Diffuse gliomas are incurable, prevalent, and aggressive central nervous system tumors. Therefore, the development of selective oncolytic viral strains for malignant neoplasms is highly relevant. This study aimed to create an oncolytic virus based on a vaccine strain of poliovirus type 3 with natural antitumor activity. To achieve this goal, we replaced the internal ribosome entry site (IRES) of poliovirus with the corresponding fragment of human rhinovirus 30. The resulting recombinant oncolytic strain RVP3 retained the serotype of poliovirus type 3, as confirmed by virus neutralization micro-test with specific antiserum. In addition, the oncolytic efficacy of RVP3 was assessed in vitro on a broad panel of cell cultures. According to the results, RVP3 has changed its tropism, losing the ability to replicate in conditionally normal cell lines of embryonic astrocytes and embryonic fibroblasts while retaining the ability to replicate in tumor cells.

Transient gene expression is one of the most common methods in molecular biology, equally relevant for basic research projects and biotechnological industries. Despite the existence of commercial transfection systems, which afford high transfection efficiency and high expression levels of reporter genes, expanding such systems to industrial scales is often problematic due to high costs of the reagents. The well-described methods of cationic and calcium-phosphate transfection are accessible and ensure reproducible results at much lower costs. This study is aimed at comparative validation of calcium phosphate and cationic (polyethylenimine-based) transfection protocols along with the commercially available TurboFect reagent for mono- and cotransfections on a panel of commonly used cell lines including HEK293T, Huh7, BHK-21, CHO and MRC5. The efficiency of transfection with plasmid constructs encoding different fluorescent proteins was measured by flow cytometry. Of all the tested methods, calcium phosphate transfection afforded the highest efficiency of plasmid DNA delivery in all the cell lines except BHK21, for which the PEI method turned out to be more efficient than calcium phosphate transfection, and CHO, for which both methods showed comparable efficiency.