Sensitization of Human Carcinoma of Nasopharynx Cells to Doxorubicin and Induction of Apoptosis by Sargassum baccularia Lipophilic Fraction

Abstract

The pharmaceutical properties of marine bioactive compounds derived from variants of the Sargassum species have long been recognized as important features for medicinal use. However, the molecular mechanisms of their anticancer activities are unclear. This study aimed to investigate the apoptosis-modulating activities of Sargassum baccularia lipophilic fraction (SBL fraction) in human carcinoma of nasopharynx cells (KB cells). Sargassum baccularia was extracted with 95 % ethanol and then fractionated through solvent-solvent partitioning with chloroform: methanol: water. It was found that SBL fraction and doxorubicin (Dox) alone inhibited proliferation in KB cells with IC50 of 85.04 ± 5.28 and 2.0 ± 0.1 µg/ml, respectively. The combined SBL fraction (10 - 50 µg/ml) and Dox (1 µg/ml) treatment produced greater cytotoxicity associated with the increasing of chromatin condensation, DNA fragmentation, and hypo-diploid cells (DNA < 2n), compared with each SBL fraction and Dox alone. Apoptosis induced by SBL fraction was associated with caspase-3 activation that was attenuated in a caspase-3 inhibitor. Thus, SBL fraction acts as potent sensitizer for doxorubicin-induced apoptosis, and it can be potentially developed into a promising adjuvant therapy for nasopharynx carcinoma.

Keywords

• Sargassum baccularia
• lipophilic fraction
• apoptosis
• carcinoma of nasopharynx cells