Introduction and objectives: Prior studies have shown that bladder trauma occurring during transurethral bladder tumor resection increases urinary levels of the cytokine transforming growth factor (TGF)-beta1. This study used complementary deoxyribonucleic acid micro-array technology to identify additional genes in human transitional cell carcinoma (TCC), whose expression is altered as a consequence of increased urinary levels of TGF-beta1.
Methods: The human TCC line 253J was cultured in standard media, or media spiked with either 10% post-transurethral bladder tumor resection urine (PTU), or PTU and anti-TGF-beta1 neutralizing antibody. Messenger ribonucleic acid from these conditions, together with messenger ribonucleic acid from stably transfected 253J cells over-expressing TGF-beta1, was hybridized with ATLAS micro-array membranes (Clontech, Palo Alto, CA) containing 588 human genes. Hybridization signal intensity was quantified using phospho-imaging. An analytic strategy based on the variance in the signal intensity ratio of specific housekeeping genes in control and experimental comparisons was used to identify significant changes in gene expression. Reverse transcriptase polymerase chain reaction of target genes was used to confirm gene over-expression and TGF-beta1 responsiveness.
Results: Seven genes were identified on micro-array: v-RAF-1, colony stimulating factor-1 receptor, v-FGR, insulin growth factor-1 receptor, epidermal growth factor receptor, alpha5 integrin, and interferon receptor-1. Reverse transcriptase polymerase chain reaction confirmed over-expression in the autocrine TGF-beta1 producing cell line and increased expression in response to exogenous TGF-beta1.
Conclusions: TGF-beta1 in PTU alters the expression of multiple genes in human TCC in vitro. The impact of these changes on the biologic phenotype of the malignant cell and the efficacy of adjuvant therapies requires further evaluation.