found some evidence that reporter expression may be reduced by approximately 15% following exposure to either Talk-pulsed or CW RF fields.

Ultraviolet-A radiation induces changes in cyclin G gene expression in mouse melanoma B16-F1 cells

Background

We have previously shown that ultraviolet-A (UVA) radiation enhances metastatic lung colonization capacity of B16-F1 melanoma cells. The aim of this study was to examine changes in expression profile of genes in mouse melanoma B16-F1 cells exposed to UVA radiation.

Results

B16-F1 melanoma cells were exposed to a single UVA radiation dose of 8 J/cm² and mRNA was isolated 4 h after the end of UVA exposure. Atlas™ Mouse Cancer 1.2 cDNA expression arrays were used for the large-scale screening to identify the genes involved in the regulation of carcinogenesis, tumor progression and metastasis. Physiologically relevant UVA dose induced differential expression in 9 genes in the UVA exposed melanoma cells as compared to the unexposed control cells. The expression of seven genes out of nine was upregulated (HSC70, HSP86, α-B-crystallin, GST mu2, Oxidative stress induced protein OSI, VEGF, cyclin G), whereas the expression of two genes was down-regulated (G-actin, non-muscle cofilin). The gene expression of cyclin G was mostly affected by UVA radiation, increasing by 4.85-folds 4 hour after exposure. The analysis of cyclin G protein expression revealed 1.36-fold increase at the 6 hour time point after UVA exposure. Cell cycle arrest in G2/M phase, which is known to be regulated by cyclin G, occurred at 4-h hour time-point, peaking 8 hours after the end of UVA irradiation, suggesting that cyclin G might play a role in the cell cycle arrest.

Conclusion

Our results suggest that UVA radiation-induces changes in the expression of several genes. Some of these changes, e.g. in expression of cyclin G, possibly might affect cell physiology (cell cycle arrest).

Questions and answers concerning applicability of proteomics and transcriptomics in EMF research

The applicability of high-throughput screening techniques of transcriptomics, proteomics and metabolomics in the search for biological and health effects of electromagnetic fields is a hotly debated issue. On the one hand, use of these modern screening technologies speeds up the discovery process and gives broader insight into biochemical events that follow the exposure to electromagnetic fields. On the other hand these modern screening technologies have the problem of reproducibility and variability between experiments and are prone to produce false positive results. These and other issues concerning the applicability of modern screening technologies were the topic of a workshop held at STUK in 2005 (30 October to 1 November) in Helsinki, Finland, and this Report summarizes the discussions at this workshop.

Mobile phone radiation causes changes in gene and protein expression in human endothelial cell lines and the response seems to be genome- and proteome-dependent

We have examined in vitro cell response to mobile phone radiation (900 MHz GSM signal) using two variants of human endothelial cell line: EA.hy926 and EA.hy926v1. Gene expression changes were examined in three experiments using cDNA Expression Arrays and protein expression changes were examined in ten experiments using 2-DE and PDQuest software. Obtained results show that gene and protein expression were altered, in both examined cell lines, in response to one hour mobile phone radiation exposure at an average specific absorption rate of 2.8 W/kg. However, the same genes and proteins were differently affected by the exposure in each of the cell lines. This suggests that the cell response to mobile phone radiation might be genome- and proteome-dependent. Therefore, it is likely that different types of cells and from different species might respond differently to mobile phone radiation or might have different sensitivity to this weak stimulus. Our findings might also explain, at least in part, the origin of discrepancies in replication studies between different laboratories.

