RNA interfering PI3Kp110β increases the sensitivity of fluorouracil induced apoptosis in human gastric cancer cells

Objective To study the effect of PI3Kp110β silencing on enhancing the ability of fluorouraci(lFU)to induce the apoptosis of human gastric cancer cells in vitro. Methods RNA interfering the sequence targeted by PI3Kp110β was transfected into lenti-virus carrier(LV-sh PI3Kp110β)and then it infected AGS gastric cancer cells for 72 hours(sh-PI3Kp110β group). Other two groups including uninfected cells(Con group)and lenti-virus containing nonsense sh RNA sequence(LV-sh NC)infected cells(sh-NC group). The efficiency of infection was observed by fluorescence microscope. The m RNA and protein expression of PI3Kp110β were determined by reverse transcriptase polymerase chain reaction(RT-PCR)and Western blotting. The stable cells of PI3Kp110β silencing expression and NC by lentivirus-mediated RNA interference were selected by puromycin. Then two groups of stable lentivirus infected cells(sh-PI3Kp110β and sh-NC)and Con group were treated with different concentrations of FU for 24 h,48 h and 72 h,respectively. Cellular proliferation of each group was measured by MTT assay. Western blotting was used to determine the relative signal molecules it may concern after the three groups was treated with or without FU for 72 h. Results Compared with Con and sh-NC groups,the expression level of PI3Kp110β was downregulated significantly in sh-PI3Kp110β group in AGS cell lines after LV-sh PI3Kp110β affected the cells 72 hours later. The stable cells of PI3Kp110β silencing expression and NC were selected. FU could inhibit the proliferation of AGS cell lines,with concentration dependence in three time points. Silencing of PI3Kp110β expression in AGS cells could improve the inhibitory effect by FU. Also,downregulation of PI3Kp110β expression by RNA interference in AGScells significantly increase the ability of FU inducing the cleavage of PARP and inhibited the expression of Bcl-2 and PI3Kp110β to induce cell apoptosis. Conclusion The expression of PI3Kp110β in gastric cancer cells were effectively decreased with RNA interference by lentivirus. Silencing PI3Kp110β expression can enhance the ability of 5-FU to inhibit cell growth and improve cell apoptosis,which may associated with activation of some apoptosis signal molecules.