OBJECTIVETo explore the effects of epigallocatechin-3-gallate (EGCG) on the proliferation of human oral epithelial cancer cell line KB cells and the molecular mechanisms.

METHODKB cells were treated with various concentrations of EGCG for 24 or 48 h. MTT assay was used to test the cell viability. The changes of cell cycle in KB cells treated with EGCG for 48 h were analyzed using flow cytometry. The expressions of cyclin A, cyclin D1 and cyclin E were detected by RT-PCR and Western blotting.

RESULTThe viability of KB cells treated with various concentrations of EGCG (25, 50, 100, 200, 400, and 800 micromol/L) for 48 h were decreased to (85.4-/+2.4)%, (80.4-/+2.8)%, (51.5-/+4.5)%, (30.2-/+1.9)%, (25.3-/+1.5)%, (20.0-/+1.1)%, respectively, showing significant difference from that of the control group [(100.0-/+2.2)%, P<0.05). EGCG decreased the viabilities of KB cells in a dose-dependent manner. Flow cytometry demonstrated that treatment with EGCG significantly increased the cell percentage in sub-G1 phase, which was (73.5-/+4.4)% after a 48-h EGCG treatment, significantly different from that in the control group [(47.3-/+3.5)%, P<0.05). EGCG-induced G1 phase arrest was correlated to the down-regulation of cyclin A and cyclin E.

CONCLUSIONEGCG inhibits the proliferation of KB cells by inducing G1 phase arrest, which involves the downregulation of cyclin E.

Catechin ; analogs & derivatives ; pharmacology ; Cell Cycle ; drug effects ; Cell Proliferation ; drug effects ; Cyclin E ; metabolism ; Flow Cytometry ; G1 Phase Cell Cycle Checkpoints ; drug effects ; Humans ; KB Cells ; Oncogene Proteins ; metabolism

BACKGROUND/AIMS: The treatment of chronic myeloid leukemia (CML) has achieved impressive success since the development of the Bcr-Abl tyrosine kinase inhibitor, imatinib mesylate. Nevertheless, resistance to imatinib has been observed, and a substantial number of patients need alternative treatment strategies. METHODS: We have evaluated the effects of deferasirox, an orally active iron chelator, and imatinib on K562 and KU812 human CML cell lines. Imatinib-resistant CML cell lines were created by exposing cells to gradually increasing concentrations of imatinib. RESULTS: Co-treatment of cells with deferasirox and imatinib induced a synergistic dose-dependent inhibition of proliferation of both CML cell lines. Cell cycle analysis showed an accumulation of cells in the subG1 phase. Western blot analysis of apoptotic proteins showed that co-treatment with deferasirox and imatinib induced an increased expression of apoptotic proteins. These tendencies were clearly identified in imatinib-resistant CML cell lines. The results also showed that co-treatment with deferasirox and imatinib reduced the expression of BcrAbl, phosphorylated Bcr-Abl, nuclear factor-kappaB (NF-kappaB) and beta-catenin. CONCLUSIONS: We observed synergistic effects of deferasirox and imatinib on both imatinib-resistant and imatinib-sensitive cell lines. These effects were due to induction of apoptosis and cell cycle arrest by down-regulated expression of NF-kappaB and beta-catenin levels. Based on these results, we suggest that a combination treatment of deferasirox and imatinib could be considered as an alternative treatment option for imatinib-resistant CML.
Antineoplastic Agents/*pharmacology ; Apoptosis/drug effects ; Apoptosis Regulatory Proteins/metabolism ; Benzoates/*pharmacology ; Cell Proliferation/drug effects ; Dose-Response Relationship, Drug ; Drug Resistance, Neoplasm/*drug effects ; G1 Phase Cell Cycle Checkpoints/drug effects ; Humans ; Imatinib Mesylate/*pharmacology ; Iron Chelating Agents/*pharmacology ; K562 Cells ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive/*drug therapy/metabolism ; Protein Kinase Inhibitors/*pharmacology ; Signal Transduction/drug effects ; Triazoles/*pharmacology

