Stearate Preferentially Induces Apoptosis in Human Breast Cancer Cells

Abstract

Stearic acid (stearate) is an 18-carbon saturated fatty acid that has been shown to inhibit invasion and proliferation and induce apoptosis in various human cell types. The specificity of stearate-induced apoptosis for cancerous versus noncancerous breast cells has not been examined, and the mechanism underlying stearate-induced apoptosis is unknown. Morphological analysis, cell viability, and caspase-3 activity assays demonstrated that stearate activated apoptosis preferentially in cancerous breast cells in a time- and dose-dependent manner. Inhibition of de novo diacylgycerol synthesis or protein kinase C (PKC) blocked stearate-induced caspase-3 activity, indicating the involvement of a novel or classical PKC isozyme. To our knowledge this is the first study showing that stearate induces apoptosis preferentially in breast cancer cells and implicates protein kinase C in the signaling cascade. These results raise the possibility of dietary stearate having a beneficial role in the prevention or treatment of breast cancer.

ACKNOWLEDGMENTS

We thank A. Ibrahim-Hashim and E. Toline for help with the preparation of the manuscript. These studies were supported by the NIH/National Center for Complementary and Alternative Medicine (NCCAM), R21 AT 001636 and R21 AT 002922 (R. W. Hardy). Its contents are solely the responsibility of the authors and do not necessarily represents of the official views of the NCCAM, or the National Institutes of Health. This study was also made possible by a predoctoral fellowship from the National Cattlemen's Beef Association (L. M. Evans, R. W. Hardy).