title: Ethanol extract of Innotus obliquus (Chaga mushroom) induces G1 cell cycle arrest in HT-29 human colon cancer cells.
abstract: OBJECTIVE
  Inonotus obliquus (I. obliquus, Chaga mushroom) has long been used as a folk medicine to treat cancer. In the present study, we examined whether or not ethanol extract of I. obliquus (EEIO) inhibits cell cycle progression in HT-29 human colon cancer cells, in addition to its mechanism of action.
  
  
  METHODS
  To examine the effects of Inonotus obliquus on the cell cycle progression and the molecular mechanism in colon cancer cells, HT-29 human colon cancer cells were cultured in the presence of 2.5 - 10 µg/mL of EEIO, and analyzed the cell cycle arrest by flow cytometry and the cell cycle controlling protein expression by Western blotting.
  
  
  RESULTS
  Treatment cells with 2.5 - 10 µg/mL of EEIO reduced viable HT-29 cell numbers and DNA synthesis, increased the percentage of cells in G1 phase, decreased protein expression of CDK2, CDK4, and cyclin D1, increased expression of p21, p27, and p53, and inhibited phosphorylation of Rb and E2F1 expression. Among I. obliquus fractions, fraction 2 (fractionated by dichloromethane from EEIO) showed the same effect as EEIO treatment on cell proliferation and cell cycle-related protein levels.
  
  
  CONCLUSIONS
  These results demonstrate that fraction 2 is the major fraction that induces G1 arrest and inhibits cell proliferation, suggesting I. obliquus could be used as a natural anti-cancer ingredient in the food and/or pharmaceutical industry.
authors: Department of Food Science and Nutrition, Dongseo University, Busan 617-716, Korea.
authors: Hyun Sook
authors: HS
authors: Lee
authors: Research Institute, Adbiotech Co. Ltd., Gangwon 200-957, Korea.
authors: Eun Ji
authors: EJ
authors: Kim
authors: Department of Technology and Home Economics Education, Kongju National University, 56 Kongjudaehak-ro, Chungnam 314-701, Korea.
authors: Sun Hyo
authors: SH
authors: Kim
keywords: Inonotus obliquus; Rb; anti-cancer; cell cycle; colon cancer