MDB-30. IDENTIFICATION AND CHARACTERIZATION OF NOVEL TRANSCRIBED ULTRACONSERVED REGIONS AS LONG NON-CODING RNAS IN MEDULLOBLASTOMA

Medulloblastoma is the most common pediatric brain tumor. While the 5-year survival rate for medulloblastoma patients has improved with molecular subgrouping, children who undergo standard of care treatments frequently experience permanent neurological deficits. Additionally, under-characterized medulloblastoma subgroups lack targeted therapies, correlating to lower survival rates for these patients. To find new therapies, a better understanding of the molecular basis of medulloblastoma is needed. This work investigates the role of “Transcribed Ultra-Conserved Regions” (TUCRs) in medulloblastoma about which there is no published literature. TUCRs represent a distinct group of 481 putative lncRNAs that are 100% conserved across human, mouse, and rat genomes. These ultra-conserved elements change 20 times slower than the average genomic region and are therefore under intense negative selection within multiple species. Since their discovery, TUCRs have only been correlated to a handful of cancers and remain exceedingly underexamined within cancer research. Using RNA-sequencing and differential gene expression analysis of medulloblastoma tumors as compared to normal human cerebellum samples, we identified a multitude of differentially expressed TUCRs spanning across all TUCR genomic annotations. In vitro experimentation using several medulloblastoma established cell lines indicated significant upregulation of these TUCR transcripts. We are currently investigating the functional effects and mechanisms of action of select differentially expressed TUCRs in medulloblastoma. Altogether, our work is investigating the oncogenic and tumor suppressive nature of TUCRs. It represents the first study of TUCRs in medulloblastoma that will significantly advance our basic understanding of this highly understudied class of molecules.