Protein kinase D1 inhibits breast cancer cell invasion via regulating matrix metalloproteinase expression.

ABSTRACT

PURPOSE: This study aimed to explore the role of protein kinase D1 (PKD1) in breast cancer invasion. MATERIALS AND METHODS: The relative expression of PKD1mRNA and protein in human invasive breast cancer tissue samples and normal samples, as well as breast cancer cell lines, were detected. Constitutively-active PKD1 and PKD1 specific shRNA were expressed in the MD-MB-231 and MCF-7 cells, respectively. The role of PKD1 in the invasive behavior of breast cancer cell line was evaluated by matrix metalloproteinase (MMP) expression. RESULTS: The results showed that PKD1, as a serine/threonine kinase, is downregulated significantly in invasive ductal carcinoma and metastatic invasive ductal carcinoma tissue than the normal tissue and the low expression of PKD1 is also found in breast cancer cell line MD-MB-231. The MMP2 and MMP9 expression in PKD1 constitutively-active MD-MB-231 cells and MCF-7 knockdown cells were decreased and increased respectively. CONCLUSION: The authors confirmed that PKD1 was downregulated in invasive breast cancer. PKD1 can negatively regulate the MMP expression and may serve as a potential therapeutic target.