title: Kaempferol suppresses cell metastasis via inhibition of the ERK-p38-JNK and AP-1 signaling pathways in U-2 OS human osteosarcoma cells.
abstract: Kaempferol is a natural flavonoid that possesses anti-proliferative and apoptosis-inducing activities in several cancer cell lines. In the present study, we investigated the anti-metastatic activity of kaempferol and its molecular mechanism(s) of action in human osteosarcoma cells. Kaempferol displayed inhibitory effects on the invasion and adhesion of U-2 osteosarcoma (OS) cells in a concentration-dependent manner by Matrigel Transwell assay and cell adhesion assay. Kaempferol also inhibited the migration of U-2 OS cells in a concentration-dependent manner at different treatment time points by wound-healing assay. Additional experiments showed that kaempferol treatment reduced the enzymatic activities and protein levels of matrix metalloproteinase (MMP)-2, MMP-9 and urokinase plasminogen activator (uPA) by gelatin and casein-plasminogen zymography assays and western blot analyses. Kaempferol also downregulated the mRNA levels of MMP-2 and MMP-9 by quantitative PCR analyses. Furthermore, kaempferol was able to reduce the protein phosphorylation of ERK, p38 and JNK by western blotting. By electrophoretic mobility-shift assay (EMSA), we demonstrated that kaempferol decreased the DNA binding activity of AP-1, an action likely to result in the reduced expression of MMP-2, MMP-9 and uPA. Collectively, our data showed that kaempferol attenuated the MAPK signaling pathways including ERK, JNK and p38 and resulted in the decreased DNA binding ability of AP-1, and hence, the downregulation in the expression and enzymatic activities of MMP-2, MMP-9 and uPA, contributing to the inhibition of metastasis of U-2 OS cells. Our results suggest a potential role of kaempferol in the therapy of tumor metastasis of OS.
authors.affiliation: Graduate Institute of Molecular Systems Biomedicine, Department of Pharmacology, China Medical University, Taichung 40402, Taiwan, ROC.
authors.forename: Hui-Jye
authors.initials: HJ
authors.lastname: Chen
authors.forename: Chung-Ming
authors.initials: CM
authors.lastname: Lin
authors.forename: Chao-Ying
authors.initials: CY
authors.lastname: Lee
authors.forename: Nai-Chen
authors.initials: NC
authors.lastname: Shih
authors.forename: Shu-Fen
authors.initials: SF
authors.lastname: Peng
authors.forename: Minoru
authors.initials: M
authors.lastname: Tsuzuki
authors.forename: Sakae
authors.initials: S
authors.lastname: Amagaya
authors.forename: Wen-Wen
authors.initials: WW
authors.lastname: Huang
authors.forename: Jai-Sing
authors.initials: JS
authors.lastname: Yang
mesh_terms: D001859:Bone Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002448:Cell Adhesion / Q000187:drug effects / Q000235:genetics; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects / Q000235:genetics; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D006801:Humans; D044949:Kaempferols / Q000494:pharmacology*; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism; D009362:Neoplasm Metastasis; D012516:Osteosarcoma / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D010766:Phosphorylation; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D014568:Urokinase-Type Plasminogen Activator / Q000235:genetics / Q000378:metabolism
chemical_list: D044949:Kaempferols; D012333:RNA, Messenger; D018808:Transcription Factor AP-1; C006552:kaempferol; D014568:Urokinase-Type Plasminogen Activator; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9