Development of Immunotherapeutic Approach for Effective Elimination of Ovarian Cancer Cells by Inducing Immunogenic Cell Death

Abstract

Ovarian cancer represents one of the most common forms of female gynecological cancer. The existing treatment modalities include surgery and chemotherapy, which are unable to treat local and long-distant micro-metastases. Near infrared photoimmunotherapy (NIR-PIT) is a newly developed treatment strategy that can selectively kill the cancer cells and induce immunogenic cell death and thereby stimulate anti-tumor immune responses. In this study, we developed five NIR-PIT agents by conjugating scFv-SNAP tag fusion proteins with BG-modified IRdye700 to target ovarian cancer cells, which expressed cell surface antigens EGFR, Her2, FOLR1, TROP2 and TF. The flow cytometry and microscopic studies confirmed the specificity of all the investigated NIR-PIT agents binding to corresponding overexpressed cancer cells. We demonstrated that all five NIR-PIT agents decreased the cell viability in a concentration dependent manner with IC50 values of ~42-283 nM. Moreover, all the examined NIR-PIT agents induced cell death by ~80-92% among them the most representing cell death occurred by irreversible necrosis or regulated necrosis. The NIR-PIT agents triggered major hallmarks of immunogenic cell death, cell surface expression of calreticulin, HSP70, HSP90 and the extracellular release of ATP and HMGB1. Furthermore, co-culturing immature dendritic cells with EGFR and TF targeting NIR-PIT agents mediated dying cancer cells enhanced dendritic cell maturation, as indicated by increased expression of CD80, CD86, CD40 and HLADR. Taken together, our results suggested that all five investigated NIR-PIT agents have great potential to be applied for ovarian cancer treatment.