@Article{,
AUTHOR = {Irena Fonda, Mojca Pernuš, Vladka Gaberc-Porekar, Maja Kenig, Anton Štalc, Anthony Meager, Viktor Menart},
TITLE = {Improvement of potential therapeutic value of tumor necrosis-α (TNF-α) by charge modulation in the tip region},
JOURNAL = {European Cytokine Network},
VOLUME = {16},
YEAR = {2005},
NUMBER = {1},
PAGES = {17--26},
URL = {http://www.techscience.com/ECN/v16n1/66232},
ISSN = {1952-4005},
ABSTRACT = {Analysis of published data reveals that the introduction of more basic amino acid residues in the
flexible N-terminal region of the human tumour necrosis factor alpha (TNF) molecule indicates a weak but
consistent trend towards increased in vitro cytotoxicity, especially when the effect of N-terminal length is taken
into account. In our laboratory, a series of TNF analogues with a charge modification in the tip region of the
molecule was prepared, and cytotoxicity measured. Similar trends in cytotoxicity with increasing basicity of the
TNF analogue were found in this study for two mouse cell lines, L929 and WEHI-164 clone 13-1, as well as for
the human line KYM-1D4. For the series of analogues as a whole, a general increase in in vitro cytotoxicity with
increasing pI values was not apparent, but some analogues with charge reversal in the tip region, for example, the
LK-805 analogue (E107K), exhibited significantly increased cytotoxicity in comparison to native TNF in a range
of cell lines, including L929, KYM-1D4-K, WEHI-164 clone 13-1, HEPA 1-6 and EAhy926 cell lines. Experiments
with heparinase-pre-treated cells demonstrated that the increased in vitro cytotoxicity of LK-805 is most probably
due to interactions with cell surface heparan sulphates that effectively concentrate it before binding to TNF
receptors occurs. Examination of structural models of TNF bound to soluble TNF receptor 1 (TNFR1) indicates
that simple mutations in the tip region most probably cannot interact with receptor binding sites, and therefore
do not directly modulate cytotoxicity.},
DOI = {}
}