Matrix stiffness enhances viability, migration, invasion and invadopodia formation of oral cancer cells via PI3K/AKT pathway in vitro.

BACKGROUND: Oral cancer (OC) is one of the major types of cancer and the most common cause of cancer-related mortality in Asia. In recent years, matrix stiffness in the tumor microenvironment has been found to play an important role in regulating tumor cell behavior. However, the regulatory mechanisms associated with matrix stiffness in OC cells remain unclear. METHODS: In this study, polyacrylamide gels with different stiffness were prepared to simulate low versus high matrix stiffness environments in tumor tissues by adjusting the acrylamide and cross-linker concentrations. Subsequently, the effects of different stiffness on OC cell survival, migration, invasion and invadopodia formation were explored based on cell counting kit-8 (CCK-8), Transwell and confocal microscopy. Meanwhile, the levels of markers relevant to phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT), apoptosis (BAX and BCL2) as well as metastasis (Cadherin-1, CDH1; Cadherin-2, and CDH2) were calculated via western blotting and real-time quantitative PCR. RESULTS: According to the results, high matrix stiffness was seen to contribute to the increased number of migrated and invaded cells as well as the enhanced viability of OC cells, along with the aggravated invadopodia formation and the up-regulation in CDH2 and BCL2 levels yet the down-regulation in CDH1 and BAX levels. Elevated PI3K/AKT phosphorylation levels were also seen in high matrix stiffness-mediated OC cells, and the intervention using LY294002 could visibly overturned the effects of high matrix stiffness on the cell migration, invasion and invadopodia formation of OC cells. CONCLUSIONS: This study reveals that matrix stiffness may enhance the invasiveness and anti-apoptotic ability of OC cells by activating the PI3K/AKT pathway, which provides a new idea for exploring the microenvironmental regulation of tumor mechanics and targeted intervention strategies.