Invasion of cancer cells into surrounding tissue is an initial step in tumor metastasis. This event, whichrequires migration of cancer cells and attachment to extracellular matrix (ECM), is regulated by elements ofthe local microenvironment, including ECM architecture.After having demonstrated the ability of the synthetic cannabinoid WIN55,512 to induce osteosarcomaMG63 cell death (1), we studied the effects of WIN on MG63 cell migration. Wound healing assay wasperformed to measure the ability of cells to migrate and fill the gap obtained by physical disruption of cellmonolayer (2). We observed a significant delay in wound closure in 5 M WIN treated cells compared tountreated cells that almost completed the healing in 24 hours (20% vs 87% of wound closure). The additionof conditioned medium obtained by confluent control cells to WIN treated cultures largely reverted thedelaying WIN action. To evaluate the influence of matrix metalloproteinases (MMPs) in the migratory ability,we analyzed MMP-2 and MMP-9 activities by zymography in WIN-treated culture medium. MMP-9zymographic activity was strongly lower in WIN-treated culture medium in comparison with medium fromcontrol cells, suggesting that WIN inhibits MMP-9 activity.Since it is known that cell/ECM interactions are mediated by SPARC (Secreted Protein Acidic and Rich inCysteine) that also modulates MMPs activity (3-4), we evaluated intra- and extracellular levels of SPARC inour experimental conditions. RT-PCR and western blotting analysis showed in WIN-treated cells an increaseboth in mRNA and protein expression of intracellular SPARC, while a decrease in extracellular protein levelwas observed. Studies are in progress to study the possible involvement of SPARC in MMPs activation andMG63 cell migration.
|Number of pages||1|
|Publication status||Published - 2014|