Study On Liquiritigenin Inhibited Migration And Its Molecular Mechanisms In Human Lung Adenocarcinoma A549 Cells

Worldwide, lung cancer is the most common cancer with high incidence and mortality. In China, lung cancer is the first death reason of malignancy, approximately 22.7% of all malignancy; Moreover, morbidity and mortality continues to rise rapidly. Several techniques, such as surgical technique, chemotherapy and radiotherapy, have achieved major advances in therapy of lung cancer. Unfortunately, these advances have brought only small improvements in survival. The 5-years survival rate of lung cancer is estimated to be only approximately 15%. The main reason of treatment failure and death is associated with tumor metastasis. Thus, effective chemopreventive treatment for metastasis would have an important impact on lung cancer mortality rates.Flavanoids are common polyphenolic compounds in nature. According to the research, flavonoids have multiple anticancer properties, which are associated with the induction of apoptosis, and inhibition of cell proliferation, cell cycle progression, angiogenesis and metastasis. Taken together, these results suggested flavanoids was a potential candidate for cancer chemoprevention. Liquiritigenin (LQ) is a flavanone extracted from Glycyrrhizae, which has multiple biological effects, such as anti-inflammation and hepatoprotection. The previous study from our laboratory indicated that LQ suppresses the proliferation of human hepatocarcinoma cell line (SMMC-7721)and human cervical carcinoma HeLa cells by inducing the mitochondria-mediated apoptosis. As a flavanone, whether LQ inhibits the migration of lung cancer cells and its underlying mechanisms remain unclear. In the present study, we investigated the effect of LQ on tumor cell migration by monitoring the regulation of MMP-2 expression. Moreover, the possible signaling pathways in human lung adenocarcinoma A549 cells were studied. Objective: This study was aimed to elucidate the effect of LQ on the migration of human lung adenocarcinoma A549 cells.Methods: The effect of LQ on A549 cell viability was examined by the MTT assay. The effects of LQ on the adhesion and migration of A549 cells were evaluated using the cell-matrix adhesion assay, wound-healing assay and Transwell chamber assay. Results: (1)The result indicated that LQ was not toxic to A549 cells with 24 h LQ treatment at a concentration between 0 and 100μM. Therefore, we applied LQ to A549 cells at above dosages (below 100μM) in all subsequent experiments. (2)In the cell-matrix adhesion assay, LQ inhibited the cell adhesion ability of A549 cells in a dose-dependent manner. After A549 cells exposure to 25~100μM LQ for 24 h, the adhesion ability has significant difference(p < 0.05)compared with control groups. (3)For the wound-healing assay, our data showed that the cell motility was significantly inhibited by 100μM LQ after 24 h incubation.(4)In vitro migration assay with Transwell chamber, we showed that LQ treatment dramatically reduced the number of migrated cells, and this inhibitory effect was in a dose-dependent manner.Conclusion: LQ can significantly inhibit the migration of A549 cells. Objective: The aim of our study was to explore the molecular mechanisms of LQ inhibit the migration of human lung adenocarcinoma A549 cells.Methods: Gelatin zymography and Western blotting Assay were performed to detect the secretion and expression of MMP-2. The effects of LQ on the phosphorylated status of Akt and extracellular signal-regulated kinase 1 and 2(ERK1/2) in A549 cells was examined by Western blotting Assay.Results: (1) Cells were treated with LQ at various concentrations (0, 10, 25, 50 and 100μM) for 24 h. LQ significantly reduced the expression of matrix metalloproteinase-2 (MMP-2) in A549 cells at both activity and protein level in a dose-dependent manner; The results showed that the treatment of LQ inhibited the protein level of phosphorylation of Akt. Meanwhile, LQ significantly mediated the activation of ERK1/2 at the higher concentration than 50μM as shown by increasing the phosphorylation of ERK1/2 in a dose-dependent manner. (2)Based on time-dependent assays, cells were treated with 50μM of LQ for various time points (0, 6, 12 and 24 h). LQ significantly inhibited the expression of(MMP-2)in A549 cells at both activity and protein level in a time-dependent manner; Moreover, our results showed that LQ also inhibited the phosphorylation of Akt and activated the phosphorylation of ERK1/2 in a time-dependent manner. (3)Densitometric analysis indicated that LY294002 (5 or 10μM) treatment reduced MMP-2 activity by 7%, 35%, respectively, and LQ (50μM) inhibited MMP-2 activity by 13% in A549 cells; whereas combined LQ and LY294002 treatment was reduced MMP-2 by almost 46%. We also found that the ERK1/2 inhibitor (U0126; 5 or 10μM)could result in reduced activity of MMP-2.Conclusion: LQ might inhibit the MMP-2 expression through suppressing the Akt phosphorylation and inhibiting the A549 cell migration. However, activation of ERK might not be involved in the regulation of MMP-2.