Docetaxel promotes the generation of anti-tumorigenic human macrophages

The taxanes Docetaxel and Paclitaxel are two of the standard chemotherapies for patients with metastatic breast cancer. The functional effect of Docetaxel and Paclitaxel on human innate immune cells of the myeloid lineage is not well established, nor is the effects these agents have on differentiation of monocytes into macrophages and dendritic cells. Therefore, the aim with this project was to determine the effects of Docetaxel and Paclitaxel on primary human monocyte differentiation, activation and function. For this purpose, primary human monocytes were isolated from healthy donors and cultured with or without Docetaxel and Paclitaxel. We found that Docetaxel promoted the differentiation of primary human monocytes into pro-inflammatory macrophages with an M1 phenotype and an ability to present antigens to T cells. Monocytes treated with Docetaxel also displayed an elevated secretion of IL-8 and IL-1β, but did not promote generation of monocytic myeloid-derived suppressor cells. In conclusion, Docetaxel appears to have an immune stimulatory effect that would be beneficial for an anti-tumorigenic type of immune response, whereas Paclitaxel seems to have less effect on myeloid cells.