Background/Aim: Organometallic complexes can decrease adhesion, migration, invasion of cancer cells, mainly through regulation of the extracellular matrix and therefore act against metastases. The aim was to investigate the anti-invasive properties of a rhenium-based metal compound, rhenium(I)-diselenoether (Re-diSe) and its effects on matrix metalloproteinase MMP-2, a key player in metastatic processes, in cultured MDA-MB231 triple-negative breast cancer cells. Materials and Methods: Matrigel was utilized to assess cancer cell adhesion to the extracellular matrix. Migration capacity was evaluated through the wound healing assay, while invasion assays were conducted using transwell invasion assay by the crystal violet dye. MMP-2 levels were quantified in the cell medium using a fluorometric kit assay. Cells were exposed to increasing concentrations of the drug (5, 10, 20, 50 and 100 mu M). Three time points of drug exposure on the cells were investigated (48, 96 and 120 h). Results: Re-diSe exhibited effectiveness even at doses as