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Updated: Feb 24, 2026
DNA Vector-based RNA Interference to Study Gene Function in Cancer
Published on: June 4, 2012
[Effect of TSC2 gene expression downregulation by lentivirus induced RNA interference on U937 cell line and its
1Department of Hematology, the Second Hospital of Shanxi Medical University, Shanxi Key Laboratory of Molecular Diagnosis and Treatment of Blood Diseases, Taiyuan 030001, China.
Abstract:
Objective: To investigate the effect of biology and mTOR pathway activity of down-regulated TSC2 gene expression on U937 leukemia cells. Methods: Gene expression was down-regulated by lentivirus induced RNA interference on TSC2 high expressed U937 cell line; the proliferation, apoptosis and differentiation were detected by CCK-8 assay, colony formation assay and flow cytometry; the gene expression level and protein kinase activity were detected by qRT-PCR and Western blot. Results: Down-regulated expression of TSC2 gene promoted U937 cell proliferation and colony formation ability (P<0.05) . The proportion in G(0)/G(1) phase of TSC2 down-regulated U937 cell was much lower than that of the control cells [ (52.53±3.75) % vs (75.10±4.33) %, t=6.829, P=0.002], the S phase [ (22.43±1.00) % vs (15.47±1.20) %, t=-5.581, P=0.019] and G(2)/M phase [ (25.03±4.34) % vs (14.33±0.91) %, t=-5.413, P=0.013] was remarkably higher than that of the control cells (P<0.05) . There were no statistically significant differences in cell apoptosis and differentiation (P>0.05) . Down-regulation of TSC2 led to the increased activity of mTOR, 4EBP1 and S6K1, but did not influence the activity of AKT. The expressions of proliferation related cyclinD1, c-myc and PTEN were also up-regulated after TSC2 silenced, but the expressions of P27KIP and BCL-XL were not changed. Conclusion: Downregulation of TSC2 could promote the proliferation of U937 cells through up-regulation of mTOR activity.
Insights
Down-regulating the TSC2 gene in U937 leukemia cells significantly increased cell proliferation and colony formation. This occurred through enhanced mTOR pathway activity, highlighting a key mechanism in leukemia progression.
Area of Science:
- Cell Biology
- Molecular Biology
- Cancer Research
Background:
- The tuberous sclerosis complex 2 (TSC2) gene plays a role in cell growth regulation.
- Dysregulation of TSC2 is implicated in various cancers, including leukemia.
- Understanding TSC2's impact on leukemia cell biology is crucial for therapeutic development.
Purpose of the Study:
- To investigate the biological effects of down-regulated TSC2 gene expression in U937 leukemia cells.
- To determine the influence of TSC2 on cell proliferation, apoptosis, and differentiation.
- To elucidate the role of the mTOR pathway in TSC2-mediated leukemia cell behavior.
Main Methods:
- Lentivirus-induced RNA interference was used to down-regulate TSC2 expression in U937 cells.
- Cell proliferation and colony formation were assessed using CCK-8 and colony formation assays.
- Flow cytometry was employed to analyze cell cycle distribution, apoptosis, and differentiation.
- Quantitative real-time PCR (qRT-PCR) and Western blot were used to measure gene and protein expression and kinase activity.
Main Results:
- Down-regulated TSC2 expression significantly promoted U937 cell proliferation and colony formation.
- TSC2 down-regulation led to a decrease in G0/G1 phase cells and an increase in S and G2/M phase cells.
- Apoptosis and differentiation showed no significant changes, while mTOR, 4EBP1, and S6K1 activities increased.
- Expressions of cyclinD1, c-myc, and PTEN were upregulated, indicating promotion of cell cycle progression.
Conclusions:
- Downregulation of TSC2 promotes U937 leukemia cell proliferation.
- The observed proliferation is mediated by the up-regulation of the mTOR signaling pathway.
- Targeting the TSC2/mTOR axis may offer a potential therapeutic strategy for leukemia.
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