ABSTRACTS – ORAL PRESENTATIONS - AMCA, spol. s r.o.

Although multiple signalling pathways are known to be modulated by arsenic
compounds, precise mechanism of action of realgar nanoparticles remains unclear. Even
though physical properties of soluble ATO and realgar nanoparticles differ significantly,
suprisingly substantial similarities in their effect on tested cells were observed.
Acknowledgements
This study is the result of the project implementation: TRANSMED 2, ITMS 26240120030
supported by the Research & Development Operational Programme funded by the ERDF
and the Joint Research Projects Cooperation of SAS-NSC No. 2010/03
60. EPIGENETIC EFFECTS OF VPA ON EXPRESSION OF CD133 IN NEUROBLASTOMA
CELL LINES IN NORMOXIA AND HYPOXIA
Ashraf M. Khalil, Jan Hraběta, Helena Maříková, Tomáš Groh, Šimon Cipro, Tomáš
Eckschlager
Department of Paediatric Haematology and Oncology, 2 nd Faculty of Medicine and
University Hospital Motol, Charles University, Prague, Czech Republic
CD133, also known as Prominin-1, is a pentaspan transmembrane glycoprotein
commonly found in the stem and progenitor cells in various tissues particularly in the
CNS. Many authors have shown the cancer stem cell (CSC) characters of CD133 positive
cells in different solid tumours (Qianga et al., 2009). The value of studying such cells is
related to the assumption they likely can initiate the tumour, relapse and metastasis.
This is due to their ability for self-renewal, high proliferative potential, maintaining and
regulating the neoplastic clone. Targeting CSCs by conventional therapy isn’t efficient to
eradicate them because they are generally resistant to conventional chemotherapy and
radiotherapy.
Increased CD133 expression is described as a sign associated with worse prognosis
in Neuroblastoma (NBL) and other tumours (Tong et al., 2008). NBL, a tumour of the
peripheral sympathetic nervous system, is the most common extracranial solid tumour
in children. Prognosis of high risk tumors is still poor, because drug resistance arises in
the majority of those patients with a little improvement in therapeutic options during
the last decade. Nowadays, epigenetic therapy is considered as a promising approach to
target CSC. Histon deacetylase inhibitors (HDACi) are tested as a new class of anticancer
agents which can induce chromatin remolding with subsequent re-expression of
epigenetically silenced genes in tumours. Valproic acid (VPA) is an established drug in the
long-term therapy of epilepsy. It has demonstrated antitumor activity as a (HDACi) such
as inhibition of the cell cycle as well as induction of apoptosis. Epigenetic modifications
such as Histon acetylation and promoter methylation have been proved to control CD133
transcription (Tabu et al., 2008). Hence, we were interested in evaluating the effect of
VPA on the expression of CD133 in normoxia and hypoxia
In this study, we have examined 4 neuroblastoma cell lines. Neither IMR-32 nor UKF-
NB4 were expressing CD133 protein whether in the control or sample treated with VPA
as reveled by westernblot. Interestingly, CD133 transcription has been reactivated and
76 Analytical Cytometry VII