Developing a co-culture model of ovarian cancer to identify immunotherapies that can overcome TGF-β-induced immunosuppression

Ovarian cancer is the most fatal gynecological malignancy, with high-grade serous ovarian cancer (HGSC) being the most commonly diagnosed and aggressive subtype. Although HGSC initially responds well to debulking surgery and platinum-based chemotherapy, approximately 80% of patients experience recurrence and subsequent treatment resistance. Immunotherapies have shown limited efficacy against HGSC, which is partly attributed to the presence of immunosuppressive cytokines in the tumor microenvironment (TME), notably transforming growth factor beta (TGF-β). TGF-β suppresses anti-tumor immunity, including the expression of granzyme B (GzmB) and other cytolytic effectors in CD8+ T cells. To address this challenge, we established a simplified co-culture model of the HGSC TME to test immunotherapies and combination strategies capable of overcoming a high-TGF-β environment. ID8 p53-/- Nf1-/- cells were transduced with a GzmB-cleavable Förster resonance energy transfer (FRET) reporter and either the chicken ovalbumin (OVA) epitope or scrambled (SCR) epitope control. Co-culturing OVA cells with OVA-specific OT-1 T cells resulted in decreased FRET-positive cells, indicating OT-1 T cells effectively target OVA cells. TGF-β inhibition with galunisertib (LY2157299, LY) restored GzmB expression in T cells and enhanced cancer killing in co-culture. Since LY monotherapy has been clinically ineffective, we aimed to identify effective combination treatments. SHP099, a SHP2 inhibitor that also increased GzmB expression in TGF-β-treated T cells, performed well in co-culture as a monotherapy but did not synergize with LY. However, we identified several agents that combined effectively with LY, including erlotinib, pazopanib, anti-PD-L1 antibody, and the PAK1 inhibitor FRAX597, each demonstrating increased T cell-mediated cancer cell killing. Our co-culture model has proven to be an effective preclinical tool for screening immunotherapies, providing valuable insights for future in vivo testing.

Department dc:contributor.department

Biomedical and Molecular Sciences

Year dc:date.issued

2024

Author dc:creator

• Potts, Amelia

Advisor dc:contributor.supervisor

• Craig, Andrew

• cancer
• immunotherapy
• ovarian
• tgf-β
• co-culture
• t cells

Statement dc:rights

• Attribution-NonCommercial-NoDerivatives 4.0 International

Licence dc:rights.uri

• http://creativecommons.org/licenses/by-nc-nd/4.0/

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/1974/33187

OAI identifier oai:identifier

oai:queensu.scholaris.ca:1974/33187