-
Cancer Science Apr 2007TZT-1027 (soblidotin), an antimicrotubule agent, has previously been evaluated in terms of its antivascular effects. In this study, Evans blue perfusion, magnetic...
TZT-1027 (soblidotin), an antimicrotubule agent, has previously been evaluated in terms of its antivascular effects. In this study, Evans blue perfusion, magnetic resonance imaging (MRI), and confocal laser scanning microscopy (CLSM) were utilized to further elucidate the antivascular effect of TZT-1027 in female nude mice and rats bearing human breast tumor MX-1, as well as in female Sprague-Dawley rats that developed breast tumors induced by dimethylbenz(a)anthracene (DMBA). Therapeutic doses of TZT-1027 caused nearly complete regression of implanted MX-1 tumors in nude mice and rats as well as DMBA-induced tumors in rats. The perfusion in MX-1 tumor implanted in nude mice was drastically reduced within 30 min after TZT-1027 administration and was completely inhibited after 6 h or more, although not reduced in normal tissue of kidney. The study using MRI demonstrated that rich blood flow within tumors was remarkably reduced 1-3 h after TZT-1027 administration both in nude rats bearing MX-1 tumors and in rats with DMBA-induced tumors. Furthermore, the study with CLSM in nude mice bearing MX-1 tumors revealed a disruption of tumor microvessels at 1 h and a destruction of tumor microvessel network at 3 h after TZT-1027 administration. In contrast, these types of vascular disorders were not observed in heart and kidney. These results suggest that TZT-1027 specifically damages tumor vasculatures, leading to extensive tumor necrosis within tolerable dose range, and confirms earlier observations that TZT-1027 exerts a considerable antivascular effect in addition to an excellent cytotoxic effect.
Topics: 9,10-Dimethyl-1,2-benzanthracene; Angiogenesis Inhibitors; Animals; Antineoplastic Agents; Breast Neoplasms; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Humans; Magnetic Resonance Imaging; Mammary Neoplasms, Experimental; Mice; Mice, Nude; Microscopy, Confocal; Oligopeptides; Rats; Rats, Nude; Tumor Cells, Cultured; Xenograft Model Antitumor Assays
PubMed: 17284247
DOI: 10.1111/j.1349-7006.2007.00418.x -
Cancer Science Dec 2006We investigated the ability of TZT-1027 (Soblidotin), a novel antimicrotubule agent, to induce antivascular effects, because most vascular targeting agents that...
We investigated the ability of TZT-1027 (Soblidotin), a novel antimicrotubule agent, to induce antivascular effects, because most vascular targeting agents that selectively disrupt tumor vasculature also inhibit tubulin polymerization. Treatment with 10(-7) g/mL TZT-1027 rapidly disrupted the microtubule cytoskeleton in human umbilical vascular endothelial cells (HUVEC), and significantly enhanced vascular permeability in HUVEC monolayers. In addition, single intravenous administration of 2 mg/kg TZT-1027 to mice bearing Colon26 tumors significantly reduced tumor perfusion and caused extravascular leakage of erythrocytes 1 h after administration. Subsequently, thrombus formation with deposition of fibrin and tumor necrosis was observed 3 and 24 h after administration, respectively. These results strongly suggest that TZT-1027 possesses antivascular effects. TZT-1027 induced apoptosis not only in HUVEC but also in C26 cancer cells (cell line of Colon26 solid tumor) in vitro, suggesting it exerts direct cytotoxicity against tumor cells in addition to its antivascular effects. A single intravenous administration of 1, 2 and 4 mg/kg TZT-1027 significantly prolonged the survival of mice with advanced-stage Colon26 tumors in a dose-dependent manner. Furthermore, TZT-1027 itself less markedly enhanced the permeability of normal vessels, but was additive with vascular endothelial growth factor, indicating the possibility that TZT-1027 selectively exerts its activity on tumor vessels. In summary, these results suggest that TZT-1027 exerts both an indirect antivascular effect and a direct cytotoxic effect, resulting in strong antitumor activity against advanced-stage tumors, and that TZT-1027 may be useful clinically for treating solid tumors.
Topics: Adenocarcinoma; Animals; Antineoplastic Agents; Cell Division; Cells, Cultured; Colonic Neoplasms; Endothelium, Vascular; Female; Fluorescent Antibody Technique; Guinea Pigs; Humans; Mice; Mice, Inbred BALB C; Microtubules; Neovascularization, Pathologic; Oligopeptides; Skin; Umbilical Veins
PubMed: 16999818
DOI: 10.1111/j.1349-7006.2006.00330.x -
The Journal of Biological Chemistry Apr 2006The chimeric anti-CD30 monoclonal antibody cAC10, linked to the antimitotic agents monomethyl auristatin E (MMAE) or F (MMAF), produces potent and highly CD30-selective...
