Abstract 698: Progranulin targeting in urothelial cancer cells inhibits motility, tumor growth in vitro and in vivo and sensitizes cells to cisplatin

Introduction and Objective: Bladder cancer is a major public health problem and affects more than 74,000 Americans with more than 16,000 estimated deaths in 2015. The majority of deaths are due to metastatic spread, commonly to the lungs. Understanding the molecular mechanisms regulating bladder tumor cell invasion and progression toward metastases is essential for developing better therapies to treat bladder cancer patients. The growth factor progranulin has emerged in recent years as an important regulator of transformation in several cancer models. We have previously established a critical role for progranulin in bladder cancer as in fact progranulin acts as an autocrine growth factor and promote motility and invasion of invasive urothelial cancer cells. In addition, progranulin is upregulated in high grade bladder cancer tissues compared to normal tissue controls suggesting that progranulin might work as a novel biomarker with predictive value for bladder cancer progression. However, whether progranulin is important for anchorage-independent growth and in vivo tumor formation of urothelial cancer cells has not been previously established. Methods: Progranulin depletion was achieved by stably transfecting tumorigenic T24T, UMUC3 urothelial cancer cells with a plasmid expressing an anti-progranulin shRNA. Progranulin-depleted and control UMUC-3 and T24T cells were tested for motility, invasion and anchorage-independent growth by soft-agar assays. Tumor formation in vivo was assessed in various UMUC-3-derived cell lines by xenograft and orthotopic models. Sensitivity to cisplatin was assessed by cell survival curves. Progranulin expression levels in a bladder tissue microarray were analyzed by HIC. Results: Progranulin-depleted T24T and UMUC-3 cells were significantly inhibited in their ability to migrate, close a wound and invade through Matrigel compared to control cells in both serum-deprived and 1% serum media. In addition, progranulin targeting strongly reduced the ability of T24T and UMUC-3 cells to grow in anchorage-independency and form colonies in soft-agar. Significantly progranulin-depleted UMUC-3 cells were severely inhibited in tumor formation in vivo as assessed by both xenograft and orthotopic models in immunocompromised mice. Importantly, progranulin depletion sensitized UMUC-3 cells to cisplatin. Finally, progranulin levels correlated with tumor progression in bladder cancer tissues. Conclusions: Our data are translationally relevant as indicate that progranulin exerts an essential functional role in the regulation of bladder cancer progression. Thus, progranulin may constitute a novel target for therapeutic intervention in bladder tumors. In addition, progranulin may serve as novel biomarker for diagnosis and prognosis of bladder cancer. Citation Format: Simone Buraschi, Shi-Qiong Xu, Manuela Stefanello, Igor Moskalev, Alaide Morcavallo, Marco Genua, Ryuta Tanimoto, Thomas Neill, Stephen C. Peiper, Leonard G. Gomella, Antonino Belfiore, Peter C. Black, Renato V. Iozzo, Andrea Morrione. Progranulin targeting in urothelial cancer cells inhibits motility, tumor growth in vitro and in vivo and sensitizes cells to cisplatin. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 698.