ave-8063 and fosbretabulin

Twenty-six compounds derived from 3'-aminocombretastatin A-4 (AmCA-4) containing a urea fragment mimicking the structure of Sorafenib, have been synthesized and evaluated as antiangiogenic compounds. Antiproliferative activity of all the synthetic ureas has been measured on tumor cell lines HT-29, MCF-7, HeLa, A-549 and HL-60 as well as on the endothelial cell line HMEC-1 and on the non-tumor cell line HEK-293. Preliminary docking studies were developed in order to predict which ureas show better interactions with the protein VEGFR-2. Then, the selected derivatives were evaluated in terms of their apoptotic effect and antiangiogenic properties. In this regard, VEGFR-2/ligand interactions were determined by flow cytometry and immunofluorescence techniques. Inhibition of VEGFR-2 tyrosine kinase activity in both the A-549 and HMEC-1 cell lines was also carried out. In addition, tube formation inhibition was studied in endothelial cells. Ortho-chloro substituted urea 5 and ortho-bromo substituted urea 8 were the most active ones in both down-regulation of VEGFR-2 and inhibition of the kinase activity of this receptor, with better results than those obtained with sunitinib and sorafenib.

Topics: Angiogenesis Inhibitors; Antineoplastic Agents, Phytogenic; Cell Line, Tumor; Cell Proliferation; Drug Screening Assays, Antitumor; Humans; Molecular Docking Simulation; Stilbenes; Urea; Vascular Endothelial Growth Factor Receptor-2

Combretastatin A-4 (CA-4) is a highly cytotoxic natural product and several derivatives have been prepared which underwent clinical trial. These investigations revealed that the cis-stilbene moiety of the natural product is prone to undergo cis/trans isomerization under physiological conditions, reducing the overall activity of the drug candidates. Herein, we report the preparation of cis-restrained carbocyclic analogs of CA-4. The compounds, which differ by the size and hybridization of the carbocyclic ring have been evaluated for their cytotoxic properties and their ability to inhibit tubulin polymerization. Biological data, supported by molecular docking studies, identified cyclobutenyl and cyclobutyl derivatives of the natural product as highly promising drug candidates.

Topics: Antineoplastic Agents; Cell Line, Tumor; Drug Screening Assays, Antitumor; G2 Phase Cell Cycle Checkpoints; Humans; Molecular Docking Simulation; Molecular Structure; Protein Binding; Stilbenes; Tubulin; Tubulin Modulators

A series of twenty-six carbamates derived from aminocombretastatin A-4 (AmCA-4) were synthesized and evaluated for their capacity to affect cell proliferation, tubulin polymerization, mitotic cell arrest, microtubule network organization, apoptosis and endothelial tubular structures in vitro. The anti-proliferative activity of the synthetic carbamates was measured on several human tumor cell lines (i.e. HT-29, MCF-7, HeLa, A-549, MDA-MB-231, HL-60) as well as on the endothelial cell line HMEC-1 and the non-tumor cell line HEK-293. The compounds showed anti-proliferative activity in the nanomolar range thereby exceeding by far the activity of combretastatin A-4 (CA-4) and, in some cases, the activity of AmCA-4. The most active compounds proved to be the carbamates bearing chloro, bromo or methoxy groups in the meta position of the phenyl ring. Moreover, all carbamates inhibited in vitro tubulin polymerization, in a similar manner to that of CA-4 and AmCA-4 by interacting with the colchicine binding site in tubulin. The synthetic carbamates proved as active as AmCA-4 in causing mitotic arrest, as assessed in A549 human lung cancer cells, and disruption of the microtubule cellular network. Some selected carbamates induced apoptosis at concentrations as low as 10 nM, being more active than AmCA-4. Finally, these selected carbamates displayed a vascular disrupting activity on endothelial cells in a dose-dependent manner. In conclusion, our data indicate that carbamates derived from aminocombretastatin A-4 represent interesting lead compounds for the design of vascular disrupting agents.

Topics: Antineoplastic Agents; Apoptosis; Carbamates; Cell Cycle Checkpoints; Cell Proliferation; Cells, Cultured; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Endothelial Cells; Humans; Microtubules; Mitosis; Molecular Structure; Polymerization; Stilbenes; Structure-Activity Relationship; Tubulin

