Sea anemone (Stichodactyla haddoni) induces apoptosis in lung cancer A549 cells: an in vitro evaluation of biological activity of mucus derivatives

Abstract

Bioactive compounds obtained from sea anemones have multiple biological effects, including cytotoxic, cytolytic and anti-carcinogenic activities. This study investigated the cellular and molecular effects of crude mucus (CM) and four derived fractions (F1, F2, F3, and F4) of sea anemone Stichodactyla haddoni on human lung cancer cell line (A549). The samples were collected from the intertidal zone of Hormuz Island in the Persian Gulf. The cytotoxicity of CM and their fractions extracted from the sea anemone was assayed using the MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay for 24 and 48 h. The F1 (30–50 kDa) fraction had the most effect on the lung cancer cell line compared with CM and F2 (10–30 kDa). The cell apoptosis was measured via expression rate of apoptotic marker genes such as BAK, BAX, and BCL2 by Real-time PCR (RT-PCR). Cell morphology was analyzed by a light microscopy though Giemsa staining. The results demonstrated that the S. haddoni mucus induced a significant reduction in the number of viable cells as well as increased cell death in a dose-dependent manner. The expression of pro-apoptotic genes such as BAK and BAX were upregulated, but BCL2 was downregulated when A549 cells treated with CM (50, 75 and 100 μg/mL) and F1, F2 fractions (5 and 25 μg/mL). The morphological characteristics of apoptotic cells were observed after treatment with CM, F1 and F2 fractions. These findings suggest that S. haddoni mucus has inhibitory effects on growth of the A549 lung cancer cells via the mitochondria-mediated apoptotic pathway. In addition, further purifying the F1 and F2 fractions, which have the greatest cytolytic effects, can hopefully help to better understand the inhibition of cancer cell growth.