One aptamer, two functions: the full-length aptamer inhibits AMPA receptors, while the short one inhibits both AMPA and kainate receptors: DOI: 10.14800/rd.1560

AMPA and kainate receptors, along with NMDA receptors, are distinct subtypes of glutamate ion channels. Excessive activity of AMPA and kainate receptors has been implicated in neurological diseases, such as epilepsy and neuropathic pain. Antagonists that block their activities are therefore potential drug candidates.  In a recent article in the Journal of Biological Chemistry by Jaremko et al. 2017, we have reported on the discovery and molecular characterization of an RNA aptamer of a dual functionality: the full-length RNA (101 nucleotide) inhibits AMPA receptors while the truncated or the short (55 nucleotide) RNA inhibits both the AMPA and kainate receptors. The full-length RNA aptamer was isolated through a specially designed, systematic evolution of ligands by exponential enrichment (SELEX) using only a single type of AMPA receptors expressed in HEK-293 cells. The design feature and the results of our recent article are highlighted here, as they demonstrate the utility of the SELEX approach and the potential of using a single AMPA receptor type to develop potent, novel RNA aptamers targeting multiple subunits and AMPA/kainate receptor subtypes with length-dependent functionalities

KSHV episomes: rugged individualists on the factory floor: DOI: 10.14800/rd.1565

We have recently developed tools to study Kaposi’s sarcoma-associated virus (KSHV) reactivation at the single-episome level. Using immunofluorescent labeling of latent nuclear antigen (LANA) protein to localize viral episomes, combined with fluorescence in situ RNA hybridization (RNA-FISH) of an intron region of immediate early transcripts, we have visualized active transcription of viral genomes in infected cells. At this level, we observed that not all episomes within a single cell were uniformly transcribed following reactivation stimuli. However, those episomes that were transcribed, formed large aggregates containing a significant fraction of cellular RNA polymerase II (RNAPII), foci consistent with previously described viral transcriptional factories. This focal assembly of RNAPII on viral episomes was accompanied by an overall decrease in the pool of cellular RNAPII. Additionally, the viral transcriptional factories localized with replicating viral genomic DNAs. This co-localization suggests that KSHV may assemble an “all-in-one” workroom for both gene transcription and DNA replication. While previous studies have reported on the variable response of individual KSHV infected cells or episomes derived from a population during reactivation, our results expose this variation further by demonstrating heterogeneity in the response of individual KSHV episomes within a single reactivating cell

Expression of ITGB1 and E-cadherin regulated by lncLSINCT5 sponging on miR-29c-3p in papillary thyroid cancer cells: DOI: 10.14800/rd.451

Papillary thyroid carcinoma (PTC) is the most predominant subtype of thyroid cancer, contributing to more than 80% of all thyroid or endocrine malignancies. However, the role of Long noncoding RNA long stress induced non-coding transcripts (LSINCT5) in papillary thyroid cancer remains largely unknown. In the present study, we found that the expression of LSINCT5 in PTC cell line was higher than that in human normal thyroid cell HT-ori3. The proliferation and migration ability of PTC cell lines TPC-1 and KAT-5 cells were significantly decreased after transfection of siLSINCT5-1 and siLSINCT5-2 compared with siNC transfection. The dual luciferase reporter gene and RIP confirmed that LSINCT5 is capable of specifically binding to miR-29c. Compared with the transfected LSINCT5 group, the proliferation and migration ability of TPC-1 cells in the co-transfected LSINCT5 and miR-29c groups were significantly decreased, and the expression of ITGB1 mRNA and protein were down-regulated either. Taken together, our data indicated that LSINCT5 can inhibit the tumor suppressive effect of miR-29c-ITGB1 axis and promote the proliferation and metastasis of PTC by targeting miR-29c-ITGB1 axis

Reciprocal Regulation among miR-181d/CRY2/FBXL3/c-myc Signaling Axis Modulates Metabolism in Colorectal Cancer: DOI: 10.14800/rd.161

Patients with CRC (colorectal cancer) usually have a poor prognosis and the cure rate of CRC remained unsatisfied due to unfavorable curative effect. It is well known that microRNAs (miRNAs) and energy metabolism have pivotal roles in CRC progression. In a recent article in Cell Death & Disease by Xiaofeng Guo. et al. 2017, we have reported an oncogenic role of miR-181d in CRC by promoting glycolysis, and its underlying molecular mechanism about a new feedback loop among miR-181d/CRY2/FBXL3/c-myc signaling axis. Among these, we have identified the level of miR-181d was upregulated in CRC and the inhibition of miR-181d decreased glycolysis in CRC cells. We also found that c-myc played a central role in regulating cell glycolysis, which is required for the metabolic shift induced by miR-181d. Besides, we have demonstrated FBXL3 and CRY2 were direct targets of miR-181d and c-myc promoted miR-181d upregulation while inhibiting the expression of CRY2 and FBXL3 in CRC cells. The data from our recent article strongly suggest a new light onto the oncogenic function of the miR-181d in CRC. Furthermore, these findings represent a novel potential approach for silencing miR-181d/c-myc signaling pathway in CRC treatment

