Tumor associated macrophages antagonize antitumor effect of chemotherapy.

120 Background: Tumor associated macrophages play an essential role in tumor progression, promoting angiogenesis, immunosupression, invasion and metastasis. However, TAMs regulation of tumor responses to chemotherapy is complicated. In different type of treatment or tumor model, TAMs can either enhance or antagonize antitumor effect of chemotherapy. Methods: We isolated TAMs from breast cancer tissues, or PBMC stimulated with culture medium of mesenchymal breast cancer cells and cocultured with breast cancer cells MCF-7 for 6-10days. After cocultured with TAMs, we treated MCF-7 with docetaxel. In vivo, we use MCF-7 with or without TAMs to generate xenografts in NOD/SCID mice and treated with docetaxel. To testify if the antagonize was dependent on specific treatment, we also treated breast cancer cells with ciaplatin. Results: With coculture of TAMs, we obversed ruduced apoptosis of docetaxel treated breast cancer cells. In mice model, TAMs co-injection xenografts antagonized the antitumor effect of docetaxel.Consisted with previous results, TAMs coculture antagonize the antitumor effect of cisplatin, suggesting the antagonize of TAMs was independent on cell cycle. Conclusions: Collectively, our study indicated the antagonize of TAMs towards chemotherapy.