ABSTRACT
Objective: Thymoquinone [TQ], as the main component of Nigella Sativa plant, shows anticancer properties. This study was aimed to evaluate the combined effect of TQ and Tamoxifen [TAM] on viability and apoptosis of human breast cancer cell lines
Materials and Methods: In this experimental study, estrogen positive MCF-7 and estrogen negative MDA-MB-231 human breast cancer cell lines were induced by TAM [2 microM] or different doses of TQ [50, 75, 100, 150 microM], individually or in combination. Cell viability and apoptosis were investigated by MTT assay and TdT-mediated deoxy-uracil nick end labeling [TUNEL] assay; Acridine orange [AO]/Ethidium bromide [EB] staining respectively. Data were analyzed by one way ANOVA and P<0.05 was considered significant
Results: In 24 hours treatment, TAM and all doses of TQ, solely or in combination, significantly reduced cell viability of both cell lines, except in MCF-7 cells treated with 50 microM TQ, and MDA-MB-231 cells treated with 50 or 75 microM TQ [P<0.01]. After 48 hours treatment, cell viability of both cell lines was reduced in all treated groups [P<0.05]. Remarkable apoptotic index was observed in combination treatment of MCF-7 or MDA-MB-231 cell lines with TAM and TQ [P<0.001]
Conclusion: The synergistic effect of TQ and TAM on human breast cancer cell lines showed cell viability reduction as well as apoptosis induction, independent to estrogen