Nuclear Receptor 4A1 (NR4A1) as a Drug Target for Renal Cell Adenocarcinoma

Erik Hedrick,Maen Abdelrahim,Stephen Safe,Un-Ho Jin,Syng-Ook Lee,Ala Abudayyeh,Gyungeun Kim,Alessandro Datti

doi:10.1371/journal.pone.0128308

Abstract

The orphan nuclear receptor NR4A1 exhibits pro-oncogenic activity in cancer cell lines. NR4A1 activates mTOR signaling, regulates genes such as thioredoxin domain containing 5 and isocitrate dehydrogenase 1 that maintain low oxidative stress, and coactivates specificity protein 1 (Sp1)-regulated pro-survival and growth promoting genes. Transfection of renal cell carcinoma (RCC) ACHN and 786-O cells with oligonucleotides that target NR4A1 results in a 40–60% decrease in cell proliferation and induction of apoptosis. Moreover, knockdown of NR4A1 in RCC cells decreased bcl-2, survivin and epidermal growth factor receptor expression, inhibited of mTOR signaling, induced oxidative and endoplasmic reticulum stress, and decreased TXNDC5 and IDH1. We have recently demonstrated that selected 1,1-bis(3'-indolyl)-1-(p-substituted phenyl)methane (C-DIM) compounds including the p-hydroxyphenyl (DIM-C-pPhOH) and p-carboxymethyl (DIM-C-pPhCO2Me) analogs bind NR4A1 and act as antagonists. Both DIM-C-pPhOH and DIM-C-pPhCO2Me inhibited growth and induced apoptosis in ACHN and 786-O cells, and the functional and genomic effects of the NR4A1 antagonists were comparable to those observed after NR4A1 knockdown. These results indicate that NR4A1 antagonists target multiple growth promoting and pro-survival pathways in RCC cells and in tumors (xenograft) and represent a novel chemotherapy for treating RCC.

Highlights

Kidney cancer is a complex and heterogenous disease and clear cell renal cell adenocarcinoma (RCC) is the most common sub-type and represents approximately 75% of renal parenchymal tumors [1,2,3]
We observed that both DIM-C-pPhOH and DIM-C-pPHCO2Me induced Annexin V staining in ACHN and 786-O cells (Fig 2C and 2D, respectively), confirming that C-DIM/NR4A1 antagonists induce apoptosis in RCC cell lines
ACHN and 786-O cells were treated with DIM-C-pPhOH and DIM-C-pPHCO2Me and after 24 hr, cells were stained with NR4A1 antibodies and DAP1 and the results show that DAP1 and the NR4A1 immunostaining were co-localized in the nucleus, demonstrating that the C-DIM/NR4A1 antagonists act through the nuclear receptor (Fig 3)

Summary

Introduction

Kidney cancer is a complex and heterogenous disease and clear cell renal cell adenocarcinoma (RCC) is the most common sub-type and represents approximately 75% of renal parenchymal tumors [1,2,3]. The incidence of RCC has been increasing and it is estimated that in 2013 over 65,000 new cases will be diagnosed and 13,680 kidney cancer patients will die from this disease [4]. Stage RCC patients with localized tumors have a good prognosis after surgical removable of the primary tumor; approximately 30% of all patients first diagnosed with. RCC already have metastatic disease [1]. Patients with RCC are unusually resistant to radio and cytotoxic drug therapies compared to responses observed for other solid tumors, and immunotherapies have provided some limited benefits for patients with RCC metastasis [5,6,7,8]. Recent developments of targeted therapies for treating RCC have primarily focused on clinical applications of receptor tyrosine kinase inhibitors, neutralizing antibodies against vascular endothelial growth factor (VEGF) and mTOR pathway inhibitors [9,10,11,12,13]

Methods

Results

Conclusion