Investigator: Heather Axen

Scientific Theme: Cancer

Abstract: It is well established that nutraceutical compounds are highly effective in arresting cancer, however, the mechanisms through which this occurs are not well understood. Small, non-protein coding RNA (miRNA) offer promising targets for this research. Among the critical avenues yet to be explored are if the effector miRNAs involved are derived from the plant extract, or if they are produced by the cancer cell as a result of the exposure to the plant compounds. To this end, the specific aims of this project are: 1) to determine if miRNA’s are involved in mitigating gastric cancer cell proliferation upon exposure to plant nutraceuticals, and 2) to determine if the source of the effector miRNA is important in preventing cancer cell proliferation; is effector miRNA from the plant miRNA, or are they produced endogenously by the cancer cell following exposure to nutraceuticals. Berries have particularly high concentrations of antioxidants and nutraceutical compounds, particularly blackberries. This proposal leverages flow cytometry and state of the art miRNA microarray technology to address the previously outlined aims. Immortalized cell lines from across the GI tract will be used for all treatments and negative controls, including: one esophageal and one colon cell line, and two gastric cancer cell lines. Treatments will include: the well-characterized nutraceutical gallic acid found in high concentrations in blackberries (40uM), blackberry extract, blackberry miRNA, as well as a treatment of blackberry miRNA applied directly to a microarray chip. Negative controls consist of untreated cells. All treatments and controls will be done in biological triplicate. Following treatment total mRNA will be extracted and hybridized to Affymetrix GeneChip miRNA 4.0 arrays. An additional three replicates will be collected for cell-cycle analysis using flow cytometry. Each cell line will be exposed to each treatment or control for 0, 3, 6, 12, 24, and 48 hours, to ensure the complete duration of each line’s cell cycle is included in the experiment.

Human Health Relevance: The primary objective of this proposal is to understand the mechanisms through which naturally occurring compounds in plants function to halt the growth of cancer of the gastrointestinal tract. Gastric cancer is a profound health concern. As the fifth most common cancer and fatality rate of over 70%, this is the third highest cause of cancer death. Preventing this and other GI tract cancers are of paramount importance. The therapeutic value of nutraceuticals demands elucidation of their functional mechanisms.