Introduction: TGFbeta1 is a potent modulator of the biology of both benign and neoplastic cells. Exocrine TGFbeta1 has been shown to alter fibronectin expression of bladder carcinoma cell lines. The present study describes the development of a stable TGFbeta1 overexpressing transitional carcinoma cell line, and evaluates the impact of autocrine TGFbeta1 production on fibronectin expression.
Materials and methods: The human transitional carcinoma cell line 253J was transfected using the pcDNA3/hTGFbeta1 expression vector under control of the CMV promoter. TGFbeta1 mRNA expression was determined by Northern analysis. TGFbeta1 protein levels were analyzed by biological assay. Subsequently, the effect of TGFbeta1 autocrine production on fibronectin expression at both the mRNA and protein level was determined. Results were compared to cells transfected with the pcDNA3/CAT and non-transfected 253J cells.
Results: Two 253J clones which uniformly expressed TGFbeta1 mRNA at 22 and four-fold increases relative to controls were identified. mRNA overexpression correlated with marked increase in biologically active TGFbeta1 protein production. Autocrine production of cellular TGFbeta1 showed a positive correlation with fibronectin expression at both the mRNA and protein levels.
Conclusions: Autocrine expression of TGFbeta1 increases cellular fibronectin production in a human transitional carcinoma cell line. Therapeutic strategies altering urothelial production of TGFbeta1 and fibronectin may be a potential strategy to potentiate intravesical BCG activity.