Abstract 2401: RD3-loss orchestrates GC-signaling independent evolution of progressive neuroblastoma

Abstract

Abstract Recently we recognized the transcriptional/translational loss of Retinal degeneration Protein 3 (RD3) in high-risk progressive neuroblastoma (HR-NB) and defined its novel tumor evolution stabilization function. Studies have shown that RD3 competitively binds to guanylate cyclases (GCs) and maintains GC expression, stability, as well as restores GC localization. Accordingly, we investigated the role of GCs, if any, in RD3-loss associated evolution of HR-NB. Utilizing an in vivo mouse model of spontaneous HR-NB coupled with ex vivo approaches using metastatic site derived aggressive cells (MSDACs), we examined the transcriptional and translational expression of GCs and validated with high-content confocal immunofluorescence. Further, utilizing a cGMP competitive enzyme immunoassay, we investigated both intracellular and soluble GC activity. Whole genome microarray analysis revealed a differential activation of GC signaling transcriptional machinery in three different clones of MSDACs (compared to parental SH-SY5Y cells) ex vivo. Immunoblotting identified a consistent translation of GCs (GC-1 and GC-2) in a manifold of metastatic tumors (compared to non-metastatic primary xenografts) in vivo and in MSDACs ex vivo. Confocal immunofluorescence analysis validated the near-identical expression of GC1 and GC2 both in SH-SY5Y cells and MSDACs. cGMP immunoassay recognized indistinguishable intracellular and soluble GC activity in clones of differentiated/undifferentiated MSDACs as opposed to the clones of SH-SY5Y. For the first time, the results of this study define the transcription and translation blueprint of GCs in HR-NB and, further imply that the RD3-loss may dictate GCs-signaling independent alternate molecular flow-through in the evolution of HR-NB. Acknowledgements: Stephenson Cancer Center, NIH COBRE 1P20GM103639-01, Broken Arrow Lady Elks Auxiliary, and Oklahoma TSET. Citation Format: Singh Meghna, Wolansky Rachel, Terence S. Herman, Natarajan Aravindan. RD3-loss orchestrates GC-signaling independent evolution of progressive neuroblastoma. [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 2401.