Alexey Yu. Fedorov

Synthesis and Biological Evaluation of 4-Arylcoumarin Analogues of Combretastatins. Part 2

A series of A-ring variously methoxylated 4-(3-hydroxy-4-methoxyphenyl)coumarins related to combretastatin A-4 was prepared by cross-coupling reactions. Cytotoxicity studies indicated a potent activity against HBL100 cell line. Substitution patterns on A-ring had only a slight effect on antiproliferative activity. For most cytotoxic compounds, the activity as potential modulators of P-gp and BCRP efflux pumps was evaluated. The results show that compounds 2 and 7 were able to restore mitoxantrone accumulation (BCRP) at concentrations similar to that of cyclosporine A. Compound 7 was the most efficient to reverse P-gp activity. All compounds were found to potently inhibit in vitro microtubule formation via a substoichiometric mode of action for the most part. Compounds 1 and 2 were found to have an apparent affinity binding constant similar to that of combretastatin A-4, i.e., 1 × 10 (6) M(-1). The molecular modeling of coumarin derivatives was performed on the basis of the molecular structure of 7, as determined by single-crystal X-ray crystallography. The calculations suggested that the presence of a methoxy group out of the plane of the chromenone moiety is an important steric hindrance factor embedding the accessibility of those molecules inside the binding pocket on tubulin.

Synthesis and biological evaluation of polymethoxylated 4-heteroarylcoumarins as tubulin assembly inhibitor

A series of syn-restricted polymethoxylated 4-heteroarylcoumarins--the isostuctural analogs of combretastatin A-4--was synthesized by Suzuki-Miyaura cross-coupling reaction and evaluated for antiproliferative activity. The 4-(1-methyl-1H-indol-5-yl)chromen-2-ones exhibit a potent cytotoxicity against HBL100 epithelial cell line with an IC(50) value amounting to 0.098 and 0.078 microM, respectively. The two compounds, having an indolyl moiety, potent inhibit in vitro microtubule assembly with a substoichiometric mode of action. A structure-activity relationship was discussed and the indolyl moiety was proved to be a good surrogate for the 3-hydroxy-4-methoxyphenyl ring of CA-4.

Exploring Selective Inhibition of the First Bromodomain of the Human Bromodomain and Extra-terminal Domain (BET) Proteins.

A midthroughput screening follow-up program targeting the first bromodomain of the human BRD4 protein, BRD4(BD1), identified an acetylated-mimic xanthine derivative inhibitor. This compound binds with an affinity in the low micromolar range yet exerts suitable unexpected selectivity in vitro against the other members of the bromodomain and extra-terminal domain (BET) family. A structure-based program pinpointed a role of the ZA loop, paving the way for the development of potent and selective BET-BRDi probes.

Synthesis and Biological Evaluation of Furanoallocolchicinoids

A series of conformationally flexible furan-derived allocolchicinoids was prepared from commercially available colchicine in good to excellent yields using a three-step reaction sequence. Cytotoxicity studies indicated the potent activity of two compounds against human epithelial and lymphoid cell lines (AsPC-1, HEK293, and Jurkat) as well as against Wnt-1 related murine epithelial cell line W1308. The results of in vitro experiments demonstrated that the major effect of these compounds was the induction of cell cycle arrest in the G2/M phase as a direct consequence of effective tubulin binding. In vivo testing of the most potent furanoallocolchicinoid 10c using C57BL/6 mice inoculated with Wnt-1 tumor cells indicated significant inhibition of the tumor growth.

Three-step one-pot organobismuth-mediated synthesis of benzo[b]pyran compounds

Tris[ortho-chloromethylphenyl]bismuth diacetate reacted with phenols and enolisable substrates in the presence of a base to afford good yields of oxaphenanthrene derivatives.

Synthesis and biological evaluation of novel anticancer bivalent colchicine-tubulizine hybrids.

A series of novel antimitotic hybrids were synthesized in good yields by linking of azide-containing colchicine congeners with acetylene-substituted tubulizine-type derivatives using copper-mediated 1,3-dipolar cycloaddition. Obtained compounds exhibit good cytotoxicity against HBL100 epithelial cell lines (IC(50)=0.599-2.93 μМ). Several newly synthesized compounds are the substoichiometric inhibitors of microtubule assembly (R=0.41-0.78). The results highlight the importance of the length of spacer linking the tubulin binding ligands in heterodimeric molecules.

Synthesis of indole-derived allocolchicine congeners exhibiting pronounced anti-proliferative and apoptosis-inducing properties

Based on the natural antimitotic agent allocolchicine as a lead structure, a series of novel indole-based allocolchicine congeners was synthesized and assessed in vitro for their cytostatic properties. Several compounds exhibited potent anti-proliferative and apoptosis-inducing activity towards lymphoma cells along with low unspecific cytotoxicity. The observed activity is supposed to result from the inhibition of microtubule assembly, as indicated by the tubulin polymerisation assay.

Perceptually Motivated Benchmark for Video Matting.

Despite recent progress in the field of video matting, neither public data sets nor even a generally accepted method of measuring quality has yet emerged. In this paper we present an online benchmark for video-matting methods. Using chroma keying and a reflection-aware stop-motion capturing procedure, we prepared 12 test sequences. Then, using subjective data, we performed extensive comparative analysis of different quality metrics. The goal of our benchmark is to enable better understanding of current progress in the field of video matting and to aid in developing new methods.

Synthesis and biological evaluation of new water-soluble photoactive chlorin conjugate for targeted delivery

A new water-soluble conjugate, consisting of a chlorin-based photosensitizing part, and a 4-arylaminoquinazoline moiety with high potential affinity to an epidermal growth factor receptors (EGFR) and vascular endothelial growth factor receptors (VEGFR), suitable for photodynamic therapy (PDT), was synthesized starting from methylpheophorbide-a in seven steps. An increased accumulation of this compound in A431 cells with high level of EGFR expression, in comparison with CHO and HeLa cells with low EGFR expression was observed. The prepared conjugate exhibits dark and photoinduced cytotoxicity at micromolar concentrations with IC50dark/IC50light ratio of 11-18. In tumor-bearing mice, the conjugate preferentially accumulates in the tumor tissue.

Antitumor Activity of Furanoallocolchicinoid-Chitosan Conjugate

Colchicine irreversibly binds to tubulin, blocks microtubule formation, and inhibits cell division. However, its usage as an antitumor agent is limited due to its distribution to many tissues and low accumulation in the tumor. The increase in molecule weight can change colchicine biodistribution and decrease side effects. The aim of this work was to study in vivo and in vitro antitumor activity of colchicine-chitosan conjugate. A new allocolchicine derivative – furanoallocolchicinoid 3 was synthesized and conjugated to chitosan (4). Both 3 and 4 induced in vitro tubulin reorganization, cell cycle arrest, and inhibition of cell proliferation in 2D and 3D cultures. Antitumor effect of chitosan, 3, and 4 was studied in Wnt-1 breast tumor bearing mice. Conjugate 4 demonstrated significantly better tumor growth inhibition than 3 possibly as a result of a better accumulation in the tumor.