Abstract
Aim: The role of protein kinase D (PKD) in the context of breast cancer cell biology is not clear. Materials and Methods: The expression of PKD isoforms was assessed in various breast cancer cell lines and PKD isoform-specific siRNAs and selective inhibitors were used to study the role of PKD in breast cancer cell growth. Results: PKD2 and PKD3 were two major isoforms expressed at the highest levels in tumorgenic HCC1806 triple-negative breast cancer cells. Silencing PKD2 or PKD3 significantly inhibited HCC1806 cell proliferation, and PKD3 silencing had a higher inhibitory effect than PKD2 silencing on cell growth and PKD-mediated signaling. HCC1806 breast cancer cells were highly responsive to PKD inhibitors but not to a general protein kinase C (PKC) inhibitor. Conclusion: We have identified PKD2 and PKD3, especially PKD3, as novel cell growth regulators in HCC1806 triple-negative breast cancer cells. Targeting PKD instead of all PKCs effectively inhibited cell proliferation in a number of breast cancer cell lines.
- Received January 5, 2013.
- Revision received January 17, 2013.
- Accepted January 17, 2013.
- Copyright© 2013 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved