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Published on: October 30, 2013
MiR-221-induced PUMA silencing mediates immune evasion of bladder cancer cells
Bin Fu1, Yibing Wang1, Xiali Zhang2
1Department of Urology, The First Affiliated Hospital of Nanchang University, Nanchang 330006, P.R. China.
Abstract:
Immune evasion of cancer cells is mainly due to the impaired transduction of apoptotic signals from immune cells to cancer cells, as well as inhibition of subsequent apoptosis signal cascades within the cancer cells. Over the past few decades, the research has focused more on the impaired transduction of the apoptotic signal from immune cells to cancer cells, rather than inhibition of the intracellular signaling pathways. In this study, miR‑221 inhibitor was transfected into bladder cancer cell lines 5637, J82 and T24 to repress the expression of miR‑221. As a result, the repression of miR‑221 on p53 upregulated modulator of apoptosis (PUMA) was abolished, resulting in increased expression of the pro-apoptotic Bax and reduced expression of the anti-apoptotic Bcl-2, which promotes apoptosis of bladder cancer cells. The expression of MMP-2, MMP-9 and VEGF-C were reduced, resulting in reduced invasiveness and infiltration capability of bladder cancer cells, thereby inhibiting the immune evasion of bladder cancer cells.
Insights
Inhibiting miR-221 in bladder cancer cells promotes apoptosis and reduces invasiveness by restoring PUMA expression. This strategy effectively combats immune evasion, offering a novel therapeutic approach.
Area of Science:
- Oncology
- Molecular Biology
- Immunology
Background:
- Cancer immune evasion often stems from disrupted apoptotic signaling pathways within cancer cells.
- Research has historically prioritized external signal transduction over internal apoptosis inhibition.
Purpose of the Study:
- To investigate the role of miR-221 in bladder cancer cell apoptosis and immune evasion.
- To explore the therapeutic potential of inhibiting miR-221 in bladder cancer.
Main Methods:
- Transfection of miR-221 inhibitor into bladder cancer cell lines (5637, J82, T24).
- Analysis of apoptosis-related gene expression (PUMA, Bax, Bcl-2).
- Assessment of invasion and infiltration markers (MMP-2, MMP-9, VEGF-C).
Main Results:
- miR-221 inhibition abolished its repression on PUMA, increasing pro-apoptotic Bax and decreasing anti-apoptotic Bcl-2.
- This led to enhanced apoptosis in bladder cancer cells.
- Expression of MMP-2, MMP-9, and VEGF-C was reduced, decreasing invasiveness and infiltration.
Conclusions:
- Repressing miR-221 can restore apoptosis signaling in bladder cancer cells.
- Inhibiting miR-221 reduces cancer cell invasiveness and infiltration, thereby overcoming immune evasion.
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