Assessing the Invasive Potential of Bladder Cancer: Development and Validation of a New Preclinical Assay

Purpose: We developed and validated an electrophysiological method for standardized preclinical assessment of the invasive potential of urothelial carcinoma of the bladder. Materials and Methods: Human UMUC-3, RT-112, HT-1197 and T24/83 bladder urothelial carcinoma cells, and UROtsa benign urothelial cells were co-cultivated with high resistance MDCK-C7 cells seeded below a 0.4 mu m pore membrane of an insert to avoid physical contact and cellular migration. Transepithelial electrical resistance in Omega cm(2) across the MDCK-C7 monolayer was measured longitudinally. Invasive potential coefficients were calculated based on the secretion of proteolytic factors by invading cells. Results: Consistent transepithelial electrical resistance breakdown patterns were reproduced in 14 or more independent samples of each cell line. Coefficients of invasive potential were significantly higher in bladder urothelial carcinoma than UROtsa cells, including a mean +/- SD of 1.5 +/- 0.32 vs 9.9 +/- 4.97 in UMUC-3, 12.5 +/- 6.61 in T24/83, 20.5 +/- 4.24 in RT-112 and 21.0 +/- 5.15 in HT-1197 cells (p <0.001). No correlation was found between the secretion patterns of matrix metalloproteinase-1, 2 and 9, and invasive potential. Stimulation of UROtsa cells with recombinant human epidermal growth factor up-regulated matrix metalloproteinase-9 secretion and significantly increased invasive potential a mean of 1.3 +/- 0.22 vs 14.6 +/- 3.28 after stimulation with 10 ng/ml epidermal growth factor (p <0.001). Conclusions: We developed a highly sensitive translational tool to study the initial process of metastatic spread of urothelial carcinoma of the bladder. The presented electrophysiological invasion assay enables reliable quantification of the invasive potential of bladder urothelial carcinoma cells before physical transmigration. It can be used to identify key molecules for bladder urothelial carcinoma invasion and develop new therapeutic strategies.