Gene expression changes in human cells after exposure to mobile phone microwaves

Possible biological effects of mobile phone microwaves were investigated in vitro. In this study, which was part of the 5FP EU project REFLEX (Risk Evaluation of Potential Environmental Hazards From Low-Energy Electromagnetic Field Exposure Using Sensitive in vitro Methods), six human cell types, immortalized cell lines and primary cells, were exposed to 900 and 1800 MHz. RNA was isolated from exposed and sham-exposed cells and labeled for transcriptome analysis on whole-genome cDNA arrays. The results were evaluated statistically using bioinformatics techniques and examined for biological relevance with the help of different databases. NB69 neuroblastoma cells, T lymphocytes, and CHME5 microglial cells did not show significant changes in gene expression. In EA.hy926 endothelial cells, U937 lymphoblastoma cells, and HL-60 leukemia cells we found between 12 and 34 up- or down-regulated genes. Analysis of the affected gene families does not point towards a stress response. However, following microwave exposure, some but not all human cells might react with an increase in expression of genes encoding ribosomal proteins and therefore up-regulating the cellular metabolism.

Ultraviolet A exposure might increase metastasis of mouse melanoma: a pilot study

BACKGROUND

The major sources of long-wave ultraviolet A radiation (UVA; 320-400 nm) exposure are extensive sunbathing and tanning in solaria. While the carcinogenic effects of mid-wave ultraviolet B radiation (UVB; 280-320 nm) are well recognized, the potentially hazardous effects of UVA are less understood. Several studies have shown that a variety of physiological processes in the cell are modified by UVA exposure, some of which might be involved in the regulation of tumor metastasis. In this study we suggest that UVA radiation could lead to the increase of metastatic capability of melanoma cells in mice.

METHOD/RESULT

A pilot in vivo study was executed using C57BL/6 mice and syngeneic B16 melanoma cell lines. Mice were intravenously (i.v.) injected with either B16-F1 or B16-F10 melanoma cells into the tail vein and then immediately exposed to UVA. Fourteen days after melanoma injection, lungs were collected and the quantity and quality of metastases were determined under a dissecting microscope. As an outcome of the pilot study we observed that i.v. injected melanoma cells formed more lung metastases in the UVA-exposed mice in comparison with the control mice.

CONCLUSION

This result suggests that the UVA exposure of mice, with melanoma cells present in blood circulation, increases the formation of melanoma metastases in lungs. Further studies should determine whether a similar pro-metastatic effect, as observed in mice, could occur in humans and whether other than melanoma tumors might be susceptible.

Ultraviolet A exposure alters adhesive properties of mouse melanoma cells

BACKGROUND

We have examined whether ultraviolet A (UVA) irradiation could alter adhesive properties of melanoma cells. As an experimental in vitro model, we have used C57BL/6 mouse-derived B16- F1 and B16-F10 melanoma cell lines and the syngeneic MS-1 endothelial cell line.

METHOD/RESULT

The melanoma cells were exposed to different doses of UVA irradiation. We have determined that a single dose of UVA at 8 and 12 J/cm(2) causes an 88% (P<0.001) and a 32% (P<0.05) increase in B16-F1 melanoma cell adhesiveness to the non-irradiated endothelial monolayer, respectively. The peak of the response was 24 h after the irradiation. The UVA dose of 8 J/cm(2) delivered in four doses separated by 1 h intervals (4 x 2 J/cm(2)) had led to a caused 149% (P<0.001) increase of B16-F1 melanoma adhesiveness already at 1 h after the last dose of UVA. Besides the induction of increase in the melanoma-endothelial cell adhesion, UVA exposure has induced a rapid decline (1 h after exposure) in homotypic melanoma-melanoma cell adhesion (clustering). The clustering decline of B16-F1 cells with a single dose of UVA at 8 J/cm(2) was by 61% (P<0.05) and by 35% (P<0.05) with 4 x 2 J/cm(2). Pilot experiments have shown that the changes of the adhesive properties of melanoma cells were accompanied by an increase in N-cadherin expression and a decline in E-cadherin expression. Such a change in cadherin expression profile has been shown to be an indicator of the increased metastatic potential.

CONCLUSION

Our results suggest that UVA radiation appears to alter the adhesive properties of melanoma cells in vitro, by diminishing the melanoma-melanoma adhesion and by increasing melanoma adhesion to the endothelium. This suggests that UVA exposure might increase the metastatic capability of the melanoma cells.

