Acar, MuradiyeGunduz, MehmetOcak, TarikGurses, Hacer EsraCetin, Elif NihanCeylan, Furkan SacitSefa, Alperen2025-10-242025-10-2420150147-958X1488-2353https://hdl.handle.net/20.500.12899/4220Purpose: A subpopulation of cancer stem cells (CSCs) in head and neck squamous cell carcinoma (HNSCC) play a critical role in invasion, metastasis, and tumour recurrence post-therapy. 5-Fluorouracil (5-FU) is a pyrimidine analogue that is used in the treatment of HNSCC. Thymoquinone (TQ), found in Cumin (Nigella sativa) seed oil, has anti-diabetic, anti-oxidant, anti-inflammatory, and antitumour effects. The purpose of this study was to examine the effects of 5-FU and TQ on CSCs. Methods: ALDH1 (+) cells were isolated from the HNSCC cell line UT-SCC-74A using magnetic activated cell sorting (MACS) and sphere formation was confirmed. Real-time RTPCR revealed was used to measure expression levels of a number of stem cell markers, including OCT4, SOX2, and KLF-4. To investigate the effects of the therapeutic agents, 5-FU and TQ, concentration-dependent assay procedures were used and cell viability after treatment was measured using XTT assay. Results: ALDH1 (+) cells formed spheres while the ALDH1 (-) cells did not. Real-time RT-PCR revealed that a number of stem cell markers, including OCT4, SOX2, and KLF-4, were up-regulated in the CSCs. XTT results showed that, when given alone at a dose of 50 ng/mL, neither agent had a statistically significant cytotoxic effect on CSCs. However, when dosed in combination, TQ and 5-FU had a synergistic effect on CSC cytotoxicity. Conclusion: We report the effects of TQ and 5-FU on CSCs in HNSCC.eninfo:eu-repo/semantics/closedAccessCarcinomaArticle384E209E2132-s2.0-84939126099Q2WOS:000359119100011Q4