Abstract 1982: β-arrestin 2 mediates tumor growth and metastasis in renal cell carcinoma cells

Abstract

Abstract Renal Cell Carcinoma (RCC) is one of the most lethal urological cancers worldwide, with incidence and mortality rates increasing in the past two decades. The disease does not present early clinical symptoms and is commonly diagnosed at the metastatic stage, leaving the 5-year survival rate at ≈ 10-20%. For a wide array of neoplasms, many key molecular determinants involved in mediating the process of tumor cell growth, invasion, and colonization at a secondary site (i.e. metastasis) have been reported. However, few molecular predictors have been identified for RCC, rendering the mechanism(s) underlying RCC metastases poorly understood. This results in the lack of effective treatment for patients with advanced RCC. G protein-coupled receptors (GPCRs) and their effectors, such as the arrestin proteins, have been implicated in tumor growth, metastasis, and angiogenesis. Arrestin proteins are well known for their function in the desensitization and trafficking of GPCRs, but have also been implicated in unique signaling pathways to regulate fundamental cellular functions, including cell cycle progression, cell migration, and survival. Furthermore, arrestin involvement has been identified in a number of breast, colorectal, lung, and hematological malignancies. However, the role of arrestin proteins in RCC is yet to be determined. Our preliminary data show that β-arrestin 2 (βarr2) protein levels correlate with growth and metastatic potential in several RCC cell lines, including ACHN and SN12C. We hypothesize that βarr2 regulates RCC tumor progression, specifically through involvement in proliferation, invasion, and metastatic processes. To test our hypothesis, we used genetic-based loss of function approaches such as interfering RNA and CRISPR/Cas9. βarr2 knockdown results indicated a role in RCC malignancy as it significantly reduces the migration and invasion of RCC cell lines in vitro. βarr2 knockout (KO) impaired 3D spheroid formation of these cells and induced morphological changes compared to control cells as observed under confocal microscopy imaging. Moreover, epithelial marker E-cadherin expression levels were elevated while mesenchymal markers twist1, twist2 and vimentin levels were decreased in the βarr2 KO cells compared to control, indicating a mesenchymal to epithelial transition. In vivo data support our hypothesis that βarr2 plays a critical role in tumor growth and metastasis. Our data suggests a role for βarr2 in RCC malignancy and present a possible target in development of therapies for patients with advanced RCC. Citation Format: Jude Masannat, Yushan Zhang, Hamsa Purayil, Iqbal Mahmud, Yehia Daaka. β-arrestin 2 mediates tumor growth and metastasis in renal cell carcinoma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1982. doi:10.1158/1538-7445.AM2017-1982