Wortmannin inhibits proliferation and induces apoptosis of MCF-7 breast cancer cells.

OBJECTIVE: The present study aimed to explore the effects of wortmannin in the proliferation and apoptosis of human breast cancer MCF-7 cells.

METHODS: The authors treated cells with 0, 1, 6.25, 12.5, 25, and 50 nM wortmannin for 24, 48, and 72 hours. Inhibition of proliferation was measured by cell counting kit-8 assay (CCK8). Apoptosis was detected with Annexin V-fluorescein isothiocyanate/propidium iodide double staining by flow cytometry. Additionally, expression of proteins involved in the PI3K pathway, specifically total Akt, phosphorylated Akt (p-Akt), and NF-kappaB was detected by Western blotting following 24 hours of wortmannin exposure.

RESULTS: Higher doses (6.25, 12.5, 25, and 50 nM) of wortmannin significantly inhibited proliferation of MCF-7 cells after 24, 48, and 72 hours of exposure compared with control MCF-7 cells incubated with DMSO alone in DMEM (p < 0.05). This inhibition increased with concentration and duration of treatment. Similarly, wortmannin at 6.25, 12.5, 25, and 50 nM concentrations significantly increased apoptosis of MCF-7 cells following 24 hours of exposure (p < 0.05). Western blotting revealed that increasing concentrations of wortmannin (6.25, 12.5, 25, and 50 nM, 24 hours) increasingly reduced expression of p-Akt and NF-kappaB; however, expression of total Akt was unaffected at any concentration of wortmannin.

CONCLUSIONS: Wortmannin inhibits proliferation and induces apoptosis of MCF-7 cells in a dose and time-dependent manner, likely through down-regulation of PI3K/Akt signaling and NF-kappaB protein expression.