A black raspberry extract inhibits proliferation and regulates apoptosis in cervical cancer cells

Objective. Cervical cancer is the second most common female cancer worldwide, and it remains a challenge to manage preinvasive and invasive lesions. Food-based cancer prevention entities, such as black raspberries and their derivatives, have demonstrated a marked ability to inhibit preclinical models of epithelial cancer cell growth and tumor formation. Here, we extend the role of black raspberry-mediated chemoprevention to that of cervical carcinogenesis. Methods. Three human cervical cancer cell lines, HeLa (HPV16-/HPV18+, adenocarcinoma), SiHa (HPV16+/HPV18-, squamous cell carcinoma) and C-33A (HPV16-/HPV18-, squamous cell carcinoma), were treated with a lyophilized black raspberry ethanol extract (RO-ET) at 25, 50, 100 or 200 mu g/ml for 1,3 and 5 days, respectively. Cell proliferation was measured by WST1 (tetrazolium salt cleavage) assays. Flow cytometry (propidium iodide and Annexin V staining) and fluorescence microscopy analysis were used to measure apoptotic cell changes. Results. We found that non-toxic levels of RO-ET significantly inhibited the growth of human cervical cancer cells, in a dose-dependent and time-dependent manner to a maximum of 54%, 52% and 67%, respectively (p<0.05). Furthermore, cell growth inhibition was persistent following short-term withdrawal of RO-ET from the culture medium. Flow cytometry and fluorescence microscopy demonstrated RO-ET-induced apoptosis in all cell lines. Conclusion. Black raspberries and their bioactive components represent promising candidates for future phytochemical-based mechanistic pathway-targeted cancer prevention strategies. (C) 2011 Elsevier Inc. All rights reserved.