Inhibitory effects of oleic and docosahexaenoic acids on lung metastasis by colon-carcinoma-26 cells are associated with reduced matrix metalloproteinase-2 and -9 activities

Effects of carp and tuna oils on 5-fluorouracil-induced antitumor activity and side effects in sarcoma 180-bearing mice

In this study, we examined the effects of fish oils on 5-fluorouracil (5-FU)-induced antitumor activity in mice. First, we examined the antitumor activity of the oral administration of two fish oils (carp oil and tuna oil) in sarcoma 180-bearing mice. Carp oil (0.2 and 0.4 mL/mouse) and tuna oil (0.2 and 0.4 mL/mouse) had no effects on tumor growth. Next, we examined the combined effects of 5-FU plus two fish oils (carp oil and tuna oil) on the antitumor activity and side effects compared to the effects of 5-FU alone (12.5 mg/kg/d). We found that carp oil (0.4 mL/mouse) or tuna oil (0.2 or 0.4 mL/mouse) enhanced the ability of 5-FU (12.5 mg/kg/d) to prevent tumor growth, without increasing side effects such as myelotoxicity and immunocompetent organ toxicity. Tuna oil (0.2 mL/mouse) slightly reduced body weight as compared to the effects of 5-FU alone and water alone (control). The area under the curve (AUC) (0-120 min) of blood 5-FU levels was reduced by the oral co-administration of 5-FU with carp oil or tuna oil. Apparent Tmax was shortened by the oral co-administration of 5-FU with carp oil or tuna oil. On the other hand, AUC (0-4 h) of 5-FU incorporation into tumor RNA fraction was not affected by the oral co-administration of 5-FU with carp oil or tuna oil.

Influence of oleic acid on the expression, activation and activity of gelatinase A produced by oncogene-transformed human bronchial epithelial cells

Invasiveness and metastatic capacity of tumor cells have been related to increased expression and activation of gelatinase-A (MMP-2). 9-octadecenoic acid (oleic acid, OA), a long-chain cis-unsaturated fatty acid, has been shown to partially inhibit the formation of lung metastatic colonies in an ex vivo model of implantation of metastatic cells into nude mice. Reduction of metastasis formation was suggested to be due to a decrease of MMP-2 activity in tumor tissue extracts. Since regulation of MMP-2 activity occurs at different levels, including gene expression, pro-enzyme activation and finally active enzyme inhibition, we here investigated the precise level of the inhibitory effect of OA on MMP-2 activity by oncogene-transformed human bronchial epithelial cells (BZR cells). OA, at the dose of 5 x 10(-5) M, was shown to inhibit by 50% MMP-2 activity released from BZR cells. Northern-blot analysis of mRNA encoding MMP-2, MT1-MMP, the physiological activator of MMP-2, and TIMP-2, the natural inhibitor of MMP-2, revealed that OA did not alter the steady-state levels of MMP-2, MT1-MMP and TIMP-2 mRNA. Also, gelatin zymography demonstrated that the extent of MMP-2 activation was not modified by OA treatment. On the contrary, OA could inhibit the fluorogenic quenching substrate (7-methoxycoumarin-4-yl)acetyl-L-Pro-Leu-Gly-Leu-[N-3-(2,4-dinitrophenyl)-L-2, 3-diaminopropionyl]-Ala-Arg-NH2 (Mca-Pro-Leu-Gly-Leu-Dpa-Ala-Arg-NH2) hydrolysis by recombinant MMP-2 with Ki = 4.3 microM. These data suggest that the beneficial influence of OA on the formation of lung metastatic colonies was independent of its influence on MMP-2 expression and/or activation, but could be attributed to inhibition of MMP-2 activity.