An investigation into the effects of albendazole on human ovarian carcinoma cells

Abstract

Paclitaxel (PTX) is an effective anti-mitotic drug. It stops cancer from spreading by interfering with the microtubule dynamics which in turn leads to cell cycle arrest and eventually cell death. Despite the clinical success in treating different types of cancers, resistance to PTX remains a major hurdle for successful treatment in relapse patients. Albendazole (ABZ) is a popular anthelmintic used world-wide for the treatment of various types of helmintic infections. In helminthes, ABZ binds to β-tubulin and inhibits microtubule polymerisation. It was subsequently found that ABZ has anti-cancer activity. This study was carried out to study the effects of ABZ on PTX sensitive and PTX resistant human ovarian carcinoma cells. Cell growth assays revealed that the anti-proliferative activity of ABZ was not only effective on the PTX-sensitive human ovarian carcinoma cell line lA9, but also on its PTX-resistant sub-line, lA9PTX22. The ICso values of ABZ in lA9 and lA9PTX22 were 205 nM and 322 nM, respectively. Confocal images demonstrated that ABZ disrupted the microtubule network and caused formation of short microtubule bundles in both cell lines. Further analysis using tubulin polymerisation assay showed that the percentage of polymerised tubulin in lA9 and lA9PTX22 was increased by 58.9 % and 20.6 % respectively. Together, these results revealed for the first time that ABZ interacts with microtubules in human cancer cells and causes their polymerisation. It was also demonstrated that ABZ increased the release of cytochrome c, an important component of the intrinsic pathway in apoptosis. It was found that the expression of Bim, a BH-3 only pro-apoptotic protein was not elevated after ABZ treatment. The results presented in this study provide some information on the effect of ABZ on the microtubule network which could relate to its apoptotic effect in human ovarian carcinoma cells.