Rapporteur report: cellular, animal and epidemiological studies of the effects of static magnetic fields relevant to human health

Three talks were presented in the session on "Cellular, Animal and Epidemiological Studies of the Effects of Static Magnetic Fields Relevant to Human Health". The first talk presented the in vitro effects of static magnetic fields on cell cultures. The second talk presented the in vivo evidence obtained from animal studies. The final, third talk, presented the evidence obtained from epidemiological studies. The overall conclusion of the three presentations and the following general discussion was that the scientific evidence available to date is weak and contains large gaps in knowledge either due to the poor quality of published studies or because of the lack of published research on certain health-related topics. It was emphasized that the rapid development of new technological applications of static magnetic fields (e.g. magnetic levitation trains or magnetic resonance imaging-MRI) results in the human population at large, in certain occupations, and in a selected population of clinical patients being exposed to ever increasing static magnetic field strengths. It is of concern that the knowledge presently available concerning the health effects of these strong static magnetic fields is lagging a long way behind technological development. In conclusion, it was suggested that there is an urgent need to perform new studies in all research areas (in vitro, in vivo and epidemiology) in order to fill the present gaps in knowledge and provide assurance that this technology will not cause any unwanted and unexpected health side effects.

Proteomics analysis of human endothelial cell line EA.hy926 after exposure to GSM 900 radiation

The human endothelial cell line EA.hy926 was exposed to mobile phone radiation and the effect on protein expression was examined using two-dimensional electrophoresis (2-DE). Up to 38 various proteins have statistically significantly altered their expression levels following the irradiation. Four proteins were identified with matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS). Two of the affected proteins were determined to be isoforms of cytoskeletal vimentin. This finding supports our earlier presented working hypothesis which indicated that the mobile phone radiation might affect the cytoskeleton and might have an effect on the physiological functions that are regulated by the cytoskeleton.

Applicability of discovery science approach to determine biological effects of mobile phone radiation

We argue that the use of high-throughput screening techniques, although expensive and laborious, is justified and necessary in studies that examine biological effects of mobile phone radiation. The "case of hsp27 protein" presented here suggests that even proteins with only modestly altered (by exposure to mobile phone radiation) expression and activity might have an impact on cell physiology. However, this short communication does not attempt to present the full scientific evidence that is far too large to be presented in a single article and that is being prepared for publication in three separate research articles. Examples of the experimental evidence presented here were designed to show the flow of experimental process demonstrating that the use of high-throughput screening techniques might help in rapid identification of the responding proteins. This, in turn, can help in speeding up of the process of determining whether these changes might affect human health.*

Non-thermal activation of the hsp27/p38MAPK stress pathway by mobile phone radiation in human endothelial cells: molecular mechanism for cancer- and blood-brain barrier-related effects

We have examined whether non-thermal exposures of cultures of the human endothelial cell line EA.hy926 to 900 MHz GSM mobile phone microwave radiation could activate stress response. Results obtained demonstrate that 1-hour non-thermal exposure of EA.hy926 cells changes the phosphorylation status of numerous, yet largely unidentified, proteins. One of the affected proteins was identified as heat shock protein-27 (hsp27). Mobile phone exposure caused a transient increase in phosphorylation of hsp27, an effect which was prevented by SB203580, a specific inhibitor of p38 mitogen-activated protein kinase (p38MAPK). Also, mobile phone exposure caused transient changes in the protein expression levels of hsp27 and p38MAPK. All these changes were non-thermal effects because, as determined using temperature probes, irradiation did not alter the temperature of cell cultures, which remained throughout the irradiation period at 37 +/- 0.3 degrees C. Changes in the overall pattern of protein phosphorylation suggest that mobile phone radiation activates a variety of cellular signal transduction pathways, among them the hsp27/p38MAPK stress response pathway. Based on the known functions of hsp27, we put forward the hypothesis that mobile phone radiation-induced activation of hsp27 may (i) facilitate the development of brain cancer by inhibiting the cytochrome c/caspase-3 apoptotic pathway and (ii) cause an increase in blood-brain barrier permeability through stabilization of endothelial cell stress fibers. We postulate that these events, when occurring repeatedly over a long period of time, might become a health hazard because of the possible accumulation of brain tissue damage. Furthermore, our hypothesis suggests that other brain damaging factors may co-participate in mobile phone radiation-induced effects.

