Book of abstract 2008

Ruthenium-based anticancer agent in combination with electroporation
exerts higher cytotoxicity than agent alone
Ajda Biček1, Maša Kandušer1, Rosana Hudej1, Damijan Miklavčič1, Michael Jakupec3,
Bernhard K. Keppler3, Iztok Turel2
1Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, SI-1000 Ljubljana, Slovenia;
2Faculty of Chemistry and Chemical Technology, Aškerčeva 5, SI-1000 Ljubljana, Slovenia; 3Institute of
Inorganic Chemistry, University of Vienna, Waehringerstr. 42, A-1090 Vienna, Austria
Indazolium trans-[tetrachlorobis(1H-indazole)ruthenate(III)] (KP1019) is a potential
anticancer agent. It has already entered clinical trials and is together with NAMI-A the
most successful representative of ruthenium-based drugs. KP1339 is a sodium salt of
KP1019 with higher solubility. It also exerts moderate cytotoxicity (1).
It is already known that addition of agents KP1019 or KP1339 to tumor cells caused
DNA-strand breaks and the loss of mitochondrial membrane potential depending on the
concentration of the anticancer agent. Therefore it is assumed that KP1019 and KP1339
have intracellular biological targets and that cytotoxic potency of the agents is directly
influenced by the cellular uptake. Electroporation can be used to facilitate delivery of
agents for which membrane represents barrier into cells. We have for example already used
electroporation to increase cytotoxic effect of agent NAMI-A on tumor cells in vitro (1).
In this work we aimed at determination whether application of electroporation modifies
in vitro cell cytotoxicity of KP1339 and KP 1019. Cell cytotoxicity was determined in
two different cell lines; B16F1 and CHO. Cells were treated either with 30 μM KP1019
or 100 μM KP1339 alone or in combination with electroporation. For electroporation
a 50 μl droplet of cell suspension containing 106 cells was placed between stainless steel
plate electrodes 2 mm apart. Pulse voltage applied during electroporation was 160 V. A
train of eight square electric pulses of 100 μs duration were delivered at 1 s interval. Cell
survival responding
p3
to anticancer agent’s cytotoxicity was mesured by MTT assay. The cell
suspension of non-pulsed cells diluted only in electroporation buffer served as the control
to which results were normalized.
Our results show that the combined treatment of either KP1019 or KP 1339 with
electroporation potentiates the effect of these ruthenium-based compounds, although this
potentiation was not statistically significant for KP1019. Electroporation alone caused
cell membrane permeabilization without seriously affecting cell viability. These results are
in agreement with our previous study with NAMI-A (2).
References:
1. Hartinger CG, Zorbas-Seifried S, Jakupec MA, Kynast B, Zorbas H, Keppler BK. (2006) From
bench to bedside-preclinical and early clinical development of the anticancer agent indazolium trans-
[tetrachlorobis(1H-indazole)ruthenate(III)] (KP1019 or FFC14A). J Inorg Biochem. 100: 891-904.
2. Bicek A, Turel I, Kanduser M, Miklavcic D. (2007) Combined therapy of the antimetastatic compound
NAMI-A and electroporation on B16F1 tumour cells in vitro. Bioelectrochemistry. 71: 113-7.
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