Limits...
50 Hz extremely low frequency electromagnetic fields enhance protein carbonyl groups content in cancer cells: effects on proteasomal systems.

Eleuteri AM, Amici M, Bonfili L, Cecarini V, Cuccioloni M, Grimaldi S, Giuliani L, Angeletti M, Fioretti E - J. Biomed. Biotechnol. (2009)

Bottom Line: This study was carried out to investigate the influence of extremely low frequency electromagnetic fields on protein oxidation and on the 20S proteasome functionality, the complex responsible for the degradation of oxidized proteins.Caco 2 cells were exposed, for 24-72 hours, to 1 mT, 50 Hz electromagnetic fields.The treatment induced a time-dependent increase both in cell growth and in protein oxidation, more evident in the presence of TPA, while no changes in cell viability were detected.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology M.C.A., University of Camerino, 62032 Camerino (MC), Italy. annamaria.eleuteri@unicam.it

ABSTRACT
Electromagnetic fields are an assessed cause of prolonging free radicals lifespan. This study was carried out to investigate the influence of extremely low frequency electromagnetic fields on protein oxidation and on the 20S proteasome functionality, the complex responsible for the degradation of oxidized proteins. Caco 2 cells were exposed, for 24-72 hours, to 1 mT, 50 Hz electromagnetic fields. The treatment induced a time-dependent increase both in cell growth and in protein oxidation, more evident in the presence of TPA, while no changes in cell viability were detected. Exposing the cells to 50 Hz electromagnetic fields caused a global activation of the 20S proteasome catalytic components, particularly evident at 72 hours exposure and in the presence of TPA. The finding that EGCG, a natural antioxidant compound, counteracted the field-related pro-oxidant effects demonstrates that the increased proteasome activity was due to an enhancement in intracellular free radicals.

Show MeSH

Related in: MedlinePlus

Effect of ELF-EMFs exposure and EGCG treatment on protein oxidation. Protein oxidation was analysed and quantified by measuring the amount of protein carbonyl groups. The densitometric analysis from six separate blots provided for quantitative analysis of the amount of protein carbonyls is present (panel A) and a representative Western blot of protein carbonyls is shown (panel B). Equal protein loading was verified by using an antibody directed against GAPDH (panel C). Caco cells were cultured with and without 150 μM EGCG, with and without TPA and exposed to ELM-EMFs for 24, 48 and 72 hours. After harvesting and lysing the cells, samples were treated according to the OxyBlot procedure (Oxidized Protein Detection Kit, Oncor). Carbonyl groups were revealed by appropriate antibodies using an Enhanced ChemiLuminescence Western blotting analysis system. Data points marked with an asterisk are statistically significant compared to their respective not exposed control cells (P < .05).
© Copyright Policy - open-access
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2722031&req=5

fig4: Effect of ELF-EMFs exposure and EGCG treatment on protein oxidation. Protein oxidation was analysed and quantified by measuring the amount of protein carbonyl groups. The densitometric analysis from six separate blots provided for quantitative analysis of the amount of protein carbonyls is present (panel A) and a representative Western blot of protein carbonyls is shown (panel B). Equal protein loading was verified by using an antibody directed against GAPDH (panel C). Caco cells were cultured with and without 150 μM EGCG, with and without TPA and exposed to ELM-EMFs for 24, 48 and 72 hours. After harvesting and lysing the cells, samples were treated according to the OxyBlot procedure (Oxidized Protein Detection Kit, Oncor). Carbonyl groups were revealed by appropriate antibodies using an Enhanced ChemiLuminescence Western blotting analysis system. Data points marked with an asterisk are statistically significant compared to their respective not exposed control cells (P < .05).

Mentions: Numerous publications reported on the ability of EGCG to act as a free radical scavenger [34, 36–39, 52]. The protective action of EGCG against the ELF-EMFs induced oxidative stress was assayed adding this polyphenol directly to the culture medium during exposure. The treatment with 150 μM EGCG caused, essentially, no change in cell viability as measured by the MTT reduction assay (data not shown). As shown in Figure 4, the enhancement in protein carbonyl groups, evident in cells exposed to the fields, was lowered in EGCG treated cells, demonstrating that EGCG protected cells from protein oxidation induced by ELF-EMFs exposure.


