Erythropoietin activates cell survival pathways in breast cancer stem-like cells to protect them from chemotherapy
Menée sur des lignées cellulaires et à l'aide de xénogreffes, cette étude met en évidence des mécanismes par lesquels, en agissant sur des cellules souches de cancer du sein, les analogues de l'érythropoïétine favorisent la progression tumorale
Recombinant erythropoietin (EPO) analogs (ESAs, erythropoiesis-stimulating agents) are clinically used to treat anemia in cancer patients receiving chemotherapy. After clinical trials reporting increased adverse events and/or reduced survival in ESAs-treated patients, concerns have raised about the potential role of ESAs in promoting tumor progression, possibly through tumor cell stimulation. However, evidence is lacking on the ability of EPO to directly affect cancer stem-like cells, which are thought to be responsible for tumor progression and relapse. We found that breast cancer stem-like cells (BCSC) isolated from patient tumors express the EPO receptor and respond to EPO treatment with increased proliferation and self-renewal. Importantly, EPO stimulation increased BCSC resistance to chemotherapeutic agents and activated cellular pathways responsible for survival and drug resistance. Specifically, the Akt and ERK pathways were activated in BCSC at early time points following EPO treatment, while Bcl-xL levels increased at later times. In vivo, EPO administration counteracted the effects of chemotherapeutic agents on BCSC-derived orthotopic tumor xenografts and promoted metastatic progression both in the presence and in the absence of chemotherapy treatment. Altogether, these results indicate that Epo acts directly on BCSC by activating specific survival pathways, resulting in BCSC protection from chemotherapy and enhanced tumor progression.