Nutr Res Pract.  2007 Sep;1(3):195-199.

Apoptotic effect of IP6 was not enhanced by co-treatment with myo-inositol in prostate carcinoma PC3 cells

• Kim HJ
• Jang YM
• Kim H
• Kwon YH

Abstract

Inositol hexaphosphate (IP6) is a major constituent of most cereals, legumes, nuts, oil seeds and soybean. Previous studies reported the anticancer effect of IP6 and suggested that co-treatment of IP6 with inositol may enhance anticancer effect of IP6. Although the anticancer effect of IP6 has been intensively studied, the combinational effect of IP6 and inositol and involved mechanisms are not well understood so far. In the present study, we investigated the effect of IP6 and myo-inositol (MI) on cell cycle regulation and apoptosis using PC3 prostate cancer cell lines. When cells were co-treated with IP6 and MI, the extent of cell growth inhibition was significantly increased than that by IP6 alone. To identify the effect of IP6 and MI on apoptosis, the activity of caspase-3 was measured. The caspase-3 activity was significantly increased when cells were treated with either IP6 alone or both IP6 and MI, with no significant enhancement by co-treatment. To investigate the effect of IP6 and MI of cell cycle arrest, we measured p21 mRNA expression in PC3 cells and observed significant increase in p21 mRNA by IP6. But synergistic regulation by co-treatment with IP6 and MI was not observed. In addition, there was no significant effect by co-treatment compared to IP6 treatment on the regulation of cell cycle progression although IP6 significantly changed cell cycle distribution in the presence of MI or not. Therefore, these findings support that IP6 has anticancer function by induction of apoptosis and regulation of cell cycle. However, synergistic effect by MI on cell cycle regulation and apoptosis was not observed in PC3 prostate cancer cells.

Keyword

Inositol hexaphosphate; myo-inositol; apoptosis; prostate cancer; cell cycle progression

MeSH Terms

Apoptosis
Caspase 3
Cell Cycle
Cell Cycle Checkpoints
Cell Line
Edible Grain
Fabaceae
Inositol
Nuts
Phytic Acid
Prostate*
Prostatic Neoplasms
RNA, Messenger
Soybeans
Caspase 3
Inositol
Phytic Acid
RNA, Messenger

Figure

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  Fig. 1 Effects of IP6 and MI on inhibition of PC3 cell growth. Twenty-four hours after plating, cells were treated with IP6, MI, or IP6 plus MI at concentrations as described for 48 h. After treatment, cells were harvested and cell numbers were estimated by trypan blue exclusion method. Each bar represents mean ± SEM (n=3) and bars with different superscripts are significantly different at p<0.05.

• 

  Fig. 2 Effects of of IP6 and MI on apoptosis of PC3 cells. Twenty-four hours after plating, cells were treated with IP6, MI, or IP6 plus MI at concentrations as described for 48 h. Caspase-3 activity was measured using colorimetric assay kit and the resulting data is expressed as percentage of the control value. Each bar represents mean ± SEM (n=3) and bars with different superscripts are significantly different at p<0.05.

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  Fig. 3 Effects of IP6 and MI on the p21 mRNA expression. Twenty-four hours after plating, cells were treated with IP6, MI, or IP6 plus MI at concentrations as described for 48 h. (A) Representative photographs of 3 independent experiments are shown. (B) The relative abundance of p21 was quantified with the control level set at 100%. Each bar represents mean ± SEM (n=3) and bars with different superscripts are significantly different at p<0.05.

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