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@INPROCEEDINGS{Dahmen:841327,
author = {Dahmen, Volker and Kriehuber, Ralf},
title = {{T}argeting specific {DNA} sequences with {I}-125-labelled
{T}riplex-forming-oligonucleotides},
reportid = {FZJ-2017-08412},
year = {2010},
abstract = {Purpose: Triplex-forming-oligonucleotides (TFOs) are able
to bind DNA in a sequence specific manner and are a
promising tool to manipulate genes or gene regulatory units
in a cellular environment. TFOs have also therapeutic
potential e.g. as a carrier for Auger-Electron-Emitter (AEE)
to target DNA of tumour cells. We established a method for
the effective labelling of TFOs with I-125 and studied the
DNA binding capabilities of labelled TFOs in vitro.
Furthermore we examined the intracellular biokinetic of TFOs
with the focus on the transfer from the cytoplasm into the
cell nucleus. Methods: TFOs specific for the genes cdkn2a,
bcl2, brca1, chk2, cdk4 were designed using TFO Target
Sequence Search (Univ. of Texas). TFO labelling with I-125
was performed with the primer extension method. Formation of
DNA triplexes was visualized with MS Imaging Plates on a
FLA-5000 Imaging System (Fujifilm, Düsseldorf) and
electrophoretic-mobility-shift-assay (EMSA). For biokinetic
studies SCL-II cells were transfected by electroporation
with Alexa488-labelled TFOs. Transfected cells were
subsequently cultured for 1, 6, 12, 18, 24, 30, 48 and 72 h
and TFO signal intensity was determined in single cells and
in isolated cell nuclei by flow cytometry (FACS-Canto II,
BD).Results: The desired Triplex-DNA-formation could be
confirmed for 53 $\%$ of all tested TFOs by EMSA.
Triplex-formation of I-125-labelled TFOs was confirmed for
10 $\%$ by autoradiographic analysis. The biokinetic studies
showed that TFO-Alexa488-positive cells were detectable as
soon as 1 h after transfection and the signal intensity
remained constant for at least 30 h. 72 h after transfection
the signal was less intense but still detectable. A
substantial loss of TFO-Alexa488-labelled positive cell
nuclei was observed within the first 6 h post-transfection
followed by a significant increase up to 18 h
post-transfection.Conclusions: Labelling of TFOs with I-125
has a strong influence on their binding capacities. TFOs
initially located in the cytoplasm are re-located to the
cell nucleus within 12 h after delivery of the TFOs probably
during cell division.},
month = {Sep},
date = {2010-09-05},
organization = {38th Annual Meeting of the European
Radiation Research Society, Stockholm
(Sweden), 5 Sep 2010 - 9 Sep 2010},
subtyp = {After Call},
cin = {S-US},
cid = {I:(DE-Juel1)S-US-20090406},
pnm = {899 - ohne Topic (POF3-899)},
pid = {G:(DE-HGF)POF3-899},
typ = {PUB:(DE-HGF)24},
url = {https://juser.fz-juelich.de/record/841327},
}