Antrodia camphorata induces apoptosis and enhances the cytotoxic effect of paclitaxel in human ovarian cancer cells.

INTRODUCTION: Antrodia camphorata is a Chinese herb. Recently, several reports demonstrated that it had growth-inhibiting effects on some cancer cells. In this study, we investigated whether the crude extract of A. camphorata could inhibit the growth of ovarian cancer cells and examined the possible mechanisms involved. We also examined whether the cytotoxic effect of paclitaxel on ovarian cancer cells would be affected by A. camphorata. MATERIALS AND METHODS: Two human ovarian cancer cell lines, SKOV-3 and TOV-21G, were treated with A. camphorata (3-300 µg/mL). An MTT assay was used to test its cytotoxic effect. The apoptosis-related factors including the activity of caspase-3, -8, and -9 and the cytochrome c level released from mitochondria were analyzed. The expression of Bcl-2 family proteins (Bcl-2, Bcl-xL, Bax, Bim, Bad, and Bak) was examined by Western blot analysis. Cell lines were further treated with paclitaxel or paclitaxel plus A. camphorata to examine the cytotoxic efficiency. RESULTS: The MTT assay revealed that A. camphorata was cytotoxic to both the ovarian cancer cells in a dose- and time-dependent manner. Activities of caspase-3, -8, and -9 and release of mitochondrial cytochrome c increased in both ovarian cancer cell lines with increased dose of A. camphorata. Western blot analysis of Bcl-2 family proteins revealed an increased expression of Bad in SKOV-3 cells, whereas increased expression of Bim and Bak and decreased expression of Bcl-xL were noted in TOV-21G cells. In addition, the cytotoxic effect of paclitaxel on SKOV-3 and TOV-21G cells was increased significantly with the addition of A. camphorata (P < 0.01) by MTT assay. CONCLUSIONS: These in vitro results suggest that A. camphorata causes a cytotoxic effect on ovarian cancer cells through the induction of apoptosis. It may also enhance the antitumor effect of paclitaxel. Further studies with the ultimate goal of conducting clinical trials are warranted.

Arsenic trioxide induces apoptosis in uveal melanoma cells through the mitochondrial pathway.

Uveal melanoma, the most common primary intraocular malignancy in adults, is highly resistant to most chemotherapeutic drugs. Arsenic trioxide (ATO) is known to inhibit ocular melanoma cell growth. However, the effects of ATO on human uveal melanoma cells are poorly understood. Therefore, this study evaluated the mechanisms of ATO and its inhibiting effects on a human uveal melanoma cell line (SP6.5). An MTT assay indicated that, compared to human fibroblasts, ATO had a stronger inhibiting effect on SP6.5 cell proliferation in a dose- and time-dependent manner. The apoptosis ratio in SP6.5 cells, which was indicated by cell DNA fragmentation, was 4.1- to 7.7-fold higher after ATO-treatment. The ATO treatment substantially increased the activities of caspase-3 and caspase-9, but not of caspase-8. These findings were consistent with the protein expression observed by Western blots. ATO also significantly enhanced expression of Bax and cytochrome c proteins but suppressed those of Bcl-2. Therefore, ATO-induced apoptosis in uveal melanoma cells occurs mainly through the mitochondrial pathway rather than through the death receptor pathway. This report is the first to evaluate the complete mitochondria-dependent apoptotic pathway of ATO in uveal melanoma cells. These results can be used to improve the clinical effectiveness of ATO treatment for uveal melanoma.