Abstract 1170: Notch pathway is overexpressed and is a therapeutic target in clear cell renal cancer
Authors: Bhagat Tushar D. , Zou Yiyu , Huang Shizeng , Park Jihwan , Palmer Matthew B. , Hu Caroline , Li Weijuan , Shenoy Niraj , Giricz Orsolya , Yu Yiting , Ko Yi-An , Izquierdo María Concepción , Park Esther , Vallumsetla Nishanth , Laurence Remi , Lopez Robert , Suzuki Masako , Pullman James , Kaner Justin , Gartrell Benjamin , Hakimi A. Ari , Greally John , Patel Bharvin , Benhadji Karim , Pradhan Kith , Verma Amit , Susztak Katalin 
Published: July 2017

Abstract
Clear cell renal cell carcinoma (CCRCC) is an incurable malignancy in advanced stages and needs newer therapeutic targets. We conducted a transcriptomic analysis of CCRCCs and matched microdissected renal tubular controls and observed an overexpression of NOTCH ligands [JAGGED1, JAGGED2) and Delta like (DLL3) family of ligands] and receptors (NOTCH1, NOTCH2, NOTCH3 and NOTCH4) in tumor tissues. Examination of the TCGA RNA-Seq dataset also revealed widespread activation of NOTCH pathway in a large cohort of CCRCC samples. Samples with NOTCH pathway activation were also clinically distinct and were associated with better overall survival.
Parallel high resolution DNA methylation and copy number analysis with the HELP assay demonstrated that both genetic and epigenetic alterations led to NOTCH pathway activation in CCRCC. NOTCH ligands, JAGGED1 was overexpressed and associated with loss of methylation of its intronic enhancer. The other NOTCH ligand, JAGGED2 was overexpressed in and associated with gene amplification in distinct CCRCC samples.
To test the causality, we transgenically expressed the intracellular domain of NOTCH1 in mice renal tubules with tubule specific deletion of VHL. The Kspcre VHLf/f ICNotch1 mice exhibited dysplastic hyperproliferation of tubular epithelial cells confirming the procarcinogenic role of NOTCH in vivo. Alteration of cell cycle pathways was seen in murine renal tubular cells with NOTCH overexpression and molecular similarity to human tumors was observed, demonstrating that human CCRCC recapitulates features and gene expression changes observed in mice with transgenic overexpression of the Notch intracellular domain.
Finally, treatment with clinical, gamma secretase inhibitor, LY3039478, led to inhibition of CCRCC cells in vitro and in vivo in CCRCC xenografts. In summary, these data reveal the mechanistic basis of NOTCH pathway activation in CCRCC and demonstrate this pathway to a potential therapeutic target.
Citation Format: Tushar D. Bhagat, Yiyu Zou, Shizeng Huang, Jihwan Park, Matthew B. Palmer, Caroline Hu, Weijuan Li, Niraj Shenoy, Orsolya Giricz, Yiting Yu, Yi-An Ko, María Concepción Izquierdo, Esther Park, Nishanth Vallumsetla, Remi Laurence, Robert Lopez, Masako Suzuki, James Pullman, Justin Kaner, Benjamin Gartrell, A. Ari Hakimi, John Greally, Bharvin Patel, Karim Benhadji, Kith Pradhan, Amit Verma, Katalin Susztak. Notch pathway is overexpressed and is a therapeutic target in clear cell renal cancer [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 1170. doi:10.1158/1538-7445.AM2017-1170