Abstract
Background:
5-FU is an antimetabolic agent used for treating slowly growing solid tumors like breast and ovarian carcinoma. Thymoquinone (TQ) is a main biologically active constituent of Nigella sativa, it has been found to demonstrate anticancerous effects in several preclinical studies, and this is because TQ possesses multi-target nature. Stem cells-derived exosomes are in the spotlight of research and are promising tissue regenerative and anticancer cell-derived nanovesicles.
Aim:
Herein, we studied the antineoplastic effects of Exosomes derived from mammary stem cells (MaSCs-Exo) on breast cancer cells, alone or combined with TQ when compared to a breast cancer chemotherapeutic agent; 5-FU.
Methods:
Our approach included performing viability test and measuring the expression of pro-apoptotic gene (Bax), anti-apoptotic gene (BCL-2) and angiogenic gene (VEGF) on Human MCF-7 cells (breast adenocarcinoma cells), the MCF-7 cells were cultured and incubated with medium containing 5-FU (25 μg/mL), Thymoquinone (200 μg/mL), MaSCs-Exo (100 μg protein equivalent), a combination of TQ (200 μg/mL) and MaSCs-Exo (100 μg).
Results:
Our obtained results show that TQ and MaSCs-Exo each can effectively inhibit breast cancer cell line (MCF-7) proliferation and growth. Also, the results show that the combination of TQ and MaSCs-Exo had higher cytotoxic effects on MCF-7 breast cancer cells than TQ or 5-FU, alone.
Conclusion:
The present study shows promising anticancer potential of exosomes isolated from mammary stem cells; this effect was potentiated by adding thymoquinone with MaSCs-derived exosomes.

Key words: Mammary stem cells, 5-fluorouracil, Apoptosis, Breast cancer, Anti-tumor