College of Agriculture & Natural Resources
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The collections in this community comprise faculty research works, as well as graduate theses and dissertations.
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Item Polyphenol Containing Sorghum Brans Exhibit an Anti-Cancer Effect in Apc Min/+ Mice Treated with Dextran Sodium Sulfate(MDPI, 2021-08-01) Lee, Seong-Ho; Lee, Hee-Seop; Lee, Jihye; Amarakoon, Darshika; Lou, Zhiyuan; Noronha, Leela E.; Herald, Thomas J.; Perumal, Ramasamy; Smolensky, DmitriyColon cancer (CC) is considered a high-risk cancer in developed countries. Its etiology is correlated with a high consumption of red meat and low consumption of plant-based foods, including whole grains. Sorghum bran is rich in polyphenols. This study aimed to determine whether different high-phenolic sorghum brans suppress tumor formation in a genetic CC rodent model and elucidate mechanisms. Tissue culture experiments used colorectal cancer cell lines SW480, HCT-116 and Caco-2 and measured protein expression, and protein activity. The animal model used in this study was APC Min+/mouse model combined with dextram sodium sulfate. High phenolic sorghum bran extract treatment resulted in the inhibition of proliferation and induced apoptosis in CC cell lines. Treatment with high phenolic sorghum bran extracts repressed TNF-α-stimulated NF-κB transactivation and IGF-1-stimulated PI3K/AKT pathway via the downregulation of β-catenin transactivation. Furthermore, high-phenolic sorghum bran extracts activated AMPK and autophagy. Feeding with high-phenolic sorghum bran for 6 weeks significantly suppressed tumor formation in an APC Min/+ dextran sodium sulfate promoted CC mouse model. Our data demonstrates the potential application of high-phenolic sorghum bran as a functional food for the prevention of CC.Item THE ROLE OF ESE-1 IN NON-SMALL CELL LUNG CANCER (NSCLC) CELLS(2020) Lou, Zhiyuan; Lee, Seong-Ho; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Lung cancer is the most life-threatening cancer in the world. The identification of the effective molecular target is essential for lung cancer prevention and therapy. Epithelial Specific ETS-1 (ESE-1) is a transcription factor associated with several types of cancer. However, the significance of ESE-1 in human non-small cell lung cancer (NSCLC) remains unclear. The objective of this dissertation was to investigate if ESE-1 expression influences the tumorigenic and metastatic activity of human non-small cell lung cancer (NSCLC) and to explore the mechanisms associated with tumorigenesis and epithelial mesenchymal transition (EMT). Overexpression of ESE-1 repressed the anchorage-independent growth of human NSCLC cells (H1299 and H1703) and led to an increase of G1 arrest and apoptosis, additionally, to repress invasion and migration. Xenograft study indicated that ESE-1 expression inhibited the formation and development of the tumor. In terms of mechanistic studies, overexpression of ESE-1 downregulates NF-κB transcriptional activity in both H1299 and H1703 cells. The downregulation might be associated with inhibition of NF-κB-p65 phosphorylation. ESE-1 is a downstream target of TGF-β-stimulated EMT. Downregulation of ESE-1 by TGF-β is dependent on Smad2/3, but not on Smad4 and other alternative pathways, including ERK, p38 MAPK, JNK, RAS, GSK3, PI3K, NF-ĸB, CDC42, PKC, and Rock signaling. We identified two putative Smad responsive elements (SRE) in the ESE-1 promoter. After cloning internal deletion and point mutated clones lacking distal and proximal SRE, which were localized at the distal and proximal regions of the ESE-1 promoter between -1500 to -713, the double mutation responsible for ESE-1 transcriptional downregulation with TGF-β induction. Moreover, EMT downstream target Snail reciprocally interacts with ESE-1. Our findings indicate that ESE-1 serves as a tumor repressor in ESE-1-null NSCLC cells, and we propose a potential use of ESE-1 as a target of lung cancer chemoprevention.Item ANTICANCER MECHANISM OF TOLFENAMIC ACID IN COLORECTAL CANCER(2016) Lou, Zhiyuan; Lee, Seong-Ho; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Colorectal cancer (CRC) is the third leading cause of cancer-related death in the United States. Chemopreventive therapies could be effective way to treat CRC. Tolfenamic acid, one of the NSAIDs, shows anti-cancer activities in several types of cancer. Aberrant Wnt/β-catenin regulation pathway is a major mechanism of colon tumorigenesis. Here, we sought to better define the mechanism by which tolfenamic acid suppresses colorectal tumorigenesis focusing on regulation of β-catenin pathway. Treatment of tolfenamic acid led to a down-regulation of β-catenin expression in dose dependent manner in human colon cancer cell lines without changing mRNA. MG132 inhibited tolfenamic acid-induced downregulation of β-catenin and exogenously overexpression β-catenin was stabilized in the presence of tolfenamic acid. Tolfenamic acid induced an ubiquitin-mediated proteasomal degradation of β-catenin. In addition, tolfenamic acid treatment decreased transcriptional activity of β-catenin and expression of Smad2 and Smad3 while overexpression of Smad 2 inhibited tolfenamic acid-stimulated transcriptional activity of β-catenin. Moreover, tolfenamic acid decreased β-catenin target gene such as vascular endothelial growth factor (VEGF) and cyclin D1. In summary, tolfenamic acid is a promising therapeutic drug targeting Smad 2-mediated downregulation of β-catenin in CRC.