Abstract B06: Single-cell RNA-seq profiling of transcriptional transition states during human retinoblastoma development

Abstract

Abstract Retinoblastoma is a rare childhood tumor initiated by biallelic inactivation of the RB1 gene and loss of function of retinoblastoma (Rb) protein. Although Rb loss is a key-initiating event, the molecular mechanisms controlling the transformation into malignancy remain unclear. In this project, we seek to define the cell state transitions that follow RB1 inactivation in a defined cell of origin, the cone photoreceptor precursor. Previously we revealed that Rb knockdown could induce cone precursors to proliferate in vitro and to form retinoblastoma-like tumors in orthotopic xenografts. Using post-mitotic cone precursors from normal human fetal retina, we describe the generation, isolation, and single-cell RNA sequencing (RNA-seq) on RB1-knockdown cells at multiple time points to profile the levels of all polyadenylated transcripts. We then use “Monocle” to pseudo-temporally order cells according to their transcriptome profiles into distinct states through which the cells pass during cell cycle entry and tumor progression. Through this single cell RNA-seq approach, we will define the transcriptional alteration events of each cell state transition, and identify potential mediators of such transitions during retinoblastoma development. In addition, we define effects of inhibitors targeting potential mediators of each cell state transition as therapeutic candidates, currently focusing on Nutlin-3a (targeting MDM2), JQ1 (targeting MYCN), and SNS-032 and SU9516 (targeting CDK2). Taken together, this study seeks to identify transformation-related events that can be pharmacologically targeted to suppress tumorigenesis in genetically predisposed children. Citation Format: Sunhye Lee, Hardeep Singh, David Cobrinik. Single-cell RNA-seq profiling of transcriptional transition states during human retinoblastoma development. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Cancer Cell Cycle - Tumor Progression and Therapeutic Response; Feb 28-Mar 2, 2016; Orlando, FL. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(11_Suppl):Abstract nr B06.