In vitro and in vivo studies of antioxidant and anti-breast cancer activities of pomiferin
| dc.contributor.advisor | Meckling, Kelly | |
| dc.contributor.advisor | Cao, Rong | |
| dc.contributor.author | Yang, Raymond X. | |
| dc.date.accessioned | 2021-03-31T15:37:16Z | |
| dc.date.available | 2021-03-31T15:37:16Z | |
| dc.date.copyright | 2008 | |
| dc.degree.department | Department of Human Biology and Nutritional Sciences | en_US |
| dc.degree.grantor | University of Guelph | en_US |
| dc.degree.name | Doctor of Philosophy | en_US |
| dc.description.abstract | Reactive oxygen species (ROS) are ubiquitous in the human body and play a pivotal role in many chronic diseases, including cancer. The human body has developed a strong antioxidant defense system. Unfortunately, this system cannot be adequately maintained with ageing. The supply of exogenous antioxidants to help the body fight these diseases is a logical approach. Polyphenols, particularly flavonoids, have been found to be strong antioxidants. In this study, the prenylated isoflavone, pomiferin, from Osage orange, was examined. I found that pomiferin had a much stronger antioxidant activity than soy isoflavones, genistein and daidzein, in three different antioxidant assays including [beta]-CLAMS, FRAP and PCL. By using both estrogen receptor positive (MCF-7) and negative (MDA-MB-435) cancer cell lines, pomiferin showed much lower IC50 values than soy isoflavones in both cell lines (5.2 ± 0.90 vs 5.4 ± 0.72 M) after 24 hr treatment. The selectivity of pomiferin between cancer cells and MCF-10A (spontaneously immortalized human breast epithelial cell line) was high. Microarray techniques were used to find the gene expression changes when all three cells were treated with 5.0 M pomiferin. At p < 0.05, 515, 691 and 59 genes were significantly regulated for MCF-7, MDA-MB-435 and MCF-10A, respectively; and at p < 0.01 cut off, 94, 105 and 1 genes, respectively. Many of these genes are associated with antioxidant enzymes, cell cycle regulation and apoptosis. To confirm the results from microarray, RT-qPCR was used to verify some of the gene expression changes. The expression of 20 out of 21 genes was confirmed. In addition, the xenograft models of MCF-7 and MDA-MB-435 cells were established to find the 'in vivo' anticancer activity of pomiferin. The tumour size was significantly reduced in MCF-7 with 0.2% and MDA-MB-435 with 0.5% of pomiferin in their diet (p < 0.05). Bioavailability of pomiferin was measured and the correlation with tumour sizes was evaluated. Plasma pomiferin level can partially explain the tumour size, but many other factors likely play a role. Further studies are needed to determine the specific mechanism(s) by which pomiferin alters specific gene expression and the differential effects in tumour versus normal cells. | en_US |
| dc.identifier.uri | https://hdl.handle.net/10214/24198 | |
| dc.language.iso | en | |
| dc.publisher | University of Guelph | en_US |
| dc.rights.license | All items in the Atrium are protected by copyright with all rights reserved unless otherwise indicated. | |
| dc.subject | reactive oxygen species | en_US |
| dc.subject | antioxidants | en_US |
| dc.subject | prenylated isoflavone | en_US |
| dc.subject | pomiferin | en_US |
| dc.subject | Osage orange | en_US |
| dc.title | In vitro and in vivo studies of antioxidant and anti-breast cancer activities of pomiferin | en_US |
| dc.type | Thesis | en_US |
Files
Original bundle
1 - 1 of 1