MiR-200c suppresses TGF-β signaling and counteracts trastuzumab resistance and metastasis by targeting ZNF217 and ZEB1 in breast cancer.

Resistance to trastuzumab and concomitantly distal metastasis are leading causes of mortality in HER2-positive breast cancers, the molecular basis of which remains largely unknown. Here, we generated trastuzumab-resistant breast cancer cells with increased tumorigenicity and invasiveness compared with parental cells, and observed robust epithelial-mesenchymal transition (EMT) and consistently elevated TGF-β signaling in these cells. MiR-200c, which was the most significantly downregulated miRNA in trastuzumab-resistant cells, restored trastuzumab sensitivity and suppressed invasion of breast cancer cells by concurrently targeting ZNF217, a transcriptional activator of TGF-β, and ZEB1, a known mediator of TGF-β signaling. Given the reported backward inhibition of miR-200c by ZEB1, ZNF217 also exerts a feedback suppression of miR-200c via TGF-β/ZEB1 signaling. Restoration of miR-200c, silencing of ZEB1 or ZNF217 or blockade of TGF-β signaling increased trastuzumab sensitivity and suppressed invasiveness of breast cancer cells. Therefore, our study unraveled nested regulatory circuits of miR-200c/ZEB1 and miR-200c/ZNF217/TGF-β/ZEB1 in synergistically promoting trastuzumab resistance and metastasis of breast cancer cells. These findings provide novel insights into the common role of EMT and related molecular machinery in mediating the malignant phenotypes of breast cancers.

Bai WD ，Ye XM ，Zhang MY ，Zhu HY ，Xi WJ ，Huang X ，Zhao J ，Gu B ，Zheng GX ，Yang AG ，Jia LT ... -  《-》

LncRNA-ATB promotes trastuzumab resistance and invasion-metastasis cascade in breast cancer.

Shi SJ ，Wang LJ ，Yu B ，Li YH ，Jin Y ，Bai XZ ... -  《Oncotarget》

Coordinated regulation of β-tubulin isotypes and epithelial-to-mesenchymal transition protein ZEB1 in breast cancer cells.

Lobert S ，Graichen ME ，Morris K 《-》

miR-200c inhibits TGF-β-induced-EMT to restore trastuzumab sensitivity by targeting ZEB1 and ZEB2 in gastric cancer.

Zhou X ，Men X ，Zhao R ，Han J ，Fan Z ，Wang Y ，Lv Y ，Zuo J ，Zhao L ，Sang M ，Liu XD ，Shan B ... -  《-》

miR-200 promotes the mesenchymal to epithelial transition by suppressing multiple members of the Zeb2 and Snail1 transcriptional repressor complexes.

Perdigão-Henriques R ，Petrocca F ，Altschuler G ，Thomas MP ，Le MT ，Tan SM ，Hide W ，Lieberman J ... -  《-》