Der Matrixmetalloproteinasen Inhibitor Actinonin hemmt die Tumorzellinvasion von CC531-Zellen ex vivo und reduziert die hepatische Metastasierung am Lebermetastasenmodell der Ratte in vivo

Abstract

The aim of the study was to examine the synthetic MMP inhibitor actinonin for its effect on the metastatic spread of CC531 tumor cells ex vivo and in vivo. Materials and methods: Ex vivo: Transwell filters (8 µm pore size, 6.5 mm Ø) were coated with 100 µl matrigel (B&D) and incubated up to gel formation. The matrigel-coated filters were each filled with 10⁴ CC531 cells. Either actinonin in various concentrations or 10% ethanol/saline (controls) was added to both sides of the filter and incubated for 24 h at 37 °C. The MMP’s - 2,3,9 and TIMP’s - 1,2 were then detected by RT-PCR on c-DNA of CC531 cells. In vivo: WAG rats (n = 10) were injected with 10⁶ CC531 cells via the intra-portal vein. Five animals (group I) were treated with actinonin (5 mg/kg BW/day i.p.) and five animals (group II) with the vehicle (50% ethanol/saline) 0-5 days after the intervention. Results: Ex vivo: In the controls (10% ethanol/saline), the CC531 cells easily penetrated the matrigel. The number of invading cells/controls decreased with increasing actinonin concentrations in the medium and stagnated at 50 µg/ml with 28.4% and 100 µg/ml with 28.2%. Since cell vitality was consistently > 92%, a direct toxic effect of actinonin could be excluded. RT-PCR on c-DNA of CC531 cells showed a MMP-9 expression relevant for the breakdown of matrigels. In vivo: Hepatic tumor replacement was < 25% in group I and 50 - 75% in group II 14 days after the intervention. Conclusions: Actinonin reduced ex vivo tumor cell invasion of CC531 cells by inhibiting the enzymatic breakdown of the basal-membrane-like matrigel and significantly decreased in vivo hepatic metastasis manifestation in the liver. Since MMP-9 inhibition seems to be of quantitative importance, selective inhibitors may be suitable for use in human colorectal liver metastases.