Author of

• 35724

  +

  FP12 - Tumor Biology and Systems Biology - Basic and Translational Science (ID 188)

  • Event: WCLC 2020
  • Type: Posters (Featured)
  • Track: Tumor Biology and Systems Biology - Basic and Translational Science
  • Presentations: 1
  • Moderators:
  • Coordinates: 1/28/2021, 00:00 - 00:00, ePoster Hall

  • 35735

    +

    FP12.11 - Single-Cell RNA Sequencing Analyses Distinguishes Transcriptional Activity of c-Myc and L-Myc in Small Cell Lung Cancer (ID 2495)

    00:00 - 00:00  |  Author(s): Abhilasha Sinha
    • Abstract
    • Slides

    Introduction
    

    Small cell lung cancer (SCLC) accounts for 15% of all lung cancer with a dismal prognosis, where the 5-year overall survival is 6%. The genomic landscape of primary SCLC tumors has revealed universal loss of RB1 and TP53 and frequent genomic amplification of oncogenes; specifically, MYC family members that are mutually exclusive of each other. Prior works have revealed that c-Myc and L-Myc expression is observed in distinct histopathological murine tumors with unique expression of neuroendocrine markers. Furthermore, we previously characterized their role as lineage factors, where c-Myc induces trans-differentiation across SCLC subtypes while L-Myc fails to convert the fate of the cell to neuroendocrine SCLC subtype (Patel et al., 2020 AACR). Together implying intrinsic differences between c-Myc and L-Myc. However, the molecular mechanisms underlying the differences still remain unexplored. Here, we apply single-cell technology to investigate the redundant and unique transcriptional activities of L-Myc and c-Myc in SCLC.

    Methods
    

    We generated a cell-based model to engineer the swapping of c-Myc and L-Myc in NCI-H82, a c-Myc amplified SCLC using overexpression and CRISPR/Cas9 systems. We performed bulk RNA-seq and single-cell RNA sequencing (scRNA-seq) on genetically engineered control NCI-H82 cells (LacZ/sgNT), NCI-H82 with L-Myc overexpression only (L-Myc/sgNT) and replaced NCI-H82 with L-Myc overexpression and c-Myc deletion (L-Myc/sgMYC).

    Results
    

    UMAP analysis of the single-cell transcriptome of these cells revealed unique clusters for control NCI-H82 (LacZ/sgNT) cells and NCI-H82 (L-Myc/sgMYC) cells. These unique clusters were differentiated by the expression of several neuronal associated genes and metabolic associated genes. This was consistent with our findings from bulk RNA-seq, where we found L-Myc induces the expression of genes that are enriched for neuronal- and neurogenesis- associated pathways. We identified specific co-regulated modules for only c-Myc expressing cells (NCI-H82 LacZ/sgNT), cells expressing both c-Myc and L-Myc (NCI-H82 L-Myc/sgNT), and only L-Myc expressing cells (NCI-H82 L-Myc/sgMYC), that distinguished c-Myc and L-Myc transcriptional activity. Furthermore, inferred regulatory relationships for c-Myc and L-Myc was supported by our previous findings that c-Myc and L-Myc have unique transcriptional networks. Additionally, unsupervised pseudotime ordering of combined genetically engineered cells revealed a lineage hierarchy that reflected the dynamic changes in the cellular state corresponding with the changes in c-Myc and L-Myc expression.

    Conclusion
    

    Collectively, we leveraged single-cell technologies and identify the molecular differences and similarities between c-Myc and L-Myc in the context of SCLC, a long-standing question in the field.

    Only Active Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login or select "Add to Cart" and proceed to checkout.