Vinblastine Derivatives Research Articles

Role of vinca alkaloids and their derivatives in cancer therapy

Vinca alkaloids and its derivatives like Vincristine, Vinblastine etc. isolated from Catharanthus roseus plants are widely used in the treatment of various types of cancers. Mode of action of Vinca alkaloids (vinblastine, vincristine, vinorelbine) is microtubule-stabilizing agents (MTAs) i.e., arrest the cell cycle via disrupting microtubule dynamics. Vincristine major side effect is neurotoxicity. Hoverer, Vincristine induce neuropathy in mice or rat, used as animal model to study effect of drugs or plants by various authors also reported in review literature. Vinca alkaloids and its derivatives were widely used drugs in combination regimens with cyclophosphamide, doxorubicin, procarbazine, Methotrexate and dacarbazine etc. in various types of cancer. In this review, we also discussed major structure modifications position of chemically synthesized vincristine and vinblastine derivatives required for potential anticancer activities. Anticancer mechanism and some major patents on vinca alkaloids derivatives also reported in this review article. The study of Vinca alkaloids and its derivatives a class of an antimitotic compounds, found essential role in anticancer therapies.

Results in Chemistry of Natural Organic Compounds. Synthesis of New Anticancer Vinca Alkaloids and Flavone Alkaloids

The antitumor indole–indoline alkaloids of the evergreen Catharanthus roseus—namely vinblastine and vincristine—are widely used in chemotherapy of cancer. Many efforts were made to synthesize more efficient derivatives with less side-effect. The 14,15-cyclopropane derivative of vinblastine was synthesized successfully by a five-step procedure starting from vindoline. Vincristine, vinorelbine and several derivatives condensed with a cyclopropane ring were synthesized. Various hybrid molecules were prepared by the coupling reaction of vindoline and methyl ester of tryptophan, which were conjugated by carrier peptides of octaarginine. Studying the halogenation reactions of vindoline and catharanthine some fluorine derivatives were obtained which showed promising antitumor activity on various tumor types. The synthesis of the Aspidospermane alkaloid bannucine and 5′-epibannucine were carried out using N-acyliminium intermediates. The same intermediate was also applied in the first synthesis of sessiline. The research group have synthesized of flavonoid alkaloids: dracocephins A and B. Further three flavonoid alkaloids, namely 8-(2”-pyrrolidinon-5′′-yl)quercetin, 6-(2′′-pyrrolidinon-5′′-yl)-(−)- and 8-(2′′-pyrrolidinon-5′′-yl)-(−)-epicatechin were prepared by acid-catalyzed regioselective Mannich reaction starting from the corresponding flavonoid precursor. Vindoline was also coupled to synthetic pharmacophores, such as triphenylphosphine and various N-heterocycles. Some of these hybrid molecules showed significant antitumor activity. Furthermore, 7-OH and 7-NH modified flavonoid derivatives were synthesized by a regioselective alkylation followed by Smiles rearrangement and hydrolysis.

Abstract 1812: In vitro and in vivo antiangiogenic activity of desacetylvinblastine monohydrazide through inhibition of VEGFR2 and Axl pathways