Laser-beam-triggered microcavitation: a novel method for selective cell destruction

We describe a new method of cell destruction that may have potential for use in antitumor therapy. Cells are loaded by phagocytosis with microparticles (<1 microm) and irradiated with short laser pulses. Absorption of laser energy by the microparticles causes localized vaporization of the fluid surrounding the microparticles, leading to the generation of transient vapor bubbles (microcavitation) around the microparticles. Using cultures of bovine aortic endothelial cells, we demonstrate that induction of intralysosomal microcavitation is an efficient, rapid and selective method of cell killing that is dependent on the number of microparticles, the number of laser pulses, and the fluence of the laser pulses. Cell killing by microcavitation is a very selective process that is restricted to cells containing microparticles, leaving other cells unaffected. Intracytoplasmic release of lysosomal hydrolases is, in part, responsible for cell death, because the protease inhibitors E64d and TLCK diminished cell killing. Using the broad-specificity caspase inhibitor Z-VAD-fmk, we determined that lysosomal hydrolases could induce apoptosis in a caspase-independent manner. We also examined the possibility of microcavitation-induced delayed effects in the cells that survived the treatment. Using flow cytometry, we determined that there was no delayed cell death between 1 and 4 days after microcavitation. Moreover, we did not observe changes in the cell cycle, in expression of the proteins BCL2, HSP70 and HSP27, or in PARP degradation. In conclusion, microcavitation induces rapid and specific cells death (limited only to cells containing microparticles), without producing delayed effects among the surviving cells.

Mast cell chymase induces apoptosis of vascular smooth muscle cells

In human coronary atheromas, the numbers of degranulated mast cells and of apoptotic smooth muscle cells (SMCs) are increased. Accordingly, the possibility exists that mast cells participate in the regulation of SMC apoptosis in the lesions. Mast cells isolated from the serosal cavities of rats were stimulated to release their secretory granules. The neutral protease chymase, present in the exocytosed granules, was found to induce apoptosis when added to rat aortic SMCs in culture. The chymase-induced apoptosis of SMCs was detected by flow cytometry, microscopic analysis of cellular morphology, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL), and electrophoretic demonstration of DNA laddering. Chymase induced SMC apoptosis in a dose- and time- dependent manner, and its proteolytic activity was essential for the proapoptotic effect. In addition to rat chymase, recombinant human chymase was also found to induce apoptosis of human coronary artery SMCs in culture. These results suggest that mast cells may participate in the apoptotic regulation of SMCs in atherosclerotic lesions.

Photodynamic therapy induces apoptosis in intimal hyperplastic arteries

Photodynamic therapy (PDT) generates free radicals through the absorption of light by photosensitizers. PDT shows promise in the treatment of intimal hyperplasia, which contributes to restenosis, by completely eradicating cells in the vessel wall. This study investigates the mechanisms of PDT-induced cell death. PDT, using the photosensitizer chloroaluminum-sulfonated phthalocyanine (1 mg/kg) and laser light (lambda = 675 nm) 100 J/cm(2) was administered to rat carotid arteries after balloon injury-induced intimal hyperplasia. Apoptosis was determined by cell morphology with light microscopy and transmission electron microscopy, DNA cleavage by terminal dUTP nick-end labeling staining, and nucleosomal fragmentation (ladder pattern) by DNA agarose gel electrophoresis. Four hours after PDT, apoptosis was observed in vascular cells, as evidenced by terminal dUTP nick-end labeling staining and transmission electron microscopy. Within 24 hours no cells were present in the neointima and media. Immunofluorescence using an alpha-smooth muscle cell actin antibody confirmed the disappearance of all neointimal and medial cells within 24 hours. No inflammatory cell infiltrate was observed during this time frame. Apoptosis was sharply confined to the PDT treatment field. These data demonstrate that vascular PDT induces apoptosis as a mechanism of rapid, complete, and precise cell eradication in the artery wall. These findings and the lack of inflammatory reaction provide the basis for understanding and developing PDT for a successful clinical application in the treatment of hyperplastic conditions such as restenosis.

