Objective: To study the suppressive effects of curcumin on breast carcinoma cells and the mechanism.
Methods: Estrogen receptor (ER) positive human breast cancer line MCF-7 and ER negative human breast cancer line MDA-MB-231 were cultured 17-beta estradiol and curcumin were added into the culture. Northern blot hybridization and Western blots were performed to detect the expression of mRNA and protein. The human ERE promoter activity was analyzed by transient transfection with CAT-reporter constructs. Invasion experiments were conducted with a Matrigel invasion chamber.
Results: Curcumin inhibit the proliferation in both estrogen receptor (ER) positive MCF-7 cells and ER negative MDA-MB-231 cells. Curcumin's antiproliferative effects are estrogen dependent in ER positive MCF-7 cells. Curcumin inhibits the expression of ER downstream genes including pS2 and TGF-alpha (transforming growth factor-alpha) in ER-positive MCF-7 cells, and this inhibition is also dependent on the presence of estrogen. In addition, curcumin exerts strong anti-invasive effects in vitro which was not estrogen dependent in the ER-negative MDA-MB-231 breast cancer cells. These anti-invasive effects appeared to be mediated through the down-regulation of MMP-2 (matrix metalloproteinase) and the up-regulation of TIMP-1 (tissue inhibitor of metalloproteinase). Curcumin inhibited the transcript levels of two major angiogenesis factors VEGF (vascular endothelial growth factor) and b-FGF (basic fibroblast growth factor) in ER-negative MDA-MB-231 cells.
Conclusion: Curcumin exerts multiple suppressive effects on breast carcinoma cells;it's mechanism of chemoprevention is pleiotropic.