Abstract Background and Objective: Tumor angiogenesis process is regulated by multiple proangiogenic pathways, such as VEGFR2 and Axl. Inhibition of VEGF/VEGFR2 signaling alone fails to block tumor neovascularization, and anti-VEGF resistance is often associated with Axl. Hence, discovery of novel agents that target multiple angiogenesis pathways is in demand. Here, we describe desacetylvinblastine monohydrazide (DAVLBH), a derivative of vinblastine (VLB) that exerts a more potent antiangiogenic effect than VLB in vitro and in vivo by inhibiting VEGFR2 and Axl pathways. Methods: The antiangiogenic effects of DAVLBH were studied in vitro (proliferation, migration, and tube formation assays) and ex vivo (aortic ring assay). In vitro pericyte migration to endothelial tubes was assessed using a three-dimensional co-culture assay. In vivo assay was performed in HeLa xenograft model. Western blotting, immunohistochemical and immunofluorescence assays were conducted to evaluate the key proteins of the VEGF/VEGFR2 and Gas6/Axl pathways. Results: DAVLBH (1 nM) inhibited VEGF- and Gas6-induced angiogenesis in vitro. At 0.75 μmol/kg, DAVLBH significantly delayed tumor growth and reduced vascular density in vivo, which was associated with the inactivation of VEGF/VEGFR2 and Gas6/Axl signalling pathways. DAVLBH blocked the compensatory upregulation of Axl in response to bevacizumab treatment in HUVECs. DAVLBH also suppressed the recruitment of pericytes to well-established endothelial tubes and reduced pericyte coverage in vivo, which was accompanied by inhibition of Axl. Conclusions: DAVLBH potently inhibited angiogenesis-mediated tumor growth by blocking the activation of VEGF/VEGFR2 and Gas6/Axl pathways. DAVLBH might serve as a promising antiangiogenic agent for cancer therapy. Note: This abstract was not presented at the meeting. Citation Format: Minfeng Chen, Xueping Lei, Qiulin Nie, Jianyang Hu, Zhenjian Zhuo, Anita Yiu, Heru Chen, Nanhui Xu, Maohua Huang, Kaihe Ye, Liangliang Bai, Wencai Ye, Dong-Mei Zhang. In vitro and in vivo antiangiogenic activity of desacetylvinblastine monohydrazide through inhibition of VEGFR2 and Axl pathways [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1812. doi:10.1158/1538-7445.AM2017-1812

Chaetomin a new calmodulin inhibitor from Chaetomium globosum

Bioassay-guided fractionation of the active organic extract of Chaetomium globosum, a fungus isolated from maize, led to the separation of one epipolythiodioxopiperazine, which was identified as chaetomin (1). Compound 1 binds to the new human calmodulin (hCaM) biosensor hCaM M124C-A350, with a k d value in the nM order (kd=57 nM), eleven-fold higher than trifluoroperazine (TFP) used as positive control. Molecular docking predicted that 1 interacts with CaM in a similar site as KAR-2 (a vinblastine derivative) compound does. In conclusion, compound 1 binds to CaM with a higher affinity, which might explain its cytotoxic effect against some cancer cell lines.

Targeted treatment of folate receptor-positive platinum-resistant ovarian cancer and companion diagnostics, with specific focus on vintafolide and etarfolatide

Among the gynecological malignancies, ovarian cancer is the leading cause of mortality in developed countries. Treatment of ovarian cancer is based on surgery integrated with chemotherapy. Platinum-based drugs (cisplatin and carboplatin) comprise the core of first-line chemotherapy for patients with advanced ovarian cancer. Platinum-resistant ovarian cancer can be treated with cytotoxic chemotherapeutics such as paclitaxel, topotecan, PEGylated liposomal doxorubicin, or gemcitabine, but many patients eventually relapse on treatment. Targeted therapies based on agents specifically directed to overexpressed receptors, or to selected molecular targets, may be the future of clinical treatment. In this regard, overexpression of folate receptor-α on the surface of almost all epithelial ovarian cancers makes this receptor an excellent “tumor-associated antigen”. With appropriate use of spacers/linkers, folate-targeted drugs can be distributed within the body, where they preferentially bind to ovarian cancer cells and are released inside their target cells. Here they can exert their desired cytotoxic function. Based on this strategy, 12 years after it was first described, a folate-targeted vinblastine derivative has now reached Phase III clinical trials in ovarian cancer. This review examines the importance of folate targeting, the state of the art of a vinblastine folate-targeted agent (vintafolide) for treating platinum-resistant ovarian cancer, and its diagnostic companion (etarfolatide) as a prognostic agent. Etarfolatide is a valuable noninvasive diagnostic imaging agent with which to select ovarian cancer patient populations that may benefit from this specific targeted therapy.