Photodynamic therapy generates a matrix barrier to invasive vascular cell migration

Photodynamic therapy (PDT) inhibits experimental intimal hyperplasia. PDT results in complete vascular wall cell eradication with subsequent adventitia but minimal media repopulation. This study was designed to test the hypothesis that PDT alters the vascular wall matrix thereby inhibiting invasive cell migration, and as such, provides an important barrier mechanism to favorably alter the vascular injury response. Untreated smooth muscle cells (SMCs) and fibroblasts were seeded on control and PDT-treated (100 J/cm(2); photosensitizer was chloroaluminum-sulfonated phthalocyanine, 5 microg/mL) 3-dimensional collagen matrix gels. Invasive cell migration was temporally quantified by calibrated microscopy. Zymography and ELISA assessed SMC matrix metalloproteinase levels. Molecular changes of gel proteins and their susceptibility to collagenase were analyzed by SDS-PAGE and Western blot. Limited pepsin digestion and histology were used to assess the in vivo relevance of the model, using an established rat carotid artery model at 1 and 4 weeks after balloon injury and PDT. PDT of 3-dimensional matrix of gels led to a 52% reduction of invasive SMCs and to a 59% reduction of fibroblast migration (P<0.001) but did not significantly affect secretion of matrix metalloproteinases. PDT induced collagen matrix changes, including cross-linking, which resulted in resistance to protease digestion. PDT led to a durable 45% reduction in pepsin digestion susceptibility of treated arteries (P<0.001) and inhibition of periadventitial cell migration into the media. These data suggest that PDT of matrix gels generates a barrier to invasive cellular migration. This newly identified effect on matrix proteins underscores its pleiotropic actions on the vessel wall, and as such, PDT may be of considerable potential therapeutic value to inhibit restenosis.

Different effects of photodynamic therapy and gamma-irradiation on vascular smooth muscle cells and matrix : implications for inhibiting restenosis

gamma-Irradiation (gamma-RT) and photodynamic therapy (PDT) are known to inhibit intimal hyperplasia. The common mechanism is that both modalities produce free radicals, but unlike gamma-RT, PDT generates them through the absorption of light by photosensitizers. The purpose of this in vitro study was to assess the differences that PDT and gamma-RT have on the fibroproliferative response after vascular injury by comparing their effects on vascular smooth muscle cells (SMCs) and on the extracellular matrix (ECM). Mitochondrial activity (tetrazolium salt), proliferation ([(3)H]thymidine incorporation), and the mechanisms of cell death (terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end labeling [TUNEL] staining) were used to assess differences between PDT (100 J/cm(2)) and gamma-RT (10 or 20 Gy) on SMC injury. The different effects on bioregulatory molecules were investigated by quantitating the proliferation of SMCs cultured with conditioned medium and on treated ECM. PDT of SMCs reduced proliferation and mitochondrial activity (0.5+/-0.75% and 1.7+/-4.25%, respectively, P<0.0001), whereas gamma-RT of SMCs decreased cell proliferation but did not affect metabolic activity. Stimulation with calf serum of gamma-RT-treated SMCs did not affect proliferation but increased mitochondrial enzyme activity (160+/-11%, P<0.0005). The conditioned medium, derived from PDT- but not gamma-RT-treated SMCs, did not stimulate effector SMC proliferation compared with gamma-RT-treated SMCs (16+/-4.1% versus 80+/-16.8%, P<0.0001). Apoptosis was the principle cytotoxic mechanism after PDT, whereas gamma-RT cells were growth arrested but viable. PDT of the ECM reduced effector SMC proliferation compared with controls and gamma-RT cells (18+/-6.5% versus 100+/-17.7% and 84+/-8.9%, respectively, P<0.0001). These data suggest that gamma-RT and PDT may inhibit restenosis but by different mechanisms. The effects of PDT are more diverse and may result in improved outcome while avoiding the teratogenic exposure due to ionizing irradiation.