Marsdenia tenacissima extract (MTE, trade name: Xiao-Ai-Ping injection) is an extract of a single Chinese plant medicine. It has been used for the treatment of cancer in China for decades, especially for esophageal cancer and other cancers in the digestive tract. In the present study, the potential mechanism for MTE's activity in esophageal cancer was explored. The effects of MTE on the proliferation of human esophageal cancer cells (KYSE150 and Eca-109) were investigated by the MTT assay, the BrdU (bromodeoxyuridine) incorporation immunofluorescence assay, and flow cytometric analysis. MTE inhibited cell proliferation through inducing G0/G1 cell cycle arrest in KYSE150 and Eca-109. Western blot analysis was employed to determine protein levels in the MTE treated cells. Compared with the control cells, the expression levels of the cell cycle regulatory proteins cyclin D1/D2/D3, cyclin E1, CDK2/4/6 (CDK: cyclin dependent kinase), and p-Rb were decreased significantly in the cells treated with MTE at 40 mg·mL(-1). In addition, MTE had an inhibitory effect on the MAPK (mitogen-activated protein kinase) signal transduction pathway, including ERK (extracellular signal-regulated kinase), JNK (c-Jun N-terminal kinase), and p38MAPK. Moreover, MTE showed little additional effects on the regulation of cyclin D1/D3, CDK4/6, and p-Rb when the ERK pathway was already inhibited by the specific ERK inhibitor U0126. In conclusion, these data suggest that MTE inhibits human esophageal cancer cell proliferation through regulation of cell cycle regulatory proteins and the MAPK signaling pathways, which is probably mediated by the inhibition of ERK activation.
Apoptosis ; drug effects ; Carcinoma ; drug therapy ; enzymology ; physiopathology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; Esophageal Neoplasms ; drug therapy ; enzymology ; physiopathology ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; G1 Phase Cell Cycle Checkpoints ; drug effects ; Humans ; MAP Kinase Signaling System ; drug effects ; Marsdenia ; chemistry

Liver fibrosis is an important health problem that can further progress into cirrhosis or liver cancer, and result in significant morbidity and mortality. Inhibiting proliferation and inducing apoptosis of hepatic stellate cells (HSCs) may be the key point to reverse liver fibrosis. At present, anti-fibrosis drugs are rare. Kinetin is a type of plant-derived cytokinin which has been reported to control differentiation and induce apoptosis of human cells. In this study, the HSCs were incubated with different concentrations of kinetin. The proliferation of rat HSCs was measured by MTT assay, cell cycle and apoptosis were analyzed by flow cytometry, and the apoptosis was examined by TUNEL method. The expression of Bcl-2 and Bax proteins was detected by immunocytochemistry staining. It was found that kinetin could markedly inhibit proliferation of HSCs. In a concentration range of 2 to 8 μg/mL, the inhibitory effects of kinetin on proliferation of HSCs were increased with the increased concentration and the extension of time (P < 0.01). Flow cytometry indicated that kinetin could inhibit the DNA synthesis from G0/G1 to S phase in a dose-dependent manner (P < 0.01). The apoptosis rates of the HSCs treated with 8, 4 and 2 μg/mL kinetin (25.62% ± 2.21%, 15.31% ± 1.9% and 6.18% ± 1.23%, respectively) were increased significantly compared with the control group (3.81% ± 0.93%) (P < 0.01). All the DNA frequency histogram in kinetin-treated groups showed obvious hypodiploid peak (sub-G1 peak), and with the increase of kinetin concentrations, the apoptosis rate of HSCs also showed a trend of increase. It was also found that kinetin could down-regulate the expression of Bcl-2, and up-regulate the expression of Bax, leading to the decreased ratio of Bcl-2/Bax significantly. The kinetin-induced apoptosis of HSCs was positively correlated with the expression of Bax, and negatively with the expression of Bcl-2. It was concluded that kinetin can inhibit activation and proliferation of HSCs by interrupting the cell cycle at G1/S restriction point and inducing apoptosis of HSCs via reducing the ratio of Bcl-2/Bax.
Animals ; Apoptosis ; drug effects ; Cell Line, Transformed ; Cell Proliferation ; drug effects ; Dose-Response Relationship, Drug ; G1 Phase Cell Cycle Checkpoints ; drug effects ; genetics ; Gene Expression Regulation ; Growth Inhibitors ; pharmacology ; Hepatic Stellate Cells ; cytology ; drug effects ; metabolism ; Kinetin ; pharmacology ; Proto-Oncogene Proteins c-bcl-2 ; antagonists & inhibitors ; genetics ; metabolism ; Rats ; Signal Transduction ; bcl-2-Associated X Protein ; agonists ; genetics ; metabolism

