【Objective】 To explore the effect of PRL-3 on proliferation and invasion of colon cancer cells through PI3K signal pathway. 【Methods】 We stably transfected PRL-3 expressing plasmid and empty plasmid into LoVo colon cancer cells and established two cell lines: LoVo-PRL-3 and LoVo-VC. We used qRT-PCR and Western blot to detect the expression of miR-21 and PTEN protein in these colon cancer cell lines. Transient transfection of miR-21mimic into LoVo-VC cells or transient transfection of miR-21 inhibitor into LoVo- PRL-3 cells were performed to evaluate the proliferation and invasive ability of these cells by CCK8 proliferating assay and transwell chamber assay. 【Results】 PRL-3 promoted proliferation and invasion of LoVo- PRL-3 cells compared with LoVo-VC cells. In LoVo- PRL-3 cells

miR-21 was up-regulated and PTEN was down-regulated. Over-expression of miR-21 promoted proliferation and invasion of LoVo-VC cells and down-regulated PTEN

while knocking down of miR-21 or over-expression of PTEN inhibited proliferation and invasion of LoVo-PRL-3 cells and restore the expression of PTEN. 【Conclusions】 Down-regulation of PTEN through up-regulating of miR-21 by PRL-3

which cumulating in enhancing signal of PI3K pathway

promoted proliferation and invasion of colon cancer cells.