Modern Methods for Assessment of microRNAs

Chemiluminescent plate assay of microRNA-155 coupled with catalytic hairpin assembly with oligonucleotide release (CHAOR)

A heterogeneous sensitive microRNA-155 assay based on a new isothermal amplification method, called catalytic hairpin assembly with oligonucleotide release (CHAOR), was developed. The principle of CHAOR was studied by non-denaturing electrophoresis. To detect the amplification product, a polyperoxidase-streptavidin conjugate (molar ratio 1:80) and an enhanced chemiluminescence reaction were used, which made it possible to increase assay sensitivity. The detection limit of microRNA-155 assay was 0.4 pM. The coefficient of variation of the chemiluminescent signal, formed upon the heterogeneous determination of miRNA-155, was less than 12 % within the working range. The efficiency of CHAOR as an amplification method was similar to that of traditional CHA, as miRNA-155 assays based on CHAOR and CHA had similar analytical parameters. In addition, the proposed assay was highly specific. Contrary to traditional CHA, CHAOR, one of whose products is a single-stranded oligonucleotide, can be used in analytical methods based on cascade amplification.

Non-coding RNAs (ncRNAs) and multidrug resistance in glioblastoma: Therapeutic challenges and opportunities

Non-coding RNAs (ncRNAs) have been recognized as pivotal regulators of transcriptional and post-transcriptional gene modulation, exerting a profound influence on a diverse array of biological and pathological cascades, including the intricate mechanisms underlying tumorigenesis and the acquisition of drug resistance in neoplastic cells. Glioblastoma (GBM), recognized as the foremost and most aggressive neoplasm originating in the brain, is distinguished by its formidable resistance to the cytotoxic effects of chemotherapeutic agents and ionizing radiation. Recent years have witnessed an escalating interest in comprehending the involvement of ncRNAs, particularly lncRNAs, in GBM chemoresistance. LncRNAs, a subclass of ncRNAs, have been demonstrated as dynamic modulators of gene expression at the epigenetic, transcriptional, and post-transcriptional levels. Disruption in the regulation of lncRNAs has been observed across various human malignancies, including GBM, and has been linked with developing multidrug resistance (MDR) against standard chemotherapeutic agents. The potential of targeting specific ncRNAs or their downstream effectors to surmount chemoresistance is also critically evaluated, specifically focusing on ongoing preclinical and clinical investigations exploring ncRNA-based therapeutic strategies for glioblastoma. Nonetheless, targeting lncRNAs for therapeutic objectives presents hurdles, including overcoming the blood-brain barrier and the brief lifespan of oligonucleotide RNA molecules. Understanding the complex relationship between ncRNAs and the chemoresistance characteristic in glioblastoma provides valuable insights into the fundamental molecular mechanisms. It opens the path for the progression of innovative and effective therapeutic approaches to counter the therapeutic challenges posed by this aggressive brain tumor. This comprehensive review highlights the complex functions of diverse ncRNAs, including miRNAs, circRNAs, and lncRNAs, in mediating glioblastoma's chemoresistance.

Quantitation of MicroRNA-155 in Human Cells by Heterogeneous Enzyme-Linked Oligonucleotide Assay Coupled with Mismatched Catalytic Hairpin Assembly Reaction

In the present work, we describe the development of a chemiluminescent enzyme-linked oligonucleotide assay coupled with mismatched catalytic hairpin assembly (mCHA) amplification for the quantitative determination of microRNA-155. To improve its sensitivity, a polymerase-free mCHA reaction was applied as an isothermal amplification method. The detection limit of the proposed assay was 400 fM. In addition, the high specificity of the assay was demonstrated. The proposed assay allowed assessment of the content of microRNA-155 in human cancer lines such as HepG2, Caco2, MCF7, and HeLa. The quantitation of microRNA-155 was performed after purification of short RNAs (less than 200 nt) from cell lysates since a high matrix effect was observed without this pre-treatment. The results of the quantitative determination of the microRNA content in cells were normalized using nematode microRNA-39, the concentration of which was determined using a heterogeneous assay developed by us using a strategy identical to that of the microRNA-155 assay.