Honokiol inhibits EMT-mediated motility and migration of human non-small cell lung cancer cells in vitro by targeting c-FLIP.
OBJECTIVE
Honokiol (HNK) is a natural compound isolated from the magnolia plant with numerous pharmacological activities, including inhibiting epithelial-mesenchymal transition (EMT), which has been proposed as an attractive target for anti-tumor drugs to prevent tumor migration. In this study we investigated the effects of HNK on EMT in human NSCLC cells in vitro and the related signaling mechanisms.


METHODS
TNF-α (25 ng/mL) in combination with TGF-β1 (5 ng/mL) was used to stimulate EMT of human NSCLC A549 and H460 cells. Cell proliferation was analyzed using a sulforhodamine B assay. A wound-healing assay and a transwell assay were performed to examine cell motility. Western blotting was used to detect the expression levels of relevant proteins. siRNAs were used to knock down the gene expression of c-FLIP and N-cadherin. Stable overexpression of c-FLIP L (H157-FLIP L) or Lac Z (H157-Lac Z) was also performed.


RESULTS
Treatment with TNF-α+TGF-β1 significantly enhanced the migration of A549 and H460 cells, increased c-FLIP, N-cadherin (a mesenchymal marker), snail (a transcriptional modulator) and p-Smad2/3 expression, and decreased IκB levels in the cells; these changes were abrogated by co-treatment with HNK (30 μmol/L). Further studies demonstrated that expression level of c-FLIP was highly correlated with the movement and migration of NSCLC cells, and the downstream effectors of c-FLIP signaling were NF-κB signaling and N-cadherin/snail signaling, while Smad signaling might lie upstream of c-FLIP.


CONCLUSIONS
HNK inhibits EMT-mediated motility and migration of human NSCLC cells in vitro by targeting c-FLIP, which can be utilized as a promising target for cancer therapy, while HNK may become a potential anti-metastasis drug or lead compound.
Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China.
Xiao-Qin
XQ
Lv
Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China.
Xin-Ran
XR
Qiao
Shandong University School of Life Sciences, Ji-nan 250100, China.
Ling
L
Su
Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China.
Shu-Zhen
SZ
Chen
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001343:Autophagy / Q000187:drug effects; D001713:Biphenyl Compounds / Q000494:pharmacology*; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein / Q000378:metabolism*; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy*; D045744:Cell Line, Tumor / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects*; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects*; D006801:Humans; D017705:Lignans / Q000494:pharmacology*; D008175:Lung Neoplasms / Q000188:drug therapy*; D000498:Allyl Compounds; D010636:Phenols
D000970:Antineoplastic Agents; D001713:Biphenyl Compounds; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; D017705:Lignans; C506386:CFLAR protein, human; C005499:honokiol; D000498:Allyl Compounds; D010636:Phenols