Demethoxycurcumin inhibited human epithelia ovarian cancer cells' growth via up-regulating miR-551a.

Curcumin is a natural agent that has ability to dampen tumor cells' growth. However, the natural form of curcumin is prone to degrade and unstable in vitro. Here, we demonstrated that demethoxycurcumin (a curcumin-related demethoxy compound) could inhibit cell proliferation and induce apoptosis of ovarian cancer cells. Moreover, IRS2/PI3K/Akt axis was inactivated in cells treated with demethoxycurcumin. Quantitative real-time reverse transcription polymerase chain reaction demonstrated that miR-551a was down-regulated in ovarian cancer tissues and ovarian cancer cell lines. Over-expression of miR-551a inhibited cell proliferation and induced apoptosis of ovarian cancer cells, whereas down-regulation of miR-551a exerted the opposite function. Luciferase assays confirmed that there was a binding site of miR-551a in IRS2, and we found that miR-551a exerted tumor-suppressive function by targeting IRS2 in ovarian cancer cells. Remarkably, miR-551a was up-regulated in the cells treated with demethoxycurcumin, and demethoxycurcumin suppressed IRS2 by restoration of miR-551a. In conclusion, demethoxycurcumin hindered ovarian cancer cells' malignant progress via up-regulating miR-551a.