{
  "abstract": "Background SMARCA4 is a frequently mutated subunit of the SWI/SNF chromatin remodeling complex. Importantly, clinical reports indicate that SMARCA4-mutant lung cancers respond poorly to immunotherapy and have dismal prognosis. However, the mechanistic basis of immunotherapy resistance is unknownMethods Various orthogonal models of SMARCA4 deficient tumors including immune-humanized, syngeneic, and genetically engineered mouse models of lung cancer.Results We show that SMARCA4 loss caused decreased response to anti-PD1 immunotherapy associated with significantly reduced infiltration of dendritic cells (DCs) and CD4+ T cells into the tumor microenvironment (TME). Mechanistically, we show that SMARCA4 loss in tumor cells led to profound downregulation of STING, IL1β and other components of the innate immune system as well as inflammatory cytokines that are required for efficient recruitment and activity of immune cells. We establish that this deregulation of gene expression is caused by cancer cell-intrinsic reprogramming of the enhancer landscape with marked loss of chromatin accessibility at enhancers of genes involved in innate immune response such as STING, IL1β, type I IFN and inflammatory cytokines. Interestingly, we observed that transcription factor NF-κB binding motif was highly enriched in enhancers that lose accessibility upon SMARCA4 deficiency. Finally, we confirmed that SMARCA4 and NF-κB co-occupy the same genomic loci on enhancers associated with STING and IL1β, indicating a functional interplay between SMARCA4 and NF-κBConclusions Our findings provide the mechanistic basis for the poor response of SMARCA4-mutant tumors to anti-PD1 immunotherapy and establish a functional link between SMARCA4 and NF-κB on innate immune and inflammatory gene expression regulation.",
  "authors": [
    {
      "affiliations": [
        "The University of Texas MD Anderson Cancer Center, Houston, TX, USA"
      ],
      "name": "Yawen Wang"
    },
    {
      "affiliations": [
        "The University of Texas MD Anderson Cancer Center, Houston, TX, USA"
      ],
      "name": "Ismail Meraz"
    },
    {
      "affiliations": [
        "The University of Texas MD Anderson Cancer Center, Houston, TX, USA"
      ],
      "name": "Md Qudratullah"
    },
    {
      "affiliations": [
        "The University of Texas MD Anderson Cancer Center, Houston, TX, USA"
      ],
      "name": "Jack Roth"
    },
    {
      "affiliations": [
        "The University of Texas MD Anderson Cancer Center, Houston, TX, USA"
      ],
      "name": "Yonathan Lissanu Deribe"
    }
  ],
  "title": "462 Dysregulated enhancer landscape and resistance to immunotherapy by SMARCA4 mutation in lung cancer",
  "uid": "b772f24e-1e7d-5b22-b035-eef62560c485"
}