Effects of exposure to DAMPS and GSM signals on ornithine decarboxylase (ODC) activity: II. SH-SY5Y human neuroblastoma cells.
ABSTRACT An increase in Ornithine Decarboxylase (ODC) activity was reported in L929 murine fibroblast cells after exposure to a digital cellular telephone signal. This result was not confirmed by several other studies, including the one reported in a companion paper. As a partner in the Perform-B programme, we extended this study to human neuroblastoma cells (SH-SY5Y), using well-defined waveguide systems to imitate exposure to radiofrequency radiation (RFR): Digital Advanced Mobile Phone System (DAMPS) or Global System for Mobile communications (GSM) signals emitted by mobile phones.
Human neuroblastoma cells (SH-SY5Y) were exposed at various Specific Absorption Rates (SAR) to DAMPS or GSM signals using different set-ups. Cell ODC activities were assayed using 14CO2 generation from 14C-labeled L-ornithine.
SH-SY5Y cells were incubated for 20 hours, and were blindly exposed to 50 Hz-modulated DAMPS-835 or 217 Hz-modulated GSM-1800 for 8 or 24 h using Information Technologies in Society (IT'IS) waveguides equipped with fans. After cell lysis, ODC activity was determined using 14C-labeled L-ornithine. ODC activity was estimated by the 14CO2 generated from 14C-labeled L-ornithine, as generated d.p.m. 14CO2/h/mg protein. The results showed that, irrespective of the signal used (835 MHz/DAMPS, or 1800 MHz/GSM) and exposure conditions (duration and SAR), human SH-SY5Y neuroblastoma cells did not exhibit any alteration in ODC enzyme activity.
This work did not show a significant effect of mobile phone RFR exposure on ODC activity in neuroblastoma cells (SH-SY5Y).
Effects of exposure to DAMPS and GSM signals on Ornithine
Decarboxylase (ODC) activity: II- SH-SY5Y human
BERNARD BILLAUDEL1, MURIELLE TAXILE1, FLORENCE POULLETIER DE GANNES1,
GILLES RUFFIE1, ISABELLE LAGROYE1,2, & BERNARD VEYRET1,2
1University of Bordeaux 1, IMS-MCM, and2EPHE, Bioelectromagnetics Laboratory, ENSCPB, 33607 Pessac, France
(Received 28 February 2008; revised 19 February 2009; accepted 3 March 2009)
exposure to a digital cellular telephone signal. This result was not confirmed by several other studies, including the one
reported in a companion paper. As a partner in the Perform-B programme, we extended this study to human neuroblastoma
cells (SH-SY5Y), using well-defined waveguide systems to imitate exposure to radiofrequency radiation (RFR): Digital
Advanced Mobile Phone System (DAMPS) or Global System for Mobile communications (GSM) signals emitted by mobile
Materials and methods:
Human neuroblastoma cells (SH-SY5Y) were exposed at various Specific Absorption Rates (SAR)
to DAMPS or GSM signals using different set-ups. Cell ODC activities were assayed using14CO2generation from14C-
SH-SY5Y cells were incubated for 20 hours, and were blindly exposed to 50 Hz-modulated DAMPS-835 or 217
Hz-modulated GSM-1800 for 8 or 24 h using Information Technologies in Society (IT’IS) waveguides equipped with fans.
After cell lysis, ODC activity was determined using14C-labeled L-ornithine. ODC activity was estimated by the14CO2
generated from14C-labeled L-ornithine, as generated d.p.m.14CO2/h/mg protein. The results showed that, irrespective of
the signal used (835 MHz/DAMPS, or 1800 MHz/GSM) and exposure conditions (duration and SAR), human SH-SY5Y
neuroblastoma cells did not exhibit any alteration in ODC enzyme activity.
