STUDIES ON THE ANTI-CANCER PROPERTIES OF ARTESUNATE: ANTI-PROLIFERATIVE AND CYTOTOXIC EFFECTS ON BREAST AND OVARIAN CANCER CELLS
Greenshields, Anna L.
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In women, breast cancer is the most prevalent cancer diagnosis while ovarian cancer represents the most lethal gynecological neoplasm. The high incidence and mortality of these cancer types, in addition to the emergence of multi-drug resistant clones, highlights the need to develop novel therapeutic agents. Artesunate (ART) is a semi-synthetic derivative of artemisinin, a natural compound derived from the Chinese herb Artemisia annua L. ART is a potent anti-malarial agent that also possesses anticancer activity. Since the use of ART as an anti-malarial agent is associated with few adverse effects, ART may represent a less toxic alternative to conventional chemotherapy. This study investigates the cytotoxic effects of ART on breast and ovarian cancer cell lines and the mechanism(s) underlying its activity. ART exhibited a potent growth-inhibitory effect on a panel of breast and ovarian cancer cell lines. Anti-cancer activity was also observed in 3D cultures of both cancer cell types. Oregon Green488 and propidium iodide (PI) staining of cancer cells revealed that ART strongly inhibited cancer cell proliferation and, depending on the cell type, arrested cells in the G1 or G2/M phases of the cell cycle. Arrest in the G2/M phase was dependent on reactive oxygen species (ROS) production. The anti-proliferative effect of ART was associated with altered expression of several cell cycle regulatory proteins in both breast and ovarian cancer cell lines, including cyclin D3, E2F-1, and CDC25C. Annexin-V-FLUOS/PI staining of ARTtreated cancer cells revealed cytotoxicity against breast and ovarian cancer cell. ARTinduced cell death was iron- and ROS-dependent. Pre-treatment of cancer cells with a pan-caspase inhibitor decreased but did not eliminate ART-induced cancer cell death, suggesting that caspase-dependent apoptosis is involved in ART-mediated cancer cell killing. ART induced ROS-dependent DNA damage as indicated by the presence of γH2AX, which implicated the DNA damage pathway in ART-induced cancer cell death. These data show that ART has a potent anti-proliferative and cytotoxic effect on both breast and ovarian cancer cells. The cytotoxic activity of ART and its excellent safety record in malaria patients make ART a worthy candidate for further investigation as a possible treatment for breast and ovarian cancer.