Abstract P5-01-07: Select neutrophils inhibit breast cancer metastases in patients via chemokine-mediated mechanisms

Abstract

Background: In both breast cancer patients and healthy women, we have previously demonstrated that select neutrophils found in breast cancer patients as opposed to healthy women are cytotoxic to breast cancer cell lines. (Granot Z et al. Cancer Cell. 2010) This work stemmed from our prior research in murine breast cancer models indicating that primary breast tumors can mobilize select neutrophils, termed Tumor Entrained Neutrophils (“TENS”); these entrained neutrophils have the unique capacity to inhibit metastatic seeding in the lung through cell-kill mechanisms. (Granot Z et al. Cancer Cell. 2010) In this study, we evaluated the relationship between select chemokines and neutrophil cytotoxicity in breast cancer patients versus healthy volunteers. Methods: Neutrophils were purified from the blood of 75 randomly selected newly diagnosed pre-operative breast cancer patients without evidence of metastatic disease, and 47 healthy female volunteers with no history of cancer. Cytotoxicity was evaluated by incubating neutrophils with luciferase labeled MDA-MB-231 cells. Luciferase activity was measured as a reflection of% cytotoxicity. Serum was also isolated from breast cancer patients and healthy volunteers. Based on prior experiments, we used the Millipore® Milliplex Human Cytokine Plex Kit to evaluate Il-1Ra, MCP-1 and TNFa in our serum samples in 50/75 of the cancer patients and 25/47 controls. We used multiple linear regression to develop a model to predict cytotoxicity as a function of the chemokines. Results: In comparison to healthy volunteers whose mean neutrophil cytotoxicity to MDA-MB-231 cells was 6.5%, pre-operative breast cancer patients demonstrated a mean neutrophil cytotoxicity of 12.7%, p<0.0001. We then evaluated the serum chemokine levels of 50 of the breast cancer patients; 31/50 had high neutrophil cytotoxicity (>10%), and 19/50 had low neutrophil cytotoxicity (<10%). We compared the serum chemokine levels in the patients to the levels found in the 25 controls. Using a multiple linear regression model, we found that the levels of these three chemokines are associated with cytotoxicity (R2 = 0.126, p = 0.022). An ANOVA decomposition of the model suggested that Il.1RA was the most predictive (p = 0.018) followed by MCP.1 (p = 0.088) and TNF.alpha (p = 0.245). Conclusion: Our work demonstrates the cytotoxic role of select neutrophils in the peripheral blood of breast cancer patients as contrasted with neutrophils from healthy women. We further demonstrate that select chemokines appear to be correlated with neutrophil cytotoxicity. We are currently evaluating the prognostic and therapeutic roles of cytotoxic neutrophils and their related chemokines in breast cancer patients. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-01-07.