Effect of thymoquinone on head and neck squamous cell carcinoma cells in vitro: Synergism with radiation.

Thymoquinone (TQ) is the main bioactive constituent present in black seed oil (Nigella sativa); it has shown anti-inflammatory and anti-neoplastic effects in various cancer cell types. The aim of the present study was to investigate the effects of TQ on head and neck squamous cell carcinoma (HNSCC) cell lines, on its own and in combination with radiation and cisplatin, respectively. The SCC25 and CAL27 HNSCC cell lines were treated with TQ alone and in combination with cisplatin or radiation, respectively. Proliferation assays and clonogenic assays were performed. Apoptosis was detected by flow cytometry. TQ exhibited dose-dependent cytotoxicity via apoptosis in the investigated cell lines. In combination with cisplatin, TQ resulted in no significant increase in cytotoxicity. Combined with radiation, TQ significantly reduced clonogenic survival compared with each treatment method alone. TQ is a promising agent in the treatment of head and neck cancer due to its anti-proliferative and radiosensitizing properties. However, the combination of TQ with cisplatin showed no therapeutic benefit in vitro.

Radiosensitization of head and neck cancer cells by the phytochemical agent sulforaphane.

BACKGROUND AND PURPOSE: Sulforaphane is a naturally occurring compound found in broccoli and other cruciferous vegetables. Recently it gained attention because of its antiproliferative properties in many cancer cell lines. The aim of this study was to investigate whether sulforaphane could act as a radiosensitizer in head and neck squamous cell carcinoma cell lines. MATERIALS AND METHODS: Four head and neck squamous cell carcinoma cell lines (i.e., (HNSCC) SCC9, SCC25, CAL27, and FADU) were treated with sulforaphane and subsequently irradiated. Then proliferation and clonogenic assays were performed. Apoptosis was detected by flow cytometry. Possible regulation of Akt and Mcl-1 was investigated by western blotting. RESULTS: Sulforaphane and radiation in combination leads to stronger inhibition of cell proliferation and of clonogenic survival than each treatment method alone. Western blot analysis of Akt and Mcl-1 showed no changed expression. CONCLUSION: Sulforaphane is a promising agent in the treatment of head and neck cancer due to its antiproliferative and radio-sensitizing properties. A combination of sulforaphane and radiation decreases clonogenic survival. Apoptosis is not regulated through Akt or the Mcl-1 protein.