Abstract 2874: De novo acquisition of RD3 loss with intensive multi-modal therapy harmonize neuroblastoma relapse

Abstract

Abstract The majority of high-risk neuroblastoma that initially responds to therapy will ultimately relapse. Acquired genetic/molecular rearrangement contributes to tumor relapse and currently, no salvage treatment regimens are known to be curative. Our studies identified the loss of retinal-degeneration-protein-3 (RD3) in progressive disease (PD) and its association with poor clinical outcomes. Herein we investigated the acquisition of RD3-loss after current standard of care (SOC, intensive multimodal therapy) in neuroblastoma. Acquired transcriptional (RNA in situ hybridization, QPCR) and translational (IHC on a custom archived cell micro array, immunoblotting) loss of RD3 with SOC was investigated with bed-to-bench approach utilizing a panel of 15 stage-4 patient derived cell-lines with known therapy status, diagnosis [DX] vs. PD after SOC). Further, RD3-loss in progressive disease, its direct role in the pathogenesis disease progression (cell migration, invasion, tumorosphere formation and metastatic potential) was investigated using mouse model of progressive neuroblastoma and in experimental in vitro and ex vivo settings coupled with gene manipulation strategies. In addition, RD3 status in response to therapy were also affirmed by in silico analysis of independent studies on bed-to-bench and experimental models. Results demonstrated RD3-loss (transcriptional/translational) acquisition with SOC in human PD. Experimental in vitro, in vivo, ex vivo studies affirmed RD3 loss in PD and, further forced RD3-rearrangements in these models defined its functional role in PD pathogenesis. Data-mining experimental studies with salvage therapeutic agents affirmed the acquisition of RD3-loss in resistant cells and in residual tumors. For the first time, these results demonstrate the de novo acquisition of RD3 loss in PD after intensive multi-modal therapy. Defining the criticality of RD3-loss in PD and the defined role of RD3 loss in PD pathogenesis, benefit of targeted reinforcement could lead to improved salvage therapy for high-risk neuroblastoma. Citation Format: Dinesh Babu Somasundaram, Karthikeyan Subramanian, Sheeja Aravindan, Zhongxin Yu, Mohan Natarajan, Terence S. Herman, Natarajan Aravindan. De novo acquisition of RD3 loss with intensive multi-modal therapy harmonize neuroblastoma relapse [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2874.