ROLE OF AUTO FLUORESCENCE IN APOPTOSIS ANALYSIS OF MCF-7 AND MDA-MB231 HUMAN BREAST CARCINOMAS TREATED WITH THYMOQUINONE

Thymoquinone (TQ) is the major active component of black seed essential oil which possess encouraging effects against cancer cells. The antitumor activities of TQ were verified in breast carcinoma in-vitro and in-vivo. Most of the times, the cellular responses to apoptosis, after TQ treatment, are evaluate by flow cytometry using annexin V-propidium iodide (PI) staining method. Although flow cytometry has become an important tool to study characteristics of individual cells but induction of auto fluorescence (AF) can decreases the technique sensitivity. In order to investigate the effect of TQ on AF induction, we assessed the fluorescence after TQ treatment. We present evidences suggesting that the change in AF is depend on cell type and TQ concentration. We show here, MDA-MB231 breast cancer cell line treated with different concentration of TQ exhibits elevated level of auto fluorescence (AF) when analyzed by flow cytometry. Consistent with this view, MCF-7 cells did not show any AF upon TQ treatment, in contrast to MDA-MB231. Finally, we presents data demonstrating that changes in AF can affect the flow cytometry results and confound the findings obtained with common dyes using for apoptosis investigation. Conclusively the effect of TQ treatment on AF induction should be considered when we want survey apoptosis effect on breast cancer cells.