Purpose: To examine the effect of TGF beta 1 and post-transurethral resection of bladder tumor (TURBT) urine on fibronectin (FN) expression by transitional carcinoma (TCC) cell lines.
Materials and methods: Northern analysis and rtPCR for mRNA transcripts, in combination with ELISA and immunohistochemistry for protein, were used to quantify the effect of TGF beta 1 and post-TURBT urine on cellular expression of FN in two TCC lines, 253J and 647V. The TGF beta 1-dependent nature of the response seen in post-TURBT urine was confirmed using exogenous TGF beta 1 or blocking antibodies to TGF beta 1. Active and latent levels of TGFb1 were measured in post-TURBT urine and urine "spiked" cell culture media.
Results: Baseline FN expression was low in the poorly differentiated, metastatic 253J line and high in the moderately differentiated 647V line. TGF beta 1 and post-TURBT urine increased FN expression at both the mRNA and protein levels in the 253J line. Anti-TGF beta 1 antibodies inhibited the effect of post-TURBT urine on FN expression in 253J cells. High levels of TGF beta 1 decreased FN expression in 647V cells. Only latent TGF beta 1 was present in samples of urine and media.
Conclusions: FN production in low expressing TCC lines can be augmented by exogenous TGF beta 1. TURBT increases latent urinary TGF beta 1 which in turn affects TCC FN expression. Altered tumor expression of FN following TURBT may influence the effectiveness of intravesical BCG.