{
  "abstract": "Background For NK-based therapies, limited persistence of functional NK cells in the tumor microenvironment (TME) remains a major barrier to realizing their full therapeutic potential in solid tumors. Increasing evidence suggests that maintenance of a stem-like NK population is key to preserving NK cell quantity and quality. Strategies to enrich this population are urgently needed. We have previously shown that tumor-derived soluble NKG2D ligand sMIC disrupted NK homeostasis and function, and an anti-sMIC antibody B10G5 revamped NK mediated anti-tumor immunity. In this study, we investigated the molecular underpinnings of sMIC-driven dysregulation and B10G5-mediated restoration of a functional intra-tumoral NK cell pool through regulation of the stem-like population.Methods We first examined tumor-infiltrating NK (TI-NK) cells from untreated and B10G5-treated TRAMP/MICB transgenic mice bearing orthotopic sMIC+ prostate tumors using single-cell RNA sequencing and multi-parametric flow cytometry. We then identified a candidate epigenetic regulator of the stem-like NK subset - upregulated by B10G5 treatment and conserved between mouse and human - by analyzing both our mouse TI-NK dataset and a public human TI-NK scRNA-seq dataset. Chemical Inhibition and CRISPR-Cas9 was then used to assess the effect of disrupting the identified regulator. Finally, NCG mice bearing MIC+ human prostate tumors were infused with human NK cells ex vivo expanded with MIC+ feeder cells in the presence or absence of B10G5, to assess whether B10G5 conferred therapeutic benefits to human NK cells as well.Results We showed that sMIC induced exhaustion, reduced metabolic fitness, and diminished functional heterogeneity of intra-tumoral NK cells. B10G5 treatment enriched a TCF1-hi stem-like NK reservoir and thereby preserved a functional NK cell pool in the TME. Mechanistically, B10G5 treatment upregulated the histone demethylase Kdm6b and epigenetically fostered a stemness program in tumor-infiltrating NK cells. Disruption of Kdm6b expression and function led to reduced TCF1 expression and diminished stem-like population. Finally, we showed that pre-programming human NK cells with B10G5 during ex vivo expansion led to better in vivo persistence and tumor control following adoptive transfer.Conclusions Our findings demonstrate that antibody targeting of the soluble NKG2D ligands sMIC enriches a stem-like NK reservoir and preserves NK functional heterogeneity, providing new mechanistic rationale for targeting the NKG2D-NKG2D ligand axis to enhance NK cell mediated anti-tumor immunity.Ethics Approval All animal studies were approved by the Institutional Animal Care and Use Committee (IACUC) committee of Northwestern University.",
  "authors": [
    {
      "affiliations": [
        "Northwestern University, Chicago, IL, USA"
      ],
      "name": "Sizhe Liu"
    },
    {
      "affiliations": [
        "Northwestern University Feinberg School of Medicine, Chicago, IL, USA"
      ],
      "name": "Tyler A Smith"
    },
    {
      "affiliations": [
        "Bristol Myers Squibb, Sunnyvale, CA, USA"
      ],
      "name": "Payal Dhar"
    },
    {
      "affiliations": [
        "Univeristy of Chicago, Chicago, IL, USA"
      ],
      "name": "Lisha Zhu"
    },
    {
      "affiliations": [
        "Univeristy of Chicago, Chicago, IL, USA"
      ],
      "name": "Geetha Priyanka Yerradoddi"
    },
    {
      "affiliations": [
        "Northwestern University, Chicago, IL, USA"
      ],
      "name": "Karla Guerra"
    },
    {
      "affiliations": [
        "Northwestern University, Chicago, IL, USA"
      ],
      "name": "Ryan J Brown"
    },
    {
      "affiliations": [
        "Northwestern University, Chicago, IL, USA"
      ],
      "name": "Weiguo Cui"
    },
    {
      "affiliations": [
        "Northwestern University, Chicago, IL, USA"
      ],
      "name": "Jennifer Wu"
    }
  ],
  "title": "903 Antibody targeting of soluble NKG2D ligands sMIC enriches a stem-like NK cell reservoir and maintains NK anti-tumor functional heterogeneity in the tumor microenvironment",
  "uid": "de732a24-f95c-56f5-840b-d03fea732cbe"
}