The anti-tumor effect of CC-I in a subcutaneous mouse tumor model.

<p>(A) Mice were implanted with ten million cells with the SW1088 or CCF-STTG1 cells. The starting tumor size for the CCF-STTG1 cells ranged from 80–100 mm³. The SW1088 cells grew more slowly so CC-I treatment was started when the tumors reached 30 mm³. CC-I was injected intraperitoneally at a concentration of 25 mg/kg body weight once a week for 7 weeks (n = 7∼10). The control group was given PBS in the same volume and regimen (n = 3–8). The tumor slowly reoccurred in the TMZ-sensitive SW1088 astrocytoma injected nude mice but did not reoccur in the TMZ resistant CCF-STTG1 injected nude mice when CC-I was discontinued (beyond 7 weeks). CC-I inhibited the tumor growth and was not lethal in any of the treatment groups. Some error bars are too small to be visible. (B) Mean body weight of mice is presented in grams. Some error bars are too small to be visible.</p

Cytotoxicity of CC-I, merbarone, and combination of CC-I and TMZ on the astrocytoma cells.

<p>(A) TMZ-resistant human CCF-STTG1 and T98G cell lines were cultured for 3 days with CC-I and other similar structure topoisomerase II inhibitor (merbarone) followed by cytotoxicity measurement by SRB assay. CC-I showed greater toxicity than merbarone on the astrocytomas. The symbols indicate a significant difference between the merbarone treated and CC-I treated groups (**p<0.01; ***p<0.001). (B) The MGMT methylated (T98G, CCF-STTG1) or un-methylated (LN-18) astrocytoma cell lines were cultured for 3 days with CC-I and determined cytotoxicity by SRB assay. T98G cells have methylated MGMT promoter, but show weak MGMT expression. CC-I is more cytotoxic to LN-18 cells which has un-methylated MGMT promoter and MGMT expression. The symbol (***) indicates the most difference between the cells (p<0.001).</p

Anti-tumor effect of CC-I in an intracranial xenograft mouse model.

<p>(A) Representative MRI images taken with T1-weighted MRI contrast (7T MR imaging system) after intracranial tumor formation (one-three weeks post-implantation of astrocytoma cells) or after tumor formation followed by injection of CC-I (25 mg/kg body weight) for 7 weeks. CC-I completely inhibited tumor growth in both astrocytoma cell lines. (B) Kaplan-Meier survival graph of intracranial brain tumor mice after the administration of CC-I. CC-I extends the survival of the mice when compared to the untreated mice (n = 9 or 11) (p<0.0001). None of the mice which received PBS (control) survived after 30 days and median survival of all those animals was 20 days (n = 3 or 4). (C) Liver and kidney toxicity of CC-I. The liver and kidney toxicity (total bilirubin, blood urea nitrogen (BUN), creatine, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase) were determined using an automated chemistry analyzer machine (Roche Cobase MIRA) and kits manufactured by Thermo Electron. These data indicate no liver or kidney toxicity by CC-I in nude mice. Toxicity data displayed as means ± SEM. (D) Mean body weight of mice in grams.</p

CC-I-induced cell death in CCF-STTG1 cells.

<p>Cell death was monitored with apoptotic and necrotic cell markers after 48 hours CC-I exposure in CCF-STTG1 cells. Cell death was determined with the recombinant annexin V conjugated to fluorescein, followed by flow cytometric analysis. Apoptotic cell death is shown in panel A. Panel B is necrotic cell death. Actinomycin D was used as a positive control to induce apoptotic cell death. The percentage of apoptotic cells following CC-I treatment was increased in a dose-dependent manner in CCF-STTG1 cells. There was not a pronounced dose dependent increase in necrotic cell death in the CCF-STTG1 cells until the higher concentration. Data assessed using Student <i>t</i> test and displayed as means ± SEM. Some error bars are too small to be visible. The symbols indicate a significant difference compared to the control. (***p<0.001).</p

Topoisomerase IIα inhibition by CC-I.

<p>(A) Structure of CC-I docked into topoisomerase IIα (pdb code 1ZXM). Topoisomerase is shown as the brown-colored ribbon with residues on the binding site. Carbon atoms of CC-I are colored green, while those of topoisomerase is colored gray. Other atoms are colored according to atom types, i.e., nitrogen-blue, oxygen-red, sulfur-yellow, and polar hydrogen white. Non-polar hydrogen atoms are not shown. (B) The CC-I concentration-dependent inhibition of human topoisomerase IIα-mediated kDNA decatenation. All experiments were carried out according to instructions from the Topogen kit (Port Orange, FL). Reactions contained 4U of enzyme, 0.26 µg of DNA substrate, and different concentrations of the CC-I dissolved in DMSO (0.5% final concentration (v/v)). Different topological forms exhibited different mobility as indicated. Linear, linear kDNA; Decat., decatenated kDNA; Nicked, nicked decatenated kDNA; circular, circular decatenated kDNA; kDNA, kinetoplast DNA. VP16 was used as a positive control. (C) CC-I did not inhibit topo-I mediated supercoiled pHOT1 DNA relaxation. The procedures are described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0108166#s2" target="_blank">method</a> section. Camptothecin (camp.) was used as a positive control. (D) CC-I dose dependently inhibited topoisomerase IIα-mediated supercoiled pHOT1 DNA relaxation. VP16 was used as a positive control. s.c. DNA, super-coiled DNA.</p

CC-I-induced cell cycle arrest in CCF-STTG1 cells.

<p>The CCF-STTG1 cells were treated with 18 or 36 µM of CC-I for 24 or 48 hours. The cells were stained with propidium iodide and then analyzed for cell cycle distribution using a FACScan analyzer. CC-I treatment significantly increased the S and G2/M cell population, but decreased in G0/G1 phase. The symbols indicate a significant difference compared to the control. (*p<0.05; **p<0.01; ***p<0.001).</p

Chemical structure and cytotoxicity of CC-I in <i>in vitro</i>.

<p>(A) The structure of CC-I. (B) Cytotoxicity of CC-I in <i>in vitro</i>. Human astrocytoma cell lines were cultured with different doses of CC-I for 3 days and then the cytotoxicity was determined by SRB assay. The LC₅₀ of CC-I to SW1088 cell lines (13.6 µM) are significantly different with the LC₅₀ of CC-I to U87-MG and CCF-STTG1 cell lines (23.6 µM and 25.4 µM) (p<0.001).</p

Combination effect of CC-I and TMZ on the T98G astrocytoma cells.

<p>T98G cells were cultured for 3 days with CC-I and TMZ, and cytotoxicity was evaluated by SRB assay. Both CC-I and TMZ treatment on the T98G cells showed much more cytotoxic effect than either single treatment. The symbol (***) indicates a significant difference between the control and single treatment groups (p<0.001).</p

Gene expression profile of human Apoptosis PCR Array in CC-I treated CCF-STTG1 cells.

<p>Gene expression profile of human Apoptosis PCR Array in CC-I treated CCF-STTG1 cells.</p

L'Avenir de Luchon : journal scientifique, littéraire, annonces et réclames : guide général des baigneurs et des touristes aux eaux thermales, bains de mer de la France et de l'étranger

28 avril 19291929/04/28 (N437)-1929/04/28.Appartient à l’ensemble documentaire : MidiPyren