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Updated: Jun 9, 2025
In Vivo Inhibition of MicroRNA to Decrease Tumor Growth in Mice
Published on: August 23, 2019
The in vivo effects of knockdown of long non-coding RNA XIST on fibroid growth and gene expression
Tsai-Der Chuang1, Nhu Ton1, Shawn Rysling1
1The Lundquist Institute for Biomedical Innovation, Torrance, California, USA.
Abstract:
The role of long non-coding RNAs in fibroid pathogenesis remains largely unexplored. In a previous study, we found elevated XIST (X-inactive specific transcript) levels in fibroids, which sponged miR-29c and miR-200c, leading to the overexpression of their target genes. This study aimed to assess the therapeutic potential of XIST downregulation in fibroid treatment. Ovariectomized SCID (severe combined immunodeficiency) mice were implanted with fibroid tumors transduced with XIST siRNA or a control via lentivirus. After 1 month, animals were sacrificed and the xenografts were removed for further analysis. XIST knockdown reduced tumor weight by 15% and increased miR-29c and miR-200c expression by 3.9-fold and 2.2-fold, respectively. The mRNA expression of miR-29c targets (COL3A1, TGF-β3, CDK2, SPARC) and miR-200c targets (CDK2, FN1, TDO2), as well as PRL, E2F1, and EZH2, was significantly decreased. Protein abundance of collagen, COL3A1, FN1, CDK2, SPARC, and EZH2 was also reduced. IHC analysis of xenograft sections using the markers of Ki67 for cell proliferation and cleaved caspase 3 for apoptosis showed decreased cell proliferation and no changes in apoptosis in the XIST knockdown xenografts. This analysis also revealed decreased collagen and E2F1 staining nuclei in the XIST knockdown xenografts. These results indicate that downregulation of XIST in fibroids has beneficial therapeutic effects, by reducing tumor growth and the expression of genes involved in cell proliferation, inflammation, and extracellular matrix regulation.
Insights
Downregulating XIST (X-inactive specific transcript) in uterine fibroids reduced tumor growth and key gene expression. This suggests XIST is a potential therapeutic target for fibroid treatment.
Area of Science:
- Reproductive Biology
- Molecular Biology
- Genetics
Background:
- Long non-coding RNAs (lncRNAs) role in fibroid pathogenesis is understudied.
- Elevated XIST (X-inactive specific transcript) in fibroids sponges miR-29c and miR-200c, upregulating target genes.
- This study investigates XIST downregulation as a potential fibroid therapy.
Purpose of the Study:
- To evaluate the therapeutic efficacy of XIST downregulation in uterine fibroids.
- To assess the impact of XIST knockdown on fibroid tumor growth and molecular markers.
Main Methods:
- Uterine fibroid xenografts in ovariectomized SCID mice were created.
- Lentiviral vectors delivering XIST siRNA or control were used for gene silencing.
- Tumor weight, miRNA and mRNA expression, protein levels, and immunohistochemistry (IHC) were analyzed.
Main Results:
- XIST knockdown reduced fibroid tumor weight by 15%.
- Expression of miR-29c and miR-200c increased significantly, while their target genes (e.g., COL3A1, TGF-β3, CDK2, SPARC, FN1, TDO2) and other key genes (PRL, E2F1, EZH2) decreased.
- Reduced protein levels of collagen, COL3A1, FN1, CDK2, SPARC, and EZH2 were observed. Cell proliferation marker Ki67 decreased, with no change in apoptosis marker cleaved caspase 3.
Conclusions:
- Downregulation of XIST demonstrates therapeutic potential for uterine fibroids.
- XIST inhibition effectively reduces tumor growth by modulating genes involved in proliferation, inflammation, and extracellular matrix regulation.
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