Chemical screening identifies novel small molecule activators of natural killer cell cytotoxicity against cancer cells

Grace Lee, Sheela Karunanithi, Bruce Posner, Hanspeter Niederstrasser, Hong Cheng, Yuriy Federov, Shivaprasad Manjappa, Karam Musaitif, Huaiyu Wang, Zachary Jackson, David Wald

Research output: Contribution to journalArticlepeer-review

Abstract

Natural killer (NK) cells are cytotoxic lymphocytes that play a major role in the innate immune system. NK cells exhibit potent cytotoxic activity against cancer cells and virally infected cells without antigen priming. These unique cytotoxic properties make NK cells a promising therapeutic against cancer. Limitations of NK cell therapy include deficiencies in high clinical efficacy often due to a need for a high NK cell to target cell ratio to achieve effective killing. In order to address the suboptimal efficacy of current adoptive NK cell therapy, a high throughput screen (HTS) was designed and performed to identify drug-like compounds that increase NK cytotoxic activity against tumor cells without affecting the normal cells. This screen was performed in a 384-well plate format utilizing an expanded primary NK cell product and ovarian cancer cells as a target cell (TC) line. Of the 8000 diverse small molecules screened, 16 hits were identified (0.2% hit rate) based on both a robust Z (RZ) score < -3 and a greater than 10% increase in NK cell killing. A validation screen had a confirmation rate of 70%. Select compounds were further validated and characterized by additional cytotoxicity assays including activity against multiple blood cancer and solid tumor cell lines, with no effect on primary human T cells. This work demonstrates that high-throughput screening can be reliably used to identify compounds that increase NK tumoricidal activity in vitro that can be further investigated and translated for potential clinical application. Précis: Our work led to the identification of promising compound that potently increases NK cell-mediated killing of a variety of different cancer cells, but no impact on the killing of normal cells. This compound demonstrates the utility of this assay.

Original languageEnglish (US)
JournalCancer Immunology, Immunotherapy
DOIs
StateAccepted/In press - 2021

Keywords

  • High-throughput screen
  • Immunotherapy
  • NK activation
  • NK cells
  • NK cytotoxicity
  • Ovarian cancer

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology
  • Oncology
  • Cancer Research

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