This work did not show a significant effect of mobile phone RFR exposure on ODC activity in neuroblastoma
An increase in Ornithine Decarboxylase (ODC) activity was reported in L929 murine fibroblast cells after
Keywords: Human neuroblastoma cells, DAMPS and GSM signals, ODC activity
The Litovitz group reported a temporary increase in
Ornithine decarboxylase (ODC) activity in L929
fibroblasts after exposure to Digital Advanced
Mobile Phone System (DAMPS-835) mobile phone
signals in a Transverse Electro-Magnetic (TEM) cell
(Penafiel et al. 1997). However, these results were
not confirmed in recent replication studies at the
Food and Drug Administration (Desta et al. 2003)
and within the Perform-B programme
in parallel in French and Finnish laboratories (Ho ¨yto ¨
et al. 2007a, and Billaudel et al. 2009).
As cell types other than L929 fibroblasts exhibit
high levels of ODC activity during neoplastic
transformation, e.g., skin and brain cells, it was
deemed relevant to test such cell types. For instance,
the role of ODC overexpression in skin cells
malignant transformation has been documented
(see for review Shantz and Levin 2007). Such models
are not available for brain cells, however it has been
proposed that alterations in the polyamine metabo-
lism may have an impact on the differentiation of
neuroblastomas (Chen et al. 1982; Frostesjo ¨ and
Heby, 1999), and high levels of ODC activity are
typically found in gliomas (Ro ¨hn et al. 2001).
Correspondence: Bernard Billaudel, University of Bordeaux 1, IMS-MCM, Site ENSCPB, 33607 Pessac cedex, France. Tel: þ33 5400 02724.
Fax: þ33 5400 06631. E-mail: email@example.com
ISSN 0955-3002 print/ISSN 1362-3095 online ? 2009 Informa Healthcare USA, Inc.
Int. J. Radiat. Biol., 2009, pp. 1–4, iFirst article
We have thus extended the previous confirmation
studies (Billaudel et al. 2009), using new well-
characterised waveguide systems (Schuderer et al.
2004a, 2004b), to expose neuroblastoma cells (SH-
DAMPS-835 and Global System for Mobile com-
munications (GSM-1800) signals. SH-SY5Y cells
were chosen as a better model than L929 fibroblasts
for our investigation, in view of the relevance of an
alteration in ODC activity in brain cells and of
mobile phone use. In a parallel experiment, our
Perform-B Finnish partner tested similar strains
using another exposure system (Sa ¨teilyturvakeskus
(STUK) resonator) and reported no significant
variations in ODC activity in SH-SY5Y, C6 cells,
whereas ODC activity decreased slightly in primary
astrocytes (Naarala et al. 2004, Ho ¨yto ¨ et al. 2007b).
Materials and methods
Unless stated otherwise, all chemicals were pur-
chased from Sigma-Aldrich (St Quentin Fallavier,
European Collection of Cell Cultures, Salisbury,
Wiltshire, UK) were cultured in Ham-F12 medium,
supplemented with 15% foetal calf serum, antibiotics
and 1% non-essential amino-acids at 378C in 5%
CO2/air. Cells were plated at a density of 46105
cells/Petri dish in 3.2 ml Ham-F12 medium (Invi-
trogen, Cergy-Pontoise, France).
Petri dishes (35-mm diameter) were incubated for
20 h before blind 8-h exposures in the Information
Technologies in Society (IT’IS) waveguides (Zurich,
Switzerland) either to 1 or 2.5 W/kg 50 Hz-
modulated DAMPS-835 signals (Schuderer et al.
2004a), or 217 Hz-modulated GSM-1800 signals
(Schuderer et al. 2004b), or sham exposed. The
temperatures and electric fields in the two wave-
guides were recorded continuously.
In the active waveguides (DAMPS-835 and
GSM-1800 signal) SAR values were planned to be
1 or 2.5 W/kg, while experimental measurements
were for: (i) 8-hour exposure: 0.99 and 0.99 and
2.48 and 2.49 W/kg, (n¼5), for DAMPS and GSM
respectively, and (ii) for 24-hour exposure: 1.00 and
1.00 and 2.49 and 2.51 W/kg, (n¼5), respectively.
