Phosphatidylinositol 3-kinase Inhibitor LY294002 Suppresses Proliferation And Sensitizes Doxorubicin Chemotherapy In Bladder Cancer Cells

Aim of this study: The phosphatidylinositol 3-kinase (PI3K) and its downstream AKT kinase have been implicated in control of major cellular responses to extracellular growth stimulation, including cell proliferation, development, differentiation, cell cycle, migration and apoptosis. In the present study, we examined whether inhibition of PI3K by LY294002 had effects on human bladder cancer cells and documented the findings that PI3K inhibitor LY294002 sensitized doxorubicin chemotherapy in human bladder cancer cell with induced apoptosis. Method: After treated with LY294002, EJ cells were conducted in MTT assay, chemosensitivity test, colony formation assay, apoptosis assay and Western blot analysis.Results: 1.The cells were treated with PI3K inhibitor LY294002 (0-50μM) for 12-48h. After treated with LY294002 12-48h, MTT was conducted. MTT assays revealed that the rate of inhibition rose when the incubation time was prolonged. LY294002 suppressed EJ viability in a dose- and time-dependent fashion.2. This assay was designed to evaluate the antiproliferative effect of LY294002 on EJ cells. Treated with LY294002 (0-50μM) for 7 days, the colony-formation efficiency of EJ cells were 61.1±1.5% at 10μM, 55.7±1.81% at 20μM, 14.7±0.69% at 30μM, 12.7±0.36% at 40μM and 0 at 50μM.The EJ cells colony-forming efficiency decreased, when the concentration of LY294002 in the culture medium increased.3. Cells were treated with LY294002 at various concentration (0, 5, 10, 20μM) and doxorubicin (2.0μg/mL). After48h, apoptosis assay was conducted to test the apoptotic indices. The cells which were treated with 5, 10, 20μM LY294002 showed an increased number of apoptotic cells compared with the control. After 48h incubation, LY294002 promoted doxorubicin-induced apoptosis in a dose-dependent manner. The apoptotic indices were significantly increased in the 10 and 20μM LY294002-treated cultures compared with the control culture (15.4±4.3% and 36.9±3.3%, respectively, versus 6.2±2.9%, P < 0.01).4. Cells were treated with LY294002 at various concentration (0, 10, 30,50μM) and doxorubicin (2.0μg/mL). The cell growth suppression was measured at 48h by MTT assay. The suppression rate in cells treated with LY294002 at 10, 30 and 50μM were higher than control (LY294002 0μM). IC50 at 10, 20 and 30μM were decreased.Conclusions:In present study, we showed the evidence that that the PI3K/Akt signaling inhibitor LY294002 suppressed bladder cancer cells proliferation and enhanced chemosensitivity of doxorubicin in human bladder cancer EJ cells.