PTEN Gene Induces Cell Invasion and Migration via Regulating AKT/GSK-3β/β-Catenin Signaling Pathway in Human Gastric Cancer.

Background: Abnormality of PTEN gene and Wnt/β-catenin signaling have been strongly implicated in various malignant cancers. Recently, it has been noted that a functional interaction/cross-talk was found between the PTEN/PI3K/AKT and Wnt/β-catenin, which plays a key role in the development of cancers. However, few related studies on gastric cancer are available.

Aim: We examined the expression of PTEN and β-catenin in gastric cancer tissues and detected whether down-regulation of PTEN promotes the migration and invasion in gastric cancer cells along with its underlying mechanism.

Materials And Methods: Immunocytochemistry, a wound healing assay, a Matrigel invasion assay, an immunofluorescence staining were performed to detect expression of PTEN and β-catenin in gastric cancer and adjacent normal tissues, cell migration, cell invasion, and the effects of PTEN knockdown on β-catenin in cells, respectively. Further, MMP-2 and MMP-9 activities were analyzed by zymography assay. The changes in related proteins were further quantified by western blotting.

Results: Low expression of PTEN was found in majority of gastric cancer tissues, which showed significant associations with differentiation grade in gastric cancer patients. Further, a negative correlation was revealed between PTEN and β-catenin protein expression in gastric cancer tissues (r = - 0.546, P < 0.01). Additionally, PTEN knockdown promoted the migration and invasion of cells and caused an obvious increase in p-AKT, p-GSK-3β, β-catenin, E-cadherin, MMP-7, MMP-2, and MMP-9 in gastric cancer cells.

Conclusion: Our results indicated PTEN gene might induce cell invasion and migration via regulating AKT/GSK-3β/β-catenin signaling pathway, playing a vital role in the progression of gastric cancer.