The CCL2-CCR2 Axis Contributes to Migration of Cabazitaxel-resistant Prostate Cancer Cells.

Abstract

Developing resistance to cabazitaxel is a major challenge in patients with docetaxel- and castration-resistant prostate cancer (CRPC) since it is frequently administered as a last resort. We have previously reported that CCL2 induces resistance to the antiproliferative effect of cabazitaxel in DU145-TxR/CxR prostate cancer cell lines. However, how CCL2 induces resistance to the antimigration effect of cabazitaxel remains unclear. We established a cabazitaxel-resistant cell line, DU145-TxR/CxR, from a previously established paclitaxel-resistant cell line, DU145-TxR, which was confirmed to show docetaxel resistance. We performed migration assay and analyzed the expression of epithelial-mesenchymal transition markers using DU145-TxR/CxR with or without CCL2 silencing with small interfering RNA (siRNA) transfection. Cabazitaxel inhibited the migration of DU145 cells through the inactivation of STAT3. A CCR2 (a specific receptor of CCL2) antagonist suppressed the migration of DU145-TxR and DU145-TxR/CxR cells under cabazitaxel treatment. Western blotting revealed that the CCR2 antagonist inhibited STAT3 phosphorylation in DU145-TxR and DU145-TxR/CxR cells under cabazitaxel treatment. CCL2 silencing with siRNA in DU145-TxR and DU145-TxR/CxR cells decreased migration through STAT3 and p38 inactivation. Furthermore, CCL2 activated AKT, and CCR2 antagonist inhibited AKT phosphorylation in DU145-TxR and DU145-TxR/CxR cells with recovery of sensitivity to cabazitaxel under cabazitaxel treatment. The CCL2-CCR2 axis is a key contributor to resistance to the antimigration effect of cabazitaxel in prostate cancer cells. CCL2-CCR2 axis inhibition may be a potential therapeutic target against chemoresistant CRPC in combination with cabazitaxel.