Cytostatic Activity of Combretastatin A-4 Derivatives in an In Vitro System.

Cytostatic activity of combretastatin A-4, its 11 analogues, and paclitaxel (Taxacad) was evaluated in vitro on human tumor cells A549 (lung adenocarcinoma) and PC-3 (prostate adenocarcinoma) in order to find the active and stable compound as a promising antitumor agent. 5-(4-Methoxyphenyl)-4-(3,4,5-trimethoxyphenyl)-isoxazole (compound 123124) and 3-(3,4,5-trimethoxyphenyl)-4-(4-methoxyphenyl)-isoxazole (compound 29310186) demonstrated the highest cytostatic activity (IC50≈8×10-9 М). The activity of two other cytotoxic compounds (2E)-1-(7-methoxy-2H-1,3-benzodioxol-5-yl)-3-(4-methoxyphenyl)prop-2-en-1-one (compound 104815) and 4-(3-amino-4-methoxyphenyl)-5-(3,4,5-trimethoxyphenyl)-1H-pyrazole hydrochloride (compound 198732) was close to that of Taxacad: IC50 65×10-9 and 80×10-9 М, respectively, and are also promising active components for the development of antitumor drugs.

Synthesis and antineoplastic properties of (1H-1,2,3-triazol-1-yl)furazans.

A method of 3-amino-4-[5-aryl(heteroaryl)-1H-1,2,3-triazol-1-yl)]furazan synthesis was optimized. Condensation of these compounds with 2,5-dimethoxytetrahydrofuran resulted in a series of previously unknown 4-[5-aryl(heteroaryl)-1H-1,2,3-triazol-1-yl)]-3-(pyrrol-1-yl)furazans. All target compounds were evaluated for both antimitotic microtubule destabilizing effect in a phenotypic sea urchin embryo assay and cytotoxicity in a panel of 60 human cancer cell lines. Pyrrolyl derivatives of triazolylfurazans were determined as antiproliferative compounds. The most potent microtubule targeting compounds 7a and 7e are of interest for further trials as antineoplastic agents.

[Expression of transmitter receptor genes in early development of sea urchin Paracentrotus lividus].

Neurotransmitters (including serotonin and acetylcholine) perform a number of prenervous functions in early sea urchin development. To detect the particular receptor components involved in these processes, we carried out a database search and nucleotide sequences homologous to serotonin receptor type 4, and the alpha6- and alpha10-subunits of nicotinic acetylcholine receptor were found among EST-clones from early Paracentrotus lividus embryos. Expression of these transcripts during early development was demonstrated using RT-PCR. These results are the first molecular biology evidence ofserotonin and acetylcholine receptor expression in sea urchin early embryogenesis.

[Localization, kinetic parameters, and functions of cholinesterase of the starfish ampulla]. / Lokalizatsiia, kineticheskie parametry i funktsional'naia rol' kholinésterazy ampul morskikh zvezd.

The starfish amplullae cholinesterase was shown to represent acetylcholinesterase and enhance its activity along with increasing motility of the starfish. Bundles of muscle fibres containing cholinesterase were found in the ampullae. Cholinesterase was shown to be localized in the muscle cells and in collagen layer in vicinity of the muscle cells. The data obtained suggest participation of the starfish ampullae cholinesterase in non-synaptic cholinergic transmission between the radial nerve axons and the muscle fibre extension. Besides, the enzyme could take part in functional relationship between the muscle cells and the outer epithelial cells of the starfish ampullae.

Recovery of acetylcholinesterase activity after irreversible inhibition by organophosphorous compounds in embryonic development.

1. Recovery of acetylcholinesterase (AChE) activity was studied using the embryos of sea urchins Strongylocentrotus intermedius and S. nudus, embryos of axolotl Ambystoma mexicanum and in the chick embryo muscle culture treated by "irreversible" organophosphorous inhibitors (OPI). 2. AChE activity was assayed by a modified Ellman's procedure. 3. It follows from the data obtained that, unlike the plutei of sea urchins and the monolayer culture of chick embryo muscle cells, the embryos of axolotl show a compensatory increase in AChE biosynthesis after inhibition by OPI. 4. This mechanism is assumed to be related to the presence of a well developed neuromuscular system in the A. mexicanum embryos. 5. It is possible that acetylcholine accumulated as a result of partial AChE inhibition is responsible for the compensatory increase in AChE biosynthesis.

[Recovery of acetylcholinesterase activity in the axolotl embryo following inhibition with the organophosphorus inhibitor Gd-7]. / Vosstanovlenie aktivnosti atsetilkholinésterazy zarodyshei aksolotlia posle ugneteniia fosfororganicheskim ingibitorom Gd-7.

The restoration of acetylcholinesterase (AChE) activity in axolotl Ambystoma mexicanum embryo after treatment at 38-42 stages with irreversibly AChE-inhibiting Gd-7 phosphororganic inhibitor in concentrations, significantly decreasing AChE activity level, but not interfering with ontogenesis has been studied. The rate of AChE activity restoration in Gd-7 treated axolotl embryo depends on the level of the enzyme restraint and the stage of the embryo development. The value of maximal restoration of AChE activity differs; it is less in embryos, treated with Gd-7 at later stages of development. The ability of the embryos to swim restores parallel to the increase in AChE activity. The data obtained suggest that axolotl embryo possess compensatory mechanism for increasing AChE biosynthesis after decrease in its activity caused by Gd-7. Acetylcholine, accumulating in the organism at partial inactivation of AChE by phosphororganic inhibitor may participate in this mechanism.

[Recovery of the acetylcholinesterase activity in a monolayer culture of chick myoblasts after irreversible inhibition by an organophosphorus inhibitor]. / Vosstanovlenie aktivnosti atsetilkholinesterazy v monosloinoi kul'ture kurinykh mioblastov posle neobratimogo tormozheniia fosfororganicheskim ingibitorom.

The recovery of the acetylcholine esterase (AChE) activity after the irreversible inhibition with an organophosphorus inhibitor B-156 was studied in a developing monolayer culture of chick myoblasts. The culture was obtained from muscles of posterior limbs of the 11 day old chick embryos. The AChE activity was estimated by the modified Ellman method from the moment of inoculation to the stage of spontaneous contractions of muscle fibres. After the B-156 treatment the AChE activity of muscle cells decreased, then started to increase and the maximum recovery of activity, below the initial level, was attained within roughly 2 days after the treatment. The AChE activity in the treated culture somewhat decreased thereafter. The lower the inhibitor concentration, i.e. the lower the value of the initial AChE inhibition, the higher the starting rate and degree of recovery of the AChE activity. The results obtained suggest that, unlike the multilayer culture of muscle tissue at later stages of differentiation no compensatory enhancement of AChE biosynthesis after irreversible inhibition of this enzyme by an organophosphorus inhibitor is observed in the monolayer culture of chick myoblasts at the early stages of myogenesis.