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 TPA treatment on p27 levels.  Autoradiographs of p27 expression in Caco cells exposed to ELM-EMFs. The densitometric analysis from six separate blots provided for quantitative analysis is presented (a) and a representative Western blot is shown (b). Equal protein loading was verified by using an antibody directed against GAPDH (c). Caco cells were cultured with or without 0.1 μM TPA for 24, 48, and 72 hours. After harvesting and lysing the cells, samples were subjected to SDS-PAGE and electroblotted on a polyvinylidene fluoride membrane. The immunostaining was performed using anti-p27 antibodies, and the detection was executed by the 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

fig8: Effect of ELF-EMFs exposure and TPA treatment on p27 levels. Autoradiographs of p27 expression in Caco cells exposed to ELM-EMFs. The densitometric analysis from six separate blots provided for quantitative analysis is presented (a) and a representative Western blot is shown (b). Equal protein loading was verified by using an antibody directed against GAPDH (c). Caco cells were cultured with or without 0.1 μM TPA for 24, 48, and 72 hours. After harvesting and lysing the cells, samples were subjected to SDS-PAGE and electroblotted on a polyvinylidene fluoride membrane. The immunostaining was performed using anti-p27 antibodies, and the detection was executed by the 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: The protein p27 is a cell cycle regulator with a pro-apoptotic effect and is also known as a 20S proteasome substrate. Its levels are therefore considered a hallmark of proteasome functionality. The immunoblot analysis performed with an antibody specific for this protein, showed a time dependent decrease of p27 expression following ELF-EMFs exposure. In the absence of TPA, a gradual decrease of p27 levels was detected reaching a 15% decrease after 48 hours and 72 hours exposure. The presence of TPA led to an overall decrease of protein levels, detectable both in control and ELF-EMFs exposed cells. Moreover, p27 levels in ELF-EMFs treated cells were a 10% lower than in unexposed control cells (Figure 8).


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 TPA treatment on p27 levels.  Autoradiographs of p27 expression in Caco cells exposed to ELM-EMFs. The densitometric analysis from six separate blots provided for quantitative analysis is presented (a) and a representative Western blot is shown (b). Equal protein loading was verified by using an antibody directed against GAPDH (c). Caco cells were cultured with or without 0.1 μM TPA for 24, 48, and 72 hours. After harvesting and lysing the cells, samples were subjected to SDS-PAGE and electroblotted on a polyvinylidene fluoride membrane. The immunostaining was performed using anti-p27 antibodies, and the detection was executed by the 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

fig8: Effect of ELF-EMFs exposure and TPA treatment on p27 levels. Autoradiographs of p27 expression in Caco cells exposed to ELM-EMFs. The densitometric analysis from six separate blots provided for quantitative analysis is presented (a) and a representative Western blot is shown (b). Equal protein loading was verified by using an antibody directed against GAPDH (c). Caco cells were cultured with or without 0.1 μM TPA for 24, 48, and 72 hours. After harvesting and lysing the cells, samples were subjected to SDS-PAGE and electroblotted on a polyvinylidene fluoride membrane. The immunostaining was performed using anti-p27 antibodies, and the detection was executed by the 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: The protein p27 is a cell cycle regulator with a pro-apoptotic effect and is also known as a 20S proteasome substrate. Its levels are therefore considered a hallmark of proteasome functionality. The immunoblot analysis performed with an antibody specific for this protein, showed a time dependent decrease of p27 expression following ELF-EMFs exposure. In the absence of TPA, a gradual decrease of p27 levels was detected reaching a 15% decrease after 48 hours and 72 hours exposure. The presence of TPA led to an overall decrease of protein levels, detectable both in control and ELF-EMFs exposed cells. Moreover, p27 levels in ELF-EMFs treated cells were a 10% lower than in unexposed control cells (Figure 8).

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