At the same time, we explored whether caspase 9 was involved in LY294002 induced cell apoptosis in CNE 2Z cells by detecting caspase 9 activity in cells treated with PI3K/ Akt inhibitor. The results show caspase 9 activity in CNE 2Z cells was up regulated by LY294002, whereas the level of caspase 9 was not changed after using ZVAD. Effects of PI3K/Akt inhibition proliferation and apoptosis in vivo Tumors generated by orthotopic implantation of the met astatic CNE 2Z cell line were used to evaluate the effect of LY294002 on proliferation and apoptosis in an orthoto pic xenograft model. All of the mice were sacrificed after 4 weeks of treatment. Treatment with LY294002 significantly reduced mean NPC tumor burden as compared with the control group.

Treatment with 10 mg/kg or 25 mg/kg LY294002 was less effective in decreasing tumor burden. Mean NPC tumor burden treated with LY294002 was remarkably decreased in a dose dependent manner, whereas mean body weight was no obvious dif ference between control and treated groups. Compared with control, TUNEL positive cells treated with LY294002 were significantly increased in a dose dependent fashion, with signif icant difference. Immunohistochemical studies for xenograft tumor tissues Finally, the histological examination and immunohisch emistry were performed to determine the biological influence of LY294002 on tumor morphology, prolifera tion, apoptosis, and expression of Akt, phosphorylated Akt. The histological changes showed that tumor cells of treated groups were more necrosis than those of control group.

Compared with control group, the expression of phosphorylated Akt was significantly decreased in treated with LY294002. Results of immunohistochemical staining with Ki67 and caspase 9 support the gross observations. A great many of NPC cells from the control group stained positive Ki67. Dacomitinib The number of proliferation cells treated with LY29400 showed significant reduction in a dose depen dent manner, with significant difference. The expression of caspase 9 appeared to have an obvious increase in the groups treated with LY294002. No significant difference was found between the expression of Akt in tumor from the control and LY294002 treated mice. Discussion The PI3K/Akt cascade is known to be an important sur vival factor in the signal transduction cascades involved in the cell survival and apoptosis. PI3K is one of the core intracellular signaling molecules in the stimulation of growth factors, subsequently phosphorylating and acti vating Akt. This signaling pathway cascades activated by some other factors play a critical role in regulating tumor cell growth, survival, motility, invasion, and differentia tion.