Small interfering RNA silencing pituitary tumor transforming gene inhibits growth of human prolactin pituitary tumor cells

Objective To observe the effect of small interfering RNA (siRNA) silencing pituitary tumor transforming gene (PTTG) on the growth of primary cultured human prolactin pituitary adenoma cells (HPAs).Methods After the HPAs were primary cultured and steadily subcultured,the cells were divided into three groups:the blank control group,the negative control group and the siRNA-PTTG transfection group.After 48 h of infection,proliferation rate of HPAs was measured by using cell counting kit-8 (CCK-8).Transfection efficiency and the apoptosis rate were tested by using flow cytometry.The expression of PTTG mRNA and protein were detected by using reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting respectively.Caspase-3 activity was measured by Caspase activity assay kit.Prolactin changes in cell supernatants were measured by radioimmunoassay.Results Compared to the blank cotnrol group and the negative control group,the transcription of PTTG mRNA and the expression of PTTG protein were significantly down-regulated in the siRNA-PTTG transfection group,and the proliferation was suppressed [the inhibition rate in the negative control group and the siRNA-PTTG transfection group was (3.02 ± 1.77) ％ and (25.38 ± 0.11) ％ respectively (P ＜ 0.05),while the apoptosis was significantly increased [the apoptosis rate in the blank control group,negative control group and siRNA-PTTG transfection group was (6.21 ± 2.36) ％,(7.23 ± 3.56) ％ and (32.33 ± 5.69) ％ respectively (P ＜ 0.05).The activity of Caspase-3 was increased (P ＜ 0.05),and the radioimmunoassay revealed that the prolactin level in the cell supernatants was significantly decreased in the siRNA-PTTG transfection group,32.9％ of the blank control group (P ＜ 0.05).Conclusion Down-regulation of PTTG expression can suppress the proliferation and induce apoptosis of HPAs,which results in the reduction of prolactin secretion. Key words: Pituitary tumor transforming gene;  RNA interference;  Human prolactin pituitary gland tumor;  Apoptosis