Nosratollah Zarghami - Department of Medical Biotechnology, Faculty of Advanced Medical Sciences, Tabriz University of Medical sciences, Tabriz, Iran
Sepideh Jalilzadeh-tabrizi - Department of Biotechnology, Urmia Branch, Islamic Azad University, Urmia, Iran.
Rana Farajzadeh - Department of Genetics, Tabriz Branch, Islamic Azad University, Tabriz, Iran.
Samaneh Ghasemali

Background: Nowadays, the encapsulation of cytotoxic chemotherapeutic agents is attracting interest as a method for drug delivery. We hypothesized that the efficiency of helenalin might be maximized by encapsulation in β- cyclodextrin nanoparticles. Helenalin, with a hydrophobic structure obtained from flowers of Arnica chamissonis and Arnica Montana, has anticancer and anti-inflammatory activity but low water solubility and bioavailability. β-Cyclodextrin (β-CD) is a cyclic oligosaccharide comprisingseven D glucopyranoside units, linked through 1,4-glycosidic bonds. Materials and Methods: To test our hypothesis, we prepared β-cyclodextrin-helenalin complexes todetermine their inhibitory effects on telomerase gene expression by realtime polymerase chain reaction (q-PCR) and cytotoxic effects by colorimetric cell viability (MTT) assay. Results: MTT assay showed that not only β-cyclodextrin has no cytotoxic effect on its own but also it demonstrated that β-cyclodextrin-helenalin complexes inhibited the growth of the T47D breast cancer cell line in a time and dosedependent manner. Our q-PCR results showed that the expression of telomerase gene was effectively reduced as the concentration of β- cyclodextrin-helenalin complexes increased. Conclusions: β-Cyclodextrin-helenalin complexes exerted cytotoxic effects on T47D cells through down-regulation of telomerase expression and by enhancing Helenalin uptake by cells. Therefore, β-cyclodextrin could be superior carrier for this kind of hydrophobic agent.

Breast cancer, Helenalin, Telomerase, β-cyclodextrin