Effects of inositol hexaphosphate on proliferation of human osteosarcoma cell line MG-63 and primary cultured osteoblasts / 西安交通大学学报(医学版)

Objective To investigate the effects of inositol hexaphosphate (IP6) on proliferation of human osteosarcoma cell line MG-63 and primary cultured osteoblasts so as to explore the optimal concentration for achieving anti-cancer effects.Methods We primary cultured and identified human osteoblasts.Then we made recovery and normal culture of human osteosarcoma cell line MG-63.We tested the proliferation of two kinds of cell lines under different concentrations of IP6 by MTT to determine the optimal concentration and then detected MG-63 cell cycle and apoptosis by flow cytometry.Results When IP6 concentration was more than 1 mmol/L,IP6 began to inhibit the proliferation of MG-63 cell line in the time-dose dependent manner.When the concentration reached 4 mmol/L,this inhibitory effect was the maximum.When IP6 concentration was 0.5 mmol/L or 1 mmol/L,the proliferation of osteoblasts was not obviously inhibited.When it was 2 mmol/L,the proliferation was slightly inhibited.A concentration of 4 mmol/L caused the apoptosis of osteoblasts.Conclusion IP6 can inhibit the proliferation of osteosarcoma cell line MG-63 and lead to its apoptosis.The optimal concentration is 2 mmol/L for achieving anti-cancer effects.

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

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.

Effects of Dietary Proteins and Inositol Hexaphosphate on the Preneoplastic Lesions and Antioxidant Enzymes of Hepatocellular Carcinogenesis in Rats / 대한지역사회영양학회지

Six-week-old Sprague Dawley rats were fed the diets of 20% casein or soy protein. Two weeks after the feeding, hepatocellular chemical carcinogenesis was initiated by diethylnitrosamine(DEN), and promoted by the diet containing 0.01% 2-acetylamino-fluorene(AAF) and two-thirds partial hepatectomy(PH). The animals were sacrificed at 8 weeks after the DEN injection. The area of placetal glutathione S-trnasferase(GST-P) positive foci, the activities of several enzymes in cellualr antioxidant enzyme systems and glucose 6-phosphatase were determined to investigate the mechanism of the anticarcinogenic effect by the dietary proteins. In another set of experiments, the drinking water of rats fed casein was supplemented with 1.5% inositol hexaphosphate(InsP6) to elucidate whether it has the comparable anticancer action of soy protein. The area and number of GST-P positive foci in the soy protein group were significantly(p<0.05) lower than those inthe casein group. The livers of rats fed casein showed moderate fattydegeneration and larger hyperplastic nodules than those of rats fed soy protein. In another set of experiments, the area and number of GST-P positive foci in the rats fed casein supplemented with InsP6 were not significantly different from those in the rats fed casein or soy protein. The lipid peroxidation of rats fed different protein sources showed no significant difference. Glutathione S-transferase(GST) activities were increased significantly(p<0.05) by carcinogen treatment in all dietary groups. Glucose 6-phosphatase(G6Pase) activities were decreased by carcinogen treatment, and hence showed a reverse relationship(r=-0.695, p<0.01) to the GST-P positive foci. Therefore, the activities in the rats fed casein were lower than those in the rats fed soy protein. These results suggest that the soy protein seems to be more anti-carcinogenic than casein by decreasing the preneoplastic lesion and by increasing the membrane stability but inositol hexaphosphate, a component of soy protein, may not be protective against hepatocarcinogenesis.

THE EXPERIMENTAL STUDY OF CELL-INDUCED DIFFERENTIATION BY INOSITOL HEXAPHOSPHATE IN HT-29 HUMAN COLON CARCINOMA CELL LINE / 营养学报

Objective To investigate the effects and mechanisms of inositol hexaphosphate on diffe-rentiation of HT-29 human colon carcinoma cell line. Method Cells were exposed to various concentrations (control,1.8 mmol/L,3.3 mmol/L) of IP6 for different time (1d,3d,5d). Its effects on the cells were evaluated by detecting follow indices:(1) Observing ultrastructure of HT-29 cells by transmission electron microscopy. (2) Detecting alkaline phosphate (ALP) activity to evaluate cell differentiation. (3) Expression of c-Myc mRNA was determined by reverse transcription polymerase chain reaction (RT-PCR). (4) Immunocytochemical stain was used to detect expression of Rb protein. Results (1) After having been treated at 3.3mmol/L concentration,the cell structure changed,and appeared tendency of differentiation,such as karyopyknosis,abundant cellular organs and microvillus increase. (2) The activity of alkaline phosphate increased along with the concentration and time. (3) RT-PCR showed that different concentrations of IP6 decreased the expression of c-Myc mRNA. (4) The immunocytochemical stain showed that different concentrations of IP6 increased expression of Rb protein. Conclusion IP6 can induce differentiation of HT-29 cell by augmenting expression of Rb,decreasing expression of c-Myc and blocking cell cycle.

EFFECTS OF INOSITOL HEXAPHOSPHATE (IP_6) ON CELL CYCLE OF HT-29 HUMAN COLON CARCINOMA CELL LINE / 营养学报

Objective: To investigate the effects and mechanisms of inositol hexaphosphate(IP6)on cell cycle of HT-29 human colon carcinoma cell line. Method: HT-29 cells were exposed to various concentrations of IP6 for certain time. The effect of IP6 on cells proliferation was evaluated by MTT assay. Flow cytometric analysis was performed for cell cycle progression. Immunocytochemical stain was used to detect the expression of p53 and p21 protein. Results: A significant dose-dependent as well as time-dependent growth inhibition was observed in IP6-treated HT-29 cells, and associated with an increase in G1 arrest; Different concentrations of IP6 decreased the abnormal expressions of p53 gene and strongly increased the expression of p21. Conclusions: IP6 had an inhibitory effect on proliferation of HT-29 cells .and its mechanisms might be related to many factors, such as inhibiting the abnormal expression of p53 gene, inducing the expression of cell cycle inhibitor p21 which block the cell cycle.

EFFECT OF DIETARY FIBER AND PHYTIC ACID ON 1,2-DIMETHYLHYDRAZINE INDUCED COLORECTAL CARCINOGENESIS / 营养学报

Objective: To evaluate the effect of dietary fiber and phytic acid inositol hexaphosphate (IP6 or Insp6) on 1,2-dimethylhydrazine(DMH) induced colorectal carcinogenesis in Wistar rats. Methods: 86 four-week-old male Wistar rats were divided randomly into 6 groups and fed with either basal fiber free diet or the basal diet supplemented with 10% pectin, 10% cellulose, 2% Na-InsP6 supplemented water, 10% pectin in combination with 2% Na-InsP6 supplemented water, 10% cellulose in combination with 2% Na-InsP6 supplemented water. After four weeks, the rats were given a weekly injection of DMH (20mg/kg bw) for 20 weeks. The rats were killed after 26 weeks. The number of total macroscopically visible neoplasms was counted and the volume of individual neoplasmas was calculated. Proliferation cell nuclear antigen (PCNA) was analyzed. Results: There was no significant difference between the treatment group and the control group in the incidence of tumors. InsP6 significantly reduced the number of tumors in rats and tumor volume. Pectin and Pectin+InsP6 significantly increased the number of tumors in rats. The expression of proliferation marker PCNA was significantly down-regulated by InsP6 and significantly increased by pectin. Conclusion: A treatment regimen of 2% Na-InsP6 in drinking water was effective in significantly reducing the risk of colorectal cancer in Wistar rats. Diet supplemented with pectin could increase the risk of colorectal cancer.