The design of modified oligonucleotides that combine in one molecule several therapeutically beneficial properties still poses a major challenge. Recently a new type of modified mesyl phosphoramidate (or µ-) oligonucleotide was described that demonstrates high affinity to RNA, exceptional nuclease resistance, efficient recruitment of RNase H, and potent inhibition of key carcinogenesis processes in vitro. Herein, using a xenograft mouse tumor model, it was demonstrated that microRNA miR-21–targeted µ-oligonucleotides administered in complex with folate-containing liposomes dramatically inhibit primary tumor growth via long-term down-regulation of miR-21 in tumors and increase in biosynthesis of miR-21–regulated tumor suppressor proteins. This antitumoral effect is superior to the effect of the corresponding phosphorothioate. Peritumoral administration of µ-oligonucleotide results in its rapid distribution and efficient accumulation in the tumor. Blood biochemistry and morphometric studies of internal organs revealed no pronounced toxicity of µ-oligonucleotides. This new oligonucleotide class provides a powerful tool for antisense technology.
Irreversible destruction of disease-associated regulatory RNA sequences offers exciting opportunities for safe and powerful therapeutic interventions against human pathophysiology. In 2017, for the first time we introduced miRNAses–miRNA-targeted conjugates of a catalytic peptide and oligonucleotide capable of cleaving an miRNA target. Herein, we report the development of Dual miRNases against oncogenic miR-21, miR-155, miR-17 and miR-18a, each containing the catalytic peptide placed in-between two short miRNA-targeted oligodeoxyribonucleotide recognition motifs. Substitution of adenines with 2-aminoadenines in the sequence of oligonucleotide “shoulders” of the Dual miRNase significantly enhanced the efficiency of hybridization with the miRNA target. It was shown that sequence-specific cleavage of the target by miRNase proceeded metal-independently at pH optimum 5.5–7.5 with an efficiency varying from 15% to 85%, depending on the miRNA sequence. A distinct advantage of the engineered nucleases is their ability to additionally recruit RNase H and cut miRNA at three different locations. Such cleavage proceeds at the central part by Dual miRNase, and at the 5′- and 3′-regions by RNase H, which significantly increases the efficiency of miRNA degradation. Due to increased activity at lowered pH Dual miRNases could provide an additional advantage in acidic tumor conditions and may be considered as efficient tumor-selective RNA-targeted therapeutic.
Development of CAR‐T therapy led to immediate success in the treatment of B cell leukemia. Manufacturing of therapy‐competent functional CAR‐T cells needs robust protocols for ex vivo/in vitro expansion of modified T‐cells. This step is challenging, especially if non‐viral low‐efficiency delivery protocols are used to generate CAR‐T cells. Modern protocols for CAR‐T cell expansion are imperfect since non‐specific stimulation results in rapid outgrowth of CAR‐negative T cells, and removal of feeder cells from mixed cultures necessitates additional purification steps. To develop a specific and improved protocol for CAR‐T cell expansion, cell‐derived membrane vesicles are taken advantage of, and the simple structural demands of the CAR‐antigen interaction. This novel approach is to make antigenic microcytospheres from common cell lines stably expressing surface‐bound CAR antigens, and then use them for stimulation and expansion of CAR‐T cells. The data presented in this article clearly demonstrate that this protocol produced antigen‐specific vesicles with the capacity to induce stronger stimulation, proliferation, and functional activity of CAR‐T cells than is possible with existing protocols. It is predicted that this new methodology will significantly advance the ability to obtain improved populations of functional CAR‐T cells for therapy.
Antisense sequence-specific knockdown of pathogenic RNA offers opportunities to find new solutions for therapeutic treatments. However, to gain a desired therapeutic effect, the multiple turnover catalysis is critical to inactivate many copies of emerging RNA sequences, which is difficult to achieve without sacrificing the sequence-specificity of cleavage. Here, engineering two or three catalytic peptides into the bulge–loop inducing molecular framework of antisense oligonucleotides achieved catalytic turnover of targeted RNA. Different supramolecular configurations revealed that cleavage of the RNA backbone upon sequence-specific hybridization with the catalyst accelerated with increase in the number of catalytic guanidinium groups, with almost complete demolition of target RNA in 24 h. Multiple sequence-specific cuts at different locations within and around the bulge–loop facilitated release of the catalyst for subsequent attacks of at least 10 further RNA substrate copies, such that delivery of only a few catalytic molecules could be sufficient to maintain knockdown of typical RNA copy numbers. We have developed fluorescent assay and kinetic simulation tools to characterise how the limited availability of different targets and catalysts had restrained catalytic reaction progress considerably, and to inform how to accelerate the catalytic destruction of shorter linear and larger RNAs even further.
The paper reports the synthesis of a series of antisense oligonucleotides (aONs) directed against different segments of the influenza A virus genome (H1N1) and screening of their antiviral activity in the influenza A virus (H1N1)/MDCK cells and influenza A virus (H1N1)/A549 cells systems. The results of screening have shown that PB1-2AUG-R aON targeted towards the AUG codon region of the segment 2 of virus genome possessed the highest antiviral activity. The synthesized morpholino analog (PMO) and the new phosphoryl guanidine oligodeoxyribonucleotide (PGO) with the sequence of oligonucleotide PB1-2AUG-R provided a comparable biological effects: the influenza virus titer in MDCK cell culture was reduced by 15 times compared to the control when PGO was used in the concentration of 10 μM and by 40 times when PMO was used in the concentration of 20 μM. For the delivery of electrically neutral analogs of oligonucleotides (PGO and PMO), the perforation method proposed for PMO was used.
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