Synthesis and in Vitro Antitumor Effect of Vinblastine Derivative−Oligoarginine Conjugates

Vinblastine is a widely used anticancer drug with undesired side effects. Its conjugation with carrier molecules could be an efficient strategy to reduce these side effects. Besides this, the conjugate could exhibit increased efficiency against resistant cells, e.g., due to the altered internalization pathway. Oligoarginines, as cell-penetrating peptides, can transport covalently attached compounds into different kinds of cells and enhance the efficiency of those compounds. We report here the coupling of vinblastine through its carboxyl group at position 16 with the N-terminal amino function of L-Trp methyl ester. After hydrolysis of the ester group, 17-desacetylvinblastineTrp was conjugated to the N-terminal amino group of oligoarginine via the C-terminal carboxyl group of the Trp moiety in solution. The antitumor effect of conjugates was studied on sensitive and resistant human leukemia (HL-60) cells in vitro. Our data suggest that all conjugates investigated possess an antiproliferative effect against the studied cells. However, the effect was dependent on the number of Arg residues in the conjugates: Arg₈ > Arg₆ ≫ Arg₄. The conjugate with Arg₈ exhibited similar efficicacy as compared with free 17-desacetylvinblastineTrp. The in vitro studies also showed that the tubulin binding ability of vinblastine was essentially preserved even in the octaarginine conjugate. We also observed that two isomers were formed during conjugation. These isomers showed different levels of activity against tubulin polymerization in vitro and in vivo. The 17-desacetylvinblastineTrp-Arg₈-1 isomer conjugate possessed high selectivity against the mitotic spindles. HRMS and NMR data suggest that 17-desacetylvinblastineTrp-Arg₈-1 and 17-desacetylvinblastineTrp-Arg₈-2 are epimers at the tryptophan α carbon atom.

Total synthesis and evaluation of a key series of C5-substituted vinblastine derivatives.

A remarkably concise seven- to eight-step total synthesis of a systematic series of key vinblastine derivatives is detailed and used to characterize the importance and probe the role of the C5 ethyl substituent (R = H, Me, Pr, CH=CH(2), C[triple bond]CH, CH(2)OH, and CHO vs Et). The analogues, which bear deep-seated structural changes accessible only by total synthesis, were prepared using a powerful intramolecular [4 + 2]/[3 + 2] cycloaddition cascade of 1,3,4-oxadiazoles ideally suited for use in the assemblage of the vindoline-derived lower subunit followed by their incorporation into the vinblastine analogues through the use of a single-step biomimetic coupling with catharanthine. The evaluation of the series revealed that the tubulin binding site surrounding this C5 substituent is exquisitely sensitive to the presence (Et > H, 10-fold), size (Me < or = Et > Pr, 10-fold), shape (Et > CH=CH(2) and C[triple bond]CH, > 4-fold), and polarity (Et > CHO > CH(2)OH, >10-20-fold) of this substituent and that on selected occasions only a C5 methyl group may provide analogues that approach the activity observed with the naturally occurring C5 ethyl group.

A Phase II Clinical Trial of Vinorelbine in Dogs with Cutaneous Mast Cell Tumors

Few effective drugs are available to treat dogs with locally aggressive or metastatic mast cell disease. Vinorelbine, a semisynthetic derivative of vinblastine, is an effective drug for the treatment of canine mast cell tumors (MCT). Twenty-four dogs with cutaneous MCT. Dogs with at least 1 measurable, cytologically confirmed, and previously untreated cutaneous MCT received a single treatment with vinorelbine at the previously established dosage of 15 mg/m2 IV. Tumor measurements and CBC were evaluated before and 7 days after treatment. Adverse events were graded according to Veterinary Cooperative Oncology Group (VCOG) guidelines. Data were accrued in accordance with a Simon's 2-stage design with a noninteresting response rate of .05, a target response of .25, and alpha and beta values of .10. Three of 24 dogs (13%) had a response to treatment, including 1 measurable complete response and 1 measurable partial response. The 3rd dog had microscopic complete response to treatment with stable measurable disease. Twenty other dogs (83%) had stable disease and 1 dog (4%) had progressive disease. Neutropenia occurred in 13 dogs (54%) (grade 1, n = 4; grade 3, n = 6; grade 4, n = 3). Gastrointestinal toxicity occurred in 11 dogs (46%) (anorexia: grade 1, n = 3; grade 2, n = 1; grade 3, n = 1; diarrhea: grade 1, n = 2; grade 3, n = 1; vomiting: grade 1, n = 5; grade 3, n = 1). Vinorelbine was associated with an overall response rate of 13% and a high prevalence of neutropenia. Additional studies are indicated to determine if repeated dosing of vinorelbine or combination of vinorelbine with other drugs increases the observed biologic activity against canine MCT.

