Abstract
Vitamin B6 is reported to have anti-tumorigenic effects, but the mechanism responsible is not well understood. We found that vitamin B6 activates p53, resulting in growth suppression and apoptosis in human breast cancer MCF-7 cells. Among the vitamin B6 analogs, pyridoxal has the strongest effect. Differences in the effects of these analogs may be related to differences in cell surface interactions. Pyridoxal was observed to show the strongest binding to the cell surface among the vitamin B6 analogs. Although epidemiological studies have shown that homocysteinemia is related to dementia, precisely how homocysteine induces dementia has not been clarified. Homocysteine is an amino acid and its metabolism requires vitamin B6, folate, and vitamin B12. We conclude that U-251MG glioma cells may secrete molecules that are cytotoxic to SH-SY5Y neuroblastoma cells upon stimulation with homocysteine. Epidemiological studies on the relationship between human plasma homocysteine concentrations and dietary habits in the Amami Islands, Kagoshima Prefecture, found that a high consumption of beans or eggs was related to lower homocysteine concentrations in men and postmenopausal women respectively.