The chimeric anti-CD30 monoclonal antibody cAC10, linked to the antimitotic agents monomethyl auristatin E (MMAE) or F (MMAF), produces potent and highly CD30-selective anti-tumor activity in vitro and in vivo. These drugs are appended via a valine-citrulline (vc) dipeptide linkage designed for high stability in serum and conditional cleavage and putative release of fully active drugs by lysosomal cathepsins. To characterize the biochemical processes leading to effective drug delivery, we examined the intracellular trafficking, internalization, and metabolism of the parent antibody and two antibody-drug conjugates, cAC10vc-MMAE and cAC10vc-MMAF, following CD30 surface antigen interaction with target cells. Both cAC10 and its conjugates bound to target cells and internalized in a similar manner. Subcellular fractionation and immunofluorescence studies demonstrated that the antibody and antibody-drug conjugates entering target cells migrated to the lysosomes. Trafficking of both species was blocked by inhibitors of clathrin-mediated endocytosis, suggesting that drug conjugation does not alter the fate of antibody-antigen complexes. Incubation of cAC10vc-MMAE or cAC10vc-MMAF with purified cathepsin B or with enriched lysosomal fractions prepared by subcellular fractionation resulted in the release of active, free drug. Cysteine protease inhibitors, but not aspartic or serine protease inhibitors, blocked antibody-drug conjugate metabolism and the ensuing cytotoxicity of target cells and yielded enhanced intracellular levels of the intact conjugates. These findings suggest that in addition to trafficking to the lysosomes, cathepsin B and perhaps other lysosomal cysteine proteases are requisite for drug release and provide a mechanistic basis for developing antibody-drug conjugates cleavable by intracellular proteases for the targeted delivery of anti-cancer therapeutics.
Topics: Antibodies; Antigens, CD20; Antineoplastic Agents; Blotting, Western; Cathepsin B; Cell Line; Cysteine Endopeptidases; Cysteine Proteinase Inhibitors; Dose-Response Relationship, Drug; Endocytosis; Endopeptidases; Flow Cytometry; Humans; Inhibitory Concentration 50; Ki-1 Antigen; Lysosomes; Microscopy, Fluorescence; Models, Chemical; Oligopeptides; Peptide Hydrolases; Peptides; Protein Binding; Subcellular Fractions; Temperature; Time Factors; beta-Galactosidase
PubMed: 16484228
DOI: 10.1074/jbc.M510026200 -
MAbs 2017Targeted therapeutics that can differentiate between normal and malignant tumor cells represent the ideal standard for the development of a successful anti-cancer...
Targeted therapeutics that can differentiate between normal and malignant tumor cells represent the ideal standard for the development of a successful anti-cancer strategy. The Sialyl-Thomsen-nouveau antigen (STn or Sialyl-Tn, also known as CD175s) is rarely seen in normal adult tissues, but it is abundantly expressed in many types of human epithelial cancers. We have identified novel antibodies that specifically target with high affinity the STn glycan independent of its carrier protein, affording the potential to recognize a wider array of cancer-specific sialylated proteins. A panel of murine monoclonal anti-STn therapeutic antibodies were generated and their binding specificity and efficacy were characterized in vitro and in in vivo murine cancer models. A subset of these antibodies were conjugated to monomethyl auristatin E (MMAE) to generate antibody-drug conjugates (ADCs). These ADCs demonstrated in vitro efficacy in STn-expressing cell lines and significant tumor growth inhibition in STn-expressing tumor xenograft cancer models with no evidence of overt toxicity.
Topics: Animals; Antibodies, Monoclonal, Murine-Derived; Antigens, Tumor-Associated, Carbohydrate; Antineoplastic Agents, Immunological; Breast Neoplasms; Cell Line, Tumor; Drug Delivery Systems; Female; Humans; Mice; Mice, Inbred BALB C; Oligopeptides
PubMed: 28281872
DOI: 10.1080/19420862.2017.1290752 -
EMBO Reports Nov 2008The tubulin vinca domain is the target of widely different microtubule inhibitors that interfere with the binding of vinblastine. Although all these ligands inhibit the...
