Analysis of immune cell functions to improve the therapeutic efficacy of a novel cell-based therapy of combined autologous monocytes and dual-interferons for ovarian cancer.

Abstract

Ovarian cancer is the second most lethal gynecologic malignancy with a 49% five-year survival rate. Although many patients initially respond to platinum-based chemotherapy, over 70% of patients diagnosed with advanced stage ovarian cancer relapse within 24 months, warranting additional treatment methods. Our group pioneered a therapeutic approach harnessing innate immune cues where autologous monocytes, interferon-a2b, and interferon- (AMIGA: autologous monocytes and interferon-gamma and -alpha) were given intraperitoneally to women with recurrent, platinum-resistant ovarian cancer. Of the 18 patients enrolled in our Phase 1 clinical trial, four patients were deemed long-term responders (LTRs). Comparing these LTRs to non-responders by flow cytometry, bulk-cell RNA-sequencing, and single-cell RNA-sequencing demonstrated that peripheral blood mononuclear cells of these LTRs had fewer immunosuppressive cells, overall increased adaptive immune responses by cell type enrichment and gene set enrichment analysis (GSEA), as well as enhanced pro-inflammatory signaling via monocyte- and T cell-specific pathways. Interestingly, sub-clusters of monocytes from responders appeared to be more transcriptionally active compared to non-responders, with higher levels of a plethora of mRNA transcripts characteristic of antigen presentation and classical/non-classical monocytes, suggesting monocyte quality could be used as a predictive biomarker for AMIGA success. CXCR3 ligands and CCL2 were also observed to increase after each treatment cycle by bulk-cell RNA-sequencing. In light of this, we assessed patient malignant ascites for relevant chemokines and found CCL2 and CXCL10, known monocyte and T cell trafficking molecules, had increased in response to AMIGA. Through in vitro 2D co-cultures, we then validated CCL2 and CXCL10 significantly increased in the presence of ovarian cancer and our treatment, and that this increase correlated with increased T cell migration. Additional studies demonstrated AMIGA does not negatively impact T cell proliferation but decreases interferon-a2b secretion. Future studies will evaluate the impact of AMIGA in vivo on T cell migration and function, as well as monocyte differentiation. By understanding how AMIGA contributes and enhances anti-tumor T cell functions in the ovarian cancer tumor microenvironment, we seek to combine innate- and adaptive-based immunotherapies to improve treatment options and, ultimately, survival of women with ovarian cancer.