ABSTRACT
Our previous proteomics study revealed that thioredoxin-interacting protein (TXNIP) was down-regulated by miR-373. However, little is known of the mechanism by which miR-373 decreases TXNIP to stimulate metastasis. In this study, we show that miR-373 promotes the epithelial-to-mesenchymal transition (EMT) in breast cancer. MiR-373 suppresses TXNIP by binding to the 3'UTR of TXNIP, which in turn, induces cancer cell EMT and metastasis. TXNIP co-expression, but not the TXNIP-3'UTR, reverses the enhancement of EMT, migration, invasion and metastasis induced by miR-373. MiR-373 stimulates EMT, migration and invasion through TXNIP-dependent reactive oxygen species (ROS) reduction. Mechanistically, miR-373 up-regulates and activates the HIF1α-TWIST signaling axis via the TXNIP pathway. Consequently, TWIST induces miR-373 expression by binding to the promoter of the miR-371-373 cluster. Clinically, miR-373 is negatively associated with TXNIP and positively associated with HIF1α and TWIST, and activation of the miR-373-TXNIP-HIF1α-TWIST signaling axis is correlated with a worse outcome in patients with breast cancer. This signaling axis may be an independent prognostic factor for patients with breast cancer.
Subject(s)
Breast Neoplasms/metabolism , Carrier Proteins/metabolism , Epithelial-Mesenchymal Transition , Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , MicroRNAs/metabolism , Nuclear Proteins/metabolism , Twist-Related Protein 1/metabolism , Animals , Binding Sites , Breast Neoplasms/genetics , Breast Neoplasms/pathology , Breast Neoplasms/therapy , Carrier Proteins/genetics , Cell Movement , Female , Gene Expression Regulation, Neoplastic , Humans , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Lung Neoplasms/genetics , Lung Neoplasms/metabolism , Lung Neoplasms/secondary , Lymphatic Metastasis , MCF-7 Cells , Mice, Inbred NOD , Mice, SCID , MicroRNAs/genetics , Neoplasm Metastasis , Nuclear Proteins/genetics , Prognosis , Promoter Regions, Genetic , RNA Interference , Reactive Oxygen Species/metabolism , Signal Transduction , Transfection , Twist-Related Protein 1/geneticsABSTRACT
Genistein exerts its anticarcinogenic effects by inducing G2/M arrest and apoptosis of cancer cells. However, the precise molecular mechanism of action of genistein has not been completely elucidated. In this study, we used quantitative proteomics to identify the genistein-induced protein alterations in gastric cancer cells and investigate the molecular mechanism responsible for the anti-cancer actions of genistein. Total 86 proteins were identified to be regulated by genistein, most of which were clustered into the regulation of cell division and G2/M transition, consistent with the anti-cancer effect of genistein. Many proteins including kinesin family proteins, TPX2, CDCA8, and CIT were identified for the first time to be regulated by genistein. Interestingly, five kinesin family proteins including KIF11, KIF20A, KIF22, KIF23, and CENPF were found to be simultaneously downregulated by genistein. Significantly decreased KIF20A was selected for further functional studies. The silencing of KIF20A inhibited cell viability and induced G2/M arrest, similar to the effects of genistein treatment in gastric cancer. And the silencing of KIF20A also increased cancer cell sensitivity to genistein inhibition, whereas overexpression of KIF20A markedly attenuated genistein-induced cell viability inhibition and G2/M arrest. These observations suggested that KIF20A played an important role in anti-cancer actions of genistein, and thus may be a potential molecular target for drug intervention of gastric cancer.