Synthesis of Vinblastine Derivatives

Synthesis of Vinblastine Derivatives

Interaction of tubulin with a new fluorescent analogue of vinblastine.

Vinblastine is an antimitotic agent that has been used extensively in cancer chemotherapy. The biological effects of the drug are believed to be the result of its interaction with tubulin, the major component of cellular microtubules. Fluorescence spectroscopy is a powerful and versatile technique for studying drug-tubulin interactions, but it rarely has been applied to studies involving vinca alkaloids. We have prepared a new fluorescent derivative of vinblastine designed to retain high affinity for tubulin while possessing a fluorophore that absorbs and emits visible light. A coumarin derivative of vinblastine, 17-deacetyl-O-(3-carbonylamino-7-diethylaminocoumarin) vinblastine (F-VLB), was prepared by reaction of 17-deacetylvinblastine with 7-diethylaminocoumarin-3-carbonyl azide. F-VLB was a potent inhibitor of in vitro microtubule assembly (IC(50) = 0.5 microM). F-VLB binding to tubulin was inhibited by vinblastine. Tubulin binding induced an increase in the F-VLB emission intensity and shifted the emission maximum to higher energy (from 500 to 480 nm). The Stokes shift of tubulin-bound F-VLB was about the same as the Stokes shift of the molecule in ethanol, indicating that the tubulin-bound fluorophore is probably on the exterior of the vinblastine binding site. Unlike vinblastine, F-VLB failed to induce self-assembly of tubulin that could be detected by light scattering or electron microscopy, although some self-association could be detected by analytical ultracentrifugation. Equilibrium binding parameters were quantitatively determined by monitoring the change in fluorescence anisotropy of F-VLB upon tubulin binding. The apparent equilibrium constant for F-VLB binding to tubulin [K(a)(app) = (7.7 +/- 0.5) x 10(4) M(-1) at 25 degrees C] was identical to the equilibrium constant for vinblastine binding to 2 microM tubulin (K(1)) measured under similar buffer and temperature conditions using ultracentrifugation [Vulevic, B., Lobert, S., and Correia, J. J. (1997) Biochemistry 36, 12828-12835]. Binding allocolchicine to tubulin did not significantly affect F-VLB's affinity for the protein [K(a)(app) = (9.1 +/- 0.4) x 10(4) M(-1) at 25 degrees C]. Analysis of the steady-state emission spectra yielded a distance between the colchicine and vinca binding sites on tubulin of approximately 40 A. F-VLB bound to paclitaxel- and glutaraldehyde-stabilized microtubules, with approximately equal affinity. We conclude that F-VLB can be used to obtain information about the vinblastine binding site on tubulin under equilibrium conditions.

Modifications in the "upper" velbenamine part of the Vinca alkaloids have major implications for tubulin interacting activities.

Vinca alkaloids represent a chemical class of major interest in cancer chemotherapy. The lead compounds vinblastine and vincristine have been employed in clinical practice for more than thirty years and remain widely used to this day. Several hundred derivatives have been synthesised and evaluated for their pharmacological activities, the majority being modified in the vindoline moiety, bearing several reactive centers. These efforts led to the identification of the amido derivative vindesine, registered in Europe in 1980 and now available in several countries. Then novel chemistry permitted the semisynthesis of derivatives modified in the velbenamine "upper" part of the molecule, creating a new potential in the Vinca alkaloids medicinal chemistry: as a result, vinorelbine, obtained by C' ring contraction of anhydrovinblastine, and is now marketed worldwide. Several strategies aimed at the total synthesis of vinblastine derivatives have been investigated, giving the opportunity to design rationally certain compounds. Modifications in the D' ring appeared to induce dramatic changes in the tubulin interactions. These observations have been confirmed recently by the identification of unprecedented pharmacological properties exerted by the novel fluorinated Vinca alkaloid, vinflunine. This review will focus more specifically on derivatives which have been modified in the velbenamine part, with the aim of inducing different chemical and pharmacological properties.

