Login to Access Video or Poster Abstract: MP98-10
Sources of Funding: This research was supported by the Intramural Research Program of the U.S. National Institutes of Health, National Cancer Institute, Center for Cancer Research.

Introduction

In this study we performed the first identified quantitative high throughput screening to identify potential targets in urothelial cancer cell lines. We noted a potential new therapy (bardoxolone methyl) and validated this compound with further in vitro studies in cell lines not included in the screen.

Methods

We screened 8 bladder cancer cell lines against 1,912 oncology-focused drugs using a 48 hr cell proliferation assay with an ATP-based readout (CellTiterGlo), for activity and potency of the compounds in a dose response manner. We identified candidate drugs based on two parameters: 1) more than 70% inhibition at 48 hours 2) a curve class of -1.1/-1.2 indicating curve class with good fit (r2>0.9). Follow up assays in additional cell lines, including viability, spheroid culture, nuclear localization assay, invasion, cell cycle and murine xenograft models were used as confirmation of efficacy and mechanism of the bardoxolone methyl.

Results

Ward clustering analysis of the initial cell lines (figure 1a) along with curve class demonstration (1b) and medication grouping efficacy (1c) is presented here. Among the candidate drugs which were most active in all compounds, bardoxolone methyl was the most attractive based on IC 50 and previous human safety studies. Invasion assays (Figure 2a) 3-dimensional culture (2b) cell cycle arrest (2c) demonstrated excellent in vitro efficacy. Murine models were then created which highlighted strong inhibition of tumor growth in murine xenograft. (Figure 2d)

Conclusions

Quantitative high throughput screening was successful in identifying bardoxolone methyl as a novel treatment of urothelial carcinoma in vitro. Repurposing of this molecule may allow for future patient trials in urothelial malignancies.

Funding

This research was supported by the Intramural Research Program of the U.S. National Institutes of Health, National Cancer Institute, Center for Cancer Research.