In vitro regulation of cell growth and angiogenesis by inositol hexaphosphate in bladder cancer.

BACKGROUND: Inositol Hexaphosphate (IP6) is a naturally occurring polyphosphorylated carbohydrate that is found in food sources high in fiber content. We hypothesized that IP6 would inhibit the cell growth rate of bladder cancer in vitro. METHODS: T24 and TCCSUP bladder cancer cell lines were treated with titrating doses of IP6 (0.3, 0.6 and 0.9 mM/well). Cell viability and vascular endothelial growth factor levels were measured. RESULTS: Significant reductions (p < 0.001) in cellular growth were noted in both cell lines at all doses and time points tested, with the exception of 0.3 mM IP6 at 24 hours in the T24 cell line. The percent inhibition of vascular endothelial growth factor was significantly higher than that observed in the TCCSUP cell line at 48 and 72 hours with 0.3 mM IP6 (p < 0.001). The T24 cells exhibited the same level of inhibition at 24 and 48 hours with 0.6 mM dose of IP6 and at 72 hours with the 0.3 mM dose (p < 0.001). CONCLUSIONS: In vitro treatment of bladder cancer with the common dietary polyphosphorylated carbohydrate IP6 significantly decreased cellular growth by anti-angiogenic mechanisms. We feel that this data warrants further investigation and consideration for initiation of clinical trials to evaluate the safety and clinical utility of this agent.