Dissociation of tubulin assembly-inhibiting and aggregation-promoting activities by a vinblastine derivative

A fluorescent vinblastine analogue, vinblastine-4′-anthranilate (Antvin), that binds to the vinca site on tubulin, inhibits tubulin assembly but does not lead to spiral or other large aggregate formation at concentrations up to 1.6 mM. As judged by turbidity, 90° light scattering and fluorescence anisotropy, little aggregation could be detected. This is in marked contrast to vinblastine and suggests that inhibition of assembly and aggregate formation can be dissociated from each other by suitable substitution in vinblastine.

Localization of the Vinblastine-binding Site on β-Tubulin

A fluorescent vinblastine derivative, vinblastine-4'-anthranilate, has been shown to inhibit polymerization of rat brain tubulin (IC50 = 4.8 microM). Binding of the drug to tubulin increases fluorescence intensity, causes a small emission blue shift, and has a quantum yield of 0.037. Fluorescence increases as a function of drug concentration, with a high affinity site and an undetermined number of lower affinity sites. Photolabeling, by exciting the fluorescent drug-tubulin complex at the absorption maximum of anthranilate, yields a covalent adduct confined to beta-tubulin. Its formation is specific in that it is blocked by maytansine or vinblastine. Tryptic hydrolysis identifies a single fluorescent beta-peptide coinciding with residues 175-213. The interactions between various ligands at this central portion of beta-tubulin are discussed.

Bioanalysis and pharmacokinetics of (investigational) vinca alkaloids.

1 6 4 Introduction Analytical methods have been developed for vinblastine and several investigational semisynthetic derivatives, using selective techniques based on highpressure liquid chromatography (HPLC). These methods were implemented in comprehensive studies of plasma pharmacokinetics, tissue distribution, excretion and metabolism in animal models. The results of these studies clearly highlight the need for such selective methods and increase our knowledge about the relation between the pharmacokineric behaviour and the pharmacodynamics of this kind of antitumour agents. The vinca alkaloids vinblastine and vincristine are two naturally occurring compounds isolated from the periwinkle plant Vinca rosea. These drugs constitute an important class of antineoplastic agents, which are now being used for over three decades in a number of palliative and, in some cases, even potentially curative multidrug regimens. In the early 1960's it was already recognized that minor changes in the molecular structure could have a great impact on the pharmacological activity of these compounds. This finding has resulted in the development of a substantial number of semisynthetic analogues with the aim of either converting non-active but abundantly present substances into active ones, or of designing new analogues with improved efficacies and/or altered antitumour spectra. Former studies had indicated that vinca alkaloids enter cells by active transport mechanisms rather than by passive diffusion. Within the cells they bind to the cytoplasmatic protein tubulin, thus interfering with the normal equilibrium that exists between tubulin monomers and structures of polymerized tubulin, the so-called microtubules. Investigations by fluorescence microscopy had shown a perceptible effect after the incubation of cells at concentrations of 5-I0 ng/ml of vinblastine, whereas a twoto fourfold increase sufficed to achieve a maximal effect (e.g. a complete dissolution of microtubules). Furthermore, results obtained by clonogenic assays had shown that the exposure duration of cells to the drug is an important determinant of the severity of the ultimate cytotoxic effect.

