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Characterization of Functionally Associated miRNAs in Glioblastoma and their Engineering into Artificial Clusters for Gene Therapy
Published on: October 4, 2019
Adenovirus-mediated shRNAs for co-repression of miR-221 and miR-222 expression and function in glioblastoma cells
Xuan Wang1, Lei Han, Anling Zhang
1Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin, P.R. China.
Abstract:
Aberrantly expressed miRNAs are linked to the regulation of oncogenes and/or tumor suppression genes within the cell signal transduction pathway network, thereby contributing to carcinogenesis. miRNA function can be antagonized, thus representing a novel anti-tumor approach for integrated cancer therapy. In this study, we designed adenovirally-expressed shRNAs that functionally co-repressed the expression of miR-221 and miR-222, which are related to glioblastoma, to overcome the low efficiency of gene therapy. In addition, we generated novel shRNAs whose 3' ends were mutated in the region complementary to the target miRNA's 5' seed region to reduce the stability of binding with the miRNA. Various inhibition levels of miRNA were achieved: classic shRNAs yielded the greatest reduction in miRNA levels, followed by mutated shRNAs and the blank control, as determined by qRT-PCR. These results were confirmed by the protein expression of p27kip1, the validated target of miR-221/222, the effect on cell cycle arrest in G1 phase, and the impact on cell apoptosis. These results suggested that we could produce shRNAs encoded by adenovirus that co-repressed multiple tumor-related miRNAs simultaneously, and that the level of repression and the effect on the function of a specific miRNA could be achieved in a semi-quantitative manner.
Insights
This study developed adenoviral shRNAs to co-repress miR-221 and miR-222, crucial in glioblastoma. This novel gene therapy approach offers semi-quantitative control over miRNA levels and anti-tumor effects.
Area of Science:
- Molecular Biology
- Genetics
- Oncology
Background:
- Aberrantly expressed microRNAs (miRNAs) regulate oncogenes and tumor suppressors, contributing to carcinogenesis.
- miRNA antagonism presents a novel therapeutic strategy for integrated cancer treatment.
Purpose of the Study:
- To develop adenovirally-expressed shRNAs for co-repression of miR-221 and miR-222 in glioblastoma.
- To engineer novel shRNAs with mutated 3' ends to modulate miRNA binding stability and achieve semi-quantitative repression.
Main Methods:
- Adenovirally-expressed short hairpin RNAs (shRNAs) designed to co-repress miR-221 and miR-222.
- Generation of mutated shRNAs with altered 3' complementarity to target miRNAs.
- Quantitative real-time PCR (qRT-PCR) to measure miRNA levels.
- Western blot analysis for p27kip1 protein expression.
- Cell cycle analysis and apoptosis assays.
Main Results:
- Adenoviral shRNAs effectively co-repressed miR-221 and miR-222 expression.
- Classic shRNAs achieved the highest miRNA reduction, followed by mutated shRNAs.
- Validated target protein p27kip1 expression increased, indicating miRNA inhibition.
- Demonstrated G1 phase cell cycle arrest and increased apoptosis.
Conclusions:
- Adenovirus-encoded shRNAs can simultaneously co-repress multiple tumor-related miRNAs.
- The level of miRNA repression and functional impact can be controlled semi-quantitatively.
- This approach holds promise for developing effective integrated cancer therapies.
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