E. V. Svirshchevskaya

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.

Lipophilic prodrugs of a triazole-containing colchicine analogue in liposomes: Biological effects on human tumor cells

Colchicine site binders—blockers of tubulin polymerization—are potential antimitotic agents for anticancer therapy. To reduce their systemic toxicity and improve biodistribution, encapsulation in nanosized liposomes may be employed. Liposomes present a convenient means for preparation of injectable for-mulations of hydrophobic compounds, however colchicine as such is known to leak through the lipid bilayer. In this study, newly synthesized triazole-containing analogues of colchicine and allocolchicine, and their palmitic and oleic esters (lipophilic prodrugs) were tested for anti-proliferative activity and apoptosis-inducing potential. In contrast to colchicine conjugates, whose activities ranged with those of colchicine, allocolchicine derivatives exhibited drastically lower effects and were discarded. Liposomes of about 100 nm in diameter composed of egg phosphatidylcholine-yeast phosphatidylinositol-palmitic or oleic prodrug, 8: 1: 1, by mol, were prepared by standard extrusion technique and tested in a panel of four human tumor cell lines. Liposome formulations preserved the biological activities of the parent colchicinoid the most towards human epithelial tumor cells. Moreover, liposomal form of the oleoyl bearing colchicinoid inhibited cell proliferation more efficiently than free lipophilic prodrug. Due to substantial loading capacity of the liposomes, the dispersions contain sufficient concentration of the active agent to test wide dose range in experiments on systemic administration to animals.

Novel water-soluble anticancer agents derived from 4-arylcoumarins

Novel 4-arylcoumarin derivatives were obtained. They are water-soluble analogs of the well-known anticancer drug combretastatin A-4. The key step of the synthesis involves the Suzuki-Miyaura cross-coupling. The water-soluble salts obtained exhibit considerable cytotoxic activity against the HBL-100 and HaCaT cell lines.

Analysis of toxicity and biocompatibility of chitosan derivatives with different physico-chemical properties

A comparative study of the toxicity and hemocompatibility of chitosan and its derivatives with different acetylation degrees, molecular masses, charges, and hydrophobicity has been performed. It has been shown that only positively charged chitosan derivatives activate platelets and suppress cell proliferation, regardless of the acetylation degree, molecular mass, and hydrophobicity. Chitosan quaternization decreases toxicity at a low degree of substitution and abruptly increases it at a high one. Negatively charged chitosan derivatives were nontoxic and compatible with blood components. It was concluded that the toxicity of chitosan and its derivatives is defined by their charge and solubility at a neutral pH.

Synthesis of new sulfur-containing derivatives of furanoallocolchicinoids

Reaction of hydroxyl-containing heterocyclic colchicinoids with S-nucleophiles led to the formation of furanoallocolchicinoid sulfides in a high yield.

LARGE SIZE DNA IN VITRO AND IN VIVO DELIVERY USING CHITOSAN TRANSFECTION

In modern medicine, many diseases can be treated using gene therapy, which requires a DNA delivery system to prevent DNA from degradation and to transport it to the cells. Liposomal reagents are expensive for such a therapy and new inexpensive biodegradable DNA carriers are required. Chitosan (Ch) is a cationic polymer with promising potency for gene delivery. Some Ch derivatives have been shown to efficiently transfect mammalian cells in vitro. However, there are many inconsistencies in the literature concerning the effectiveness of Ch systems for in vivo gene transfer. The aim of this work was to develop a Ch-based vector for in vivo delivery of a large-size DNA fragment coding for the far-red fluorescent protein (RFP). Among several Ch derivatives, hexanoyl-Ch (HCh) with a molecular weight of 20 kDa effectively transfected cells in vitro. Intratumoural injection of polyplexes in colon and lung tumours resulted in local expression of RFP in tumours.

CELL BINDING AND PENETRATION OF QUATERNIZED CHITOSAN DERIVATIVES

Chitosan (Ch) is an attractive biopolymer with multiple reactive groups. However it is poorly soluble at neutral pH. Quaternization improves its solubility and permits the development of various positively charged drug delivery systems. The aim of this work was to study the solubility, toxicity, cell binding, and penetration of 20 kDa chitosan with 9, 40, 58 and 98% of quaternary ammonium group substitution (ChQ1 to ChQ4 accordingly). We showed that ChQ with substitution degree >40% was soluble in a wide pH range. Unexpectedly ChQ2 and ChQ3 were more toxic to cells than Ch, ChQ1 and ChQ4. Higher toxicity of ChQ was found against macrophage like cell line RAW264.7 than against epithelial cells MiaPaCa-2. All ChQ, in contrast to unmodified Ch, easily bound and penetrated the cells with the highest uptake by ChQ4. Thus, quaternized chitosan derivatives can be used for biomedical applications.

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.

Interactions of chitosan and its derivatives with cells (review)

Mechanisms of interaction between chitosan, various macromolecules or drug delivery systems and mammalian cells are reviewed. Modernly the role of different physicochemical properties of chitosan and chitosan nanoparticles on the mechanisms of cell bunding, endocytosis and redistribution are poorly understood.

Characterization of physicochemical parameters of nanoparticles formed from modified chitosan

Chitosan is a biodegradable and biocompatible polysaccharide widely used in different applications in medicine. The polycationic structure of the polymer provides many possibilities for its modification. One of the most interesting applications of chitosan is the development of nanosized delivery systems for biologically active molecules. The functional properties of these delivery systems depend severely on the structure and properties of nanoparticles. Using dynamic light scattering, atomic force microscopy, and to confocal microscopy, we have shown that both hexanoyl chitosan (HC) and succinoyl chitosan (SC) formed nanoparticles of comparable diameters from 120 to 250 nm. Using several methods of analysis helped us identify a minor fraction with a larger size of 600 to 700 nm formed by nanoparticle aggregates. The determined ζ potential was from −20 to −25 mV for SC nanoparticles and from 30 to 35 mV for HC nanoparticles.