Anodic behavior of someVinca alkaloids with cytostatic activity: Effect of pH

The anodic oxidation mechanism of the Vinca alkaloids vinblastine, its semisynthetic derivatives vindesine and 5′-noranhydrovinblastine, and of vincristine, all with closely similar structures, was studied at a glassy carbon disk electrode in buffered aqueous media using differential pulse and cyclic voltammetry. The effect of pH on the mecharism showed that it is a complex multistep electron transfer with deprotonation steps involved and that the final products, dimers or polymers, adsorb strongly to the electrode, forming an unreactve film on the electrode surface. The electrochemical differential pulse voltammograms showed a correlation between the vinblastine derivatives, whereas vincristine reacts at different potentials. These differences in the anodic oxidation mechanisms of the compounds studied can be related to their neurotoxicity and myelosuppression effects. These effects may be due to the metabolite and/or degradation products of the compounds and result from how they are attached to, or transported across, cellular structures such as cell membranes.

Differential in vitro action of S-12363, a new vinblastine derivative, and of its epimer on microtubule proteins

The action of two epimers of a new vinblastine derivative that differ in their in vivo antitumor activity and their cytotoxicity was studied in vitro in brain microtubule proteins. These two compounds, called S-12363 and S-12362, could not be distinguished from one another or from other active vinca alkaloids by their ability to prevent microtubule assembly. However, they differed strongly both from one another and from vincristine and vinblastine in their ability to induce the formation of tubulin paracrystals and in the stability of the paracrystals following temperature shifts from 0 degree to 37 degrees C and vice versa. The most potent drug, S-12363, induced considerable tubulin aggregation, which was even more pronounced than that observed in the presence of vincristine. Previous results have shown that S-12363, in contrast to vincristine, induces no neurotoxic effects. This observation is in disagreement with a direct relationship between tubulin aggregation and neurotoxicity.

Interaction of a new photosensitive derivative of vinblastine, NAPAVIN, with tubulin and microtubules in vitro

We have synthesized a new photoreactive vinblastine derivative, 3-[[2-amino(4-azido-2-nitrophenyl)ethyl]-amino)-carbonyl)-O4-deceatyl -3-de (methoxycarbonyl)-vincaleukoblastine (NAPAVIN), which can be photoactivated with light in the 455-nm region as well as with ultraviolet irradiation. Previous studies had shown that photoactivated NAPAVIN is much more effective than vinblastine in inhibiting cell proliferation of multidrug resistant cell lines. The experiments reported here demonstrate that the unirradiated derivative is very similar to vinblastine in its interactions with brain tubulin and microtubules, regarding inhibition of in vitro assembly, binding, aggregation, and production of protofilament spirals. Irradiation of [3H]NAPAVIN in the presence of tubulin led to covalent binding of the drug to both subunits of the protein. Labeling also occurred when NAPAVIN was first irradiated, then incubated with tubulin in the dark, indicating the production of a fairly stable reactive species with a half-life of about 400 min. We conclude that labeling by this compound, under some conditions, occurs not by a nitrene but by an electrophilic photoproduct.

ChemInform Abstract: Synthesis of Vinca Alkaloids and Related Compounds. Part 48. Synthesis of (+)‐Catharanthine and (.+‐.)‐Allocatharanthine.

AbstractCoupling of catharanthine (IXa), the major alkaloid of Catharanthus roseus, with vindoline leads to vinblastine derivatives which show antitumor activity.

ChemInform Abstract: Novel Synthesis of Vinblastine Derivatives. Part 6. Synthesis of 20′‐Deethyl‐20′‐deoxy‐C′‐homovinblastine.

AbstractThe coupling of the azecinoindole derivative (I) with vindoline (II) via the respective chloroindolenine leads, after cyclization, to a mixture of the major isomers (IVa), (IVb) and the minor isomers (IVc), (IVd).

ChemInform Abstract: Novel Synthesis of Vinblastine Derivatives. Part 5. Concept and Studies of the Synthesis of 20′‐Deethyl‐20‐deoxy‐C′‐homovinblastine ‐ Octahydro‐3H‐azecino(5,4‐b)indole Derivatives.

AbstractA concept for the synthesis of a C'‐homovinblastine derivatives is presented, and potential intermediates (IXb) and (XI) pointing to this goal are prepared as shown in the scheme.