Effect of Isoalantolactone on Apoptosis in MCF-7 Cells Via Mitochondrial and Phosphatidylinositol 3-Kinase /Akt Signaling Pathways

Xiu-Juan ZHANG

ABSTRACT

OBJECTIVE:

To study the effect of isoalantolactone on inhibiting proliferation of MCF-7 and induce apoptosis in vitro and further to explore its machinism via mitochondrial and phosphatidylinositol 3-kinase/Akt signaling pathways.

METHODS:

The subject investigated isoalantolactone in MCF-7 cells proliferation inhibition by MTT and SRB methods, and matching the results of two methods; observing morphological changes by inverted microscope and each phase of apoptosis of MCF-7 cells effected by isoalantolactone after 24 h with Hoechst 33258 staining method. Using transmission electron microscopy to observe MCF-7 cells morphology change to determine the mechanism of research; rhodamine 123 tag, laser confocal scanning microscope detection isoalantolactone on the effect of MCF-7 cells mitochondrial membrane potential; Using Western blot to the expression of Bcl-2, Bax, Akt and p-Akt; detecting caspase-3 activity in MCF-7 cells by colorimetry method.

RESULTS:

Isoalantolactone has strong inhibition of proliferation in MCF-7 cells, IC50 values of MTT and SRB methods were 15.21 and 14.908 μg•mL-1, and in a dose -dependent manner; the morphological of MCF-7 cells was changed after the treatment by Hoechst staining method; morphological changes were observed under transmission electron microscopy of cells display, the drug group cells showed typical apoptotic characteristics of different periods. With the concentrations of isoalantolactone increasing, the level of mitochondrial membrane potential reduced. Western blot result showed that, isoalantolactone could down regulate the expression of anti apoptotic protein Bcl-2, p-Akt, and up regulate the expression of pro-apoptotic protein Bax, had no effect on the expression of Akt protein. And the activity of caspase-3 could be raised by increasing dosage, compared with the control group with significant difference(P < 0.01).

CONCLUSION:

Isoalantolactone effectively inhibites the proliferation of MCF-7 cells through mitochondrial and phosphatidylinositol 3-kinase/Akt signaling pathways, which is regulated by activation of caspase-3, down-regulation of Bcl-2, and up-regulation of Bax. Isoalantolactone-induced apoptosis is involved in mitochondrial and the PI3K/Akt pathway.