Piperine, an
alkaloid from black pepper, is reported to have anticancer activities. In this study, we investigated the effect of
piperine on the growth and motility of
triple-negative breast cancer (TNBC) cells.
Piperine inhibited the in vitro growth of TNBC cells, as well as
hormone-dependent
breast cancer cells, without affecting normal mammary epithelial cell growth. Exposure to
piperine decreased the percentage of TNBC cells in the G2 phase of the cell cycle. In addition, G1- and G2-associated
protein expression was decreased and p21(Waf1/Cip1) expression was increased in
piperine-treated TNBC cells.
Piperine also inhibited survival-promoting Akt activation in TNBC cells and caused caspase-dependent apoptosis via the mitochondrial pathway. Interestingly, combined treatment with
piperine and γ radiation was more cytotoxic for TNBC cells than γ radiation alone. The in vitro migration of
piperine-treated TNBC cells was impaired and expression of
matrix metalloproteinase-2 and -9
mRNA was decreased, suggesting an antimetastatic effect by
piperine. Finally, intratumoral administration of
piperine inhibited the growth of TNBC xenografts in immune-deficient mice. Taken together, these findings suggest that
piperine may be useful in the treatment of TNBC.