Introduction

Clear cell renal cell carcinoma (ccRCC) is the most common type of renal cell carcinomas. During diagnosis, metastasis is found in over 30% of patients. Despite conducted targeted therapy, survival time of patients with metastatic renal cell carcinoma ranges from three months to two years. Recent reports indicate an important role of inflammatory and angiogenic processes in the ccRCC development. Monocyte Chemotactic Protein-1 Induced Protein (MCPIP-1) is a novel multifunctional modulator involved in the regulation of inflammatory response, apoptosis and angiogenesis. However its role in tumorigenesis is unknown.

Aim

The main objective of our study was to determine the role of anti-inflammatory protein MCPIP1 in growth, angiogenesis and metastasis of clear cell renal cell carcinoma.

Materials and methods

ccRCC cell lines (Caki-1 and Caki-2) were transduced with MCPIP1 shRNA and control shRNA lentiviral vectors and selected with puromycin. The level of genes and protein involved in proliferation, angiogenesis and metastasis were studied by real-time PCR, western blot and flow cytometry. Chemotaxis and invasion assay were performed to check migration and invasion. To study the level of proangiogenic factors ELISA and LUMINEX assays were used. NOD-SCID mice were used in in vivo experiments.

Results

Our study shows that MCPIP1 downregulation increases proliferation rate, survival and migration properties of ccRCC cells. Additionally reduction of MCPIP1 protein level increases the expression of pro-angiogenic factors such as SDF1, VEGF and IL8 what was paralleled by an increased migration of endothelial cells toward conditioned media from MCPIP1 deficient ccRCC cells. We also demonstrate, that silencing of MCPIP1 protein in ccRCC leads to an increase in tumor growth in vivo, after subcutaneous injection of NOD-SCID mice. We observed a significant increase in the number and the area of blood vessels in tumors formed by cells with downregulation of MCPIP1 and greater ability to metastasize to the lungs.

Conclusions

We showed that reduction of MCPIP1 protein level in ccRCC cells is crucial for tumor growth, blood vessel formation in the emerging tumor and metastasis. Moreover, ccRCC cells with downregulation of MCPIP1 secreted factors and proteins essential for the process of angiogenesis. Obtained results may contribute to increased understanding of the biology of clear cell renal cell carcinoma, which in the future may help in identifying new, more effective therapeutic purposes or improving existing ones.

Acknowledgement

This study was supported by research grant from the National Science Centre to KM 2013/09/D/NZ/00249 and grant from the Jagiellonian University BMN 7/2015. Faculty of Biochemistry, Biophysics and Biotechnology of the Jagiellonian University is a partner of the Leading National Research Center (KNOW) supported by the Ministry of Science and Higher Education

Citation Format: Katarzyna Miekus, Paulina Marona, Jolanta Jura. MCPIP1 affects growth, angiogenesis and metastasis of clear cell renal cell carcinoma. [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 3398.