Efficient downregulation of ErbB-2 induces TACC1 upregulation in breast cancer cell lines

The ErbB-2 gene, whose overexpression is observed in many types of tumorsincluding breast cancer, plays an important role in carcinoma formation. Dysregulationof the human transforming acidic coiled-coil 1 (TACC1) and ErbB-2 genes is thoughtto be important in the development and progression of breast cancer. However,a putative interaction between ErbB-2 and TACC1 remains undetermined in breastcancer. After infecting BT474 cells with lentiviral-mediated ErbB2-specific shRNA,we detected the expression of ErbB-2 and TACC1 by real-time PCR and western blotting.ErbB-2 mRNA expression was decreased in the Lenti-ShERBB2 infected cells, andwestern blotting indicated a concordant reduction in ErbB-2 protein. TACC1 expressionat the mRNA and protein levels was significantly upregulated by ErbB-2 silencingin BT474 cells. CCK-8 assay indicated that the inhibition of ErbB-2 expressionincreased the sensitivity of BT474 cells to docetaxel treatment. These findingsprovide proof and the foundation for the molecular and biological relationshipsof ErbB-2 and TACC1 in breast cancer.