Abstract
Head and neck squamous cell carcinomas (HNSCCs) are known for their aggressive growth and propensity to metastasize. The authors investigated the effect of a novel nutrient mixture (NM) containing ascorbic acid, lysine, proline, and green tea extract on human HNSCC cell line FaDu in vivo and in vitro. Athymic male nude mice (n = 12) were inoculated with 3 × 106 FaDu cells subcutaneously and randomly divided into 2 groups: group A was fed a regular diet and group B a regular diet supplemented with 0.5% NM. Four weeks later, the mice were sacrificed and their tumors were excised, weighted, and processed for histology. In vitro, FaDu cells were cultured in Dulbecco's modified Eagle's medium and exposed to NM at 0 to 1000 µg/mL in triplicate. Cell proliferation was assessed by MTT assay, matrix metalloproteinase (MMP) secretion by gelatinase zymography, invasion through Matrigel, apoptosis by live-green caspases, and cell morphology by hematoxylin—eosin staining. NM inhibited the growth of tumors by 55% (P = .0002) and exhibited dose-dependent toxicity on FaDu cells in vitro, with 53% (P = .0003) at 1000 µg/mL NM. Zymography revealed MMP-2 and phorbol 12-myristate 13-acetate—induced MMP-9 secretion. NM inhibited secretion of both MMPs in a dose-dependent manner, with virtual total inhibition at 1000 µg/mL. NM significantly inhibited FaDu invasion through Matrigel with total block at 1000 µg/mL. NM induced dose-dependent apoptosis. In conclusion, NM has therapeutic potential in the treatment of HNSCC by significantly suppressing tumor growth and significantly inhibiting MMP secretion and invasion of HNSCC cells in vitro.