50 Hz extremely low frequency electromagnetic fields enhance protein carbonyl groups content in cancer cells: effects on proteasomal systems.

Eleuteri AM, Amici M, Bonfili L, Cecarini V, Cuccioloni M, Grimaldi S, Giuliani L, Angeletti M, Fioretti E - J. Biomed. Biotechnol. (2009)

Effect of ELF-EMFs exposure and EGCG treatment on protein oxidation. Protein oxidation was analysed and quantified by measuring the amount of protein carbonyl groups. The densitometric analysis from six separate blots provided for quantitative analysis of the amount of protein carbonyls is present (panel A) and a representative Western blot of protein carbonyls is shown (panel B). Equal protein loading was verified by using an antibody directed against GAPDH (panel C). Caco cells were cultured with and without 150 μM EGCG, with and without TPA and exposed to ELM-EMFs for 24, 48 and 72 hours. After harvesting and lysing the cells, samples were treated according to the OxyBlot procedure (Oxidized Protein Detection Kit, Oncor). Carbonyl groups were revealed by appropriate antibodies using an Enhanced ChemiLuminescence Western blotting analysis system. Data points marked with an asterisk are statistically significant compared to their respective not exposed control cells (P < .05).
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2722031&req=5

fig4: Effect of ELF-EMFs exposure and EGCG treatment on protein oxidation. Protein oxidation was analysed and quantified by measuring the amount of protein carbonyl groups. The densitometric analysis from six separate blots provided for quantitative analysis of the amount of protein carbonyls is present (panel A) and a representative Western blot of protein carbonyls is shown (panel B). Equal protein loading was verified by using an antibody directed against GAPDH (panel C). Caco cells were cultured with and without 150 μM EGCG, with and without TPA and exposed to ELM-EMFs for 24, 48 and 72 hours. After harvesting and lysing the cells, samples were treated according to the OxyBlot procedure (Oxidized Protein Detection Kit, Oncor). Carbonyl groups were revealed by appropriate antibodies using an Enhanced ChemiLuminescence Western blotting analysis system. Data points marked with an asterisk are statistically significant compared to their respective not exposed control cells (P < .05).
Mentions: Numerous publications reported on the ability of EGCG to act as a free radical scavenger [34, 36–39, 52]. The protective action of EGCG against the ELF-EMFs induced oxidative stress was assayed adding this polyphenol directly to the culture medium during exposure. The treatment with 150 μM EGCG caused, essentially, no change in cell viability as measured by the MTT reduction assay (data not shown). As shown in Figure 4, the enhancement in protein carbonyl groups, evident in cells exposed to the fields, was lowered in EGCG treated cells, demonstrating that EGCG protected cells from protein oxidation induced by ELF-EMFs exposure.

Bottom Line: This study was carried out to investigate the influence of extremely low frequency electromagnetic fields on protein oxidation and on the 20S proteasome functionality, the complex responsible for the degradation of oxidized proteins.Caco 2 cells were exposed, for 24-72 hours, to 1 mT, 50 Hz electromagnetic fields.The treatment induced a time-dependent increase both in cell growth and in protein oxidation, more evident in the presence of TPA, while no changes in cell viability were detected.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology M.C.A., University of Camerino, 62032 Camerino (MC), Italy. annamaria.eleuteri@unicam.it

ABSTRACT
Electromagnetic fields are an assessed cause of prolonging free radicals lifespan. This study was carried out to investigate the influence of extremely low frequency electromagnetic fields on protein oxidation and on the 20S proteasome functionality, the complex responsible for the degradation of oxidized proteins. Caco 2 cells were exposed, for 24-72 hours, to 1 mT, 50 Hz electromagnetic fields. The treatment induced a time-dependent increase both in cell growth and in protein oxidation, more evident in the presence of TPA, while no changes in cell viability were detected. Exposing the cells to 50 Hz electromagnetic fields caused a global activation of the 20S proteasome catalytic components, particularly evident at 72 hours exposure and in the presence of TPA. The finding that EGCG, a natural antioxidant compound, counteracted the field-related pro-oxidant effects demonstrates that the increased proteasome activity was due to an enhancement in intracellular free radicals.

Show MeSH
Related in: MedlinePlus