Induction of apoptosis by phloroglucinol isolated from Ecklonia Cava in HT-29 human colon cancer cells

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 366-382-Physiological Impacts of Endocrine Disrupting Chemicals
Basic/Translational
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-368
Taek-Jeong Nam*, Mi-Hye Kang, Min-Kyeong Lee, In-Hye Kim and Youn-Hee Choi
Pukyong Natl Univ, Busan, South Korea
Phloroglucinol (PG) is a polyphenol compound derived from Ecklonia cava (known as brown algae) that has beneficial biological activities, including anti-oxidant, anti- inflammatory, and anti-cancer properties. Here, we investigated the signaling pathways related to the anticancer effects of PG in HT-29 human colon cancer cells.

 MTS assays revealed that PG significantly induced cell death in a dose-dependent manner. HT-29 cells treated with PG displayed apoptotic features, such as cell cycle arrest at the G0/G1 phase. Consistent with this, Western blotting showed that PG treatment resulted in decreased expression of Cdk4, Cdk6 and cyclinD1, and increased expression of p27.         

 We observed that PG-induced apoptosis leads to the formation of the death-induced signaling complex involving Fas, FADD, procaspase-8 and AIF. These responses were accompanied by a change in the mitochondrial membrane potential along with activation of the Bcl-2 family proteins.

 We also analyzed the effect of PG on the insulin-like growth factor (IGF-IR) signaling pathway. PG decreased the expressions of IGF-IR and IRS-I, and reduced the activities of mitogen-activated protein kinases (MAPKs) and ERK phosphorylation. Although further studies are required to reveal the multiple mechanisms behind the activities of PG, our findings suggest that it inhibits the proliferation of HT-29 human colon cancer cells, as observed by measuring cell death via induction of apoptosis. Therefore, PG may have therapeutic potential against the pathogenesis of colon cancer in humans.

Nothing to Disclose: TJN, MHK, MKL, IHK, YHC

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm