Abstract A77: Lyophilized black raspberries modulate microRNA targets inhuman cervical cancer cells

Abstract

Abstract Cervical cancer is the second most common female cancer worldwide and is expected to result in 11,270 new cases and 4,070 deaths this year in the United States. Advances in the early detection of malignant lesions continue to lower cervical cancer mortality; however, cervical cancer remains a challenge for prevention and the management of pre-invasive disease. A long latency precedes the development of many invasive cervical cancers, and provides an extended window for cancer risk reducing interventions. Natural food products and bioactive food components have attracted significant interest as nutraceutical-based cancer prevention strategies. MicroRNAs (miRs) play important roles in diverse biological processes, including development, cell differentiation, proliferation and apoptosis. It has been shown that microRNAs are deregulated in many cancers, and consequently represent new targets for cancer treatments. Previously, we demonstrated that a lyophilized black raspberry (LBR, Rubus occidentalis) extract inhibited the proliferation of human cervical cancer cells [HeLa (HPV16−/HPV18+, adenocarcinoma), SiHa (HPV16+/HPV18−, squamous cell carcinoma) and C-33A (HPV16−/HPV18−, squamous cell carcinoma)] in a dose- and time-dependent manner. To investigate the role of microRNAs in the growth inhibitory activity of LBR extract on cervical cancer cells, we performed global microRNA profiling (667 unique miRs) using the TaqMan MicroRNA Array v2.0 on HeLa, SiHa and C-33A cells. Cervical cells were treated with 200µg/mL LBR extract or 0.02% DMSO (delivery vehicle control) for 1 day and 3 days, respectively. HeLa, SiHa, and C-33A cells demonstrated approximately 300 microRNA changes following 1 day or 3 days of LBR extract exposure. Once controlled for delivery vehicle effects, all cells demonstrated significant (2^- Ct Method, 2-fold cutoff, p<0.05) LBR extract-dependent miR regulation (HeLa, 101 miRs; SiHa, 70 miRs; and C-33A, 68 miRs). Ingenuity Pathway Analysis predicted that at least 27 unique LBR extractmodulated microRNAs were involved in carcinogenesis. Interestingly, despite histopathologic and genetic background differences, five microRNAs demonstrated the same expression profile in all cervical cells following LBR extract exposure: miR-26a-2*, miR-923 (up-regulated) and miR-19a*, miR-885-5p, miR-937 (down-regulated). In addition, potential oncomiRs miR-184 and miR-145 were down-regulated by LBR extract uniquely in SiHa cells. Suppression of oncomiR-184 and oncomiR-145 was validated by real time RT-PCR (2.4-fold and 2.1-fold decrease, respectively). In conclusion, LBR inhibits growth and modulates microRNA expression in human cervical cancer cells in conserved (all cell types) and unique profiles. Further studies will identify the mechanistic role of these microRNAs in LBR-mediated growth suppression and cervical carcinogenesis. Citation Information: Cancer Prev Res 2010;3(1 Suppl):A77.