In-Hwa Choi

Effect of Orostachys japonicus on Cell Growth and Apoptosis in Human Hepatic Stellate Cell Line LX2

Orostachys japonicus (O. japonicus), used to treat diseases such as various cancers, gastric ulcers, fever, hepatitis, arthritis, eczema, for hemostasis, and intoxication in folk medicine, has been an important constituent in many herbal formulae. We demonstrated that the water extract of O. japonicus led to growth inhibition of LX2 cells by inducing apoptosis through the caspase activation, related to the MAPK pathway. O. japonicus inhibited proliferation of LX2 cells in a dose- and time-dependent manner, increased the apoptosis fraction at cell cycle progression with an accompanying DNA fragmentation, and resulted in a significant decrease in Bcl-2 and an increase in Bax mRNA levels. Exposure of LX2 cells to O. japonicus induced caspase-3 activation, however when the LX2 cells were also treated with the pan-caspase inhibitor Z-VAD-FMK and the caspase-3 inhibitor Z-DEVE-FMK, apoptosis was blocked. O. japonicus inhibited anti-apoptotic Mcl-1 protein and MEK/ERK phosphorylation in LX2 cells. The results indicate that O. japonicus inhibits the cell growth of LX2 cells by inducing apoptosis through caspase activity. O. japonicus down-regulated Mcl-1 protein levels and inhibited the phosphorylation of MEK/ERK, suggesting that it mediates cell death in LX2 cells through the down-regulation of Mcl-1 protein via a MEK/ERK-independent pathway.

Artemisia capillaris Thunb. inhibits cell growth and induces apoptosis in human hepatic stellate cell line LX2

SUMMARY Artemisia capillaris (A. capillaries) is known to play roles in many cellular events, such as cellproliferation, differentiation, and apoptosis. We investigated the antifibrogenic efficacy of A.capillaris in the immortalized human hepatic stellate cell line LX2. Cell proliferation wasdetermined by the MTT assay. Cell cycle was analyzed by the flow cytometry. Apoptotic cellswere measured using a cell death detection ELISA. Caspase activity was detected by acolorimetric assay. The mRNA level of Bcl-2 and Bax mRNA were measured by real-time PCR.MEK and ERK protein were detected by Western blot analysis. We provide evidence that A.capillaris induces cell cycle arrest, apoptosis, and potently inhibits the mitogen-activatedprotein kinase pathway. A. capillaris inhibited cell proliferation of LX2 cells in a dose- andtime-dependent manner, increased the apoptosis fraction at cell cycle analysis with anaccompanying DNA fragmentation, and resulted in a significant decrease in Bcl-2 mRNA levelsand an increase in Bax expression. Exposure of LX2 cells to A. capillaris induced caspase-3activation, but co-treatment of A. capillaris with the pan-caspase inhibitor Z-VAD-FMK, andthe caspase-3 inhibitor Z-DEVE-FMK, blocked apoptosis. A. capillaris down-regulated Mcl-1protein levels and inhibited phosphorylation of MEK/ERK, suggesting that it mediates celldeath in LX2 cells through the down-regulation of Mcl-1 protein via a MEK/ERK-independentpathway.Key words: Artemisia capillaris Thunb.; Apoptosis; Caspase activity; Immortalized human hepaticstellate cells LX2; MEK/ERK*Correspondence: Youngchul Kim, Department of InternalMedicine, College of Oriental Medicine, Kyung HeeUniversity, Seoul 130-702, Korea. Tel: +82-2-958-9236; fax:+82-2-958-9120; E-mail: yckim@khmc.or.kr