Association of p53, K-ras and proliferating cell nuclear antigen with rat lung lesions following exposure to simulated nuclear fuel particles

Expression of p53, K-ras, and proliferating cell nuclear antigen (PCNA) and mutations of p53 and K-ras genes in lung lesions of Han/Wistar rats were investigated by immunohistochemistry and direct DNA sequencing following a long-term exposure of animals to neutron-activated UO2 particles. The p53 protein was overexpressed in all five malignant tumors, in 62% of benign tumors, and in 42% of hyperplastic lesions examined. K-ras protein and PCNA levels were only slightly elevated in all types of lung lesions. In three malignant tumors a C-->T transition was detected in codon 288 (human 290) of the p53 gene, but this mutation was not present in seven other tumors analyzed. No mutations were detected in codons 12/13 and 61 of the K-ras gene in any of the five tumors analyzed. Our findings suggest that K-ras overexpression is a rare alteration, whereas p53 protein overexpression (sometimes associated with mutated p53 gene), as assessed with the CM5 antibody, is a relatively common phenomenon in hot particle-induced preneoplastic and neoplastic rat lung lesions.

The effects of the broadband UVA radiation on myeloid leukemia cells: the possible role of protein kinase C in mediation of UVA-induced effects

We examined the effects of broadband UVA radiation (320-400 nm) on a rat myeloid leukemia cell line-chloroma (ChL). A Phillips face tanner model HB 171/A was used as a light source. Chloroma were irradiated through a 5 mm thick glass filter that cut off all of the UVB contamination. The irradiances were measured, from 250 to 400 nm, with a well-characterized and calibrated double-grating spectroradiometer Optronic 742. The overall uncertainty of dose evaluation was estimated to be +/-15% (2 sigma). The cells were irradiated with UVA doses of 4 and 8 J/cm2 and cultured thereafter for 24 h. After this period of time, a marked decline up to 50% was observed in cell proliferation in UVA-irradiated ChL cultures. The cell proliferation decline was found to be caused by simultaneously occurring G2/M phase cell cycle arrest and apoptosis in part of the UVA-irradiated ChL population. Concomitantly, with the decline in cell proliferation, an increase was observed in the expression of the major histocompatibility (MHC) class I and II antigens. Because protein kinase C (PKC) is known to regulate cell proliferation, apoptosis and expression of MHC antigens, and because UVA was shown to regulate PKC activity/expression, we therefore examined whether UVA irradiation has any effect on the expression of isozymes of PKC. Western blots revealed that ChL express alpha, beta I, delta, epsilon, eta, and zeta/iota isozymes of PKC and that expression of all isozymes declined 24 h after UVA irradiation (8 J/cm2). Finally, PKC activation in ChL by exposure to phorbol ester caused cell cycle arrest in G1 phase but did not induce apoptosis. This suggests that the previously shown UVA-induced PKC activation in ChL might be responsible for the induction of MHC antigens but the simultaneously observed ChL apoptosis is likely to be mediated by PKC down-regulation. All together, our results suggest that UVA, at irradiance levels that resemble the outdoor exposure, may have profound effects on the immune-related properties of leukocytes. Thus, we speculate that in vivo the immune functions of leukocytes passing through dermal capillaries might be altered by exposure to solar UVA radiation.