The tubulin vinca domain is the target of widely different microtubule inhibitors that interfere with the binding of vinblastine. Although all these ligands inhibit the hydrolysis of GTP, they affect nucleotide exchange to variable extents. The structures of two vinca domain antimitotic peptides--phomopsin A and soblidotin (a dolastatin 10 analogue)--bound to tubulin in a complex with a stathmin-like domain show that their sites partly overlap with that of vinblastine and extend the definition of the vinca domain. The structural data, together with the biochemical results from the ligands we studied, highlight two main contributors in nucleotide exchange: the flexibility of the tubulin subunits' arrangement at their interfaces and the residues in the carboxy-terminal part of the beta-tubulin H6-H7 loop. The structures also highlight common features of the mechanisms by which vinca domain ligands favour curved tubulin assemblies and destabilize microtubules.
Topics: Ligands; Microtubules; Models, Molecular; Mycotoxins; Oligopeptides; Protein Structure, Tertiary; Tubulin; Vinblastine
PubMed: 18787557
DOI: 10.1038/embor.2008.171 -
In Vivo (Athens, Greece) 2007TZT-1027 (Soblidotin), a microtubule-depolymerizing agent, has antivascular activity which disrupts newly formed tumor vasculature. In this study, it was investigated...
BACKGROUND
TZT-1027 (Soblidotin), a microtubule-depolymerizing agent, has antivascular activity which disrupts newly formed tumor vasculature. In this study, it was investigated whether TZT-1027 has also antiangiogenic activity preventing neovascularization.
MATERIALS AND METHODS
Antiangiogenic activities were evaluated in vivo in a chick embryo chorioallantoic membrane (CAM) assay and in vitro in a tube formation assay on human umbilical vein endothelial cells (HUVEC). RT-PCR and skimmed milk zymography analyses were performed to clarify the involvement of angiogenesis-related proteolytic enzymes and transcription factors.
RESULTS
TZT-1027 at doses of 0.01 and 0.06 microg/egg showed potent antiangiogenic activities in the CAM assay (80% and 100% inhibition, respectively), with no lethal toxicity to the chick embryo. TZT-1027 at doses of 0.01-10 ng/mL prevented tube formation, while 1-100 ng/mL disrupted the preformed vascular tube. However, mRNA and protein expression were unchanged.
CONCLUSION
TZT-1027 showed antiangiogenic activity at lower doses than it exhibited its antivascular activity. We believe it would exert its antiangiogenic activity, even if kept in a tumor at reduced concentrations to keep its antivascular activity to a minimum.
Topics: Allantois; Angiogenesis Inhibitors; Animals; Antineoplastic Agents; Chick Embryo; Chorion; DNA Primers; Endothelium, Vascular; Humans; Oligopeptides; Reverse Transcriptase Polymerase Chain Reaction; Umbilical Veins; Urokinase-Type Plasminogen Activator
PubMed: 17436580
DOI: No ID Found -
Antimicrobial Agents and Chemotherapy Dec 2002The mechanism of action of the fungicidal peptide auristatin PHE was investigated in Cryptococcus neoformans. Since auristatin PHE causes budding arrest in C. neoformans...
The mechanism of action of the fungicidal peptide auristatin PHE was investigated in Cryptococcus neoformans. Since auristatin PHE causes budding arrest in C. neoformans (T. Woyke, G. R. Pettit, G. Winkelmann, and R. K. Pettit, Antimicrob. Agents Chemother. 45:3580-3584, 2001), microtubule integrity and nuclear localization in auristatin PHE-treated cells were examined. Iterative deconvolution in conjunction with an optimized C. neoformans microtubule immunolabeling procedure enabled detailed visualization of the microtubule cytoskeleton in auristatin PHE-treated C. neoformans. The effect of auristatin PHE on C. neoformans microtubule organization was compared with that of the tubulin-binding agent nocodazole. Both drugs produced complete disruption first of cytoplasmic and then of spindle microtubules in a time- and concentration-dependent manner. Sub-MICs of auristatin PHE caused complete microtubule disruption within 4.5 h, while 1.5 times the nocodazole MIC was required for the same effect. For both drugs, disruption of microtubules was accompanied by blockage of nuclear migration and of nuclear and cellular division, resulting in cells arrested in a uninucleate, large-budded stage. Nocodazole and the linear peptide auristatin PHE are remarkably different in structure and spectrum of activity, yet on the cellular level, they have similar effects.
