[MiR-4443 promotes migration and invasion of breast cancer cells by inhibiting PEBP1 expression]

Upregulated expression of miR-4443 and miR-4488 in drug resistant melanomas promotes migratory and invasive phenotypes through downregulation of intermediate filament nestin

BACKGROUND

BRAF-mutant melanoma patients benefit from the combinatorial treatments with BRAF and MEK inhibitors. However, acquired drug resistance strongly limits the efficacy of these targeted therapies in time. Recently, many findings have underscored the involvement of microRNAs as main drivers of drug resistance. In this context, we previously identified a subset of oncomiRs strongly up-regulated in drug-resistant melanomas. In this work, we shed light on the molecular role of two as yet poorly characterized oncomiRs, miR-4443 and miR-4488.

METHODS

Invasion and migration have been determined by wound healing, transwell migration/invasion assays and Real Time Cell Analysis (RTCA) technology. miR-4488 and miR-4443 have been measured by qRT-PCR. Nestin levels have been tested by western blot, confocal immunofluorescence, immunohistochemical and flow cytometry analyses.

RESULTS

We demonstrate that the two oncomiRs are responsible for the enhanced migratory and invasive phenotypes, that are a hallmark of drug resistant melanoma cells. Moreover, miR-4443 and miR-4488 promote an aberrant cytoskeletal reorganization witnessed by the increased number of stress fibers and cellular protrusions-like cancer cell invadopodia. Mechanistically, we identified the intermediate filament nestin as a molecular target of both oncomiRs. Finally, we have shown that nestin levels are able to predict response to treatments in melanoma patients.

CONCLUSIONS

Altogether these findings have profound translational implications in the attempt i) to develop miRNA-targeting therapies to mitigate the metastatic phenotypes of BRAF-mutant melanomas and ii) to identify novel biomarkers able to guide clinical decisions.

Long non-coding RNA ENST00000469812 promotes Enterovirus type 71 replication via targeting the miR-4443/NUPR1 axis in rhabdomyosarcoma cells

Hand, foot, and mouth disease (HFMD) caused by Enterovirus type 71 (EV71) is a serious threat to children's health. However, the pathogenic mechanism of EV71 is still unclear. Long non-coding RNAs (lncRNAs), some of which bind to miRNA as competitive endogenous RNAs (ceRNA) and weaken the silencing effect on the mRNA of downstream target genes, play a key role in regulating the viral infection process. In this study, through experimental verification, we found miR-4443 to be downregulated in cells infected with EV71. Next, by predicting lncRNAs that potentially regulate miR-4443, we found that EV71 infection induced upregulation of lncRNA ENST00000469812 and then further downregulated miR-4443 expression by direct interaction. We also demonstrated that nuclear protein 1 (NUPR1) is one of the target genes of miR-4443 and is involved in the ENST00000469812/miR-4443/NUPR1 regulatory axis. Finally, the ENST00000469812/miR-4443/NUPR1 regulatory axis exhibited a positive effect on EV71 replication. Here, we lay a foundation for exploring the pathogenic mechanism of EV71 and identify potential targets for HFMD treatment.

miR-17-5p and miR-4443 Promote Esophageal Squamous Cell Carcinoma Development by Targeting TIMP2

Background

Esophageal squamous cell carcinoma (ESCC) is one of the most frequently diagnosed cancers in the world with a high mortality rate. The mechanism about ESCC development and whether miRNAs play a critical role remains unclear and needs carefully elucidated.

Materials and Methods

High-throughput miRNA sequencing was used to identify the different expression miRNAs between the ESCC tissues and paired adjacent normal tissues. Next, both CCK-8, Transwell and apotosis assay were used to evaluate the role of miRNA in ESCCcells. In addition, we used bioinformatic tools to predict the potential target of the miRNAs and verified by Western Blot. The function of miRNA-target network was further identified in xenograft mice model.

Results

In ESCC, we identified two miRNAs, miR-17-5p and miR-4443, were significantly upregulated in ESCC tissues than adjacent normal tissues. TIMP2 was proved to be the direct target of both two miRNAs. The miR-17-5p/4443- TIMP2 axis was shown to promote the tumor progression in vitro and in vivo experiments.

Conclusions

This study highlights two oncomiRs, miR-17-5p and miR-4443, and its potential role in ESCC progression by regulating TIMP2 expression, suggesting miR-17-5p and miR-4443 may serve as a novel molecular target for ESCC treatment.