TITLE:
Vernonia amygdalina—Induced Growth Arrest and Apoptosis of Breast Cancer (MCF-7) Cells
AUTHORS:
Clement G. Yedjou, Ernest B. Izevbigie, Paul B. Tchounwou
KEYWORDS:
Vernonia amygdalina; MCF-7 Cells; Apoptosis; Necrosis; Cellometer Imaging
JOURNAL NAME:
Pharmacology & Pharmacy,
Vol.4 No.1,
January
30,
2013
ABSTRACT: Breast cancer is the second leading cause of cancer-related deaths of women in the United States. Fortunately, the mortality rate from breast cancer has decreased in recent years due to an increased emphasis on early detection and more effective treatments. Although great advancements have been made in the treatment and control of cancer progression, significant deficiencies and room for improvement remain. The central objective of this research was to further determine the in vitro mechanisms of Vernonia amygdalina (VA) leaf extracts as an anticancer candidate for the treatment of breast cancer. To achieve our objective, MCF-7 cells were treated with different concentrations of VA for 24 hand 48 h. Cell viability, live and dead cells were determined by the means of trypan blue exclusion test. Live and dead cells were further evaluated by propidium iodine (PI) assay using the Cellometer Vision. Cell apoptosis was measured by flow cytometry assessment using annexin V/PI kit. Data obtained from the trypan blue test demonstrated that VA treatment reduces cell viability in a concentration- and time-dependent manner. Result of the PI assay showed a gradual increase in the population of necrotic cells (fluorescence positive cells) in VA-treated cells compared to the control cells (fluorescence negative cells). Treatment of these cancer cells (MCF-7) for 48 h at concentrations ranging from 250 μg/mL to 1000 μg/mL caused early signs of apoptosis resulting from phosphatidylserine externalization as judged by annexin V assay. We observed a strong concentration-response relationship with regard to VA exposure and annexin V/PI positive cells. In summary, our finding demonstrates that VA-induced cytotoxicity and apoptosis in MCF-7 cells involve phosphatidylserine externalization accompanied by secondary necrotic cell death. With previous findings in our laboratory, the data generated in the present study confirms that VA is a valuable botanical therapeutic agent for the treatment of breast cancer.