Topics: Cryptococcus neoformans; Dose-Response Relationship, Drug; Microtubules; Nocodazole; Oligopeptides
PubMed: 12435680
DOI: 10.1128/AAC.46.12.3802-3808.2002 -
Japanese Journal of Cancer Research :... Aug 2000TZT-1027, a dolastatin 10 derivative, is an antimicrotubule agent with potent antitumor activity both in vitro and in vivo. In this study, we performed biochemical and...
TZT-1027, a dolastatin 10 derivative, is an antimicrotubule agent with potent antitumor activity both in vitro and in vivo. In this study, we performed biochemical and histopathological examinations, and evaluated TZT-1027-induced tumoral vascular collapse and tumor cell death in an advanced tumor model, murine colon 26 adenocarcinoma. In addition, we studied the effects of TZT-1027 on cultured human umbilical vein endothelial cells (HUVEC). Tolerable doses of TZT-1027 induced tumor-selective hemorrhage within 1 h. This hemorrhage occurred mainly in the peripheral area of the tumor mass. Measurements of tumoral hemoglobin content and dye permeation revealed that the hemorrhage occurred firstly and tumor blood flow stopped secondarily. The vascular damage was followed by continuous induction of apoptosis of the tumor cells, tumor tissue necrosis, and tumor regression. In cultured HUVEC, TZT-1027 induced marked cell contraction with membrane blebbing in 30 min. These cell changes were completely inhibited by K252a, a broad-spectrum inhibitor of protein kinases. These effects of TZT-1027 on both tumor vasculature and HUVEC were greater than those of vincristine. In conclusion, TZT-1027 quickly attacked the well-developed vascular system of advanced tumors by a putative protein kinase-dependent mechanism, and then blocked tumor blood flow. Therefore, TZT-1027 has both a conventional antitumor activity and a unique anti-tumoral vascular activity, making it a potentially powerful tool for clinical cancer therapy.
Topics: Animals; Antineoplastic Agents; Cell Survival; Colonic Neoplasms; DNA Fragmentation; Disease Models, Animal; Endothelium, Vascular; Female; Hemoglobins; Humans; Mice; Mice, Inbred BALB C; Microtubules; Neoplasm Transplantation; Neovascularization, Pathologic; Oligopeptides; Permeability; Tumor Cells, Cultured
PubMed: 10965026
DOI: 10.1111/j.1349-7006.2000.tb01022.x -
Japanese Journal of Cancer Research :... Jul 2000TZT-1027, a derivative of dolastatin 10 isolated from the Indian Ocean sea hare Dolabella auricularia in 1987 by Pettit et al., is a potent antimicrotubule agent. We... (Comparative Study)
Comparative Study
TZT-1027, a derivative of dolastatin 10 isolated from the Indian Ocean sea hare Dolabella auricularia in 1987 by Pettit et al., is a potent antimicrotubule agent. We have compared the activity of TZT-1027 with that of dolastatin 10 as well as the vinca alkaloids vinblastine (VLB), vincristine (VCR) and vindesine (VDS). TZT-1027 and dolastatin 10 inhibited microtubule polymerization concentration-dependently at 1 - 100 microM with IC50 values of 2.2 +/- 0.6 and 2.3 +/- 0.7 microM, respectively. VLB, VCR and VDS inhibited microtubule polymerization at 1 - 3 microM with IC50 values of 2.7 +/- 0.6, 1.6 +/- 0.4 and 1.6 +/- 0.2 microM, respectively, but showed a slight decrease in inhibitory effect at concentrations of 10 microM or more. TZT-1027 also inhibited monosodium glutamate-induced tubulin polymerization concentration-dependently at 0.3 - 10 microM, with an IC50 of 1.2 microM, whereas VLB was only effective at 0.3 - 3 microM, with an IC50 of 0.6 microM, and caused so-called "aggregation" of tubulin at 10 microM. Scatchard analysis of the binding data for [(3)H]VLB suggested one binding site (Kd 0.2 +/- 0.04 microM and Bmax 6.0 +/- 0.26 nM / mg protein), while that for [(3)H]TZT-1027 suggested two binding sites, one of high affinity (Kd 0.2 +/- 0.01 microM and Bmax 1.7 +/- 0.012 nM / mg protein) and the other of low affinity (Kd 10. 3 +/- 1.46 microM and Bmax 11.6 +/- 0.83 nM / mg protein). [(3)H]TZT-1027 was completely displaced by dolastatin 10 but only incompletely by VLB. [(3)H]VLB was completely displaced by dolastatin 10 and TZT-1027. Furthermore, TZT-1027 prevented [(3)H]VLB from binding to tubulin in a non-competitive manner according to Lineweaver-Burk analysis. TZT-1027 concentration-dependently inhibited both [(3)H]guanosine 5'-triphosphate (GTP) binding to and GTP hydrolysis on tubulin. VLB inhibited the hydrolysis of GTP on tubulin concentration-dependently to a lesser extent than TZT-1027, but no inhibitory effect of VLB on [(3)H]GTP binding to tubulin was evident even at 100 microM. Thus, TZT-1027 affected the binding of VLB to tubulin, but its binding site was not completely identical to that of VLB. TZT-1027 had a potent inhibitory effect on tubulin polymerization and differed from vinca alkaloids in its mode of action against tubulin polymerization.
