Abstract
The present study aimed to investigate the role of homeobox B4 (HOXB4) in breast cancer. Analysis of The Cancer Genome Atlas data revealed that HOXB4 expression was positively associated with expression of the StAR-related lipid transfer domain protein 13 (STARD13), and the overall survival of patients with breast cancer. Immunohistochemistry and quantitative polymerase chain reaction assays demonstrated that HOXB4 expression was downregulated in breast cancer tissues compared with adjacent normal tissues and was additionally positively associated with STARD13 expression. HOXB4 promoted STARD13 expression in breast cancer cells. Chromatin immunoprecipitation and luciferase reporter assays confirmed that HOXB4 directly bound to the STARD13 promoter. Additionally, HOXB4 inhibited breast cancer cell migration and the epithelial-mesenchymal transition through the STARD13/Ras homolog (Rho) family member A/Rho associated protein kinase signaling pathway. HOXB4 overexpression enhanced the sensitivity of breast cancer cells to doxorubicin and reversed resistance in doxorubicin-resistant cells. Overall, the results indicated that HOXB4 inhibited breast cancer cell migration and enhanced the sensitivity of breast cancer cells to doxorubicin by targeting STARD13.