[Show abstract][Hide abstract] ABSTRACT: Emodin (1, 3, 8-trihydroxy-6-methylanthraquinone) is an active constituent isolated from the root of Rheum palmatum L and is the main effective component of some Chinese herbs and plants. Pharmacological studies have demonstrated that emodin exhibits anti-cancer effects on several human cancers. However, the molecular mechanisms of emodin-mediated tumor regression have not been fully defined. This study was performed to investigate the antiproliferative and antimetastatic effects of emodin on pancreatic cancer in vitro and in vivo. Our results showed that emodin induced a higher percentage of growth inhibition and apoptosis in the pancreatic cancer cell line SW1990 compared to that of control, and emodin suppressed the migration and invasion of SW1990 cells in a dose-dependent manner. To investigate the possible mechanisms involved in these events, we performed electrophoretic mobility shift assay (EMSA) and Western blot analysis, and found that emodin significantly down-regulated NF-κB DNA-binding activity, survivin and MMP-9 in SW1990 cells. Moreover, the expression of cleaved caspase-3 was up-regulated in SW1990 cells after treatment with emodin. In addition, a metastatic model simulating human pancreatic cancer was established by orthotopic implantation of histologically intact human tumor tissue into the pancreatic wall of nude mice. Oral administration of emodin significantly decreased tumor weight and metastasis compared to control. Furthermore, the expression of NF-κB, survivin and MMP-9 were also suppressed in tumor tissues after treatment with emodin. Collectively, our results indicated that emodin exerts antiproliferative and antimetastatic activity on pancreatic cancer both in vitro and in vivo, which may be related to down-regulation of NF-κB and its regulated molecules such as survivin and MMP-9 proteins. Consequently, these results provide important insights into emodin as an anti-invasive agent for the therapy of human pancreatic cancer.
[Show abstract][Hide abstract] ABSTRACT: Many studies have demonstrated that emodin inhibits the growth and induces the apoptosis and chemo-sensitization of various cancer cells in animal models. The aim of this study was to investigate the molecular mechanism of the chemo-sensitization potential of emodin on gemcitabine in pancreatic cancer cell lines via inhibition of nuclear factor-κB (NF-κB). SW1990 and SW1990/GZ cells were treated with: i) emodin (20 µmol/l), ii) NF-κB inhibitor Bay 11-7082 (5 µmol/l), iii) gemcitabine (20 µmol/l), iv) pre-treated with emodin for 24 h followed by coincubation with gemcitabine for 24 h, or v) pre-treated with Bay 11-7082 for 1 h followed by treatment with gemcitabine for 24 h. SW1990 and SW1990/GZ cells were also treated with emodin (20, 40 and 80 µmol/l). Cellular proliferation and apoptosis were detected by the Cell Counting Kit-8 (CCK-8) assay and flow cytometry. NF-κB protein was detected by Western blotting. SW1990/GZ cell morphological changes were observed under optical and fluorescence microscopes. Emodin strongly inhibited the proliferation and induced the apoptosis of both pancreatic cancer cell lines. Furthermore, emodin combined with gemcitabine induced a higher percentage of growth inhibition and apoptosis in both pancreatic cancer cell lines compared to gemcitabine alone. Pre-treatment of SW1990/GZ cells with Bay 11-7082 for 1 h followed by gemcitabine resulted in greater inhibitory and apoptosis rates compared to gemcitabine alone. The resistant pancreatic cell line SW1990/GZ presented higher constitutive NF-κB protein expression compared to the SW1990 cells. Emodin not only down-regulated NF-κB in a dose-dependent manner in SW1990 and SW1990/GZ cells under unstimulated conditions, but also inhibited gemcitabine-induced NF-κB protein expression. Emodin potentiated the antitumor effects of gemcitabine in pancreatic cancer, which was related to the down-regulation of NF-κB.
Preview · Article · Mar 2011 · Molecular Medicine Reports