Topics: Animals; Antineoplastic Agents; Antineoplastic Agents, Phytogenic; Antineoplastic Combined Chemotherapy Protocols; Binding, Competitive; Cattle; Depsipeptides; Drug Interactions; Guanosine Triphosphate; Hydrolysis; Kinetics; Microtubules; Oligopeptides; Paclitaxel; Swine; Tubulin; Tubulin Modulators; Vinblastine
PubMed: 10920282
DOI: 10.1111/j.1349-7006.2000.tb01007.x -
Annals of Oncology : Official Journal... Apr 2004TZT-1027 is a synthetic dolastatin 10 analog with antineoplastic properties in various cell lines and tumor xenografts. The purpose of this phase I study was to evaluate... (Clinical Trial)
Clinical Trial
Phase I and pharmacokinetic study of TZT-1027, a novel synthetic dolastatin 10 derivative, administered as a 1-hour intravenous infusion every 3 weeks in patients with advanced refractory cancer.
BACKGROUND
TZT-1027 is a synthetic dolastatin 10 analog with antineoplastic properties in various cell lines and tumor xenografts. The purpose of this phase I study was to evaluate the safety and toxicity, maximum tolerated dose, pharmacokinetics and pharmacodynamics, clinical and metabolic antitumor activity of TZT-1027 when given as a 1-h intravenous infusion every 3 weeks in patients with refractory solid tumors.
PATIENTS AND METHODS
Patients had a histologically verified refractory tumor with measurable disease, were > or = 18 years old, had an Eastern Cooperative Oncology Group performance status <2 and adequate bone marrow, liver, renal and cardiac function. Dose-limiting toxicity was defined as platelets <25 x 10(9)/l, neutrophils <0.5 x 10(9)/l for >5 days, febrile neutropenia > or = 38.5 degrees C with grade 4 (National Cancer Institute-common toxicity criteria) neutropenia, or grade 3/4 non-hematological toxicity excluding nausea and vomiting. The last dose was the dose where > or = 2 out of six patients experienced dose-limiting toxicity in cycle one. The maximum tolerated dose was one dose level below with less than two of six patients with dose-limiting events.
RESULTS
Twenty-one non-selected, fully evaluable patients were enrolled. The majority were male (19) and the median age was 55 years (range 39-67). Dose levels of TZT-1027 ranged from 1.35 to 3.0 mg/m(2). The median number of cycles was two (range 1-4). Dose-limiting toxicities were observed in three patients at the 3.0 mg/m(2) dose level, including neutropenia, fatigue and a short lasting, reversible peripheral neurotoxic syndrome. The most common toxicities per patient were fatigue, anorexia, alopecia, nausea, constipation, leukopenia and neutropenia. Based on RECIST criteria, the best response was stable disease in seven patients. The pharmacokinetic evaluation revealed a T(1/2) of approximately 7 h and linear kinetics.
CONCLUSIONS
The recommended dose of TZT-1027 for the 3-weekly administration is 2.7 mg/m(2). Neutropenia, fatigue and a reversible peripheral neurotoxic syndrome are dose-limiting with this schedule. TZT-1027 may be associated with neurological side-effects in patients previously exposed to neurotoxic compounds such as oxaliplatin.
Topics: Adult; Aged; Alopecia; Anorexia; Antineoplastic Agents; Area Under Curve; Constipation; Depsipeptides; Dose-Response Relationship, Drug; Fatigue; Female; Humans; Infusions, Intravenous; Leukopenia; Male; Middle Aged; Nausea; Neoplasms; Neutropenia; Oligopeptides
PubMed: 15033678
DOI: 10.1093/annonc/mdh141