Abstract
Kheng Leong Ooi, PhD1, Tengku Sifzizul Tengku Muhammad, PhD2,3, Lee Yein Lam, BSc1, and Shaida Fariza Sulaiman, PhD1
DOI: 10.1177/1534735411433203
Previous cytotoxic (anticancer) evaluations of Elephantopus mollis were mainly focused on its elephantopin derivatives neglecting the combined effect of the phytochemicals in its traditionally used extracts. In this study, the cytotoxic mechanism of its extracts was investigated using methylene blue assay. The cytotoxic screening results revealed the ethyl acetate extract as the most potent extract by displaying prominent dose-dependent and time-dependent growth inhibitions in human liver carcinoma HepG2 cells with the lowest EC50 value of 9.38 ± 0.43 μg/mL after 72 hours of treatment. Acute exposure of the HepG2 cells to the ethyl acetate extract produced a significant regulation of caspase-3 with the peak expression at 8 hours of treatment (P < .05). DNA fragmentation indicated by DeadEnd Apoptosis Detection System–labeled nuclei cells confirmed that the extract induced apoptotic cell death through caspase-3-dependent pathway in HepG2 cells.
Wei Jiang, MD1, Qing Cong, MD1, Yisheng Wang, MD1, Bin Ye, PhD4, Congjian Xu, MD, PhD1,2,3
DOI: 10.1177/1534735411433833
Ginkgolide B (GB), the primary active component of Ginkgo biloba extracts, may have antitumor properties. The objective of this study was to determine the effects and possible mechanisms of GB in ovarian cancer cells. In this study, human ovarian cancer cell lines (SKOV3 and CAOV3) were treated with different concentrations of GB alone or in combination with Cis-diaminodichloroplatinum (CDDP). An MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was performed to determine cell viability. The apoptosis rates of cells were measured by flow cytometric analysis. The expression of apoptosis-associated and proliferation-associated proteins was detected by Western blot. The cytotoxicity of GB was analyzed using a lactate dehydrogenase assay. Treatment with 100 μM GB for 3 days significantly inhibited SKOV3 and CAOV3 cell proliferation by 57.3% and 63.1% compared with control cells, respectively, as determined by MTT assay. Similarly, the apoptotic cell population was increased when treated with GB in a dose-dependent manner both in SKOV3 and CAOV3 cells. These effects were characterized by the upregulation of p21, p27, cleaved capase-3, and cleaved caspase-8 and downregulation of cyclin D1. In addition, a combined treatment of low concentrations of GB and CDDP showed an additive effect on the inhibition of SKOV3 cell proliferation. Furthermore, GB had significantly less cytotoxicity than CDDP in normal human ovarian surface epithelial cells. This study suggests that GB can be proposed as an effective antiproliferative and apoptosis-inducing agent with interesting translational application in ovarian cancers, used in addition to conventional chemotherapy.
Kuei-Li Lin, MS1, Ching-Ming Chien, PhD1, Chih-Hua Tseng, PhD1, Yeh-Long Chen, PhD1, Long-Sen Chang, PhD2, and Shinne-Ren Lin, PhD1
DOI: 10.1177/1534735411433834
Furano-1,2-naphthoquinone (FNQ), a biologically active component of Avicennia marina, has been demonstrated to display anticancer activity. FNQ exerted cytotoxicity with the G2/M cell cycle arrest and apoptosis in Ca9-22 cells. FNQinduced G2/M arrest was correlated with a marked decrease in the expression levels of cyclin A and cyclin B, and their activating partner cyclin-dependent kinases (CDK) 1 and 2 with concomitant induction of p27. FNQ-induced apoptosis was accompanied by Bax and Bad upregulation, and the downregulation of Bcl-2, Bcl-XL, Mcl-1, and X-linked inhibitor of apoptosis (XIAP), resulting in cytochrome C release and sequential activation of caspase-9 and caspase-3. Mechanistic studies showed that FNQ suppressed Src phosphorylation, PI3K, and Akt activation in Ca9-22 cells. Moreover, the Src inhibitor PP2 reduced the phosphorylation of Src and activation of PI3K/Akt, which was comparable with FNQ treatment. The combined treatment of FNQ with PP2 enhanced the cell cycle arrest and apoptosis and also led to the downregulation of Bcl-XL, Mcl-1, XIAP, cyclin A, cyclin B, CDK1, and CDK2 and upregulation of p27, Bax, and Bad. These findings suggest that FNQ-mediated cytotoxicity of Ca9-22 cells is related with the G2/M cell cycle arrest and apoptosis via inactivation of Src and PI3K/Akt–mediated signaling pathways.