Alterations in histone deacetylase 8 lead to cell migration and poor prognosis in breast cancer

Aims Alterations in histone proteins can lead to breast tumorigenesis. Selective histone deacetylase 8 (HDAC8) inhibitors with fewer adverse effects have been developed. A more comprehensive study of alterations and its mechanisms in HDAC8 is required. In this study, we investigated mechanisms of dysregulation of HDAC8 expression and its biological role and pathways in breast cancer. Main methods Alterations in HDAC8 were analyzed in Taiwanese breast cancer patients; and in tissue samples from The Cancer Genome Atlas (TCGA) data set that were derived from Western countries. Knockdown by si-HDAC8, treatment with the HDAC8-specific inhibitor PCI-34051, SRB assays, wound healing, Transwell migration assays, Illumina BeadArray™ arrays and Ingenuity Pathway Analysis (IPA) were performed in breast cancer cells. Key findings HDAC8 mRNA expression was upregulated in paired breast cancer tissue from Taiwanese patients and in paired breast cancer tissues from the TCGA data set. Hypomethylation of promoter regions was significantly correlated with HDAC8 mRNA overexpression in 588 breast cancer patients from the TCGA data set and was associated with poor prognosis in early-stage breast cancer. HDAC8 mRNA overexpression was associated with late stages and tumor progression. Wound healing and Transwell migration assays revealed that knockdown by si-HDAC8 or PCI-34051 treatment significantly inhibited breast cancer cell migration. Knockdown by si-HDAC8, Illumina BeadArray™ arrays and IPA found that ID3 and PTP4A2 pathways were regulated by HDAC8 in cancer cell migration. Significance Hypomethylation of the HDAC8 promoter is correlated with HDAC8 overexpression and breast cancer progression and is a potential prognosis marker and drug target.