Comparative temperature measurements (Figure 1a
and 1b) between active and non-active waveguides
did not show significant differences using both
DAMPS and GSM. Mean temperature variation
never exceeded 0.038C. Immediately after exposure,
cells were treated as previously described (Billaudel
et al. 2009) for ODC extraction and stored until
Measurement of ODC activity
The measurement protocol was based on published
work (Ja ¨nne and Williams-Ashman 1971, Seely and
Pegg 1983). Briefly, after lysis and centrifugation,
aliquots of supernatant were incubated for 1 h at
Courtaboeuf, France), before trapping
erated by ODC using hyamine hydroxide (Packard,
Rungis, France) contained in a hanging centre well
(Kontes, Vineland, NJ, USA). The hyamine hydro-
xide in the centre well was then transferred to a
scintillation vial containing Pico-Fluor (Packard,
Rungis, France) and counted by liquid scintillation
(Beckman Coulter France, Paris Nord 2, Villepinte,
France) (see Billaudel et al. 2009).
14C-labeled L-ornithine (Perkin-Elmer,
Figure 1. Recording of air temperature variations during exposure
at 1 or 2.5 W/kg SAR levels for 8 or 24 hours of neuroblastoma
cells (SH-SY5Y): (a) to DAMPS-835 MHZ signal, (b) to GSM-
1800 signal using IT’IS waveguide set up. Error bar indicate the
standard error of the mean (SEM) for n¼4–5 independent
B. Billaudel et al.
ODC activities calculated from duplicate assays were
averaged for each test. These independent values
were used to calculate both the average cellular ODC
activity and the standard error of the mean (SEM)
for each exposure condition. For each experiment,
calculation of the averages of duplicate assays for
each of the exposure conditions gave the daily ODC
activity ratio. This ratio is expressed as exposed/
control for experimental treatments and as wave-
guide 1/waveguide 2 for sham-versus-sham control
experiments. ODC activity ratio is used to account
for variations between experiments in control ODC
activity. Data were analysed using the Statview
software (SAS Institut Inc., Cary, NC, USA).
Statistical comparisons were performed on raw data
using Mann-Whitney test for unpaired values (ODC
activity expressed as pmol/h/mg protein and ODC
activity ratios). The statistical power was 85% to
detect a 30% increase in ODC activity ratios using
five independent samples, the variation coefficient
having been calculated based on historical controls
for ODC activity ratios (activity ratios were used to
minimise day-to-day variations in absolute activities).
Statistical analysis of sham-sham exposure results
confirmed that there was no difference between the
two waveguides in terms of ODC activity (Table I).
No significant modification of ODC activity (ex-
pressed in pmol/h/mg protein) was observed in
exposed SH-SY5Y neuroblastoma cells, as shown
in Table I. At exposure times of 8 and 24 h, using the
DAMPS signal at SAR levels of 1 or 2.5 W/kg, the
ratio was not statistically different from unity
(Figure 2a): p¼0.71 and p¼0.08 at 8 h (n¼4–5),
and p¼0.08 and p¼0.27 at 24 h, respectively
(n¼4–5). When the GSM signal was used at SAR
of 1 or 2.5 W/kg, this ratio (Figure 2b) was not
statistically different: p¼0.69 and p¼0.50 at 8 h
(n¼5), and p¼0.50 and p¼0.69 at 24 h, respec-
Our previous data (see companion paper) on lysed
L929 cells were in agreement with those reported by
the Owen group at FDA (Desta et al. 2003) and by
our Finnish Perform-B partner (Ho ¨yto ¨ et al. 2007a).
These findings do not support the hypothesis that
low-level RFR induced increased ODC activity.
