I initially chose two cell lines that represented the spectrum of bladder cancer cell lines: UMUC-3 and RT4. The former is a mesenchymal, high-grade, and a luminal tumor. The latter is an epithelial, low-grade, and a basal tumor. Later the screen was expanded to six additional cell lines. The cells were treated with 1,912 oncology-focused drugs using a 48 hr cell proliferation assay with an ATP-based readout (CellTiterGlo), and activity of the compounds in a dose response manner was calculated. Encouraged by the preliminary results showing HSP90 inhibitors, topoisomerase I inhibitors, and HDAC inhibitors all being effective, we extended the screen to 8 bladder cancer cell lines. We found similar results except now combinations were also explored. Some of the combinations that we hope to explore in animal models include a novel SMAC mimetic + gemcitabine or mitomycin C. We also identified 8 novel agents that may function as intravesical agents and are currently evaluating their use as well. Finally, we identified a topotecan derivative (SN-38) from the screen that looks promising. We are asking our collaborators to bind existing Pan-IR700 conjugate to SN-38 to increase the cytotoxicity of this new conjugate. During this past year, we have focused our efforts on two new novel compounds: flavopiridol and bardoxolone methyl. For flavopiridol, we have established in vitro and in vivo activity across a wide range of bladder cancer cell lines. In addition, we have secured a material transfer agreement with a company to obtain a new water soluble formulation of flavopiridol that we will evaluate for possible intravesical administration. We have collaborated with Dr. Bivalacqua at Johns Hopkins to treat rats with carcinogen induced tumors with intravesical flavopiridol and intravesical flavopiridol encapsulated within nanoparticles. The experiments have been performed and the removed bladders are being analyzed by immunohistochemistry for response to the different forms of flavopiridol. For bardoxolone methyl, we have established that the drug is active in vitro especially in spheroid cultures. Furthermore, we have worked out a potential mechanism of action. Ongoing in vivo work demonstrates activity across different bladder cancer cell lines. This work will be published in conjunction with a summary of the high throughput screening data.
| Ahmed, Kamran; Khan, Shahid A; Hayn, Matthew H et al. (2014) Analysis of intracorporeal compared with extracorporeal urinary diversion after robot-assisted radical cystectomy: results from the International Robotic Cystectomy Consortium. Eur Urol 65:340-7 |
