In vitro and in vivo assessment of high-dose vitamin C against murine tumors.

Vitamin C is widely used in clinical settings and is well known for its safety. Previous studies have shown the efficacy of intravenous vitamin C; however, intratumoral delivery of vitamin C has yet to be attempted. In the present study, the biological effects of high-dose vitamin C on tumor cells were investigated in vitro by using the MTT assay and flow cytometry. When administered in vitro, high-dose vitamin C inhibited the proliferation of murine colon and breast cancer cells, and induced tumor cell apoptosis. Cytotoxicity of vitamin C was partially reversed by N-acetyl-cysteine at a relatively low dosage. In addition, synergistic anti-tumor effects of vitamin C and cisplatin were observed. In vivo, intratumoral delivery of vitamin C delayed tumor growth in murine solid tumor models. Considering its low toxicity and availability, the present study indicates that vitamin C may be a novel therapeutic method for patients with advanced tumors.