Cell types other than L929 fibroblast cells, such as
skin and brain cells, have been reported expressing
high levels of ODC activity in relation to carcinogen-
esis process. Moreover, to maximise the relevance of
this study, we focused on the effect of mobile phone
signals on SH-SY5Y neuroblastoma cells. Irrespec-
tive of the signal (835 MHz/DAMPS, or 1800 MHz/
GSM) and exposure conditions used, there was no
alteration in ODC activity in human SH-SY5Y
neuroblastoma. This absence of effects on another
cell type is thus consistent with the previous findings
on L-929 cells and at odds with those of the Litovitz
group (Penafiel et al. 1997). However, the exposure
set-up was different, based on waveguides instead of
In parallel, using 217 Hz-modulated GSM signals
in the same frequency range (872–900 MHz) and the
STUK exposure system, our Finnish Perform-B
partner group did not observe any alterations in
ODC activity in the various secondary cell lines
tested (Ho ¨yto ¨ et al. 2007a, 2007b). However, they
observed a 59% decrease in ODC activity in primary
astrocytes at SAR levels of 1.5 and 6 W/kg (Ho ¨yto ¨
et al. 2007b). The authors emphasised that the
function of the primary cells is closer to normal
tissues than that of secondary transformed cell lines,
Table I. ODC activity in SH-SY5Y cells after sham-sham
experiments or exposure in various set-ups to different mobile
phone signals. n (E/S)¼number of Sham exposed (S) and
Exposed (E) samples. Sham¼mean ODC activity of sham
cultures as pmol
sed¼mean ODC activity of exposed cultures as pmol
generated/h/mg protein+SEM. In sham-sham experiments Sham
1 refers to chamber 1 of exposure set-up and Sham 2 to chamber
2. Statistical comparisons were performed on raw data using non-
parametric methods (Mann-Whitney test for unpaired values).
14CO2 generated/h/mg protein+SEM. Expo-
ODC activity (pmol/h/mg protein)-SH-SY5Y cells-DAMPS-835
MHz (Wavequide ITIS)
Sham-sham (8h) 4/7 358+108
ODC activity (pmol/h/mg protein)- SH-SY5Y cells-GSM-1800
MHz (Wavequide ITIS)
5/5787+ 143 841+2160.754
5/5 168+63 173+27 0.754
SH-SY5Y cells, ODC activity, and mobile phone
and suggest further studies using primary astrocytes
to confirm their findings. The effect of temperature
should thus be studied on those primary cells.
ODC enzyme activity was not altered in human SH-
SY5Y neuroblastoma cells, irrespective of the signal
(835 MHz/DAMPS or 1800 MHz/GSM) and
exposure conditions. The impact of RFR on poly-
amine metabolism can no longer be considered to
play a significant role in altering the physiology of
these tumour cells. It is, therefore, safe to conclude
in agreement with our Finnish partner (Ho ¨yto ¨ et al.
2007b), that with transformed cell lines there is no
evidence from experiments using various exposure
set-ups and conditions that ODC activity is altered
under low-level RFR exposure.
J. Schuderer and N. Kuster at IT’IS are gratefully
acknowledged for their expertise in dosimetry. We
thank R. Owen from FDA for stimulating comments
as a PERFORM B external advisor. This work was
supported by the Mobile Manufacturers Forum and
GSM Association (PERFORM B programme), the
Aquitaine Council for Research, E´cole Pratique des
Hautes Etudes and the Centre National de la
Declaration of interest: The authors report no
conflicts of interest. The authors alone are respon-
sible for the content and writing of the paper.
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Figure 2. ODC activity in neuroblastoma cells (SH-SY5Y)
exposed to DAMPS-835 or GSM-1800 signal at 1 or 2.5 W/kg
SAR levels for 8 or 24 hours. The results are expressed as mean of
the ODC activity ratios+SEM in exposed samples to ODC
activity in the matched sham samples (n¼4–5).
B. Billaudel et al.