Objective      To study the PTP4A1 gene expression silenced by lentiviral vector-mediated siRNA and the effect on biological behavior in human tongue squamous cancer cell line TCA8113.       Methods      T

he cells were divided into three groups including a KD group (TCA8113 cells treated with siRNA-PTP4A1)

a NC group (TCA8113 cells treated with empty lentivirus)

and a CON group (TCA8113 cells without treatment). Real-time PCR and Western blotting were applied to detect the expression of PTP4A1. MTT assay was used to detect the inhibition of cell proliferation. Flow cytometry was performed to detect the cell apoptosis and cell cycle. Bcl-2 and Bax protein expression levels were detected by Western blotting. Clone formation was measured by plate clone forming test. Cells were subcutaneously injected into nude mice to induce  tumors.       Results      In the KD group

the inhibitory rates of mRNA and protein of PTP4A1 were above 55% and 60% (

P

0.05). The cell proliferation was significantly suppressed in the KD group compared with the NC group and CON group. The cell apoptotic rate in the KD group [(17.48±0.70)%

]

was significantly higher than that in the NC group [(7.34±0.70)%

]

and CON group [(4.86±0.25)%

]

(

P

0.01)

and the cells in the KD group were arrested at G

1

/G

0

phase and S phase (

P

0.05). Western blot results showed that Bcl-2 protein expression level decreased (

P

0.01)

but Bax protein expression level increased (

P

0.01). Compared with the NC group and CON group

the clone formation ability of the cells in vitro (

P

0.01) and the tumor growth in nude mice in vivo decreased significantly in the KD group (

P

0.01).       Conclusion      Silencing PTP4A1 expression is effective in inhibiting tumor biological behavior in human tongue squamous cancer cell line TCA8113 in vivo and in vitro. PTP4A1 may play an important role in the development of human tongue squamous cell carcinoma.