Histone Potentiates Inositol Hexakisphosphate in Inducing Apoptosis of HONE-1 Nasopharyngeal Cancer Cells

Abstract Inositol hexakisphosphate (InsP6) requires relatively high concentrations to induce apoptosis of cancer cells, which can possibly cause apoptosis of normal cells. Anticancer ability of InsP6 could be preserved by combining with histone, so InsP6 can be used at low concentrations. The effect of InsP6 and histone combination has not been investigated on nasopharyngeal cancer cells. The current study elucidated the effect of InsP6 and its combination with histone on the apoptosis of HONE-1 cells. The most effective concentration and the cellular mechanisms by which this combination exerts its anticancer effects were also investigated. HONE-1 and NIH3T3 cells (as normal control cells) were treated with InsP6 and/or histone in different concentrations. Apoptosis percentages of the treated cells were measured with sub-G1 assay. Nuclear fragmentation and mitochondrial membrane potential (∆Ψm) reduction in the treated HONE-1 cells were confirmed with 4',6-diamidino-2-phenylindole (DAPI) staining and ∆Ψm assay, respectively. The combination of 10 μM InsP6 and 10 μg/mL histone had the optimal ability to induce the apoptosis of HONE-1 cells. This combination did not induce apoptosis of NIH3T3 cells. The apoptosis-inducing ability of this combination was higher than that of 10 μM InsP6 merely. The ability of InsP6 to induce apoptosis of HONE-1 cells could be enhanced by histone application. Combination of 10 μM InsP6 and 10 μg/mL histone might be the optimal concentrations for inducing apoptosis in HONE-1 cells.