The aim of this study was to investigate the antitumor and antivascular effects of PD806, a new oral prodrug of AVE8063 in vitro and in vivo. The cytotoxicity of PD806 was determined against H22, Walker 256, A549, MCF-7, and BEL-7402 cells using MTT assays. Plasma pharmacokinetic analysis of AVE8063 generated in rats after a single oral administration of PD806 was carried out using the high-performance liquid chromatography method. H22 tumor-bearing mice models were used to show the antitumor activity. Antivascular responses were monitored by in vivo MRI and immunohistochemistry (CD31) in W256 tumor-bearing rats. A blood test and histopathology were performed to evaluate the toxicity of PD806. PD806 showed cytotoxicity against five types of tumor cell lines with the IC50 values in the micromolar concentration. A pharmacokinetic study indicated that PD806 converted into the active form, AVE8063, which showed a half-life of 5.24±0.70 h in rats. Daily oral administration of PD806 inhibited the growth of subcutaneously implanted H22 tumors in a dose-dependent manner. The tumor volume in the 300 mg/kg PD806 group was obviously smaller than that of the vehicle control group from day 6 onward (P<0.05), with inhibition rates of 62% on day 30. PD806 in the three-dose group significantly prolonged the survival of the H22 tumor-bearing mice (P<0.05). At 24 h after PD806 (150 and 200 mg/kg) was administered orally, tumor vascular shutdown was found on CE-T1WI with the presence of extended necrosis and tumor residue at the periphery. The enhancement ratio decreased significantly from 1.00±0.00 at baseline to 0.26±0.08 and 0.17±0.06, respectively (P<0.01). The necrosis ratio measured from CE-T1WI increased significantly from 34% in average at baseline to 52.96 and 60.30%, respectively (P<0.05). Immunohistochemical staining of tumor sections showed a marked reduction in CD31 staining vessels, with microvessel density reduced significantly to 8.71±1.76 and 3.33±1.04, respectively, compared with the vehicle control group (P<0.01). The results of hematology and histopathology showed that PD806 exerted no obvious toxicity during the treatment period. In conclusion, our results indicate that PD806 is an effective and safe vascular disrupting agent.

Topics: Administration, Oral; Angiogenesis Inhibitors; Aniline Compounds; Animals; Antineoplastic Agents; Body Weight; Cell Line, Tumor; Citrates; Half-Life; Humans; Male; Mice, Inbred Strains; Prodrugs; Rats, Sprague-Dawley; Stilbenes; Survival Rate; Xenograft Model Antitumor Assays

The synthesis and biochemical activities of novel water-soluble β-lactam analogues of combretastatin A-4 are described. The first series of compounds investigated, β-lactam phosphate esters 7a, 8a and 9a, exhibited potent antiproliferative activity and caused microtubule disruption in human breast carcinoma-derived MCF-7 cells. They did not inhibit tubulin polymerisation in vitro, indicating that biotransformation was necessary for their antiproliferative and tubulin binding effects in MCF-7 cells. The second series of compounds, β-lactam amino acid amides (including 10k and 11l) displayed potent antiproliferative activity in MCF-7 cells, disrupted microtubules in MCF-7 cells and also inhibited the polymerisation of tubulin in vitro. This indicates that the β-lactam amides did not require metabolic activation to have antiproliferative effects, in contrast to the phosphate series. Both series of compounds caused mitotic catastrophe and apoptosis in MCF-7 cells. Molecular modelling studies indicated potential binding conformations for the β-lactam amino acid amides 10k and 11l in the colchicine-binding site of tubulin. Due to their aqueous solubility and potent biochemical effects, these compounds are promising candidates for further development as microtubule-disrupting agents.

Topics: Amino Acids; Antineoplastic Agents; Cell Proliferation; Dose-Response Relationship, Drug; Humans; MCF-7 Cells; Microtubules; Models, Molecular; Molecular Structure; Phosphates; Solubility; Stilbenes; Structure-Activity Relationship

A series of Z and E combretastatin A-4 analogs bearing different substituents (OH, F, NO(2), NH(2), B(OH)(2)) in the 3' position were synthesized. These derivatives and Z and E combretastatin A-1 were analysed by monitoring their ability to inhibit cell growth in Saccharomyces cerevisiae. Combretastatin A-1 (2a), A-4 (2b) and compound 2c were found to inhibit yeast growth. Moreover, combretatstatin A-4 (2b) and compound 2c induced a G1 arrest by affecting the synthesis of Clb5 protein, the principal S-phase cyclin. The G1 arrest is coincident with the activation of the stress activated kinase Snf1.

Topics: Cyclin B; Drug Evaluation, Preclinical; G1 Phase; Protein Serine-Threonine Kinases; S Phase; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Stereoisomerism; Stilbenes

Several derivatives of combretastatin have been prepared bearing a cyclopropyl unit instead of the natural occurring cis-double bond. Final products and synthetic intermediates were evaluated for their cytotoxic properties in two human cancer cell lines.

