In this study, 4,7-dimethoxy-5-methyl-l,3-benzodioxole (SY-1) was isolated from three different
sources of dried fruiting bodies of Antrodia camphorate (AC). AC is a medicinal mushroom that
grows on the inner heartwood wall of Cinnamomum kanehirai Hay (Lauraceae), an endemic
species that is used in Chinese medicine for its anti-tumor and immunomodulatory properties.
In this study, we demonstrated that SY-1 profoundly decreased the proliferation of human
colon cancer cells (COLO 205) through G0/G1 cell-cycle arrest (50–150 mM) and induction of
apoptosis (>150 mM). Cell-cycle arrest induced by SY-1 was associated with a significant
increase in levels of p53, p21/Cip1 and p27/Kip1, and a decrease in cyclins D1, D3 and A. In
contrast, SY-1 treatment did not induce significant changes in G0/G1 phase cell-cycle
regulatory proteins in normal human colonic epithelial cells (FHC). The cells were cultured in
soft agar to evaluate anchorage-independent colony formation, and we found that the number
of transformed colonies was significantly reduced in the SY-1-treated COLO 205 cells. These
findings demonstrate for the first time that SY-1 inhibits human colon cancer cell proliferation
through inhibition of cell growth and anchorage-independent colony formation in soft agar.
However, the detailed mechanisms of these processes remain unclear and will require further
investigation.
