Inhibitory effects of c9, t11-conjugated linoleic acid on invasion of human gastric carcinoma cell line SGC-7901

Abstract

Aim: To investigate the effect of c9, t11-conjugated linoleic acid (c9, t11-CLA) on the invasion of human gastric carcinoma cell line and its possible mechanism of preventing metastasis.

Methods: Using reconstituted basement membrane invasion, chemotaxis, adhesion, PAGE substrate zymography and RT-PCR assays, we analyzed the abilities of invasion, direct migration, adhesion of intracellular matrix, as well as the activity of type IV collagenase and expression of tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 mRNA in SGC-7901 cells which were treated with gradually increased concentrations (25, 50, 100 and 200 micromol/L) of c9, t11-CLA for 24 h.

Results: At the concentrations of 200 micromol/L, 100 micromol/L and 50 micromol/L, c9,t11-CLA suppressed the invasion of SGC-7901 cells into the reconstituted basement membrane by 53.7 %, 40.9 % and 29.3 %, respectively, in comparison with the negative control. Only in the 200 micromol/L c9,t11-CLA group, the chemotaxis of SGC-7901 cells was inhibited by 16.0 % in comparison with the negative control. C9,t11-CLA also could inhibit the adhesion of SGC-7901 cells to laminin, fibronectin and Matrigel, increase the expression of TIMP-1 and TIMP-2 mRNA, and reduce type IV collagenase activities in the serum-free medium supernatant of SGC-7901 cells.

Conclusion: c9,t11-CLA can inhibit the invasion of SGC-7901 cells at multiple procedures in tumor metastasis cascade, which may be associated with the induction of TIMP-1 and TIMP-2 mRNA expression.

Figure 1

Effect of c9,t11-CLA on invasion of SGC-7901 cells detected by reconstituted basement membrane invasion assay (100 ×). A: There are more invading SGC-7901 cells in the nega-tive control group. B: There are less invading SGC-7901 cells in the 200 μmol/L c9,t11-CLA group.

Figure 2

Effect of c9,t11-CLA on chemotaxic migration of SGC-7901 cells detected by chemotaxied-motion assay (100 ×). A: There are more invading SGC-7901 cells in the negative con-trol group. B: There are less invading SGC-7901 cells in the 200 μmol/L c9,t11-CLA group.

Figure 3

Effect of c9,t11-CLA on the attachment ability of SGC-7901 cells.

Figure 4

Effects of c9,t11-CLA on Gelatinase secretion in SGC-7901 cells detected by zymography. A, B, C, D are 200 μmol/L, 100 μmol/L, 50 μmol/L, 25 μmol/L c9,t11-CLA, respectively. E is the negative control group.

Figure 5

Quantitation of 92 and 72 kDa type IV Collagenase levels in SGC-7901 cells by ChemiImager 4000. A, B, C, D are 200 μmol/L, 100 μmol/L, 50 μmol/L, 25 μmol/L c9,t11-CLA, respectively. E is the negative control group.

Figure 6

Effects of c9,t11-CLA on expression of TIMP-1 mRNA and TIMP-2 mRNA in SGC-7901 cells detected by RT-PCR. Top: Expression of TIMP-1 mRNA. Middle: Expression of TIMP-2 mRNA. A, B, C, D are 20 μmol/L, 100 μmol/L, 50 μmol/L, 25 μmol/L c9,t11-CLA, respectively. E is the negative control group.

Figure 7

Quantitation of TIMP-1 and TIMP-2 mRNA levels in the SGC-7901 cells by ChemiImager 4000. A, B, C, D are 200 μmol/L, 100 μmol/L, 50 μmol/L, 25 μmol/L c9,t11-CLA, respectively. E is the negative control group.