Biologic Effects Of Inositol Hexaphosphate (IP₆) On Human Colon Carcinoma Cell Line HT-29

Objective:To investigate the biological effects of inositol hexaphosphate(IP₆) on HT-29 human colon carcinoma cells and its mechanisms.Methods:1 HT-29 cells were treated with IP₆ in the same concentration(3.3mmol/L) during different time(3days,6months,12months),took the HT-29 cells without treatment of IP₆ as control.The effect of IP₆ on HT-29 cells' tumorigenic ability was evaluated by nude mice experiments.2 HT-29 cells were treated with IP₆ in the same concentration(3.3mmol/L) during different time(3days,6months,12 months),took the HT-29 cells without treatment of IP₆ as control.The cloning efficiency was detected by Double-layer soft agar culture;the IAP and LDH activity were assayed by Spectrophotometry;bcl-2 and c-Myc expression state in cells were determined by reverse transcription polymerase chain reaction(RT-PCR); the expression of PCNA and Cyt-c were detected by Immunocytochemical stain.Results:1 Nude mice experiment indicated a significant time-dependent tumorigenic ability inhibition was observed in IP₆-treated HT- 29 cells.2 Double-layer soft agar culture showed that the cloning efficiency decline in IP6 treated HT-29 cells.3 Spectrophotometry analysised that different time of IP₆ increased the activities of IAP and LDH(P<0.01),and indicate time-dependent effect.4 Reverse transcription polymerase chain reaction(RT-PCR) showed that IP₆ decreased the expression of bcl-2 and c-Myc mRNA of HT-29 cells(P<0.01),and indicate time-dependance.5 The immunocytochemical stain showed that different time of IP₆ decreased the expression of PCNA(P<0.05) and increased the expression of Cyt-c(P<0.01),and the effects are significant time-dependant.Conclusion:1 The results showed that IP₆ had a significant time-dependent inhibition effect on tumorigenic ability of HT-29 cells.2 IP₆ could inhibit HT-29 cell proliferation,decrease cloning efficiency and the level of PCNA expression,and all along with the extension of time the effect became more obvious.3 IP₆ can promote HT-29 cell differentiation,the role performanced in the cell colony-forming ability,cell differentiation-related gene c-Myc expression decrease and differentiation markers enzyme(alkalinephosphatase of intestinal) activity increase.The result shows obvious time-dependent tendency.4 IP₆ can promote HT-29 cell apoptosis,which may be inseparably related to the mitochondrial pathway of apoptosis,in which bcl-2,Cyt-c to participate,and it's closely related with the time.