RESUMO
Enhanced invasion and migration of non-small cell lung cancer (NSCLC) cells is the major cause of metastasis and poor prognosis in NSCLC. This study was conducted to investigate the role and mechanism of lncRNA KCNQ1OT1 in the proliferation, invasion, and migration of NSCLC cells. The expression of KCNQ1OT1 in NSCLC was analyzed in the StarBase database, and the target miRNA of KCNQ1OT1 as well as the target genes of the miRNA was predicted. Then, the mRNA expression levels of KCNQ1OT1, miR-496, and HMGB1 were detected in clinical tissue samples and cells by qRT-PCR assay. Besides, the protein levels of HMGB1 were detected by Western blot. MTT assay, transwell assay, and scratch assay were used to determine the proliferation, invasion, and migration ability of NSCLC cells, respectively. Correlation analysis was performed to assess the correlation between the expression of KCNQ1OT1, miR-496, and HMGB1 in clinical NSCLC samples. Dual-luciferase reporter gene assay was conducted to analyze the interaction between KCNQ1OT1 and miR-496 and between miR-496 and HMGB1. The database results showed that KCNQ1OT1 was highly expressed in NSCLC. Similarly, we found that the expression level of KCNQ1OT1 was significantly higher in NSCLC tissues and cells than that in the corresponding normal tissues and cells. The results of MTT assay, transwell assay, and scratch assay demonstrated that KCNQ1OT1 significantly enhanced the proliferation, invasion, and migration of NSCLC cells. Further mechanism exploration revealed that KCNQ1OT1 could sponge miR-496, and miR-496 directly targeted and regulated the expression of HMGB1. The expression of miR-496 and either KCNQ1OT1 or HMGB1 were negatively correlated in NSCLC, while the expression of KCNQ1OT1 and HMGB1 were positively correlated. Compared with normal paracancer tissues, miR-496 was much lower and HMGB1 was much higher expressed in NSCLC tissues. The results of cotransfection also further demonstrated that miR-496 inhibitor or sh-HMGB1 cotransfected with sh-KCNQ1OT1 could significantly decrease or increase the ability of sh-KCNQ1OT1 to inhibit the proliferation, invasion, and migration of H1299 cells, respectively. In conclusion, lncRNA KCNQ1OT1 promotes the invasion and migration of NSCLC cells through miR-496/HMGB1 signaling axis.
RESUMO
OBJECTIVE: To study the effect of secretory leukocyte protease inhibitor (SLPI) on the expression of MMP-9 and IL-8 in normal human bronchial epithelial (NHBE) cells induced by cigarette smoke extract (CSE), and therefore to explore the mechanisms of SLPI for protecting the local airways of chronic inflammatory diseases. METHODS: The experiments of cultured airway epithelia cells in vivo were randomly divided into 4 groups, including a control group, a CSE group, a SLPI group, and a SLPI + CSE group. The expression level of IL-8 in NHBE cell supernatant was examined by ELISA. The expression level of MMP-9 protein in NHBE cells was evaluated by using immunocytochemical stain method. One way analysis of variance was employed in significance test of different groups, followed by SNK test with equal variances and Dunnett3 test with unequal variances. RESULTS: A small quantities of MMP-9 and IL-8 expression were observed in the control group NHBE cells. The mean integral expression of MMP-9 protein was (3.1 +/- 0.5), and the concentration of IL-8 in NHBE cell supernatant was (4.9 +/- 0.6) ng/L. After exposure to CSE for different times, the expression of MMP-9 and IL-8 in NHBE cells of the CSE group was higher than those of in control group. The expression levels of MMP-9 and IL-8 were dependent on CSE exposure time within certain limits. The highest expression was observed at the time of 24 h exposure to CSE. The mean integral expression of MMP-9 protein was 6.6 +/- 0.4, and the concentration of IL-8 in NHBE cell supernatant was (17.7 +/- 1.9) ng/L. But subsequently the levels decreased significantly in 36 h. When NHBE cells were exposed to 10 microg/L SLPI, the expression levels of MMP-9 and IL-8 were inhibited. The integral expression of MMP-9 protein was 0.8 +/- 0.5, and the concentration of IL-8 in NHBE cell supernatant was (0.7 +/- 0.6) ng/L. CONCLUSION: SLPI inhibited the expression of MMP-9 and IL-8 in NHBE cells induced by cigarette smoking extract.
