Elevated hydrostatic pressure promotes ameloblastoma cell invasion through upregulation of MMP-2 and MMP-9 expression via Wnt/β-catenin signalling.

BACKGROUND

The process of marsupialization involves the release of intracystic pressure and the fluid contained within. Marsupialization of cystic ameloblastoma is controversial; therefore, we investigated how hydrostatic pressure influences biological behaviours of ameloblastoma cells and its underlying mechanisms.

MATERIALS AND METHODS

An ameloblastoma epithelial cell line, hTERT -AM, was exposed to different hydrostatic pressures with or without Dickkopf-related protein 1 (also known as DKK), a canonical Wnt signalling pathway inhibitor. A CCK-8 assay, a monolayer wound assay, and a Transwell assay were used to determine cell proliferation, migration and invasion, respectively. qRT-PCR and Western blot were used to detect expression of MMP-2, MMP-9, RANKL and other downstream targets of Wnt signalling.

RESULTS

Elevated hydrostatic pressure promoted migration and invasion of ameloblastoma cells, but inhibited proliferation. Expression of MMP-2, MMP-9, LEF-1, cyclin D1, c-Jun and c-Myc was significantly upregulated under elevated hydrostatic pressure, and these effects could be abolished by DKK1. Expression of RANKL, which is thought to be a downstream target of Wnt signalling, did not significantly change under elevated hydrostatic pressure.

CONCLUSIONS

This study indicates that elevated hydrostatic pressure promotes the migration and invasion of ameloblastoma cells by activating the Wnt/β-catenin pathway, thereby increasing expression of MMP-2, MMP-9 and other Wnt signalling downstream targets. This suggests that marsupialization may reduce invasiveness and reverse the bone resorption process by lowering intracystic hydrostatic pressure in cystic ameloblastoma.