Umbilical Cord Blood-derived Neutrophils inhibit ovarian cancer proliferation by secreting CCL3

Background: Neutrophils are a main type of immune cells involved in many important processes. During tumor progression neutrophils have manifested both tumor-promoting and inhibiting activities. Human umbilical cord blood (UCB)-derived Neutrophils (UCBN) were reported to have anti-tumor activity with ovarian cancer cell lines in vitro in our previous studies. However, the underlying mechanism remains unclear. This present study aims to uncover mechanisms underlying the inhibitory role of UCBN in ovarian cancer compared with peripheral blood-derived Neutrophils (PBN). Methods: : UCBN and PBN were isolated from freshly obtained human umbilical cord blood and peripheral blood respectively. Cytokine cocktail (IFN-β, IFN-r, and LPS) were used to activate UCBN and PBN in vitro . Mechnism of activated UCBN anti-tumor were done by multi-omic: transcriptomic and Proteomics analysis, followed by experimental validation with flow cytometry, cell killing assays and proteome profiler array. Results: : The transcriptomic analysis showed that the top upregulated genes in fresh isolated UCBN compared with PBN mainly focus on neutrophils activation and cell killing. High activity UCBN displayed strong ovarian tumor cell killing activity than PBN in vitro. Transcriptomic and proteomics analysis both revealed that the top upregulated molocules in activated UCBN were mainly involved in biologic processes related to regulation of cytokine secretion. United multi-omic analysis with proteome profiler array, we screened the anti-tumor molecule CCL3, which activated IFN-r related pathway JAK/STAT to killing tumor cells by RNA-seq. Conclusions: : Hence UCBN may constitute a viable strategy for ovarian cancer immunotherapy.