Suppression of IL-1beta-induced MUC5AC Gene Expression by Ginkgo biloba Extract(EGb 761) in Human Airway Epithelial Cells

BACKGROUND AND OBJECTIVES: The purpose of this study is to investigate whether Ginkgo biloba extract (EGb 761) can suppress IL-1beta-induced MUC5AC gene expression in NCI-H292 human airway epithelial cells and to discover what its possible mechanism is. MATERIALS AND METHODS: NCI-H292 human pulmonary mucoepidermoid carcinoma cell line was used. MUC5AC mRNA and protein were measured using the RT-PCR and Western blot analysis. The activation of mitogen activated protein kinases (MAPKs) were determined by means of the Western blot analysis. RESULTS: MUC5AC was induced by treating the NCI-H292 cells with 10 ng/ml of IL-1beta for 24 hours. A pre-treatment of 200 microgram/ml of EGb 761 significantly suppressed the IL-1beta induced MUC5AC expression. The inhibition of MUC5AC gene expression by EGb 761 was noted to be suppressed via both the extracellular signal-regulated kinase (ERK) and the p38 MAPK pathways in a kinase-specific inhibitor study. CONCLUSION: EGb 761 suppresses IL-1beta-induced MUC5AC gene expression in the human airway epithelial cells. Therefore, it may be considered as a possible anti-hypersecretory agent.

Mechanism of Apoptosis Induced by Ginkgo Biloba Extract(Egb 761) in Oral Cavity Cancer Cell Lines / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: According to our previous study Ginkgo biloba extract (EGb 761) induces inhibition of cell proliferation and apoptosis in SCC 1483 oral cavity cancer cells. On the other hand, in lipopolysaccharide-stimulated RAW 264.7 cells, activation of mitogen activated protein kinase (MAPK) is the key event in the inhibition of inflammation by EGb 761. Therefore, we have investigated whether MAPK pathway is involved in the apoptotic process by EGb 761 in oral cavity cancer cell lines or not. SUBJECTS AND METHOD: In SCC 1483 oral cavity cancer cell lines, Western blot analysis, Fluorescence-activated cell sorter (FACS) analysis, and transient transfection using MAPK-dominant negative constructs were used. RESULTS: When SCC 1483 oral cavity cancer cell lines were treated with the concentration of 250 microgram/ml EGb 761, activation of extracellular signal-regulated kinase (ERK) and apoptosis were noted. This apoptosis was inhibited by the treatment with ERK inhibitor (PD 98059). In the transiently transfected cells by MAPK/ERK kinase 1 (MEK1)-dominant negative construct, phosphorylations of ERK and p90 ribosomal S 6 protein kinase (RSK1) were inhibited which led to the inhibition of apoptosis by EGb 761. The inhibition of apoptosis was also noted in the transfected cells by RSK1 dominant negative construct and cAMP response element binding protein (CREB)-dominant negative construct. CONCLUSION: In conclusion, the apoptosis of SCC 1483 oral cavity cancer cell lines by EGb 761 is linked to the activation of ERK and it can happen via ERK MAPK/RSK1/CREB signal transduction pathway.