RNA methylation in lymphoid malignancies: DOI: 10.14800/rd.1563

N6-methyl-adenosine (m6A) modification is the most abundant internal modification in mammalian RNA and plays an important role in gene expression mechanisms such as mRNA splicing, nuclear export, transcript stability and translational efficiency. The extent and the significance of m6A modifications in pathological conditions, especially hematological malignancies such as lymphomas are not known. In this study, the global m6A methylation by an immunocapture method in normal B cells (GMO 6990), and in the B cell neoplastic cells such as diffuse large B cell lymphoma (DB), Burkitt’s lymphoma (Raji) and a relapsed pre-B cell acute lymphoblastic leukemia (ALL) (NALM6) cells are discussed. Variable mRNA expression of RNA methylases such as methyltransferase like 3 (METTL3) and Wilms tumor 1 associated protein (WTAP) that methylates internal adenosine residues in mRNA was observed in normal and lymphoma cells as quantified by qRT-PCR. Further, an mRNA demethylase, Fat mass and obesity associated enzyme (FTO) mRNA expression was found to be high in lymphoma cells compared to normal B cells. A similar trend was also observed between normal and ALL patients at diagnosis. Overall, our studies suggest that altered RNA methylation and enzymes controlling this process may be of significance in the pathology of lymphoid malignancies

microRNA-7: A critical sensitizer for TRAIL sensitivity in glioblastoma cells: DOI: 10.14800/rd.1620

TRAIL (TNF-related apoptosis-inducing ligand) is a promising anticancer agent because of its tumor-specifc apoptosis inducer activity without affecting normal cells. MicroRNAs (miRNAs) emerge as important regulators of cell viability. Our recent studies showed that miR-7 is a potential sensitizer for TRAIL-induced apoptosis in glioblastoma (GBM) cells, and XIAP is a critical gene in the apoptotic process as a direct downstream gene of miR-7. Additionally, this regulatory axis could also exert in other types of tumor cells. More importantly, we confirmed that co-delivery of sTRAIL and tumor suppressor miR-7 by MSCs leads to synergistic cancer killing effect. Thus, miR-7 has been demonstrated to be a critical sensitizer for TRAIL-induced apoptosis through regulating XIAP and highlights a novel therapeutic strategy for the treatment of GBM

RNA processing and ribosome biogenesis in bone marrow failure dsorders: DOI: 10.14800/rd.1531

Bone marrow failure disorders (BMFDs), which are characterized by an early pro-apoptotic phase which results in faulty hematopoiesis and anemia, more often than not progress to outright acute myelogenous leukemia (AML). Recent findings have indicated that most if not all of these disorders have a very significant RNA processing component to their pathology. This review aims to highlight some of normal processes of RNA metabolism that have been recently demonstrated to be altered in BMFDs

Long non-coding RNA Rpph1 promotes inflammation in diabetic nephropathy: DOI: 10.14800/rd.450

As the main complication of diabetes-related kidney damage, diabetic nephropathy (DN) is a complex clinical problem worldwide. As long non-coding RNAs (lncRNAs) play vital roles in DN, we would like to investigate the effect of lncRNA Rpph1 on glomerular mesangial inflammatory cytokines in diabetic nephropathy (DN). Compared with normal mice, Rpph1 was significantly up-regulated in kidney tissues of DN mice. Meanwhile, high-glucose cultured mesangial cells showed significantly up-regulation of Rpph1 expression in cultured mesangial cells. In addition, bioinformatics confirmed that Rpph1 does not have the ability to encode proteins. Moreover, the levels of TNF-? and MCP-1 were significantly up-regulated after overexpression of Rpph1 while down-regulation of Rpph1 results in the decreased expression of TNF-? and MCP-1. In conclusion, the lncRNA Rpph1 is highly expressed in mesangial cells of DN mice and the expression of inflammation-related factors is enhanced in high glucose environment which suggest that Rpph1 may be associated with the development of diabetic nephropathy

Effect of miR-382 on triple negative breast cancer cell line 4T1 by targeting PGC-1? DOI: 10.14800/rd.449

Breast cancer is one of the most frequent and malignant types of cancer in women, with an increasing morbidity and mortality rate. Treatment of triple negative breast cancer remains a challenge, since the efforts made with targeted therapies were ineffective. MicroRNAs (miRNAs) could play important roles in cancers via post-transcriptionally regulating target genes via binding to specific sequences in the 3\u27-UTR of downstream target genes. In the present study, the effect of miR-382 on the biological behaviors of triple negative breast cancer 4T1 cells is investigated. The expression of PGC-1? in the 4T1 cells transfected with miR-382 mimics was significantly decreased, while it was obviously increased after transfection with anti-miR-382. Moreover, the cell migration and proliferation activity were significantly increased in the miR-382+pCDNA-PGC-1? group when compared with the control+pCDNA3.1 group. However, the antitumor effect of miR-382 was blocked by overexpression of PGC-1?. Our results showed that miR-382 inhibits the proliferation and metastasis of 4T1 cells by down-regulating PGC-1?, suggesting miR-382 might be a therapeutic target in triple negative breast cancer

Long Non-coding RNA Landscape in Colorectal Cancer: DOI: 10.14800/rd.1628

Increasing number of reports have shown the involvement of LncRNAs in the tumour progression in multiple cancers including colorectal and female reproductive cancers such as ovarian and breast. In particular, the profiling of lncRNAs in colorectal cancer (CRC), which is within the top three cancers in both female and male, have identified 556 upregulated and 1040 downregulated lncRNAs as compared to normal tissue. In this highlight, we looked at the mechanism in which some of these lncRNAs can act in CRC development and progression through promoting survival, proliferation and invasion and metastasis. Furthermore, we also look into the possibility of a cytoskeletal protein, gelsolin and its possible interaction with lncRNAs