Topics: Antineoplastic Agents; Cell Line, Tumor; Cyclopropanes; Humans; Stilbenes; Tubulin Modulators

A new trifluorinated amino-combretastatin analogue, (Z)-2-(4'-methoxy-3'-aminophenyl)-1-(3,4,5-trifluorophenyl)ethene, prepared by chemical synthesis, was found to be a potent inhibitor of tubulin assembly (IC(50)=2.9 microM), and cytotoxic against selected human cancer cell lines. This new lead compound is among the most active from a group of related structural modifications.

Topics: Antineoplastic Agents, Phytogenic; Bibenzyls; Combinatorial Chemistry Techniques; Drug Design; Drug Screening Assays, Antitumor; Humans; Hydrocarbons, Fluorinated; Inhibitory Concentration 50; Molecular Structure; Stereoisomerism; Stilbenes; Structure-Activity Relationship; Tubulin; Tubulin Modulators

A novel series of 2-amino and 2'-aminocombretastatin derivatives were synthesized and evaluated for antitumor activity. Several compounds had excellent antiproliferative activity as inhibitors of tubulin polymerization. Compounds 11, 20, and 21 with IC(50) values of 1.6, 1.7, and 1.8 microM, respectively, exhibited more potent inhibition of tubulin polymerization than colchicine and approximately as active as combretastatin A-4. They also displayed antiproliferative activity with an IC(50) values ranging from 11 to 44 nM in a variety of human cell lines from different organs. Structure activity relationship information suggests that the NH(2) substituent at the 2-position of either ring A or ring B in combretastatin molecular skeleton may play an important role in the bioactivity of this series of compounds.

Topics: Antineoplastic Agents; Cell Line, Tumor; Cell Proliferation; Colchicine; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Humans; Stilbenes; Structure-Activity Relationship; Tubulin Modulators

A series of cis- and trans-stilbenes related to combretastatin A-4 (1a), with a variety of substituents at the 3'-position of the aryl B-ring, were synthesized and evaluated for inhibitory activity employing six human cancer cell lines (NCI-H460 lung carcinoma, BXPC-3 pancreas, SK-N-SH neuroblastoma, SW1736 thyroid, DU-145 prostate, and FADU pharynx-squamous sarcoma) as well as the P-388 murine lymphocyte leukemia cell line. Several of the cis-stilbene derivatives were significantly inhibitory against all cell lines used, with potencies comparable to that of the parent 1a. All were potent inhibitors of tubulin polymerization. The corresponding trans-stilbenes had little or no activity as tubulin polymerization inhibitors and were relatively inactive against the seven cancer cell lines. In terms of inhibition of both cancer cell growth and tubulin polymerization, the dimethylamino and bromo cis-stilbenes were the most potent of the new derivatives, the latter having biological activity approaching that of 1a. As part of the present study, the X-ray crystal structure of the 3'-O-phosphate of combretastatin A-4 (1b) was successfully elucidated. Compound 1b has been termed the "combretastatin A-4 prodrug", and it is currently undergoing clinical trials for the treatment of human cancer patients.

Topics: Animals; Anti-Infective Agents; Antineoplastic Agents; Biopolymers; Cell Line, Tumor; Colony Count, Microbial; Crystallography, X-Ray; Drug Screening Assays, Antitumor; Humans; Mice; Microbial Sensitivity Tests; Molecular Structure; Stereoisomerism; Stilbenes; Structure-Activity Relationship; Tubulin

A series of combretastatin A-4 (CA-4) analogues were synthesized, and their cytotoxic effects against murine Colon 26 adenocarcinoma and inhibitory activity on tubulin polymerization were evaluated. Since CA-4 has limited aqueous solubility, the target compounds were designed to improve solubility by introduction of a nitrogen-containing group. Among the compounds synthesized, those with an amino moiety in place of the phenolic OH of CA-4 showed potent antitubulin activity and cytotoxicity against murine Colon 26 adenocarcinoma in vitro. Some of the compounds which were potent in vitro were evaluated in the murine tumor model Colon 26 in vivo. Among these, 13bHCl, 21aHCl, and 21bHCl showed significant antitumor activity in the animal model, while CA-4 was ineffective. 13bHCl and 21aHCl were further evaluated in two murine tumor models (Colon 38 and 3LL) and human xenografts HCT-15. These compounds showed potent antitumor activity comparable or superior to that of CDDP. The structure-activity relationships of this series of compounds are also discussed.

Topics: Acrylonitrile; Adenocarcinoma; Aniline Compounds; Animals; Anisoles; Antineoplastic Agents; Antineoplastic Agents, Phytogenic; Biopolymers; Cell Survival; Colonic Neoplasms; Drug Screening Assays, Antitumor; Humans; Mice; Neoplasm Transplantation; Solubility; Stilbenes; Structure-Activity Relationship; Transplantation, Heterologous; Tubulin; Tumor Cells, Cultured