Invasive breast cancer reprograms early myeloid differentiation in the bone marrow to generate immunosuppressive neutrophils

AJ Casbon, D Reynaud, C Park… - Proceedings of the …, 2015 - National Acad Sciences
AJ Casbon, D Reynaud, C Park, E Khuc, DD Gan, K Schepers, E Passegué, Z Werb
Proceedings of the National Academy of Sciences, 2015National Acad Sciences
Expansion of myeloid cells associated with solid tumor development is a key contributor to
neoplastic progression. Despite their clinical relevance, the mechanisms controlling myeloid
cell production and activity in cancer remains poorly understood. Using a multistage mouse
model of breast cancer, we show that production of atypical T cell-suppressive neutrophils
occurs during early tumor progression, at the onset of malignant conversion, and that these
cells preferentially accumulate in peripheral tissues but not in the primary tumor. Production …
Expansion of myeloid cells associated with solid tumor development is a key contributor to neoplastic progression. Despite their clinical relevance, the mechanisms controlling myeloid cell production and activity in cancer remains poorly understood. Using a multistage mouse model of breast cancer, we show that production of atypical T cell-suppressive neutrophils occurs during early tumor progression, at the onset of malignant conversion, and that these cells preferentially accumulate in peripheral tissues but not in the primary tumor. Production of these cells results from activation of a myeloid differentiation program in bone marrow (BM) by a novel mechanism in which tumor-derived granulocyte-colony stimulating factor (G-CSF) directs expansion and differentiation of hematopoietic stem cells to skew hematopoiesis toward the myeloid lineage. Chronic skewing of myeloid production occurred in parallel to a decrease in erythropoiesis in BM in mice with progressive disease. Significantly, we reveal that prolonged G-CSF stimulation is both necessary and sufficient for the distinguishing characteristics of tumor-induced immunosuppressive neutrophils. These results demonstrate that prolonged G-CSF may be responsible for both the development and activity of immunosuppressive neutrophils in cancer.
National Acad Sciences