Objective     To investigate the effects of 2 kinds of ω-3 polyunsaturated fatty acid

eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)

on the adhesion and invasion of PC-3

a high metastatic human prostate tumor cell line

and explore the possible mechanism.      Methods     MTT assay was used to determine the effects of EPA or DHA on the proliferation of PC-3 cells. Adhesion assay and invasion assay were used to observe the anti-adhesion and anti-invasion effects of EPA or DHA on PC-3 cells

respectively. RT-PCR analysis was conducted to detect the expression of RhoA

Rac1

Rac2 and Cdc42 mRNAs.       Results     Both EPA and DHA inhibited the growth of PC-3 cells in a dose-dependent manner. After treated with EPA or DHA of 60 μmol/L

the adhesion and invasion abilities of the cells were decreased. The adhesion rate were lesser than that of the control when adhered for 30

60

90 and 120 min on matrigel

and the invasion inhibitory rate were (35.65±7.76)% in EPA treated group and (41.32±5.86)% in DHA treated group (P＜0.01). The expressions of RhoA

Rac2 and Cdc42 in PC-3 cells were all decreased in compare with those of the control.      Conclusion     These results suggest that ω-3 PUFA can inhibit the adhesion and invasion of PC-3 cells by down-regulating the expression of the Rho GTPase.