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Updated: Jul 16, 2026
An Orthotopic Bladder Tumor Model and the Evaluation of Intravesical saRNA Treatment
Published on: July 28, 2012
Knockdown by shRNA identifies S249C mutant FGFR3 as a potential therapeutic target in bladder cancer
D C Tomlinson1, C D Hurst, M A Knowles
1Cancer Research UK Clinical Centre, St James's University Hospital, Beckett Street, Leeds, UK.
Abstract:
More than 60% of low-grade non-invasive papillary urothelial cell carcinomas contain activating point mutations of fibroblast growth factor receptor 3 (FGFR3). The phenotypic consequences of constitutive activation of FGFR3 in bladder cancer have not been elucidated and further studies are required to confirm the consequences of inhibiting receptor activity in urothelial cells. We measured FGFR3 transcript levels and demonstrated that transcript levels were significantly more abundant in low-stage and grade tumours. We identified a tumour cell line, 97-7, expressing the most common FGFR3 mutation (S249C) at similar FGFR3 transcript levels to low-stage and grade tumours. In these cells, S249C FGFR3 protein formed stable homodimers and was constitutively phosphorylated. We used retrovirus-mediated delivery of shRNA to knockdown S249C FGFR3. This induced cell flattening, decreased cell proliferation and reduced clonogenicity on plastic and in soft agar. However, no effects of knockdown of wild-type FGFR3 were observed in telomerase immortalized normal human urothelial cells, indicating possible dependence of the tumour cell line on mutant FGFR3. Re-expression of S249C FGFR3 in shRNA-expressing 97-7 cells resulted in a reversal of phenotypic changes, confirming the specificity of the shRNA. These results indicate that targeted inhibition of S249C FGFR3 may represent a useful therapeutic approach in superficial bladder cancer.
Insights
Activating mutations in fibroblast growth factor receptor 3 (FGFR3) drive bladder cancer. Inhibiting the S249C FGFR3 mutation in urothelial cells reduced proliferation and clonogenicity, suggesting a targeted therapy approach.
Area of Science:
- Oncology
- Molecular Biology
- Urology
Background:
- Activating point mutations in fibroblast growth factor receptor 3 (FGFR3) are prevalent in over 60% of low-grade, non-invasive papillary urothelial cell carcinomas.
- The functional impact of constitutively active FGFR3 in bladder cancer and the potential of inhibiting its activity remain incompletely understood.
Purpose of the Study:
- To elucidate the phenotypic consequences of constitutive FGFR3 activation in bladder cancer.
- To investigate the therapeutic potential of targeting the S249C FGFR3 mutation in urothelial cells.
Main Methods:
- Measured FGFR3 transcript levels in tumors and identified the 97-7 cell line expressing the common S249C FGFR3 mutation.
- Utilized retrovirus-mediated shRNA to knockdown S249C FGFR3 and assessed phenotypic changes.
- Re-expressed S249C FGFR3 to confirm knockdown specificity.
Main Results:
- S249C FGFR3 protein exhibited stable homodimerization and constitutive phosphorylation in the 97-7 cell line.
- Knockdown of S249C FGFR3 led to cell flattening, reduced proliferation, and decreased clonogenicity.
- Knockdown of wild-type FGFR3 in normal urothelial cells showed no significant effects, suggesting tumor cell dependence on mutant FGFR3.
Conclusions:
- Constitutive activation of S249C FGFR3 drives specific phenotypic changes in bladder cancer cells.
- Targeted inhibition of S249C FGFR3 demonstrates therapeutic potential for superficial bladder cancer.
