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Novel two-stage screening procedure leads to the identification of a new class of transfection enhancers

Authors

  • Birgit Neukamm,

    1. Institute of Microbiology and Genetics, Technical University Berlin, Gustav-Meyer-Allee 25, D-13355 Berlin
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    • These authors contributed equally to the work.

  • Andreas Weimann,

    1. Institute of Laboratory Medicine and Biochemistry, Charité Medical School Berlin, Virchow Hospital Medical Center, Augustenburger Platz 1, D-13353 Berlin, Germany
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    • These authors contributed equally to the work.

  • Shuling Wu,

    1. Institute of Laboratory Medicine and Biochemistry, Charité Medical School Berlin, Virchow Hospital Medical Center, Augustenburger Platz 1, D-13353 Berlin, Germany
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  • Margrete Danevad,

    1. Institute of Laboratory Medicine and Biochemistry, Charité Medical School Berlin, Virchow Hospital Medical Center, Augustenburger Platz 1, D-13353 Berlin, Germany
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  • Christine Lang,

    1. Institute of Microbiology and Genetics, Technical University Berlin, Gustav-Meyer-Allee 25, D-13355 Berlin
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  • Reinhard Geßner

    Corresponding author
    1. Institute of Laboratory Medicine and Biochemistry, Charité Medical School Berlin, Virchow Hospital Medical Center, Augustenburger Platz 1, D-13353 Berlin, Germany
    • Biomedical Research Center, Charité Medical School Berlin, Augustenburger Platz 1, D-13353 Berlin, Germany.
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Abstract

Background

Non-viral gene transfer efficiency is low as compared to viral vector systems. Here we describe the discovery of new drugs that are capable of enhancing non-viral gene transfer into mammalian cells using a novel two-stage screening procedure.

Methods

First, potential candidates are preselected from a molecular library at various concentrations by a semi-automated yeast transfection screen (YTS). The maximal transfection efficiency of every positive drug is subsequently determined in independent experiments at the optimal concentration and compared to the inhibitory effect of the drug on cell growth (IC50). In a subsequent mammalian cell transfection screen (MTS), the maximal transfection efficiency and the IC50 are determined for all preselected drugs using a human cell line and a luciferase reporter gene construct.

Results

Employing our novel system we have been able to identify a new class of transfection enhancers, the tricyclic antidepressants (i.e. doxepin, maprotiline, desipramine and amoxapine). All positive drugs enhanced gene transfer in both yeast and human cell lines, but lower concentrations were sufficient for mammalian cells. With a triple combination of doxepin, amoxapine and chloroquine we obtained a transfection efficiency that exceeded that of chloroquine, one of the best-known transfection enhancers of mammalian cells, by nearly one order of magnitude.

Conclusions

Non-viral gene transfer efficiency can be increased significantly using new transfection enhancers that are identified by a novel, semi-automated two-stage screening system employing yeast cells in the first and specific human target cells in the second round. Copyright © 2006 John Wiley & Sons, Ltd.

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