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Updated: Jun 27, 2026
An Orthotopic Bladder Cancer Model for Gene Delivery Studies
Published on: December 1, 2013
Rapamycin inhibits in vitro growth and release of angiogenetic factors in human bladder cancer
Guido Fechner1, Katarina Classen, Doris Schmidt
1Department of Urology, University of Bonn, Bonn, Germany. guido.fechner@ukb.uni-bonn.de
Objectives:
To evaluate the in vitro effects of rapamycin in human transitional cell carcinoma and to clarify the possible rapamycin-hypoxia interactions.
Methods:
Monolayer cultures of RT112 (G1), RT4 (G1-2), T24 (G3), and SUP (G4) cells were incubated in medium with or without rapamycin (10 microM, 100 microM) in different gaseous conditions (1% oxygen plus 5% carbon dioxide plus 94% nitrogen or 95% oxygen plus 5% carbon dioxide or 21% oxygen plus 78% nitrogen). Cell vitality and proliferation were determined using the microculture tetrazolium assay. Apoptotic cells were quantified by flow cytometry. Enzyme-linked immunosorbent assay was used to visualize inhibition of the mammalian target of rapamycin (mTOR) by rapamycin and synthesis of vascular endothelial growth factor.
Results:
Rapamycin delayed proliferation of cancer cell lines but did not induce apoptosis. No direct hypoxia interactions of rapamycin were found. Enzyme-linked immunosorbent assay gave evidence of mTOR inhibition in all cell lines and a significant decrease of hypoxia-induced vascular endothelial growth factor synthesis.
Conclusions:
Because proliferation in bladder cancer cells was delayed, but no apoptosis was induced, cell cycle arrest caused by rapamycin was feasible. Rapamycin decreased hypoxia-induced synthesis of vascular endothelial growth factor. These findings should be substantiated in an animal model to verify the antiangiogenetic effects of rapamycin.
Insights
Rapamycin delays bladder cancer cell proliferation and inhibits vascular endothelial growth factor synthesis but does not induce apoptosis. Further studies are needed to confirm its antiangiogenic effects in vivo.
Area of Science:
- Oncology
- Pharmacology
Background:
- Transitional cell carcinoma (TCC) is a significant cause of cancer mortality.
- Understanding the effects of targeted therapies like rapamycin on TCC is crucial for developing new treatment strategies.
- Investigating the interplay between rapamycin and tumor hypoxia may reveal novel therapeutic approaches.
Purpose of the Study:
- To investigate the in vitro effects of rapamycin on human transitional cell carcinoma cell lines.
- To explore potential interactions between rapamycin and hypoxic conditions in TCC.
Main Methods:
- Human TCC cell lines (RT112, RT4, T24, SUP) were treated with varying concentrations of rapamycin under different oxygen levels.
- Cell vitality, proliferation, and apoptosis were assessed using MTT assays and flow cytometry.
- Mammalian target of rapamycin (mTOR) inhibition and vascular endothelial growth factor (VEGF) synthesis were evaluated using ELISA.
Main Results:
- Rapamycin demonstrated a dose-dependent delay in TCC cell proliferation without inducing apoptosis.
- No direct interaction between rapamycin and hypoxia was observed.
- Rapamycin effectively inhibited mTOR signaling and significantly reduced hypoxia-induced VEGF synthesis.
Conclusions:
- Rapamycin may exert its anti-cancer effects in TCC through cell cycle arrest rather than apoptosis induction.
- Rapamycin's ability to decrease VEGF synthesis suggests potential antiangiogenic properties.
- Further in vivo validation is recommended to confirm the antiangiogenic potential of rapamycin in bladder cancer.
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