Although previous reports showed drug-eluting stent (DES) could effectively inhibit neointima formation, in-stent restenosis (ISR) remains an important obstacle. The purpose of this study was to investigate different effects of paclitaxel on proliferation and cell cycle regulators between vascular smooth muscle cells (VSMCs) and vascular endothelial cells (VECs) of rats in vitro. The cultured VSMCs and VECs of rats from the same tissues were examined by using immunohistochemistry, flow cytometry and Western blotting in control and paclitaxel-treated groups. The results showed paclitaxel could effectively inhibit proliferation of VSMCs and VECs. However, as compared with VECs, proliferation of VSMCs in paclitaxel-treated group decreased less rapidly. The percentage of cells in G0-G1 and G2-M phases was reduced, and that in S phase increased after treatment for 72 h. The expression of cyclin D1 and B1, p27 and PCNA in VSMCs of paclitaxel-treated group was up-regulated, but that of p21 down-regulated as compared with VECs. It is concluded that there are significant differences in the expression of cell cycle regulators and proliferation rate between paclitaxel-treated VSMCs and paclitaxel-treated VECs, suggesting that the G1-S checkpoint regulated by paclitaxel may play a critical role in the development of complications of DES, which provides new strategies for treatments of ISR.
Animals ; Blotting, Western ; Cell Cycle ; drug effects ; Cell Cycle Proteins ; metabolism ; Cell Proliferation ; drug effects ; Cells, Cultured ; Cyclin B1 ; metabolism ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p27 ; metabolism ; Endothelial Cells ; drug effects ; metabolism ; Flow Cytometry ; G1 Phase Cell Cycle Checkpoints ; drug effects ; Immunohistochemistry ; Microscopy, Fluorescence ; Muscle, Smooth, Vascular ; cytology ; Myocytes, Smooth Muscle ; drug effects ; metabolism ; Paclitaxel ; pharmacology ; Proliferating Cell Nuclear Antigen ; metabolism ; Rats ; Tubulin Modulators ; pharmacology

Matrine (MT), the effective component of Sophora flavescens Ait, has been shown to have anti-inflammation, immune-suppressive, anti-tumor, and anti-hepatic fibrosis activities. However, the pharmacological effects of MT still need to be strengthened due to its relatively low efficacy and short half-life. In the present study, we report a more effective thio derivative of MT, MD-1, and its inhibitory effects on the activation of hepatic stellate cells (HSCs) in both cell culture and animal models. Cytological experiments showed that MD-1 can inhibit the proliferation of HSC-T6 cells with a half-maximal inhibitory concentration (IC50) of 62 μmol/L. In addition, MD-1 more strongly inhibits the migration of HSC-T6 cells compared to MT and can more effectively induce G0/G1 arrest and apoptosis. Investigating the biological mechanisms underlying anti-hepatic fibrosis in the presence of MD-1, we found that MD-1 can bind the epidermal growth factor receptor (EGFR) on the surface of HSC-T6 cells, which can further inhibit the phosphorylation of EGFR and its downstream protein kinase B (Akt), resulting in decreased expression of cyclin D1 and eventual inhibition of the activation of HSC-T6 cells. Furthermore, in rats with dimethylnitrosamine (DMN)-induced hepatic fibrosis, MD-1 slowed the development and progression of hepatic fibrosis, protecting hepatic parenchymal cells and improving hepatic functions. Therefore, MD-1 is a potential drug for anti-hepatic fibrosis.
Alkaloids ; pharmacology ; Animals ; Cell Line ; Cyclin D1 ; metabolism ; Dimethylnitrosamine ; toxicity ; Enzyme Activation ; drug effects ; ErbB Receptors ; metabolism ; G1 Phase Cell Cycle Checkpoints ; drug effects ; Hepatic Stellate Cells ; metabolism ; pathology ; Liver Cirrhosis ; chemically induced ; metabolism ; pathology ; prevention & control ; Phosphorylation ; drug effects ; Proto-Oncogene Proteins c-akt ; metabolism ; Quinolizines ; pharmacology ; Rats

