Siglec-7 glyco-immune binding mAbs or NK cell engager biologics induce potent antitumor immunity against ovarian cancers

Sci Adv. 2023 Nov 3;9(44):eadh4379. doi: 10.1126/sciadv.adh4379. Epub 2023 Nov 1.

Abstract

Ovarian cancer (OC) is a lethal gynecologic malignancy, with modest responses to CPI. Engagement of additional immune arms, such as NK cells, may be of value. We focused on Siglec-7 as a surface antigen for engaging this population. Human antibodies against Siglec-7 were developed and characterized. Coculture of OC cells with PBMCs/NKs and Siglec-7 binding antibodies showed NK-mediated killing of OC lines. Anti-Siglec-7 mAb (DB7.2) enhanced survival in OC-challenged mice. In addition, the combination of DB7.2 and anti-PD-1 demonstrated further improved OC killing in vitro. To use Siglec-7 engagement as an OC-specific strategy, we engineered an NK cell engager (NKCE) to simultaneously engage NK cells through Siglec-7, and OC targets through FSHR. The NKCE demonstrated robust in vitro killing of FSHR+ OC, controlled tumors, and improved survival in OC-challenged mice. These studies support additional investigation of the Siglec-7 targeting approaches as important tools for OC and other recalcitrant cancers.

MeSH terms

  • Animals
  • Antigens, CD / metabolism
  • Biological Products* / metabolism
  • Female
  • Humans
  • Killer Cells, Natural
  • Mice
  • Ovarian Neoplasms* / metabolism
  • Ovarian Neoplasms* / therapy
  • Sialic Acid Binding Immunoglobulin-like Lectins / metabolism

Substances

  • Biological Products
  • Antigens, CD
  • Sialic Acid Binding Immunoglobulin-like Lectins