Inhibitory effects of dietary glucosylceramides on squamous cell carcinoma of the head and neck in NOD/SCID mice

Sphingolipids, components of cellular membranes in eukaryotic cells, have roles in the regulation of tumor growth, inflammation, angiogenesis, and immunity. We investigated the effects of dietary glucosylceramides, sphingolipids isolated from rice bran, on tumor growth of human head and neck squamous cell carcinoma. The tumor cell line SCCKN cells isolated from well-differentiated human head and neck cancer were subcutaneously inoculated into the right flank of NOD/SCID mice, to establish an SCCKN xenograft model. Rice bran glucosylceramides (300 mg/kg/day) were administered orally to the mice for 14 consecutive days. Dietary glucosylceramides significantly inhibited the growth of the xenograft tumor in comparison with the control group. The TUNEL stain revealed that treatment of mice with glucosylceramides increased the number of apoptotic cells in the implanted tumor tissues and that apoptosis induction was accompanied by the formation of active/cleaved caspase-3. These results suggest that dietary glucosylceramides possibly exert anti-tumor activity by inducing apoptosis of head and neck squamous cell carcinoma. Therefore, their potential usefulness in treatment and prevention of human head and neck squamous cell carcinoma warrants further investigation.