Induction of apoptosis in target cells is a key mechanism by which chemotherapy promotes cell killing. The purpose of this study was to determine whether Indole-3-Carbinol (I3C) and Genistein in combination with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induce apoptosis in endometrial cancer cell (Ishikawa) and to assess apoptotic mechanism. The MTT assay and flow cytometry were performed to determine cell viability and cell cycle. The induction of apoptosis was measured by caspase-3 activity test, DNA fragmentation assay, annexin V binding assay and western blot analysis. There was no effect in cell growth inhibition and cell cycle progression alone or in two-combination. However, the treatment of I3C and Genistein followed by TRAIL showed significant cell death and marked increase in sub-G1 arrest. Three-combination treatment revealed elevated expression of DR4, DR5 and cleaved forms of caspase-3, caspase-8, PARP. The Flip was found down regulated. Moreover, increase in caspase-3 activity and DNA fragmentation indicated the induction of apoptosis. The results indicate that I3C and Genistein with TRAIL synergistically induced apoptosis via death receptor dependent pathway. Our findings might provide a new insight into the development of novel combination therapies against endometrial cancer.
Anticarcinogenic Agents/*pharmacology ; Apoptosis/*drug effects ; Caspase 3/metabolism ; Caspase 8/metabolism ; Cell Line, Tumor ; Drug Synergism ; Endometrial Neoplasms/metabolism/pathology ; Female ; G1 Phase Cell Cycle Checkpoints/drug effects ; Genistein/*pharmacology ; Humans ; Indoles/*pharmacology ; Poly(ADP-ribose) Polymerases/metabolism ; Receptors, TNF-Related Apoptosis-Inducing Ligand/metabolism ; TNF-Related Apoptosis-Inducing Ligand/*pharmacology

BACKGROUND/AIMS: Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide, and it has a poor prognosis and few therapeutic options. Radiotherapy is one of the most effective forms of cancer treatment, and P53 protein is one of the key molecules determining how a cell responds to radiotherapy. The aim of this study was to determine the therapeutic efficacy of iodine-131 in three human HCC cell lines. METHODS: Western blotting was used to measure P53 expression. The effects of radiotherapy with iodine-131 were assessed by using the clonogenic assay to evaluate cell survival. Flow cytometry was carried out to examine the effects of iodine-131 on cell death, oxidative stress, reduced intracellular glutathione expression, the mitochondrial membrane potential, and the cell cycle. RESULTS: The P53 protein was not expressed in Hep3B2.1-7 cells, was expressed at normal levels in HepG2 cells, and was overexpressed in HuH7 cells. P53 expression in the HuH7 and HepG2 cell lines increased after internal and external irradiation with iodine-131. Irradiation induced a decrease in cell survival and led to a decrease in cell viability in all of the cell lines studied, accompanied by cell death via late apoptosis/necrosis and necrosis. Irradiation with 131-iodine induced mostly cell-cycle arrest in the G0/G1 phase. CONCLUSIONS: These results suggest that P53 plays a key role in the radiotherapy response of HCC.
Apoptosis/*radiation effects ; Blotting, Western ; Carcinoma, Hepatocellular/metabolism/pathology/radiotherapy ; Cell Line, Tumor ; Cell Survival/drug effects ; G1 Phase Cell Cycle Checkpoints/radiation effects ; *Gamma Rays ; Glutathione/metabolism ; Hep G2 Cells ; Humans ; Iodine Radioisotopes/chemistry/pharmacology/therapeutic use ; Liver Neoplasms/metabolism/pathology/radiotherapy ; Phosphorylation ; Reactive Oxygen Species/metabolism ; Tumor Suppressor Protein p53/*metabolism

