Abstract

Objective: To investigate the anticancer activity of two diterpenes [palmonine F (C1) and palmonine D (C2)] and three steroids [cholesta-5,22-dien-3β-ol (C3), stigmasterol (C4) and 5α-cholest-5-en-3β-ol (C5)], isolated from the Mediterranean gorgonian Eunicella singularis, against MCF-7 breast cancer cell line. Methods: This study was performed on standard monolayer two-dimensional (2D) model to evaluate apoptosis by means of AnnexinV-FITC/PI flow cytometry and on three-dimensional (3D) spheroid model using Celigo imaging cytometer for spheroids size analysis. Results: Results indicated that both diterpenes and steroids exhibited an important apoptotic activity in a concentration-dependent manner with EC50 values of 13, 49, 30, 66 and 65 μg/ mL for C1, C2, C3, C4 and C5, respectively. Treatment of MCF-7 3D cell model with C1–C5 induced growth regression of spheroids in a concentration-dependent manner similar to the clinical anti-breast cancer drug Taxol; over ten days of incubation, growth rates were < 1.5 at Day 10 with all tested compounds at 200 μg/mL. Conclusions: The present study indicates that the two diterpenes C1 and C2 and the three steroids C3, C4 and C5, isolated from Eunicella singularis, might be used as anti-breast cancer candidate drugs for further development.

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