Optimal in vitro gene delivery with cationic lipids requires an excess of cationic charges with respect to DNA phosphates. In these conditions, in vivo delivery will be hampered by interference from cationic lipid-binding macromolecules either circulating or in the extracellular matrix. To overcome this problem, we are developing a modular transfection system based on lipid-coated DNA particles reminiscent of enveloped viruses. The particle core consists of the lipopolyamine-condensed nucleic acid in an electrically neutral ratio to which other synthetic lipids with key viral properties are hydrophobically adsorbed. As a first result, we have found that a good transfection level can be achieved simply with the neutral core particle, provided a zwitterionic lipid (dioleoyl phosphatidylethanolamine) is added to completely coat the DNA. Addition of lipids bearing a fusogenic or a nuclear localization peptide head group to the particles does not significantly improve an already efficient system, in contrast to polylysine-based gene transfer methods that rely on lysosomotropic or fusogenic agents to be effective. This emphasizes the distinctive properties of the lipopolyamines, including cell membrane destabilization, endosome buffering capacity, and possibly nuclear tropism. Most importantly, addition of lipids with a triantennary galactosyl residue drives the neutral nucleolipidic particles to the asialoglycoprotein receptor of human hepatoma HepG2 cells: Transfection increases approximately 1000-fold with 25% galactolipid. This receptor-mediated process is saturable and slightly less efficient than receptor-independent transfection obtained in vitro with a large excess of cationic lipid alone. Yet, electrically silent particles may provide an attractive solution for gene transfer in vivo where their external saccharide coat should allow them to diffuse within the organism and reach their target cells.

The liver fluke Opisthorchis felineus is a member of the triad of epidemiologically important liver fluke species belonging to the family Opisthorchiidae and the major agent causing opisthorchiasis over a vast territory, covering Russia, Kazakhstan and several European countries. The similarity between the diseases caused by O. felineus and other liver flukes, O. viverrini and Clonorchis sinensis, in clinical manifestations and course suggests that the scenarios of their development and, possibly, complications have much in common. The International Agency for Research on Cancer classified O. viverrini and C. sinensis as group 1 agents and the major factors inducing cholangiocarcinoma in endemic regions. However, a carcinogenic potential of O. felineus is poorly studied. This review characterizes O. felineus, briefs the epidemiological situation in Western Siberia, the world's largest opisthorchiasis focus, and assesses the carcinogenic potential of this liver fluke. The review is based on a comprehensive analysis of the published medical data on opisthorchiasis and its complications in Western Siberia. Results of performed analysis reflect the actual epidemiological situation in opisthorchiasis focus and suggest an association of this disease with bile duct cancer.

The liver fluke Opisthorchis felineus is a member of the triad of epidemiologically relevant species of the trematode family Opisthorchiidae, and the causative agent of opisthorchiasis felinea over an extensive range that spans regions of Eurasia. The International Agency for Research on Cancer classifies the infection with the liver flukes Opisthorchis viverrini and Clonorchis sinensis as group 1 agents and a major risk factor for cholangiocarcinoma. However, the carcinogenic potential of the infection with O. felineus is less clear. Here, we present findings that support the inclusion of O. felineus in the Group 1 list of biological carcinogens. Two discrete lines of evidence support the notion that infection with this liver fluke is carcinogenic. First, novel oxysterol-like metabolites detected by liquid chromatography-mass spectroscopy in the egg and adult developmental stages of O. felineus, and in bile, sera, and urine of liver fluke-infected hamsters exhibited marked similarity to oxysterol-like molecules known from O. viverrini. Numerous oxysterols and related DNA-adducts detected in the liver fluke eggs and in bile from infected hamsters suggested that infection-associated oxysterols induced chromosomal lesions in host cells. Second, histological analysis of liver sections from hamsters infected with O. felineus confirmed portal area enlargement, inflammation with severe periductal fibrosis and changes in the epithelium of the biliary tract characterized as biliary intraepithelial neoplasia, BilIN. The consonance of these biochemical and histopathological changes revealed that O. felineus infection in this rodent model induced precancerous lesions conducive to malignancy.