Development of a Low-Cost Stem-Loop Real-Time Quantification PCR Technique for EBV miRNA Expression Analysis

Critical review of Epstein-Barr virus microRNAs relation with EBV-associated gastric cancer

Epstein-Barr virus (EBV)-associated gastric cancer (EBVaGC) is regarded as the most prevalent malignant tumor triggered by EBV infection. In recent years, increasing attention has been considered to recognize more about the disease process's exact mechanisms. There is accumulating evidence that showing epigenetic modifications play critical roles in the EBVaGC pathogenesis. MicroRNAs (miRNAs), as critical epigenetic modulators, are single-strand short noncoding RNA (length ~ <200 bp), which regulate gene expression through binding to the 3'-untranslated region (3'-UTR) of target RNA transcripts and either degrade or repress their activities. In the latest research on EBV, it was found that this virus could encode miRNAs. Mechanistically, EBV-encoded miRNAs are involved in carcinogenesis and the progression of EBV-associated malignancies. Moreover, these miRNAs implicated in immune evasion, identification of pattern recognition receptors, regulation of lymphocyte activation and lethality, modulation of infected host cell antigen, maintain of EBV infection status, promotion of cell proliferation, invasion and migration, and reduction of apoptosis. As good news, not only has recent data demonstrated the crucial function of EBV-encoded miRNAs in the pathogenesis of EBVaGC, but it has also been revealed that aberrant expression of exosomal miRNAs in EBVaGC has made them biomarkers for detection of EBVaGC. Regarding these substantial characterizes, the critical role of EBV-encoded miRNAs has been a hot topic in research. In this review, we will focus on the multiple mechanisms involved in EBVaGC caused by EBV-encoded miRNAs and briefly discuss their potential application in the clinic as a diagnostic biomarker.

Comparison of three PCR-based assays for SNP genotyping in plants

BACKGROUND

PCR allelic discrimination technologies have broad applications in the detection of single nucleotide polymorphisms (SNPs) in genetics and genomics. The use of fluorescence-tagged probes is the leading method for targeted SNP detection, but assay costs and error rates could be improved to increase genotyping efficiency. A new assay, rhAmp, based on RNase H2-dependent PCR (rhPCR) combined with a universal reporter system attempts to reduce error rates from primer/primer and primer/probe dimers while lowering costs compared to existing technologies. Before rhAmp can be widely adopted, more experimentation is required to validate its effectiveness versus established methods.

RESULTS

The aim of this study was to compare the accuracy, sensitivity and costs of TaqMan, KASP, and rhAmp SNP genotyping methods in sugar beet (Beta vulgaris L.). For each approach, assays were designed to genotype 33 SNPs in a set of 96 sugar beet individuals obtained from 12 parental lines. The assay sensitivity was tested using a series of dilutions from 100 to 0.1 ng per PCR reaction. PCR was carried out on the QuantStudio 12K Flex Real-Time PCR System (Thermo Fisher Scientific, USA). The call-rate, defined as the percentage of genotype calls relative to the possible number of calls, was 97.0, 97.6, and 98.1% for TaqMan, KASP, and rhAmp, respectively. For rhAmp SNP, 24 of the 33 SNPs demonstrated 100% concordance with other two technologies. The genotype concordance with either technologies for the other 9 targets was above 99% (99.34-99.89%).

CONCLUSION

The sensitivity test demonstrated that TaqMan and rhAmp were able to successfully determine SNP genotypes using as little as 0.2 ng DNA per reaction, while the KASP was unable to ascertain SNP states below 0.9 ng of DNA per reaction. Comparative cost per reaction was also analyzed with rhAmp SNP offering the lowest cost per reaction. In conclusion, rhAmp produced more calls than either TaqMan or KASP, higher signal to NTC data while offering the lowest cost per reaction.

Next-generation sequencing of miRNAs in clinical samples of Epstein-Barr virus-associated B-cell lymphomas

Epstein-Barr virus (EBV) encodes 49 microRNAs (miRNAs) in the BART and BHRF1 regions of its genome. Although expression profiles of EBV-encoded miRNAs have been reported for EBV-positive cell lines and nasopharyngeal carcinoma, to date there is little information about total miRNA expression, including cellular and viral miRNAs, in the primary tumors of EBV-associated B-lymphoproliferative disorders. In this study, next-generation sequencing and quantitative real-time reverse transcription-PCR were used to determine the expression profiles of miRNAs in EBV-infected cell lines and EBV-associated B-cell lymphomas, including AIDS-related diffuse large B-cell lymphoma (DLBCL), pyothorax-associated lymphoma, methotrexate-associated lymphoproliferative disorder, EBV-positive DLBCL of the elderly, and Hodgkin lymphoma. Next-generation sequencing revealed that EBV-encoded miRNAs accounted for up to 34% of total annotated miRNAs in these cases. Expression of three miR-BHRF1s was significantly higher in AIDS-related DLBCL and pyothorax-associated lymphoma compared with methotrexate-associated lymphoproliferative disorder and EBV-positive DLBCL of the elderly, suggesting the association of miR-BHRF1s expression with latency III EBV infection. Heat map/clustering analysis of expression of all miRNAs, including cellular and EBV miRNAs, by next-generation sequencing demonstrated that each EBV tumor, except methotrexate-associated lymphoproliferative disorder, formed an isolated cluster. Principal component analysis based on the EBV-encoded miRNA expression showed that each EBV tumor formed a distinguished cluster, but AIDS-related DLBCL and pyothorax-associated lymphoma formed larger clusters than other tumors. These data suggest that expression of miRNAs, including EBV-encoded miRNAs, is associated with the tumor type and status of virus infection in these tumors.