Bladder cancer kills 13,000 Americans each year, but very few research projects target this disease. Most of these deaths are due to metastatic spread, commonly to the lungs. A fuller understanding of the molecular mechanisms driving growth and dissemination of bladder cancer is likely to provide new therapeutic opportunities. RalA and RalB, two homologous GTPases play an important role in growth and lung metastasis in xenograft models of human bladder cancer. Furthermore, these paralogs are activated by phosphorylation at sites regulated by Aurora-A and PKC, two kinases associated with human bladder cancer growth and progression. To define signaling pathways downstream of Ral, genome-wide analysis of Ral dependent gene expression was carried out and revealed that RalA and RalB regulate the expression of CD24, a GPI-linked glycoprotein and biomarker of metastasis development in bladder cancer. Moreover, this data identified the zinc finger transcription factor RREB1 as a putative regulator of CD24 expression and RalBP1, an effector of both Ral paralogs, as a regulator of RREB1 activity. Based on this data, we formulate the Guiding Hypothesis that RalA and RalB regulate a new downstream signaling pathway consisting of RalBP1, RREB1 and CD24 via which they contribute to bladder cancer growth and lung metastasis and furthermore, that biomarkers of RalA and RalB activation such as phosphorylation or transcriptional signatures are prognostic for development of bladder cancer metastasis in patients.
Three Specific Aims test this hypothesis:
In Aim 1, the role of RalA and RalB phosphorylation in bladder cancer growth, migration and lung metastasis will be determined using phospho inactive mutants. The prognostic relevance of Ral paralog phosphorylation to metastasis development will be evaluated in tissues from patients with locally advanced bladder cancer.
Aim 2 will determine how RalBP1 regulates RREB1 activity and how RREB1 in turn, regulates CD24 expression. Since genome-wide profiling of Ral dependent gene expression led to the discovery of CD24, we will use tissues from Aim 1 and advanced computational tools to generate paralog specific signatures of Ral expression. The ability of these signatures to predict the development of metastatic disease in patients will be evaluated.
In Aim 3 we evaluate the requirement of CD24 for bladder carcinogenesis and progression. A CD24 knockout mouse will be used to study the necessity of CD24 in chemically induced bladder carcinogenesis and/or subsequent invasion and metastasis of resultant tumors. A separate study will test whether anti-CD24 antibodies can inhibit growth of established bladder cancer lung metastases. Establishing the biological relevance of Ral phosphorylation to bladder cancer lung metastasis and the regulatory connections between RalBP1, RREB1 and CD24 provide opportunities for therapy. Translational studies associated with this mechanistic work provide biomarker predictors for metastasis development in patients while a preclinical study provides a foundation for the near term development of novel therapies directed at established metastatic disease.

Public Health Relevance

Bladder cancer kills 13,000 Americans each year, but few research projects are targeted to this disease. For most of these patients, the cause of death is attributable to metastatic spread, commonly to the lungs. The goal of this project is to understand the mechanisms that underlie lung metastasis in human bladder cancer and use this knowledge to predict and treat this condition in patients.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA075115-14
Application #
8147807
Study Section
Tumor Progression and Metastasis Study Section (TPM)
Program Officer
Woodhouse, Elizabeth
Project Start
1997-09-01
Project End
2013-04-30
Budget Start
2011-05-01
Budget End
2012-04-30
Support Year
14
Fiscal Year
2011
Total Cost
$340,613
Indirect Cost
Name
University of Colorado Denver
Department
Surgery
Type
Schools of Medicine
DUNS #
041096314
City
Aurora
State
CO
Country
United States
Zip Code
80045
Nickerson, M L; Witte, N; Im, K M et al. (2017) Molecular analysis of urothelial cancer cell lines for modeling tumor biology and drug response. Oncogene 36:35-46
Agarwal, Neeraj; Dancik, Garrett M; Goodspeed, Andrew et al. (2016) GON4L Drives Cancer Growth through a YY1-Androgen Receptor-CD24 Axis. Cancer Res 76:5175-85
Yan, Chao; Theodorescu, Dan; Miller, Bettina et al. (2016) Synthesis of novel Ral inhibitors: An in vitro and in vivo study. Bioorg Med Chem Lett 26:5815-5818
Jones, Robert T; Felsenstein, Kenneth M; Theodorescu, Dan (2016) Pharmacogenomics: Biomarker-Directed Therapy for Bladder Cancer. Urol Clin North Am 43:77-86
Frantzi, Maria; van Kessel, Kim E; Zwarthoff, Ellen C et al. (2016) Development and Validation of Urine-based Peptide Biomarker Panels for Detecting Bladder Cancer in a Multi-center Study. Clin Cancer Res 22:4077-86
Marie, Chelsea; Verkerke, Hans P; Theodorescu, Dan et al. (2015) A whole-genome RNAi screen uncovers a novel role for human potassium channels in cell killing by the parasite Entamoeba histolytica. Sci Rep 5:13613
Hensel, Jonathan; Duex, Jason E; Owens, Charles et al. (2015) Patient Mutation Directed shRNA Screen Uncovers Novel Bladder Tumor Growth Suppressors. Mol Cancer Res 13:1306-15
Earl, Julie; Rico, Daniel; Carrillo-de-Santa-Pau, Enrique et al. (2015) The UBC-40 Urothelial Bladder Cancer cell line index: a genomic resource for functional studies. BMC Genomics 16:403
Zhao, D; Besser, A H; Wander, S A et al. (2015) Cytoplasmic p27 promotes epithelial-mesenchymal transition and tumor metastasis via STAT3-mediated Twist1 upregulation. Oncogene 34:5447-59
Borah, Sumit; Xi, Linghe; Zaug, Arthur J et al. (2015) Cancer. TERT promoter mutations and telomerase reactivation in urothelial cancer. Science 347:1006-10

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