The KAT module of the SAGA complex maintains the oncogenic gene expression program in MYCN-amplified neuroblastoma.

Pediatric cancers are frequently driven by genomic alterations that result in aberrant transcription factor activity. Here, we used functional genomic screens to identify multiple genes within the transcriptional coactivator Spt-Ada-Gcn5-acetyltransferase (SAGA) complex as selective dependencies for MYCN-amplified neuroblastoma, a disease of dysregulated development driven by an aberrant oncogenic transcriptional program. We characterized the DNA recruitment sites of the SAGA complex in neuroblastoma and the consequences of loss of SAGA complex lysine acetyltransferase (KAT) activity on histone acetylation and gene expression. We demonstrate that loss of SAGA complex KAT activity is associated with reduced MYCN binding on chromatin, suppression of MYC/MYCN gene expression programs, and impaired cell cycle progression. Further, we showed that the SAGA complex is pharmacologically targetable in vitro and in vivo with a KAT2A/KAT2B proteolysis targeting chimeric. Our findings expand our understanding of the histone-modifying complexes that maintain the oncogenic transcriptional state in this disease and suggest therapeutic potential for inhibitors of SAGA KAT activity in MYCN-amplified neuroblastoma.

Transcriptional Antagonism by CDK8 Inhibition Improves Therapeutic Efficacy of MEK Inhibitors.

Aberrant RAS/MAPK signaling is a common driver of oncogenesis that can be therapeutically targeted with clinically approved MEK inhibitors. Disease progression on single-agent MEK inhibitors is common, however, and combination therapies are typically required to achieve significant clinical benefit in advanced cancers. Here we focused on identifying MEK inhibitor-based combination therapies in neuroblastoma with mutations that activate the RAS/MAPK signaling pathway, which are rare at diagnosis but frequent in relapsed neuroblastoma. A genome-scale CRISPR-Cas9 functional genomic screen was deployed to identify genes that when knocked out sensitize RAS-mutant neuroblastoma to MEK inhibition. Loss of either CCNC or CDK8, two members of the mediator kinase module, sensitized neuroblastoma to MEK inhibition. Furthermore, small-molecule kinase inhibitors of CDK8 improved response to MEK inhibitors in vitro and in vivo in RAS-mutant neuroblastoma and other adult solid tumors. Transcriptional profiling revealed that loss of CDK8 or CCNC antagonized the transcriptional signature induced by MEK inhibition. When combined, loss of CDK8 or CCNC prevented the compensatory upregulation of progrowth gene expression induced by MEK inhibition. These findings propose a new therapeutic combination for RAS-mutant neuroblastoma and may have clinical relevance for other RAS-driven malignancies. SIGNIFICANCE: Transcriptional adaptation to MEK inhibition is mediated by CDK8 and can be blocked by the addition of CDK8 inhibitors to improve response to MEK inhibitors in RAS-mutant neuroblastoma, a clinically challenging disease.

Beyond Sentences: Using the Expression, Reception, and Recall of Narratives Instrument to Assess Communication in School-Aged Children With Autism Spectrum Disorder.

Purpose: Impairments in the social use of language are universal in autism spectrum disorder (ASD), but few standardized measures evaluate communication skills above the level of individual words or sentences. This study evaluated the Expression, Reception, and Recall of Narrative Instrument (ERRNI; Bishop, 2004) to determine its contribution to assessing language and communicative impairment beyond the sentence level in children with ASD. Method: A battery of assessments, including measures of cognition, language, pragmatics, severity of autism symptoms, and adaptive functioning, was administered to 74 8- to 9-year-old intellectually able children with ASD. Results: Average performance on the ERRNI was significantly poorer than on the Clinical Evaluation of Language Fundamentals-Fourth Edition (CELF-4). In addition, ERRNI scores reflecting the number and quality of relevant story components included in the participants' narratives were significantly positively related to scores on measures of nonverbal cognitive skill, language, and everyday adaptive communication, and significantly negatively correlated with the severity of affective autism symptoms. Conclusion: Results suggest that the ERRNI reveals discourse impairments that may not be identified by measures that focus on individual words and sentences. Overall, the ERRNI provides a useful measure of communicative skill beyond the sentence level in school-aged children with ASD.