Anti-cancer activity and immunoadjuvant properties of edible bird's nest extracts on human breast cancer cell line

Abstract

Edible Bird’s Nest (EBN) is well regarded as an immune enhancing nutraceutical food especially among the Chinese. Current cancer therapies bring adverse side effects, thus identification of a safe adjuvant medicine like EBN can provide a quality life for patients. Researches on the effect of EBN extract on the human breast cancer cell line (MCF-7) and human immune cells are still very limited. The aim of this study is to evaluate the anti-cancer activity and immunoadjuvant properties of EBN extract on MCF-7 cell line. Primarily, 3 types of EBN extracts coded as HMG, EHMG and pHMG were prepared using the water extraction method. These EBN extracts were then tested on their cytotoxicity level against MCF-7 and human immune cells (CD8+ and CD14+). Production of the key pro-apoptotic and anti-apoptotic molecules released in MCF-7, CD8+ and CD14+ cells before and after EBN treatment were measured through mRNA expression level, ELISA and Multiplex assay. Among the 3 EBN extracts, HMG showed the highest cytotoxic effect towards MCF-7 cells with IC50 of 15 ^g/mL. However, HMG showed no harm towards CD8+ and CD14+ cells with cell viability of more than 90%. qRT-PCR results for nonactivated and activated CD8+ and CD14+ cells showed increased of pro-apoptotic gene expression while lower anti-apoptotic gene expression after treated with HMG in single and co-culture. At the same time, supplementation of HMG increased the apoptosis through down regulation of anti-apoptotic genes and the up-regulation of pro-apoptotic genes in MCF-7 cells. Enhancement of pro-apoptotic and down regulation of anti-apoptotic soluble factors by non-activated and activated CD8+ and CD14+ cells in single and co-culture after treated with HMG also showed in ELISA and multiplex assay. In conclusion, the present study showed that HMG extract is a potential anti-cancer agent and causes no harm to human immune cells. qRT-PCR, ELISA and multiplex tests also verified that HMG acts as an immunoadjuvant by enhancing pro-apoptotic function in the human immune cells.