Allicin inhibits the invasion of lung adenocarcinoma cells by altering tissue inhibitor of metalloproteinase/matrix metalloproteinase balance via reducing the activity of phosphoinositide 3-kinase/AKT signaling.

Allicin, the main active principle associated with chemistry, has various antitumor activities. However, to the best of our knowledge, there is no available information to address the anti-invasive effect and associated mechanism in lung adenocarcinoma. In the present study, cell viability assay, cell adhesion assay, western blot analysis, Transwell migration and invasion assays and reverse transcription-quantitative polymerase chain reaction were performed. Allicin was identified to inhibit the adhesion, invasion and migration of lung adenocarcinoma cells in a dose-dependent manner, accompanied by decreasing mRNA and protein levels of matrix metalloproteinase (MMP)-2 and MMP-9. Conversely, the mRNA and protein levels of tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 were increased in a dose-dependent manner. Furthermore, it was revealed that allicin treatment significantly suppressed the phosphorylation of AKT (P<0.05), but not the total protein expression of AKT. Combined treatment with LY294002, an inhibitor of phosphoinositide 3-kinase (PI3K)/AKT signaling, and allicin led to the synergistic reduction of MMP-2 and MMP-9 expression, followed by an increase in TIMP-1 and TIMP-2 expression. The invasive capabilities of lung adenocarcinoma cells were also suppressed. However, insulin-like growth factor-1 (an activator of PI3K/AKT signaling) reversed the effects of allicin on cell invasion and expression of MMP-2, MMP-9, TIMP-1 and TIMP-2. The present study concluded that allicin may inhibit invasion of lung adenocarcinoma cells by altering TIMP/MMP balance, via reducing the activity of the PI3K/AKT signaling pathway. This indicated that allicin may be recognized as an anti-invasive agent for lung adenocarcinoma treatment.