Long non-coding RNA DLX6-AS1/miR-141-3p axis regulates osteosarcoma proliferation, migration and invasion through regulating Rab10

Osteosarcoma in a ceRNET perspective

Osteosarcoma (OS) is the most prevalent and fatal type of bone tumor. It is characterized by great heterogeneity of genomic aberrations, mutated genes, and cell types contribution, making therapy and patients management particularly challenging. A unifying picture of molecular mechanisms underlying the disease could help to transform those challenges into opportunities.This review deeply explores the occurrence in OS of large-scale RNA regulatory networks, denominated "competing endogenous RNA network" (ceRNET), wherein different RNA biotypes, such as long non-coding RNAs, circular RNAs and mRNAs can functionally interact each other by competitively binding to shared microRNAs. Here, we discuss how the unbalancing of any network component can derail the entire circuit, driving OS onset and progression by impacting on cell proliferation, migration, invasion, tumor growth and metastasis, and even chemotherapeutic resistance, as distilled from many studies. Intriguingly, the aberrant expression of the networks components in OS cells can be triggered also by the surroundings, through cytokines and vesicles, with their bioactive cargo of proteins and non-coding RNAs, highlighting the relevance of tumor microenvironment. A comprehensive picture of RNA regulatory networks underlying OS could pave the way for the development of innovative RNA-targeted and RNA-based therapies and new diagnostic tools, also in the perspective of precision oncology.

miR-141-3p Enhanced Radiosensitivity of CRC Cells

BACKGROUND

Colorectal cancer (CRC) is recognized as one of the frequently diagnosed malignancies, and numerous microRNAs (miRs) are identified to be active in CRC.

OBJECTIVE

This work aimed to clarify the effect of miR-141-3p on the radiosensitivity of CRC cells.

METHODS

Firstly, CRC cell lines were cultured and applied to construct radiation-resistant CRC cells via X-ray treatment. The expression levels of miR-141-3p and long non-coding RNA DLX6 antisense RNA 1 (lncRNA DLX6-AS1) in CRC cells were measured using real-time quantitative polymerase chain reaction. After transfection with miR-141-3p mimics and 24 h treatment with 6- MV X-ray (0, 2, 4, 6 Gy), the survival fraction (SF) and the colony formation ability of CRC cells were determined using the cell counting kit-8 and colony formation methods. The interactions between miR-141-3p and DLX6-AS1 were analyzed using the dual-luciferase assay. The impact of miR-141-3p on DLX6-AS1 stability was detected after adding actinomycin-D. The role of DLX6- AS1 in the radiosensitivity of CRC cells was explored by transfecting oe-DLX6-AS1 into radiation- resistant CRC cells overexpressing miR-141-3p.

RESULTS

The relative expression levels of miR-141-3p were downregulated in CRC cells and further declined in radiation-resistant cells. Upregulation of miR-141-3p relative expression reduced SF and the colony formation ability while amplifying the radiosensitivity of radiation-resistant CRC cells. miR-141-3p directly bound to DLX6-AS1 to reduce DLX6-AS1 stability, and therefore downregulated DLX6-AS1 expression. DLX6-AS1 overexpression counteracted the role of miR- 141-3p overexpression in amplifying the radiosensitivity of radiation-resistant CRC cells.

CONCLUSION

miR-141-3p binding to DLX6-AS1 significantly decreased DLX6-AS1 stability and expression, promoting the radiosensitivity of CRC cells.

Crosstalk between long non-coding RNA DLX6-AS1, microRNAs and signaling pathways: A pivotal molecular mechanism in human cancers

Long non-coding RNAs (lncRNAs) are a type of non-protein coding RNA, which have been found to play multiple roles in various molecular and cellular processes by epigenetic regulation of gene expression at post transcriptional levels. LncRNAs may act either as an oncogene or as a tumor suppressor gene in different cancers. Aberrant expression and dysregulation of lncRNAs has been correlated with cancer development and tumor growth via several different signaling pathways. Therefore, lncRNAs could serve as diagnostic biomarkers and as therapeutic targetes in many human cancers. Previous studies have reported that dysregulated expression of the lncRNA called DLX6-AS1 in various cancer types, such as lung, colorectal, bladder, ovarian, hepatocellular, pancreatic and gastric. DLX6-AS1 plays an important role in tumorigenesis by affecting cell proliferation, migration, invasion, EMT, and apoptosis. DLX6-AS1 exerts these regulatory effects by interfering with various microRNA axes and signaling pathways including, Wnt/βcatenin, Notch, P13/AKT/mTOR, and STAT3. This review focuses on the possible mechanisms by which DLX6-AS1 regulates tumor initiation and progression. Accordingly, DLX6-AS1 may act as a novel potential biomarker for cancer diagnosis or therapy in future.

MicroRNA-374a-5p inhibits neuroinflammation in neonatal hypoxic-ischemic encephalopathy via regulating NLRP3 inflammasome targeted Smad6

AIMS

Neonatal hypoxic-ischemic encephalopathy (HIE) is still an important cause of neurological dysfunction. At present, there is no reliable biochemical index in clinical examination. Increasing evidence demonstrates that microRNAs (miRNAs) are involved in the process of HIE, and miR-374a-5p is down-regulated in HIE infants. In this study, the aim is to investigate the role and mechanism of miR-374a-5p in HIE.

MAIN METHODS

Sprague-Dawley (SD) rats were used to establish model of neonatal HIE, pathologic changes and inflammatory response of brain tissues were measured. Subsequently, primary microglia were induced by LPS (1 μg/ml) in vitro, the miR-374a-5p mimic, Ad-Smad6 adenovirus vector and NLRP3 siRNA oligo were applied for microglial transfection. Furthermore, the target relationship between miR-374a-5p and Smad6 was analyzed, while microglia activity and inflammatory factor (IL-1β, TNF-α and IL-6) levels were detected.

KEY FINDINGS

Herein, we found that over-expression of miR-374a-5p significantly attenuated brain injury and strongly inhibited the release of pro-inflammatory cytokines in neonatal rat HIE model. In vitro, miR-374a-5p inhibited LPS-induced microglial pro-inflammatory cytokines production by regulating NLRP3 inflammasome. In addition, Smad6 was identified as a direct target of miR-374a-5p, and miR-374a-5p had a negative regulatory effect on Smad6 expression. By targeting Smad6, miR-374a-5p inhibited the activation of NLRP3 inflammatory signals in microglia and the subsequent release of pro-inflammatory factors.

SIGNIFICANCE

Our study recognized that miR-374a-5p as a novel regulator of microglial activation in neonatal HIE highlighted potential therapeutic target for the treatment of neonatal hypoxic-ischemic brain injury.