Abstract
The roles of oncogenic miRNAs are widely recognized in many cancers. Inhibition of single miRNA using antagomiR can efficiently knock-down a specific miRNA. However, the effect is transient and often results in subtle phenotype, as there are other miRNAs contribute to tumorigenesis. Here we report a multi-potent miRNA sponge inhibiting multiple miRNAs simultaneously. As a model system, we targeted miR-21, miR-155 and miR-221/222, known as oncogenic miRNAs in multiple tumors including breast and pancreatic cancers. To achieve efficient knockdown, we generated perfect and bulged-matched miRNA binding sites (MBS) and introduced multiple copies of MBS, ranging from one to five, in the multi-potent miRNA sponge. Luciferase reporter assay showed the multi-potent miRNA sponge efficiently inhibited 4 miRNAs in breast and pancreatic cancer cells. Furthermore, a stable and inducible version of the multi-potent miRNA sponge cell line showed the miRNA sponge efficiently reduces the level of 4 target miRNAs and increase target protein level of these oncogenic miRNAs. Finally, we showed the miRNA sponge sensitize cells to cancer drug and attenuate cell migratory activity. Altogether, our study demonstrates the multi-potent miRNA sponge is a useful tool to examine the functional impact of simultaneous inhibition of multiple miRNAs and proposes a therapeutic potential.
Highlights
MiRNAs are small endogenous RNAs that can inhibit protein expressions of target mRNAs, by interacting mainly to its 3’UTR and degrade mRNAs or inhibit translation [1, 2]
We reasoned that the spacer would reduce non-specific binding of miRNAs and generate enough space so several miRNAs can bind to miRNA binding sites (MBS) stably without overlapping on each other [16]
For the MBS of miR-221 and 222, we introduced a common nucleotide sequence as they are identical in their seed sequence and only 4 bases are mismatched in full miRNA sequence
Summary
MiRNAs are small endogenous RNAs that can inhibit protein expressions of target mRNAs, by interacting mainly to its 3’UTR and degrade mRNAs or inhibit translation [1, 2]. There are number of miRNA-regulating agents being tested in clinical/ preclinical trials These include miR-122 inhibitor for HCV driven hepatitis [6, 7] and anti-miR-34a for cardiovascular diseases [8]. Another miRNA regulating agents is microRNA sponge that is initially introduced on 2007 [9]. The expression of artificial RNA with specific (and usually multiple) miRNA binding sites can absorb endogenous miRNA ( the name comes in), essentially depleting the target miRNA in cells. Recent papers have shown the inhibition of multiple oncogenic miRNAs by miRNA sponges in Ewing sarcoma (targeting miR-106a~363 cluster) [18]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