Various kinds of schiff base metal complexes have been proven to induce apoptosis of tumor cells. However, it remains largely unknown whether schiff base zinc complexes induce apoptosis in human cancer cells. Here, we synthesized a novel schiff base zinc coordination compound (SBZCC) and investigated its effects on the growth, proliferation and apoptosis of human osteosarcoma MG-63 cells. A novel SBZCC was synthesized by chemical processes and used to treat MG-63 cells. The cell viability was determined by CCK-8 assay. The cell cycle progression, mitochondrial membrane potential and apoptotic cells were analyzed by flow cytometry. The apoptosis-related proteins levels were determined by immunoblotting. Treatment of MG-63 cells with SBZCC resulted in inhibition of cell proliferation and cell cycle arrest at G1 phase. Moreover, SBZCC significantly reduced the mitochondrial membrane potential and induced apoptosis, accompanied with increased Bax/Bcl-2 and FlasL/Fas expression as well as caspase-3/8/9 cleavage. Our results demonstrated that the synthesized novel SBZCC could inhibit the proliferation and induce apoptosis of MG-63 cells via activating both the mitochondrial and cell death receptor apoptosis pathways, suggesting that SBZCC is a promising agent for the development as anticancer drugs.
Antineoplastic Agents ; chemical synthesis ; pharmacology ; Apoptosis ; drug effects ; Caspase 3 ; genetics ; metabolism ; Caspase 8 ; genetics ; metabolism ; Caspase 9 ; genetics ; metabolism ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cell Survival ; drug effects ; Coordination Complexes ; chemical synthesis ; pharmacology ; Fas Ligand Protein ; genetics ; metabolism ; G1 Phase Cell Cycle Checkpoints ; drug effects ; Gene Expression Regulation, Neoplastic ; drug effects ; Humans ; Membrane Potential, Mitochondrial ; drug effects ; Mitochondria ; drug effects ; metabolism ; pathology ; Osteoblasts ; drug effects ; metabolism ; pathology ; Proto-Oncogene Proteins c-bcl-2 ; genetics ; metabolism ; Schiff Bases ; chemistry ; Signal Transduction ; Zinc ; chemistry ; bcl-2-Associated X Protein ; genetics ; metabolism ; fas Receptor ; genetics ; metabolism

Fucoidan is an active component of seaweed, which inhibits proliferation and induces apoptosis of several tumor cells while the detailed mechanisms underlying this process are still not clear. In this study, the effect of Fucoidan on the proliferation and apoptosis of human breast cancer MCF-7 cells and the molecular mechanism of Fucoidan action were investigated. Viable cell number of MCF-7 cells was decreased by Fucoidan treatment in a dose-dependent manner as measured by MTT assay. Fucoidan treatment resulted in G1 phase arrest of MCF-7 cells as revealed by flow cytometry, which was associated with the decrease in the gene expression of cyclin D1 and CDK-4. Annexin V/PI staining results showed that the number of apoptotic cells was associated with regulation of cytochrome C, caspase-8, Bax and Bcl-2 at transcriptional and translational levels. Both morphologic observation and Hoechst 33258 assay results confirmed the pro-apoptotic effect of Fucoidan. Meanwhile, the ROS production was also increased by Fucoidan treatment, which suggested that Fucoidan induced oxidative damage in MCF-7 cells. The results of present study demonstrated that Fucoidan could induce G1 phase arrest and apoptosis in MCF-7 cells through regulating the cell cycle and apoptosis-related genes or proteins expression, and ROS generation is also involved in these processes.
Antineoplastic Agents ; chemistry ; pharmacology ; Apoptosis ; drug effects ; genetics ; Blotting, Western ; Breast Neoplasms ; genetics ; metabolism ; pathology ; Caspase 8 ; genetics ; metabolism ; Caspases ; genetics ; metabolism ; Cell Proliferation ; drug effects ; Cell Size ; drug effects ; Cyclin D1 ; genetics ; metabolism ; Cyclin-Dependent Kinase 4 ; genetics ; metabolism ; Cytochromes c ; genetics ; metabolism ; Dose-Response Relationship, Drug ; Fucus ; chemistry ; G1 Phase Cell Cycle Checkpoints ; drug effects ; genetics ; Gene Expression Regulation, Neoplastic ; drug effects ; Humans ; MCF-7 Cells ; Microscopy, Fluorescence ; Molecular Structure ; Polysaccharides ; chemistry ; pharmacology ; Proto-Oncogene Proteins c-bcl-2 ; genetics ; metabolism ; Reactive Oxygen Species ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; drug effects ; bcl-2-Associated X Protein ; genetics ; metabolism